xref: /dports/finance/weberp/webERP/includes/phplot/ChangeLog

This is the Change Log for PHPlot.
The project home page is http://sourceforge.net/projects/phplot/
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2011-07-30 (lbayuk)     ===== Released as 5.5.0 =====
    * phplot.php: Updated version comment and version constant
    * README.txt: Updated for new release
    * NEWS.txt: Add text for new release

2011-07-28
    * Fixed problem found in testing with bubbles plot: data array
      with no Y,Z values at all got undefined property warnings.

    * Feature request #3352301 "Bubble plots":
      + Added new data type 'data-data-xyz', which includes a Z value
        for each Y.
      + Extended CheckDataArray(), DecodeDataType() and
        FindDataLimits() to understand new data type.
      + Added new plot type 'bubbles' for bubble plots, using data
        type 'data-data-xyz'. The Z value controls the bubble size.
      + New internal function DrawBubbles() to draw bubble plot.
      + New tunable parameters bubbles_min_size and bubbles_max_size.

2011-07-25
    * Feature request #3374495 "Data URL encoding":
      + New function EncodeImage() returns the plot image as a string,
        with 3 available encodings: raw, base64, and dataurl. The dataurl
        encoding implements RFC2397 embedding of image data in a URL,
        and allows a single PHP script to produce an HTML page with the
        plot image embedded within.
      + New internal function GetImageType() for code shared between
        PrintImage() and EncodeImage().
      + New function SetFailureImage() disables the normal behavior
        where PHPlot produces an image containing an error message in
        case of a fatal error. Suppressing this is necessary when using
        the new EncodeImage(), to avoid unexpected image data on stdout.
      + New member variable suppress_error_image, set by
        SetFailureImage(), checked by PrintError() to not make an image.

2011-07-22
    Preparing for move from CVS to Subversion.
    * Makefile: Remove 'tag' target. This was unused (and CVS-specific).
    * phplot.php: Remove reference to CVS in comment and version const.

2011-07-21
    * Fixed bug #3370548 "Reverse legend line order for stackedbars":
      New function SetLegendReverse(True) to draw lines in the legend
      in order from the bottom up, rather than top down. This is
      mostly intended for stackedbars and stackedarea plots.

2011-07-04
    * Code cleanup: Removed extra loop variable $cnt from plot drawing
      functions, where it was either unused or redundant.

2011-06-12
    * Fixed bug 3312064 "PHP errors with invalid data arrays":
      PHPlot now checks the data array more carefully, to reject invalid
      arrays and prevent PHP warning or notice errors with bad data arrays.
      + SetDataValues() checks the data array argument to make sure it uses
        0-based, sequential integer indexes, and that each element is an array.
      + CheckDataArray() (called early by DrawGraph()) uses the data type for
        more specific checking.  It makes sure each row has the right number of
        entries. (E.g. text-data >=1, data-data >=2, data-data-error =2+3N.)
      + DrawArea() ('area' and 'stackedarea' plots) returns without drawing
        anything if there are < 2 rows, to avoid a PHP warning from
        ImageFilledPolygon(). The 2-row minimum requirement is now documented.
      + DrawLines(), DrawLinesError(), and DrawSquared() return without
        drawing anything if there are no data values at all, to avoid a PHP
        warning from array_fill().
      + DrawOHLC() ('ohlc', 'candlesticks', and 'candlesticks2' plots) now
        checks early that there are 4 data columns, and fails if not.  This
        is to avoid a PHP warning when assigning line thicknesses.

2011-06-05
    * Fixed bug 3312134 "Allow missing points in OHLC plots":
      You can now skip points in the 3 OHLC plot types by using empty strings
      ('') for the 4 values in the row. All rows must still have 4 values, but
      if any is non-numeric the row will be skipped.

2011-05-27 (lbayuk)     ===== Released as 5.4.0 =====
    * phplot.php: Updated version comment and version constant
    * README.txt: Updated for new release
    * NEWS.txt: Add text for new release

2011-05-25
    * Added class constant PHPlot::version with the PHPlot release version.

2011-05-23
    * Fix bug 3296884 "Undefined variable with stackedbars":
      This is part 2 of the fix. (Part 1 fixed the undefined variable error
      when the first stack was all zeros, but did not fix related problems.)

      Changed DrawStackedBars() and DrawHorizStackedBars():
      + Do not ignore zero values. A leading zero value is significant if the
        axis is moved in the direction opposite to the stack direction.  Now
        PHPlot will draw a bar segment from the axis to zero in this case.
        Also a trailing zero value will produce a color cap on shaded bars.
      + Determine each stack direction before drawing it.  This is necessary
        to be able to draw the leading 0 segment case correctly.

2011-05-21
    * Feature request #3303654 "Force tick mark at specific value":
      + New functions SetXTickAnchor and SetYTickAnchor.
      + CalcTicks() adjusts the starting tick point so that an anchor
        point, if set, will coincide with a tick mark (or would, if the
        data range were extended).

2011-05-15
    * Feature request #3291155 "More flexible legend positioning":
      You can now position the legend by specifying that any point on the
      legend box be placed at any point on the image, plot area, or relative
      to the main title.  You can get the legend box size from PHPlot, and
      use it (for example) to adjust the plot area margins.
      + Added new public function SetLegendPosition() which provides
        much move flexible control over the legend position.
      + Re-implemented SetLegendPixels() and SetLegendWorld() by
        just having them call SetLegendPosition().
      + Added new public function GetLegendSize() which returns the
        height and width of the legend box.
      + New internal function GetLegendSizeParams() with code split
        off from DrawLegend() and used by GetLegendSize() too.
      + New internal function GetLegendPosition() calculates the legend
        position. This implements all the new position modes.
      + Removed internal class variables legend_x_pos, legend_y_pos,
        and legend_xy_world. Replaced with an array: legend_pos, which
        holds the legend position parameters set by SetLegendPosition().

2011-05-08
    * Merged 5.3.2 release changes. (The two entries below this, 2011-05-01
      and 2011-04-26, came before 5.3.2, but 5.3.2 was a single patch applied
      against 5.3.1 and not against current CVS.)

2011-05-01
    * Feature request #3292825 "Use point shape markers in legend box":
      + Implement optional use of point shapes instead of color boxes in the
        legend, for use with points and linepoints plots.
      + Add new function SetLegendUseShapes() to enable use of point shapes
        in the legend.
      + New internal class variable legend_use_shapes.
      + Removed optional never-used 3rd argument to SetLegendStyle().
      + Add new internal function DrawShape() which now implements DrawDot()
        but takes device coordinates, for use by DrawLegend().

    * Fix bug #3294604 "Center vertical alignment for legend text":
      + Legend text lines are now vertically centered on the middle of
        the color box or marker shape, rather than using bottom alignment.

2011-04-26
    * Moved legend functions together into one section, and removed
      commented-out public variable declarations for legend variables.
      No functionality changes are introduced.
      (This is being done in anticipation of two upcoming changes to
      legend code. I dislike moving functions around because it makes it
      hard to use 'diff' to check changes, but it is helpful to have
      functions that work together placed together in the script. As
      a compromise, do the re-arrangement in its own change.)

2011-05-06 (lbayuk)     ===== Released as 5.3.2 =====
    * phplot.php: Updated version
    * README.txt: Updated for new release
    * NEWS.txt: Add text for new release
   Note: This release was built off of the CVS branch tagged
   rel5_3_1_patches, not HEAD.

2011-05-06
    * For bug 3296884 "Undefined variable with stackedbars":
      A temporary fix was made against phplot-5.3.1 to avoid an undefined
      variable error when the first stack in a stackedbars plot has all zero
      values. The fix avoids the error message, and the plots are OK in most
      cases. There are still issues with label position, and if the axis
      is moved. These will be addressed in a future fix.

2011-01-15 (lbayuk)     ===== Released as 5.3.1 =====
    * phplot.php: Updated version
    * README.txt: Updated for new release
    * NEWS.txt: Add text for new release

2011-01-09
    * Fixed some style / indent errors, and 1 redundant test.

2011-01-03
    * For bug 3143586 "Multiple plots per image - fixes & docs":
      Make sure there is a documented way to reset PHPlot feature
      settings, especially those for which the default settings result
      in automatic calculated values. Where possible, calling a Set*()
      function with no arguments should reset the feature to defaults.

