xref: /dports/audio/audacity/audacity-Audacity-3.1.3/libraries/lib-theme/AColor.cpp

/**********************************************************************

  Audacity: A Digital Audio Editor

  AColor.cpp

  Dominic Mazzoni


********************************************************************//**

\class AColor
\brief AColor Manages color brushes and pens

It is also a place to document colour usage policy in Audacity

*//********************************************************************/

#include "AColor.h"
#include "AColorResources.h"

#include <wx/colour.h>
#include <wx/dc.h>
#include <wx/dcmemory.h>
#include <wx/graphics.h>
#include <wx/settings.h>
#include <wx/utils.h>

#include "AllThemeResources.h"
#include "Theme.h"

bool AColor::inited = false;
wxBrush AColor::lightBrush[2];
wxBrush AColor::mediumBrush[2];
wxBrush AColor::darkBrush[2];
wxPen AColor::lightPen[2];
wxPen AColor::mediumPen[2];
wxPen AColor::darkPen[2];

wxPen AColor::cursorPen;
wxBrush AColor::indicatorBrush[2];
wxPen AColor::indicatorPen[2];
// wxPen AColor::playRegionPen[2];
wxBrush AColor::playRegionBrush[1];

wxBrush AColor::muteBrush[2];
wxBrush AColor::soloBrush;

wxPen AColor::clippingPen;

wxBrush AColor::envelopeBrush;
wxPen AColor::envelopePen;
wxPen AColor::WideEnvelopePen;

wxBrush AColor::labelTextNormalBrush;
wxBrush AColor::labelTextEditBrush;
wxBrush AColor::labelUnselectedBrush;
wxBrush AColor::labelSelectedBrush;
wxBrush AColor::labelSyncLockSelBrush;
wxPen AColor::labelUnselectedPen;
wxPen AColor::labelSelectedPen;
wxPen AColor::labelSyncLockSelPen;
wxPen AColor::labelSurroundPen;
wxPen AColor::trackFocusPens[3];
wxPen AColor::snapGuidePen;

wxPen AColor::tooltipPen;
wxBrush AColor::tooltipBrush;

// The spare pen and brush possibly help us cut down on the
// number of pens and brushes we need.
wxPen AColor::sparePen;
wxBrush AColor::spareBrush;

wxPen AColor::uglyPen;
wxBrush AColor::uglyBrush;

//
// Draw an upward or downward pointing arrow.
//
void AColor::Arrow(wxDC & dc, wxCoord x, wxCoord y, int width, bool down)
{
   if (width & 0x01) {
      width--;
   }

   wxPoint pt[3];
   int half = width / 2;

   if (down) {
      pt[0].x =     0; pt[0].y = 0;
      pt[1].x = width; pt[1].y = 0;
      pt[2].x =  half; pt[2].y = half;
   }
   else {
      pt[0].x =     0; pt[0].y = half;
      pt[1].x =  half; pt[1].y = 0;
      pt[2].x = width; pt[2].y = half;
   }

   dc.DrawPolygon(3, pt, x, y);
}

//
// Draw a line, inclusive of endpoints,
// compensating for differences in wxWidgets versions across platforms
//
void AColor::Line(wxDC & dc, wxCoord x1, wxCoord y1, wxCoord x2, wxCoord y2)
{
   const wxPoint points[] { { x1, y1 }, { x2, y2 } };
   Lines( dc, 2, points );
}

// Draw lines, INCLUSIVE of all endpoints
void AColor::Lines(wxDC &dc, size_t nPoints, const wxPoint points[])
{
   if ( nPoints <= 1 ) {
      if (nPoints == 1)
         dc.DrawPoint( points[0] );
      return;
   }

   for (size_t ii = 0; ii < nPoints - 1; ++ii) {
      const auto &p1 = points[ii];
      const auto &p2 = points[ii + 1];

      // As of 2.8.9 (possibly earlier), wxDC::DrawLine() on the Mac draws the
      // last point since it is now based on the NEW wxGraphicsContext system.
      // Make the other platforms do the same thing since the other platforms
      // "may" follow they get wxGraphicsContext going.

      // PRL:  as of 3.1.1, I still observe that on Mac, the last point is
      // included, contrary to what documentation says.  Also that on Windows,
      // sometimes it is the first point that is excluded.

#if defined(__WXMAC__) || defined(__WXGTK3__)
      dc.DrawLine(p1, p2);
#else
      dc.DrawPoint(p1);
      if ( p1 != p2 ) {
         dc.DrawLine(p1, p2);
      }
#endif
   }

#if defined(__WXMAC__) || defined(__WXGTK3__)
      ;
#else
      dc.DrawPoint( points[ nPoints - 1 ] );
#endif
}

//
// Draws a focus rectangle (Taken directly from wxWidgets source)
//
void AColor::DrawFocus(wxDC & dc, wxRect & rect)
{
   // draw the pixels manually: note that to behave in the same manner as
   // DrawRect(), we must exclude the bottom and right borders from the
   // rectangle
   wxCoord x1 = rect.GetLeft(),
         y1 = rect.GetTop(),
         x2 = rect.GetRight(),
         y2 = rect.GetBottom();