      + Changed SetLegendPixels() arguments to be optional with default
        NULL meaning reset to automatic positioning.

      + Fixed SetXAxisPosition() and SetYAxisPosition() to accept empty
        string '' to mean reset to default automatic positioning.
        Make arguments optional, defaulting to empty string.

      + Changed SetNumXTicks() and SetNumYTicks() arguments to be
        optional with default empty string '' meaning reset to
        of automatic calculation.

    * Changed SetPointShapes() to use CheckOptionArray(). This
      simplifies the function with no change in operation.

    * Extend copyright years to 2011.

2010-12-30
    * Fix for bug 3147397 "Data colors missing with multiple plots":
      + Do not truncate the data_colors and related arrays, so the full
        set of colors will be available for subsequent plots on the image.
        (Color indexes are still allocated in the image only as needed.)
      + New internal functions GetColorIndexArray() and
        GetDarkColorIndexArray(), replacing previous use of array_map().
      + Removed internal function truncate_array() - no longer used.
      + Changed SetColorIndexes(), NeedDataDarkColors(), and
        NeedErrorBarColors() to only allocate the color indexes that will
        be needed (instead of allocating all colors in the truncated color
        descriptor arrays).

2010-12-28
    * Instead of throwing an error, SetLegend(NULL) now clears the legend
      array. This can be useful with multiple plots on an image. Before
      this change, only SetLegend(array()) did that (possibly by accident).

2010-12-27
    * Do not have SetDefaultStyles() call deprecated SetLabelColor().

    * Fixes for bug 3143586 "Multiple plots per image - fixes & docs":
      + Fix DrawLegend so it doesn't forget that the legend position
        was specified in world coordinates. This fixes the legend
        position for plots after the first.
      + Don't draw the image border more than once (although this would
        probably have no impact on the resulting image). This parallels
        the behavior for the main plot title and the image background.
        Replaced member variables background_done and title_done with a new
        member array done[] which will track when these elements were done.

2010-12-06
    * Fix comments above CalcPlotAreaWorld(). Deleted incorrect information
      from before data-data-yx existed, and before DecodeDataType rewrite.

2010-12-04 (lbayuk)     ===== Released as 5.3.0 =====
    * phplot.php: Updated version
    * README.txt: Updated for new release
    * NEWS.txt: Add text for new release

2010-12-03
    * Feature request 3127005 "Ability to suppress X/Y axis lines":
      Added SetDrawXAxis() and SetDrawYAxis() to control flags which
      will suppress drawing the X or Y axis lines. (These lines were
      probably the only PHPlot elements that could not be turned off.)
      Changed DrawXAxis() and DrawYAxis() to conditionally draw the
      axis lines.

2010-11-28
    * Feature request 3117873 "Data value labels in more plot types":
      Implemented Data Value Labels for plot types points, lines,
      linepoints, and squared.  Added 2 class variables which can be
      set to control the distance and angle of the labels from points.
      New internal function CheckDataValueLabels() calculates position
      and text alignment for these labels.

    * Updated comments for Set[XY]DataLabelPos to match the text in
      the manual, which was rewritten to clarify label types.

2010-11-23
    * Code cleanup. Moved some functions around to group "plot drawing
      helpers" separately from "plot drawing". No changes to operation.

2010-11-21
    * Feature request 3111166 "Control legend colorbox width":
      Added a class variable legend_colorbox_width which can be changed
      to make the colorboxes wider or narrower.

2010-11-16
    * Feature request 3093483 "Investing support chart types":
      Added 3 new plot types: Basic OHLC (Open/High/Low/Close), Candlesticks,
      and Filled Candlesticks. Implemented with one new function to handle the
      3 new plot types: ohlc, candlesticks, and candlesticks2.

2010-11-11
    * Moved information about plot types into a new static member array
      plots[]. (This is an internal change with no impact on usage, but will
      make it easier to add new plot types.) SetPlotType() no longer needs a
      list of plot types to check, FindDataLimits() does not need to check for
      specific plot types to to process the data array, and DrawGraph() uses
      data from the array rather than knowing about all the plot types.

2010-10-31
    * Changed internal CalcBarWidths() to take two arguments which indicate
      how it should calculate bar widths, rather than having it check the
      plot_type directly. (Taken from another, experimental change. This
      minimizes places where plot_type is directly used.)

2010-10-03 (lbayuk)     ===== Released as 5.2.0 =====
    * phplot.php: Updated version
    * README.txt: Updated for new release
    * NEWS.txt: Add text for new release
    * Makefile: Removed HorizontalBars.txt from release. This is now all
          documented in the reference manual.

2010-10-01
    * Rewrite color handling. Default and specified colors are now validated,
      converted to RGBA arrays, and saved. The colors indexes are not
      allocated until graph drawing time. Unneeded colors are not allocated.

      Fix bug 3045131 "SetTransparentColor problems": Transparency setup is
      deferred to graph drawing time, after most other colors are allocated.
      Fixes SetTransparentColor order dependency, and works with data colors.

      Fix bug 3049726 "Optimize color allocation": Colors allocation is
      deferred to graph drawing time, and colors for most elements are only
      allocated if needed. In particular, the data colors and dark colors,
      which used 32 slots, now only get defined as needed.

      Feature request (partial) 3077554 "Finer control over plot element
      colors": The colors of the main, X, and Y titles can now be controlled
      separately.

      Change details:
      New internal functions:
          GetColorIndex(), GetDarkColorIndex()
              Allocate pre-parsed colors for elements.
          SetColorIndexes()
              Does the deferred color allocation and defaults.
          NeedDataDarkColors(), NeedErrorBarColors()
              Called by graph drawing functions if those colors are needed.
          GetDataColor(), GetDataErrorColors(), GetBarColors()
              Custom or standard data color assignment for most plot types.
          truncate_array()
             Shorten an array. Used to limit data color allocation.

      Removed internal functions:
          SetIndexColor(), SetIndexDarkColor()
              Unneeded. Color handling is now in two separate phases.

      Removed internal member variable:
          data_colors_alpha
              PHPlot no longer calls SetDataColors before plotting, so this
              variable is not needed to preserve the default alpha.

      New internal member variables:
          transparent_color
              Saves color value from SetTransparentColor. For bug 3045131.
          x_title_color, y_title_color, ndx_x_title_color, ndx_y_title_color
              For title colors. DrawXTitle and DrawYTitle use them now.

      Changed internal member variables:
          i_border, plot_bg_color, bg_color, label_color, text_color, etc.
              All variables for colors now always hold a parsed 4-component
              (RGBA) color specification as an array, and are no longer
              statically initialized to a color name.

      New public functions:
          SetXTitleColor(), SetYTitleColor()
              These can be used to make the 3 titles have different colors.

2010-09-26
    * Don't let SetXDataLabelPos() accept 'xaxis' or 'all' as valid.
      Don't let SetXTickLabelPos(), SetYTickLabelPos() accept 'all' as valid.
      These were never implemented and never documented.


    * Feature request #3073679 "Stacked bar plots with negative values":
      Allow stacked bar plots (vertical and horizontal) to work with negative
      values.  Changed FindDataLimits() to not take abs() values for
      stackedbar when calculating the data range.  Changed DrawStackedBars()
      and DrawHorizStackedBars() to handle negative values, including proper
      label positions.  The first non-zero value in a row sets the direction
      of the bar. Mixing positive and negative values within a row works but
      the results are not useful.

    * New internal DrawBar() moves common code from 4 bars and stackedbars
      drawing functions and makes it easier to deal with shading vs bar
      direction.

2010-09-24
    * Fix bug 3074402 "Fix Y axis default for horizontal plots":
      Make the default axis positions symmetrical for vertical plots
      (X and Y) and horizontal plots (Y and X). This fixes the problem
      with horizontal bar/thinbarline plots that have negative data,
      where the Y axis stayed on the left and the bars went rightward.

2010-09-01
    * Fix bug 3056991 "Internal methods should be 'protected'":
      Changed CheckDataArray(), number_format(), FindDataLimits(), and
      DrawBackground() to be 'protected'. The test suite no longer calls
      these directly. For SetIndexColor(), SetRGBColor(), DrawText(),
      SizeText(), xtr(), and ytr(), left these as public with a comment
      indicating they should be treated as protected.

    * Fix bug 3057000 "Review 'deprecated' methods":
      + Changed deprecated method SetNewPlotAreaPixels() to just call
      SetPlotAreaPixels(). It was suspicious as coded, and was found
      to be equivalent to SetPlotAreaPixels().
      +  Removed SetColor(), which didn't do anything. It was calling
      SetRGBColor and discarding the result. After reviewing the
      history of this in all CVS versions, it does not seem to have
      ever been coded correctly, so there is no harm in removing it.
      + All other deprecated methods seem OK and are left as is.

2010-08-30 (lbayuk)     ===== Released as 5.1.3 =====
    * phplot.php: Updated version
    * README.txt: Updated for new release
    * NEWS.txt: Add text for new release

2010-08-27
    * Fix bug 3051832 "Let PHP/GD find the font file":
      Instead of checking for file existence, PHPlot now uses a non-drawing GD
      operation to validate a TrueType font in SetFontTTF(). This allows GD to
      use its internal search path, making it likely that fonts can be found
      without needing a platform-dependent path in your script.  Full paths
      will still work, so there is no compatibility issue.

    * Fix bug 3051906 "Better choice for default TT font":
      Removed "benjamingothic.ttf" as the default TT font setting. This has
      not been included in PHPlot since 2004. Changed SetFontTTF() to call
      new GetDefaultFontTTF(), which will try a number of sans-serif font
      names the first time it needs a default TT font. Considering the above
      fix to finding fonts, this has a good chance of finding a working
      font. It is known to work on Windows and some Linux distributions.

2010-08-19
    * Makefile: Removed phplot_data.php from list of files to release.
      Reference bug report 3048267. This file has not been maintained or
      tested, and has bugs.  It will remain in CVS, but not be included
      in PHPlot releases.

2010-08-17
    * Change new DrawLinePoints(). It does not have to check and
      handle error bar plots, as DrawDots and DrawLines will do that.

2010-08-16
    * Rewrote DecodeDataType(). Previous implementation was hard to
      extend and inefficient. Now it uses new class variables (not a
      returned array) and is only called once, by DrawGraph. Changed all
      users of data_type to use the new variables.

      In CheckDataArray(), calculate data_columns properly for
      text-data-single data type (pie chart) too. Simplify DrawPie
      to use this, and merge 2 of the 3 cases.

      Have a single function handle each plot type, so it can properly
      check the data type and report a correct error message showing
      all supported types. For example, DrawBars is now the entry point
      for both bars and horizontal bars; DrawGraph does not directly
      call DrawHorizBars. Similar for DrawStackedBars and
      DrawHorizStackedBars.  Lines, Points, and Linepoints also now
      have a single function each, dispatching to others as needed.
      (These changes were split off from an upcoming, larger change.)

2010-08-14
    * Fixes to SetDataValues: need to clear out the 2 arrays before
      setting values in a loop, else if the function is used more than
      once then old values will remain.
      Move records_per_group calculation outside the loop.
      (These were split off from upcoming, larger changes.)

    * Part 4 of horizontal plots: implement horizontal thinbarline plots.
      Added new data type 'data-data-yx' (label, Y, X1, X2, ...).
      DrawThinBarLines() now draws either vertical or horizontal plots, and
      supports data types text-data, data-data, text-data-yx, data-data-yx.

      Fixed DecodeDataType() to handle text-data-single too, for completeness.

    * Fix for over-padding style and color arrays. These were padded to
      records_per_group, but that is the maximum data array row size.
      The number of actual data sets is less, and depends on the data type.
      Calculate the correct number as data_columns at the top of DrawGraph,
      and use that to pad the arrays. Also moved early error checking in
      DrawGraph() into new CheckDataArray().

2010-08-09
    * Code cleanup. This is a large change to unify the comment and
      coding stye used in PHPlot. The PEAR style guide is being used
      as a reference, but PHPlot will never be 100% compliant.
      This patch introduces no functional changes at all.
        - Limit line length to 110.
        - Remove obsolete, partially implemented Doxygen comments.
        - Add descriptive comment above functions where missing.
        - Use consistent comment markers and control structure spacing.
        - Remove ctags-confusing end of function comments.
        - Rewrote a few if/else blocks for cleaner logic.
        - Re-order some functions for consistency (X, then Y).

2010-08-04
    * Implemented horizontal stacked bar plots:
      Use the same data type introduced for horizontal bars, 'text-data-yx',
      and the same plot type 'stackedbars', to make a horizontal stacked bar
      plot.  Data value labels, both at the ends of the bars and within the
      bars ('plotstack' labels) are available with horizontal stacked bars.

    * Internal function DrawDataLabel() is replaced by DrawDataValueLabel(),
      with different usage. The new function can also check to see if a label
      fits in the allocated space.

    * Fixed the text size check in stacked bar plots for data value labels
      within the bars. The check only worked correctly for 0 degree labels. It
      now works with any text angle. It suppresses the label if it is too high
      (for vertical stacked bar plots) or too wide (for horizontal stacked bar
      plots) to fit in the bar segment to which it belongs. Note that it only
      checks in the bar direction. If the text is too wide (for vertical bars),
      or too high (for horizontal bars), it will still be plotted, but will
      cross the sides of the bar.

2010-07-28
    * Allow callbacks to return a value (to support new data_color callback).
    * Feature request 3034164 "Extended control of data colors":
      Define new callback 'data_color' for picking the data color.
      Changed internal plot drawing functions DrawDots, DrawLines, DrawSquared,
      DrawBars, DrawStackedBars, DrawDotsError, DrawThinBarLines,
      DrawLinesError, and DrawHorizBars to use the data_color callback
      (if defined) to select the data colors.
    * SetRGBArray code cleanup (no functional changes).

2010-07-27
    * Fixes for error bars:
      Code cleanup in DrawYErrorBar(), with no functional change.
      Suppress duplicate drawing of error bars with 'linepoints' error plots.
      This was already fixed for data labels. Now error bars will only be
      drawn by the 'points' part, not the 'lines' part. There should be no
      visible changes to plots. (This is needed for a future change).

2010-07-26
    * Horizontal bar charts (still an experimental feature) can now have data
      value labels.
    * HorizontalBars.txt: Fix incorrect description of bar direction. Add
      text explaining the new data value labels.

2010-06-29 (lbayuk)     ===== Released as 5.1.2 =====
    * phplot.php: Updated version
    * README.txt: Updated for new release
    * NEWS.txt: Add text for new release

2010-06-26
   * Feature request 2885930 "Horizontal Bars":
     Horizontal bar charts are implemented, as an experimental feature.
     A new data type 'text-data-yx' was added, which works with
     'bars' plot type to produce a horizontal bar chart from a data
     array with X values for each Y value. Changes were made to
     FindDataLimits, CalcMargins, CalcPlotAreaWorld, CalcBarWidths,
     and CalcMaxDataLabelSize to handle the new data type. Other
     changes were made to handle label position defaults and grid
     defaults. New drawing functions were added for horizontal bars.

   * HorizontalBars.txt: new documentation file for experimental feature.
   * Makefile: List new documentation file.

2010-06-25
   * Each plot-type drawing function now checks that it is getting a data
     type that it knows how to handle. A new internal function unifies the
     checking and error message. (This is associated with an upcoming,
     bigger change.)

     Compatibility: If you were using an invalid data type for a plot type
     whose function did not check, will now get an error.

   * Removed some dubious code from DrawLines() and DrawSquared() and
     rewrote comments there. The code initialized lastx[0] and lasty[0],
     but lasty was mapped using the X (rather than Y) function.  This was
     obviously wrong, but closer inspection showed that the values were
     never, used so the code was removed.

2010-06-13
   * Truecolor.txt: removed
   * Makefile, README.txt: Removed reference to Truecolor.txt. Full
     documentation for truecolor images is now in the Reference Manual.

2010-06-02
   * Fix bug 3010116 "Bad rendering of title in multi-plot image
     when using TTF":
     Make sure the main title is drawn only once. (If drawn multiple
     times with TrueType font text, the anti-aliasing effects result
     in poor quality text.)

2010-05-31
   * Improvements to truecolor support (from feature request 2947679):
     Truecolor support is now better integrated. The derived class only
     has the constructor now, and the base class itself provides the alpha
     color component support through the internal functions SetIndexColor(),
     SetIndexDarkColor(), and SetRGBColor(). This means alpha channel
     works with palette images too (in so far as GD supports this).

   * Truecolor.txt: Updated per changes to truecolor support.

   * Image tiling with mode 'scale' in tile_img(), used with image and
     plot area backgrounds, now uses imagecopyresampled() rather than
     imagecopyresized(). They are the same with palette images, but the
     resampled copy gets better results with truecolor images.

2010-05-29
    * Feature request 3002606 "Add to plot and image border options":
        Added options 'right', 'top', and 'bottom' to SetPlotBorderType()
      (existing options are 'left', 'sides', 'none', and 'full'). This
      now also accepts an array of the above options, giving complete
      control over which sides to draw.
        Added option 'solid' to SetImageBorderType() to use the actual
      color set with SetImageBorderColor(), rather than the darker
      shade as type 'plain' does (for some reason).
        New function SetImageBorderWidth() sets the width of the image
      border. The image border width is now accounted for in margin
      calculations, although existing plots will not change.

2010-04-04 (lbayuk)     ===== Released as 5.1.1 =====
    * phplot.php: Updated version
    * README.txt: Updated for new release
    * NEWS.txt: Add text for new release

2010-04-01
    * Remove & from argument in SetDataValues(). The data array is not
      modified and does not need to be passed by reference. (There is
      no performance advantage, either.)

2010-03-29
    * Feature request 2947679 "Support for alpha blending/Truecolor":
      Implemented truecolor image support with a new class
      PHPlot_truecolor, extended color specifications to allow
      specification of an alpha value, and added a new optional parameter
      to SetDataColors for a default alpha value for all data colors.
      This feature is *EXPERIMENTAL* (see next item).

    * Truecolor.txt: New file, documentation for the new truecolor capability.
      (The Truecolor feature is experimental, which means it is subject to
      change in incompatible ways and the documentation has not yet been
      incorporated into the PHPlot Reference Manual.)

    * Makefile: Include new documentation file in release.

2010-03-26
    Fixed bug 2976735 "Improvements and fixes for 'area' plots":
    Rewrote DrawArea() function which handles 'area' plot.
        Part 1: This is related to feature request 2947679, Truecolor support
    with transparency. The area plot function was filling each area from the X
    axis up to the Y value, resulting in area overlaps. This wasn't a problem
    with opaque colors, but with transparency, the overlapping areas resulted
    in changed colors. The rewritten function fills the area between each line
    instead of from each line down to the X axis. Plots with opaque colors
    will not change.
        Part 2: Area plots now work when the X axis is moved up with
    SetXAxisPosition().
        Part 3: Fixed FindDataLimits() for area (and stackedbars too) to
    take absolute values of Y values. The drawing function was doing this,
    but not FindDataLimits, resulting in incorrect limits if any Y<0.
        Part 4: The rewritten DrawArea() also handles a new plot type
    'stackedarea'.  This is an area plot where the Y values are stacked,
    similar to 'stackedbars'.
        Note: As part of the changes, it is now an error to try an area plot
    with an unequal number of Y points for each X.

2010-03-23
    * Feature request 2973995 "Add y-Data to Stackedbars":
      Implemented Y Data Labels for Stacked Bar charts (stackedbars).
      The labels are enabled with SetYDataLabelPos, same as with bar charts.
      There are two types of labels: above the stack with the total, and
      within the bars at each segment. 'plotin' turns on the upper ones, and
      'plotstack' turns both on.

    * Other changes:
      + Removed unimplemented second argument to SetYDataLabelPos.
      + Fixed questionable logic in SetYDataLabelPos when given an argument
        that belongs with SetYTickLabelPos.
      + Fix comments at top of plot-type Draw functions.

    * Fix for bug 2974639 "Stacked bars plot breaks with X axis != 0":
      Stacked bar plots with non-zero X axis position no longer break apart
      into segments with gaps. The bars are drawn up from the X axis, and
      any segments or partial segments below the X axis are not drawn.

2010-03-22
    * Change related to feature request 2947679 - Fix 'dot' point shape:
      Use imagefilledellipse(), not imagefilledarc(), when drawing the 'dot'
      point shape. The fix was needed for future support of truecolor images
      with transparency, but filled dots from imagefilledellipse() look
      better (rounder) with regular images and opaque colors.
      Credit to mvaldez for identifying the problem and providing the fix.

2010-03-04
    * Fix for bug 2963757 "point_counts undefined error in 5.1.0":
      Fixed CheckPointParams so it sets point_counts even when the point shape
      and point size arrays are already the same size and do not need padding.

2010-01-26
    * Fix for bug 2938219 "Bars go in wrong direction":
      Fixed CalcAxisPositions() to be consistent in positioning the X axis.
      When all Y values are <0 and the Y=0 line is not part of the plot range,
      PHPlot will now default the X axis to the top of the plot, not the
      bottom.  This fixes the problem with bars to negative Y values being
      drawn downward if Y=0 is visible, but upward if Y=0 is not visible.
      This also affects thinbarline plots.
      Credit to lauryn1298 for finding the bug.

2009-12-24 (lbayuk)     ===== Released as 5.1.0 =====

2009-12-18
    * Change for bug 1795971 "Fix default data colors":
      The default Data Color and Error Bar Color arrays now have 16
      different colors, no duplicates, and nothing so light that it
      is invisible.
      Using '' or False as the argument to SetDataColors, SetErrorBarColors,
      and SetDataBorderColors now re-initializes the map to the defaults.
      This was previously undocumented, and in some cases set the map to
      something different from the default.

2009-12-15
    * Cleanup: Remove DrawAxisLegend() - empty function marked TODO,
      not really clear what it was meant to do.

2009-12-14
    * Fix for bug 2914403 "Pie + X/Y titles: Undefined property error":
      In DrawGraph(), don't try to draw X or Y titles for pie charts.

    * Feature request 2899921: "allow different format for data and tick
      labels"; Bug 2906436: "Fixes for X Tick Labels vs X Data Labels",
      and partial implementation of changes from user 'adoll' regarding
      tick vs data labels:

      New public functions:
      + SetXDataLabelType() : Sets formatting for X Data Labels
      + SetYDataLabelType() : Sets formatting for Y Data Labels (bar charts)
      + SetXDataLabelAngle() : Sets text angle for X Data Labels
      + SetYDataLabelAngle() : Sets text angle for Y Data Label (bar charts)
      The defaults for these are set up to be fully backward compatible
      with previous releases of PHPlot (except see the next item).

      Re-used function name SetXDataLabelAngle():
      + This has been deprecated and undocumented since 2003-12-07, and
        used to just call SetXLabelAngle(). For new behavior, see above.

      Changes to public functions:
      + SetXDataLabelPos() and SetXTickLabelPos() no longer cancel each
        other out (set the other control variable to 'none'). Instead,
        they are both considered before plot drawing.

      Changes to internal functions:
      + DrawDataLabel() now uses the font, angle, and color arguments as
        provided, and does not substitute values if they are empty.
      + SetLabelType() now takes mode='xd' and 'yd' for X Data and Y Data
        label formatting; 'x' and 'y' are for tick labels only now.
      + Functions that work on Data labels now call FormatLabel() with the
        new mode parameter value 'xd' or 'yd, and use the new
        data_label_angle variables.
      + New CheckLabels(), used by DrawGraph to process label parameters.
      + CalcMargins() - Rewritten to handle changes to Tick and Data labels.

      Changes to internal class variables:
      + New: x_data_label_angle, y_data_label_angle
      + Do not initialize x_tick_label_pos or x_data_label_pos, so that
        CheckLabels() can tell if they were set or not and apply defaults.
      + Initialize y_data_label_pos to 'none', not 'plotleft'.
      + Add 2 more indexes to label_format[] array: 'xd' and 'yd'.

    * Cleanup:
      + Delete unused internal class variable: draw_y_data_label_lines
      + Delete unused function SetDrawYDataLabelLines()

2009-12-07
    * Fix bug 1795972 "Fix default point shapes":
      +  Added 10 new point shapes to the existing 10 shapes.
      +  Changed the default point shape from all 'diamond' to a
         selection of up to 10 different shapes.
      +  Fixed bug in the code that tried to set the point shapes
         and sizes arrays to be the same size. This was not working,
         resulting in unexpected point sizes.
      +  Changed default point size to 6 for all shapes. It was trying
         to be "5, 5, 3" but due to several bugs this was not working.
      +  Do not adjust shape sizes to even numbers (was done for only two
         shapes).  Instead, consistently truncate size/2 when needed.
      NOTE: These may change the look of 'points' and 'linepoints' plots.

    * Changed startup initialization code:
      +  SetDefaultStyles() was doing some odd things using a variable
         called "session_set", with comments referring to non-existent
         session support code. This has been removed. There should be
         no visible changes from this. PHPlot does not use PHP sessions.

2009-12-04
    * Fix for bug 2908256, errors in pie charts with bad data array:
      (From a Drupal contrib module report by thekevinday.)
      With pie charts only, a data array with no valid Y values resulted
      in PHP error messages. All other plot types handle this by producing
      an image without a graph.
      Fixed DrawPieChart to behave this way too. If there are no valid Y
      values, or if the sum of all Y values is 0, do not error out, but
      don't draw a pie chart either.
      Also, pie charts now ignore non-numeric Y values, like other plot types.

2009-11-20 (lbayuk)
    * Fix for bug 2900914 "Problem with display of 0 on Y axis":
      Changed how X and Y values are stepped by tick intervals, to avoid
      cumulative round-off error. This fixes the problem when Y crosses 0 with
      a tick step such as 0.1 resulting in a long label for a very small but
      non-zero number. Fixed DrawXTicks, DrawYTicks, and CalcMaxTickLabelSize.
      (Originally reported by cncnet)

2009-11-19 (lbayuk)
    * Improve support for using callbacks to annotate plots:
      Added new callback 'draw_all', called after all drawing.
      Supply plot_area[] as argument to some drawing callbacks.
      Added new method GetDeviceXY() to translate from world coordinates.
      Allow NULL or '' for $font in DrawText() internal method, meaning to
          use the generic font. If callbacks want to use DrawText, this
          avoids them having to reference the internal fonts[] array.

2009-11-01 (lbayuk)
    * Address bug report 2886365 "Declare all functions and variables in
      PHP5 style"
      PHP5 deprecates the use of 'var' to declare a class member variable.
      All initialized class member variables are now declared 'public'.
      (It was tempting to make most or all 'protected' or 'private', but
      that would likely break too much, including the PHPlot Test Suite.)

      Most class member functions which are meant for internal use only are
      now declared 'protected', so they cannot be called from scripts
      (except in child classes). (Note PHP5 does not deprecate the use of
      just 'function' to mean public, so public functions were not changed.)
      Internal functions are those documented in the manual under Developer's
      Guide, Internal Functions. If your code breaks because you are using
      a method which is now protected, please post the details on the help
      forum.

      Some member variables which were set in the constructor are now
      initialized with the class instead. (No impact.)

      Removed commented-out, FIXME-noted code for interim labels.

2009-10-12 (lbayuk)
    * Bug report 2839547, allow SetImageBorderType('none') to reset the image
      border type.  Also checked for other cases where there is no reset;
      found one that exists (Set[XY]LabelType) but needs to be documented.

2009-07-09 (lbayuk)
    * Added a hook $plot->locale_override which can be set to True to prevent
      PHPlot from loading locale settings from the environment with
      setlocale(LC_ALL, ''). This is necessary for testing PHPlot on Windows,
      where you cannot force a locale with an environment variable. It might
      also be needed for people who want PHPlot's locale to differ from the
      web server's locale.

2009-06-12 (lbayuk)     ===== Released as 5.0.7 =====

2009-06-11 (lbayuk)
    * Change PHPlot license to LGPL, per Afan.
        phplot.php, phplot_data.php - Change license notice.
        rgb.inc.php - Change top comments and remove bottom marker.
        COPYING - new file, text of LGPL.
        LICENSE.* - removed files - old licenses.
        Makefile - change list of distributed files.

    * Fix for bug 2803900: SetRGBArray('large') does not work. The include
      file defined a different array name than the main script expected.
      (This bug seems to have happened over 8 years ago.) Fixed the array
      names to match. Also removed the ./ prefix from the included filename
      so it will be found if on the include path but not in the script
      directory.  Also added error check if the rgb.inc.php include file
      is needed and not found.

2009-05-25 (lbayuk)
    * Added new feature to allow partial margin or plot area specification.
      You can omit, or specify as NULL, any of the 4 arguments to
      SetMarginsPixels() or SetPlotAreaPixels(), and this means PHPlot
      should use the automatically calculated margin on that side.
      Credit to adoll for this feature.

2009-05-17 (lbayuk)
    * Fix for bug 2791502 "Error plots treat missing Y values as 0":
      Plots with data type data-data-error now support missing Y values,
      instead of treating them as 0. This works with lines, points,
      and linepoints plot types, and also honors SetDrawBrokenLines.


    * Fix for bug 2792860 "Wrong DataLabelLines with missing Y":
      Do not draw X Data Label Lines at points with missing Y values.


    * Fix for bug 2786350 "Missing Y data results in bad auto-range":
      Rewrote FindDataLimits to ignore missing Y values, rather than
      treating them as if 0, for calculating range.
      Bug report and analysis by mrten.

    * Fix for bug 2786354 "Incorrect auto-range for data-data-error":
      For data-data-error data type, apply the positive and negative error
      amounts for each Y point to that point only, rather than applying the
      largest errors to the overall minimum and maximum Y value for the row.

    Note: The two fixes above can change existing plots which rely on
      automatic Y range calculation. The first fix affects plots with
      missing Y values and min(Y)>0. The second fix can affect plots using
      data-data-error data type and different error values for different
      points. In both cases the new Y range can be smaller than before.

2009-01-20 (lbayuk)     ===== Released as 5.0.6 =====

2009-01-18 (lbayuk)
    * Fix for bug 1891636 "Misaligned TTF X Labels":
	  PHPlot was using the actual bounding box of each line of text
      to allocate space and set the text positioning, but was ignoring the
      fact that the text baseline is not the same as the bottom of the
      bounding box. This resulted in uneven alignment of the X labels if
      they had different heights (for example, month names Jul and Aug).

      PHPlot now calculates the size of text for allocation (SizeText) using
      the descenders on the last line, and calculates the size for drawing
      (DrawText) only to the baseline. PHPlot also now uses a fixed line
      spacing for each line of text in a font, rather than the actual text
      height. This allows separately drawn multi-line labels to align.

    * Changes to line spacing when using multi-line labels:
	  PHPlot was using the class variable line_spacing to mean the
      number of pixels between lines of multi-line labels. This made the
      spacing too small for larger fonts, and it was not possible to adjust
      line spacing for different types of text.

	  PHPlot now interprets line_spacing as the number of pixels only
      for GD text, and as a scale factor for the font's built-in line
      spacing for TrueType text. In addition, a new optional argument is
      added to SetFont, SetFontGD, and SetFontTTF to set a line spacing
      specific to that type of text.

    * Changes had to be made to the legend drawing code to accommodate the
      changes to font handling.

      Note: The line spacing change results in slightly looser spacing on
      multi-line TrueType text labels, and slightly taller legends, compared
      to version 5.0.5.

2008-09-21 (lbayuk)
    * Interim fix for bug 1932571 "Data-Data Plot fails with same X values".
      PHPlot will no longer hang when the range of X values is 0 (that is, when
      x_min == x_max). It will arbitrarily set an X range of 1, so the
      calculated tick step is not 0. This is a temporary fix. Work on a smarter
      X and Y range calculation is in progress, which will handle edge cases
      like this better, but it isn't ready and this bug has been open too long.
      Credit to andyl for finding the bug.

    * Fix font path: Use DIRECTORY_SEPARATOR constant not '/'.

    Extended the label formatting capabilities, adding 'printf' and 'custom'
    types, added a prefix and suffix for 'data' type, and allow format controls
    to be included in SetXLabelType and SetYLabelType.

    External changes:
    * Added 'printf' label type. The caller specifies the print format as the
      2nd argument to SetXLabelType or SetYLabelType (default '%e').
             $plot->SetXLabelType('printf', '%5.2f');

    * Added 'custom' label type. The caller supplies a callback (typically a
      function name) and optional pass-through argument as the 2nd and 3rd
      arguments to Set[XY]LabelType.  The function is called as $f($value, $arg)
      to return the formatted $value.
             $plot->SetXLabelType('custom', 'myfunction', $arg_value);

    * In addition to Set[XY]TimeFormat, the format string for type 'time' can
      now be set as the 2nd argument to Set[XY]LabelType.
             $plot->SetXLabelType('time', '%H:%M');

    * In addition to SetPrecision[XY], the precision for type 'data' can now be
      set as the 2nd argument to Set[XY]LabelType. A 3rd and 4th argument
      can supply a prefix and suffix for 'data' formatting. (All optional)
             $plot->SetXLabelType('data', 2, '$', 'US');

    Internal changes:
    * Class variables x_precision, y_precision, x_label_type, y_label_type,
      x_time_format, and y_time_format have been removed.

    * New class array variable label_format[], with elements 'x' and 'y' which
      are arrays for label formatting. Elements in the sub-arrays are not
      initialized until needed.

    * New function SetLabelType, which implements Set[XY]LabelType now.

    * FormatLabel() was rewritten to support the new label formatting.

    Compatibility:
    * Any code that directly references class variables related to label
      formatting will break, except for data_units_text. Use the documented
      function methods instead.  Setting data_units_text as a suffix is
      deprecated but still works.

    * The 'data' type precision for 'Y' is still used for pie chart labels.

2008-07-12 (lbayuk)
    Multiple comment spelling error fixes. No functional changes.

2008-07-06 (lbayuk)
    Changes to allow mixing GD fixed-font text and TrueType Font (TTF) text
    on the same plot.
    (This change came from work done trying to fix TTF text positioning,
    where it looks like additional information needs to be stored for TrueType
    fonts. The old font data structure was awkward to extend, and allowing
    mixed GD/TTF text was on the to-do list anyway.)

    External changes:
    * SetFontGD(), SetFontTTF(): New functions to set a font, with type.
    * SetFont(): Now calls SetFontGD or SetFontTTF depending on $use_ttf.
    These changes should be fully compatible with existing programs.

    Internal changes:
    * Updated comments explaining SetUseTTF() now sets the default type
      (not the only type) of text used.
    * Put all the font data into a class array. (Replaces $this->generic_font
      with $this->fonts['generic'], etc.)
    * ProcessTextGD() and ProcessTextTTF() now take the font array as one
      argument, rather than separate arguments for font path and size.

2008-01-13 (lbayuk)     ===== Released as 5.0.5 =====
    * phplot.php: Updated version
    * README.txt: Updated for new release
    * NEWS.txt: Add text for new release
    * Makefile: Remove 'Callbacks' from release target, as this material is
      now in the reference manual.

2008-01-07 (lbayuk)
    Copyright updated to 2008 and PHP4 no longer listed as supported.

    Major rewrite of the margin calculation functions to address multiple
    problems.  Fixes for bugs 1856207 "Margin error with 'xaxis'/'yaxis'
    position, 1843012 "Make margins, drawing consistent", and 945439
    "x_tick_label_height not set correctly".

    Note: These changes are inter-dependent and cannot be split up.

    * Defer all calculations to DrawGraph time, to eliminate order dependencies.
      These functions now just store their arguments in the object, and all
      calculations happen later:
    + SetXAxisPosition, SetYAxisPosition
    + SetMarginsPixels
    + SetPlotAreaPixels (Stores margins, not area, now.)
    + SetPlotAreaWorld
    + SetXTickIncrement, SetYTickIncrement

    * A new callback 'debug_scale' was added to trace the margin and scale
      calculations.

    * CalcMargins was rewritten. Actual sizes of tick and data labels are now
      used, rather than guesses like "use size of biggest Y value". A minimum
      value (3 x safe_margin, or 15 pixels) applies to each margin.

    * FindDataLimits no longer needs to find the longest data label, since
      CalcMargins now does that more precisely.

    * DrawXTitle and DrawYTitle now use position offsets calculated by
      CalcMargins. Note: These titles are now offset from the plot area,
      not the image area. The titles will move if you had set the plot area
      or margins.

    * DrawYTick, DrawXTick rewritten to use pre-calculated offsets, and common
      code moved to new CalcTicks().

    * DrawXDataLabel: Use pre-calculated offsets for text.

    * DrawGraph: Rewrote top section (before drawing anything) to do the
      calculations in the proper order, unconditionally.

    * Class variables removed:
      x_label_inc, y_label_inc, _x_label_cnt : These were never used.
      title_height, x_title_height, y_title_width : Now internal to CalcMargins.
      data_limits_done : No more need to remember if FindDataLimits called.

    * New class variables added:
      plot_margins_set : Keeps track of user-set plot area or automatic.
      x_label_top_offset, x_label_bot_offset, x_offset_axis_offset,
          y_label_left_offset, y_label_right_offset, y_label_axis_offset,
          x_title_top_offset, x_title_bot_offset,
          y_title_left_offset, y_title_left_offset : Label offsets

    * New internal functions:
      CalcPlotAreaPixels : Deferred calculations taken out of SetPlotAreaPixels
        and SetMarginsPixels.
      CalcPlotAreaWorld : Deferred calculations taken out of SetPlotAreaWorld.
      CalcAxisPositions : Calculate axis positions, moved from CalcTranslation.
      CalcTicks : Calculate X and Y tick interval. This still uses the
        same simple method (basically range/10), but now we could drop in a new
        algorithm much more easily. This is now also used by CalcMargins.
        Code taken out of DrawXTicks and DrawYTicks.
      CalcMaxTickLabelSize : So CalcMargins can use the exact tick label sizes.
      CalcMaxDataLabelSize : So CalcMargins can use the exact data label sizes.
      DrawXTick : Code split out from DrawXTicks for symmetry with DrawYTick.


2007-12-13 (lbayuk)
    * Changed ProcessTextTTF() so SizeText() will return integers. It rounds
      the calculated values up, so the bounding box really contains the text.
      This also prevents unneeded float calculations in derived values.

2007-12-09 (lbayuk)
    Major rewrite of the text drawing functions to address multiple problems.
    Note: These changes are inter-dependent and cannot be split up.

    * Fixed bug 1813070 "Bad position for multi-line TrueType text":
      TTF text is now drawn line-by-line, not as a block, for proper
      alignment and positioning.

    * Fixed bug 1813071 "Wrong title height for multi-line TTF text":
      Corrected miscalculation of overall height of multi-line TTF titles.
      This bug resulted in over-sized margins.
      The height is now computed line-by-line, including the inter-line spacing.

    * Fixed bug 1813474 "DrawText alignment arguments wrong":
      Corrected meaning of 'top' vs 'bottom' alignment. PHPlot now follows
      the usual conventions: 'top' alignment means top of text to reference.
      DrawText default for vertical alignment is still 'bottom', but the
      meaning was corrected.  All callers of DrawText were fixed.

    * Fixed bug 1816844 "Fix order dependency for setting titles":
      Defer processing titles strings until DrawGraph(), so there is no
      more order dependency (no need to set font before setting title strings).

    * Fixed bug 1819668 "Horiz. align multi-line text: GD vs TTF":
      The new text routines draw TTF text line-by-line and correctly do
      right-, center-, and left- alignment of each line within a text block.

    * Fixed bug 1826513 "FIXME in DrawLegend: Max label length":
      Use actual width of widest legend line to calculate legend box size.

    * Partial fix for bug 945439 "x_tick_label_height not set correctly":
      In FindDataLimits(), save the longest data label, not just its length,
      and use the actual rendered size of that string in CalcMargins() for
      the margin calculations.
      Also take into account which of the tick or data labels are visible.
      This is not a complete fix, but is a significant improvement.

    The following changes were made related to the above fixes:

    + Replaced internal function TTFBBoxSize(), which didn't work right, with
      SizeText(). It returns the orthogonal bounding box of a block of text,
      and works with both GD and TTF text.

    + DrawText() and SizeText() call a single function ProcessText(), which is
      the only place GD text and TTF text are distinguished. (So eventually
      we will be able to mix GD and TTF text on a plot.)

    + New internal functions ProcessTextGD() and ProcessTextTTF() draw (or size)
      GD and TTF text respectively. These are only called by ProcessText().
      These are re-implementations which properly position and align text.

    + Removed class variables title_angle, x_title_angle, and y_title_angle. The
      titles only work at their fixed angles anyway (0, 0, and 90 respectively).

    + Line spacing set with SetLineSpacing() now affects TTF text as well as
      GD text. Previously, it only affected GD text. The default line spacing
      happens to be usable for TTF text.

    + Added new callback hook 'debug_textbox' for developing, testing, and
      documenting. It provides access to the text area bounding box.

    + Removed unneeded class variables x_tick_label_height, y_tick_label_width,
      x_tot_margin, y_tot_margin.

2007-11-25
    * Improve error handling:
      Internal functions PrintError() and DrawError() are now the same. Both
      will draw the error message into the image and output it, and then
      trigger a user-level error. If no error handler has been set, it will
      exit, as before. But now the error message should also get logged, or
      written to the standard error stream, depending on the SAPI in use.
      You can now establish an error handler to catch most PHPlot errors and
      do some cleanup before exit.

      This fix also covers bug #1823774 "Default Font Path and Error Message
      Output".

      Fixed the return value of most PHPlot functions, to return False on
      error, else True. Since uncaught errors are fatal anyway, this only
      affects code with an error handler that returns, which is not
      recommended and unsupported at this time. These changes are for
      possible future error handling options.

2007-11-22
    * Fix bug 1836528 "Insufficient checking of parameter values":
      Rewrote CheckOption to correctly validate option choices.
      (It previously accepted substrings and other incorrect values.)
      PHPlot methods that use CheckOption now must be called with valid option
      values. Empty strings are also no longer accepted.

2007-11-17 (lbayuk)
    * Change to callbacks to support extra arguments.
      The PHPlot class can now pass extra arguments to a callback function.
      Callback functions now take the following form:
          my_callback($img, $passthru_arg, ...)
      Where '...' is zero or more additional arguments supplied by PHPlot to
      the callback. Each implemented callback reason will define any
      additional arguments it uses. The existing defined callbacks have not
      changed and do not currently pass any extra arguments.

2007-11-10 (lbayuk)
    * Fix bug 1827263 "Spoiled up pie-chart if $val is close to zero":
      Skip pie slices which would result in an integer angle of zero
      degrees, because the GD arc filling function will draw a complete
      circle for that case.
      Credit to Viacheslav <webdeveloper.ua at gmail.com> for finding this.

    * Removed 8 of the functions (class methods) marked 'deprecated'.  Only
      deprecated functions which seem to have been for internal use have
      been removed. Even old scripts shouldn't be using them, and they are
      becoming a problem to maintain.
      Removed: SetImageArea() DrawDotSeries() DrawLineSeries() CalcXHeights()
      CalcYWidths() DrawLabels() InitImage() DrawDashedLine().

2007-10-20 (lbayuk)     ===== Released as 5.0.4 =====
    * phplot.php: Updated copyright, version, and authors comments at top.
    * README.txt: Updated for new release
    * NEWS.txt: Add text for new release

2007-10-18 (lbayuk)
    * Add callbacks - experimental feature:
      New functions SetCallback, GetCallback, RemoveCallback.
      New internal function DoCallback.
      Added callback hooks to DrawGraph.

      Re-arranged code in DrawGraph to bring pie chart drawing into the main
      switch on plot type, rather than a special case in its own block. This
      makes it easier to follow and easier to add callback hooks.

    * Callbacks: New file, documentation for the new callbacks feature.
      (This won't be in the manual while it is an experimental feature.)

2007-10-15 (lbayuk)
    * Fix for bug 1813021: Miss-positioned right-justified vertical GD text.
      Fixed DrawText() to correctly position 90 degree right-justified text
      drawn in a fixed GD font. This could be seen with 90 degree Y tick
      labels. (Found by accident while working on TrueType text problems.)
      Also some code cleanup in DrawText: use elseif where appropriate.

2007-10-09 (lbayuk)
    * Code cleanup: Simplify SetIndexColor() and SetIndexDarkColor().
      There is no need to first try ImageColorExact, then ImageColorResolve
      if that fails. ImageColorResolve does all that for us.

      Code cleanup: Rewrite SetRGBColor(). It now detects if an unrecognized
      color name or color value form is used, and draws an error message.
      Before this it would get a PHP index error and "headers already sent"
      condition.

    * Code cleanup: Remove duplicated code for loading image files.
      Added new class-private function GetImage() which loads an image based
      on the image type, and also returns the image size. This replaces
      duplicated code in tile_img() and SetInputFile().
      Also fixed comment at top of SetImageFile which said it was deprecated.
      It isn't - it is used by the constructor. Moved the function out of the
      'deprecated' area up to below where it is used.

    * Code cleanup: PHPlot should not define or affect anything outside its
      own class.
      - Removed the check for __FUNCTION__ (PHP 4.3 and up). This is obsolete.
      - Do not set error_reporting to E_ALL. Although it is recommended that
      scripts do this, it is not the place of loaded classes to do it.
      - Remove unused global constant TOTY.
      - Removed constants MAXY and MINY. Global constants like this are bad.
      These were used as magic index values into data[] to hold min and max Y
      values for the row. Instead, put them in separate arrays which are
      named data_miny[] and data_maxy[]. (This seems to be only used by the
      data line drawing function.)

      Comment cleanup: Remove one commented-out partial function DrawPlotLabel,
      and fix another commented-out code fragment in DrawYErrorBar. Both of
      these had unmatched braces in them which caused a balance-braces check
      to fail.

    * Code cleanup, array padding: Get rid of functions outside the class
      and remove the interim fix for PHP 5 (which changed the behavior of
      array_merge).  Rewrote external function array_pad_array() as a new
      class function pad_array().  It does not need access to the class,
      but I don't think PHPlot should add to the global namespace more
      than necessary.  The third argument (array to use for padding) was
      never used, so it was removed. It always pads the array with itself.
      It now only works on 'usual integer indexed' arrays (0-based
      sequential integer index). The was previously required but
      undocumented for some of the arrays (like line_widths); now it is
      required for all style arrays and will be documented. Now we can pad
      the array to the required length, not just N times its previous
      length, and we don't need array_merge.  Deleted external function
      array_merge_php4() as it is no longer used.

      Deleted PHP end marker ?>. You don't need this and it can cause
      problems with extra whitespace in your output.

2007-09-24 (lbayuk)
    * Code cleanup: Fix ternary operator misuse.  This doesn't change
      behavior, but it was annoying me so I fixed it.
      Replaced all cases of code like this: $a = ($a > $b) ? $b : $a
      With just: if ($a > $b) $a = $b

    * Fix Makefile 'release' target to set owner/group when creating
      the tar file. This avoids having to run it as root, but it needs
      GNU tar to work.

2007-09-08 (lbayuk)
    * Fix for bug 1790441: Removed the PHPlot quasi-destructor function and
      the register_shutdown_function() call which arranged for it to be used.
      This was preventing release of memory when a PHPlot object was unset,
      because the registered shutdown function held a reference to it.
      So rather than improving memory use, it had the opposite effect.
        Note: It is no longer necessary or recommended to use reference
        assignment ($plot =& new PHPlot) for PHPlot object creation.
      Thanks to annajilly for the thorough analysis, bug report, and fix.

2007-09-05 (lbayuk)
    * Rewrote FormatLabel() to ignore blank label values. Adapted from a
      patch and feature request submitted by Gerhard Reithofer (exgerhardr).
      Blank labels used to produce an error if the LabelType was set to
      'time', and zero if set to 'data'. Now they are just ignored. This
      provides a simple way to have labels only at selected intervals when
      using time or data formats. For example, you can have a date/time
      label at every 10th data point by setting the labels for the other 9
      to be empty strings. Also: Removed $which_pos values 'plotx' and
      'ploty'.  These were unused by PHPlot and this is an internal-only
      function so there is no compatibility issue. Removed error checking on
      $which_pos for the same reason; the error message used an undefined
      variable anyway so it wouldn't have worked.

2007-08-26 (lbayuk)
    * Allow SetLegendStyle colorbox_align argument to be 'none', to suppress
      the colorboxes in the legend.

      Fix comment on $legend_text_align: empty means right, not left.

      Rewrote DrawLegend layout code to make it easier to understand. The
      result should be within 1 or 2 pixels of the previous size and position.

    * Fixes for bug 1779115: SetLegendWorld() fails on undefined vars
      Store the given coordinates and remember that they need to be converted
      from world to pixel coordinates, but defer trying to actually convert
      them until it is time to draw the legend. This way, there are no
      problems with the scale having to being set up first (which is nearly
      impossible to do).  Made the following changes:

        Changed legend class variables to be uninitialized, and unset (rather
        than empty string) means use the defaults. Added a new variable:
        $legend_xy_world. If it is set, (legend_x_pos, legend_y_pos) need to
        be converted to pixel coords. If it is unset, they are already pixel
        coords (or undefined, meaning defaults).

        Changed usage of internal function DrawLegend(): removed all arguments.
        X and Y were always the class variables anyway, and now it needs to
        also use the new flag to tell it if X and Y are world or pixel coords.
        The third argument was unused.

        Removed third, unused, default NULL argument from SetLegendPixels and
        SetLegendWorld.

        Changes to DrawLegend to convert x, y coords to pixel coordinates
        if they came from SetLegendWorld. Also account for new usage of
        the class variables: Test for unset to mean use default.

2007-08-04 (lbayuk)
    * New feature: control legend text and color box alignment.
      Adds a new function SetLegendStyle to adjust the alignment of the
      text and the color boxes inside the legend.
      Based on part of bug 1208054, contributed by David Hern�ndez Sanz.

2006-12-02 (lbayuk)
    * Fixes for bug 1605555: Y Data Labels use wrong font and not formatted.
      Use y_label_font (not x_label_font) for Y Data Labels.
      Use the formatted value for the label, not the original text.
      (This applies to bar charts only, with the new Y data labels.)

    * One fix for bug 1208054: Localization of number format.
      If number formatting is enabled with 'data' format type, PHPlot previously
      used dot for decimal point and comma for thousands separator, and there
      was no way to change it.

      This fix adds a new function:
               SetNumberFormat($decimal_point, $thousands_separator)
      to set the separators.  In addition, if that function is not used,
      PHPlot will now try to use locale-dependent separators. If locale
      information is not available, it will fall back to the old defaults
      of dot and comma.

      Note: This change may have some negative effects. 1) If your locale is
      "C" or "Posix", you might not get a thousands separator now by default.
      You should be using a more specific locale. 2) If your PHP script is
      forcing a specific locale with setlocale(), PHPlot will probably undo
      that because it uses setlocale(LC_ALL, '') to import locale information
      from the environment.  We have to do that, or a locale set through
      the environment is ignored. But it will override a manually set locale.

    * Fix for bug 937944: X/Y Tick Counts
      PHPlot could draw one too few Y tick marks, and one too many X tick marks.

      Changed the code to stop drawing X (Y) tick marks when the current X (Y)
      value exceeds the maximum X (Y) value plus a small fudge factor. The fudge
      factor accounts for cumulative error when repeatedly adding a delta to
      the X (Y) value.

      Notes: The bug report was writing about Y tick counts only, but X tick
      counts can also be wrong. The proposed fix in the bug report does not
      work in all cases.

      This fix changes the appearance of many plots which were missing the
      top-most Y tick mark. The extra X-tick mark problem is less common.

===== Released as 5.0rc3 =====

2006-11-13 (lbayuk)
    * Fix for bug 1437912: x-axis label misalignment [bar charts]
      The calculations were redone from scratch.
      New control variable 'bar_extra_space', which works in addition to
      'group_frac_width' to control how much extra space is around the bars.
      Made bar widths match for 'stackedbars' and 1-bar-per-group 'bars'.

      NOTE: This changes the appearance of charts. bars in 'stackedbars'
      will now be thinner, and bars in 'bars' graphs will be thicker. I
      saw no reason for them being different before.

      This fix required fixing the positioning on the new bar data labels,
      which was off before.  The bar data labels will now be centered.
      Additional fixes to bar chart data labels:
         For negative values, the label will center under the bar.
         Fixed X-adjustment to account for shading.
         Fixed to not suppress the data label if the value is 0.


2006-11-10 (lbayuk)
    * Fix for bug 1594457: DrawError text wrap and background fix
      Do error image white background correctly, and word-wrap the text.

    * Fix for bug 1594458: Suppress lines or points in 'linepoints'
      Don't draw X data labels twice for 'linepoints'.
      Allow SetPointShapes value 'none' to suppress points, and allow
      SetLineStyles value 'none' to suppress lines. This allows a 'linepoints'
      graph to mix lines only, points only, and both on the same graph.


2006-11-09 (lbayuk)
    * Fixes for bug 1446523:
      + Wrong variable name in deprecated SetAxisFontSize()
      + Fails to properly handle error if SetDataValues() was never
        called, or not called with a data array.

    * Fix for bug 1117122: Pie Chart ignores SetPlotAreaPixels
      Don't let DrawGraph recalculate the plot area for pie charts if the
      user already set it with SetPlotAreaPixels.

      NOTE: This fix may slightly change the appearance of some pie charts,
      whether or not they use SetPlotAreaPixels.

    * Fix for bug 1103992: Wrong max Y calculated for stackedbars
      Changes FindDataLimits to calculate max Y correctly. It was counting
      the first Y value in each record twice, which is always wrong but
      only affected stackedbars because the Y values are summed.

    * Fix for bug 1096199: Wrong error bar colors in DrawDotsError.
      Rewrites DrawDotsError to make it work like DrawLinesError to
      correctly increment the record and color indexes.
      Also fixes uninitialized x_now_pixels.

    * Fix for bug 1096197: No borders on unshaded Draw[Stacked]Bars
      Unshaded Bars and StackedBars covered the border with the rectangle.
      The fix is to draw the rectangle, then the border.

      NOTE: This fix changes chart appearance. Bars and Stacked Bars
      will now get a black border around each bar by default, if you
      turn off the 3D-shading. If you want borderless, unshaded bars
      you need to use SetDataBorderColors to set the data border colors
      to be the same as the data colors.

    * Fix for bug 1333164: Negative data values, if string variables, result
      in unfilled bars. The problem was a string-to-string compare of a
      negative number with the empty string x_axis_position. Fixed by
      initializing x_axis_y_pixels to 0 if SetXAxisPosition was not used.


2005-04-17 (afan)
    * Fix for bug [ 1161072 ] SetInputFile warning, background overwrite

    * Bug 1182672 fixed

2005-04-15 (afan)
    * fix for bug: [ 1182666 ] Y Auto-scale rounds in wrong direction

    * Fix for bugs 1144644 TrueType font path problems and 1106328 TTF
      path/filename inconsistency

    * Fix Bug: [ 1117120 ] X Title sizing uses Y Title font height

2005-04-13 (afan)
    * Error in SetLineStyles() - does not accept an array argument


2005-03-29 (afan)
    * Small typo fixed in SetYDataLabelPos

    * Update SetDataLabelPos: For past compatibility we accept plotleft,
      ...but pass it to SetTickLabelPos

2005-03-26 (afan)
    * Change to line 3802: data lables now work with multiple bars with *$idx

2005-03-25 (afan)
    * Added Function DrawDataLabels to put data labels in world coords,
      added call from DrawBars and modified SetYDataLabelPos to flag
      whether or not to call DrawDataLabels.

2005-01-20 (migueldb)
    * Many bugfixes reported and solved by L. J. Bayuk. Thanks!
      + fixed bug #1096190
      + FindDataLimits(): fixed bug #1096192
      + CalcTranslation(): fixed bug #1101317
      + DrawImageBorder(): fixed bug 1096200
      + DrawXDataLabel(): fixed bug 1099879
      + DrawDots(): fixed bug #1096194

===== Released as 5.0rc2 =====

2004-10-24 (migueldb)
    * array_merge_php4(): added to cope with the bug introduced by
        the change in array_merge() from PHP4 to PHP5 (I haven't verified this)
    * Fixed some divisions by zero, thanks to an old bug report.

2004-09-09 (migueldb)
    * SetPointSize(): deprecated
    * SetPointSizes(): added as replacement for SetPointSize().
      Now able to set point sizes on a per line basis.
    * SetPointShape(): deprecated.
    * SetPointShapes(): added as replacement for SetPointShape().
      Now able to set point shape on a per line basis.
    * DrawDot(): now needs record number to decide which dot shape and
      size to draw.
    * CalcMargins(): dirty fix for x data label placing.
    * tile_img(): fixed tile placement.

2004-06-14 (migueldb)
    * SetXTickLabelPos() and others: more on the bug reported by Jo Demol.
    * Fixed bug reported by Jo Demol.

2004-05-11 (migueldb)
    * SetBgImage(): added.
    * SetPlotAreaBgImage(): added.
    * SetInputFile(): deprecated.
    * DrawBackground(): now accepts images as backgrounds.
    * DrawPlotAreaBackground(): now accepts images as backgrounds.
    * tile_img(): internal method added.

..........
Editor's Note: For older changes to PHPlot, please see the CVS logs.