   // -1 for brush, so it just sets the pen colour, and does not change the brush.
   UseThemeColour( &dc, -1, clrTrackPanelText );

   wxCoord z;
   for ( z = x1 + 1; z < x2; z += 2 )
      dc.DrawPoint(z, y1);

   wxCoord shift = z == x2 ? 0 : 1;
   for ( z = y1 + shift; z < y2; z += 2 )
      dc.DrawPoint(x2, z);

   shift = z == y2 ? 0 : 1;
   for ( z = x2 - shift; z > x1; z -= 2 )
      dc.DrawPoint(z, y2);

   shift = z == x1 ? 0 : 1;
   for ( z = y2 - shift; z > y1; z -= 2 )
      dc.DrawPoint(x1, z);

}

void AColor::Bevel(wxDC & dc, bool up, const wxRect & r)
{
   if (up)
      AColor::Light(&dc, false);
   else
      AColor::Dark(&dc, false);

   AColor::Line(dc, r.x, r.y, r.x + r.width, r.y);
   AColor::Line(dc, r.x, r.y, r.x, r.y + r.height);

   if (!up)
      AColor::Light(&dc, false);
   else
      AColor::Dark(&dc, false);

   AColor::Line(dc, r.x + r.width, r.y, r.x + r.width, r.y + r.height);
   AColor::Line(dc, r.x, r.y + r.height, r.x + r.width, r.y + r.height);
}

void AColor::Bevel2
(wxDC & dc, bool up, const wxRect & r, bool bSel, bool bHighlight)
{
   int index = 0;
   // There are eight button states in the TCP.
   // A theme might not differentiate between them all.  That's up to
   // the theme designer.
   //   Button highlighted (i.e. hovered over) or not.
   //   Track selected or not
   //   Button up or down.
   // Highlight in most themes is lighter than not highlighted.
   if ( bHighlight && bSel)
      index = up ? bmpHiliteUpButtonExpandSel : bmpHiliteButtonExpandSel;
   else if ( bHighlight )
      index = up ? bmpHiliteUpButtonExpand : bmpHiliteButtonExpand;
   else if( bSel )
      index = up ? bmpUpButtonExpandSel : bmpDownButtonExpandSel;
   else
      index = up ? bmpUpButtonExpand : bmpDownButtonExpand;

   wxBitmap & Bmp = theTheme.Bitmap( index );
   wxMemoryDC memDC;
   memDC.SelectObject(Bmp);
   int h = wxMin( r.height, Bmp.GetHeight() );


   dc.Blit( r.x,r.y,r.width/2, h, &memDC, 0, 0, wxCOPY, true );
   int r2 = r.width - r.width/2;
   dc.Blit( r.x+r.width/2,r.y,r2, h, &memDC,
      Bmp.GetWidth() - r2, 0, wxCOPY, true );
}

wxColour AColor::Blend( const wxColour & c1, const wxColour & c2 )
{
   wxColour c3(
      (c1.Red() + c2.Red())/2,
      (c1.Green() + c2.Green())/2,
      (c1.Blue() + c2.Blue())/2);
   return c3;
}

void AColor::BevelTrackInfo(wxDC & dc, bool up, const wxRect & r, bool highlight)
{
#ifndef EXPERIMENTAL_THEMING
   Bevel( dc, up, r );
#else
   // Note that the actually drawn rectangle extends one pixel right of and
   // below the given

   wxColour col;
   col = Blend( theTheme.Colour( clrTrackInfo ), up ? wxColour( 255,255,255):wxColour(0,0,0));

   wxPen pen( highlight ? uglyPen : col );
   dc.SetPen( pen );

   dc.DrawLine(r.x, r.y, r.x + r.width, r.y);
   dc.DrawLine(r.x, r.y, r.x, r.y + r.height);

   col = Blend( theTheme.Colour( clrTrackInfo ), up ? wxColour(0,0,0): wxColour(255,255,255));

   pen.SetColour( col );
   dc.SetPen( highlight ? uglyPen : pen );

   dc.DrawLine(r.x + r.width, r.y, r.x + r.width, r.y + r.height);
   dc.DrawLine(r.x, r.y + r.height, r.x + r.width, r.y + r.height);
#endif
}

// Set colour of and select brush and pen.
// Use -1 to omit brush or pen.
// If pen omitted, then the same colour as the brush will be used.
// alpha for the brush is normally 255, but if set will make a difference
// on mac (only) currently.
void AColor::UseThemeColour( wxDC * dc, int iBrush, int iPen, int alpha )
{
   if (!inited)
      Init();
   // do nothing if no colours set.
   if( (iBrush == -1) && ( iPen ==-1))
      return;
   wxColour col = wxColour(0,0,0);
   if( iBrush !=-1 ){
      col = theTheme.Colour( iBrush );
      col.Set( col.Red(), col.Green(), col.Blue(), alpha);
      spareBrush.SetColour( col );
      dc->SetBrush( spareBrush );
   }
   if( iPen != -1)
      col = theTheme.Colour( iPen );
   sparePen.SetColour( col );
   dc->SetPen( sparePen );
}

void AColor::UseThemeColour( wxGraphicsContext * gc, int iBrush, int iPen, int alpha )
{
   if (!inited)
      Init();
   // do nothing if no colours set.
   if( (iBrush == -1) && ( iPen ==-1))
      return;
   wxColour col = wxColour(0,0,0);
   if( iBrush !=-1 ){
      col = theTheme.Colour( iBrush );
      col.Set( col.Red(), col.Green(), col.Blue(), alpha);
      spareBrush.SetColour( col );
      gc->SetBrush( spareBrush );
   }
   if( iPen != -1)
      col = theTheme.Colour( iPen );
   sparePen.SetColour( col );
   gc->SetPen( sparePen );
}


void AColor::Light(wxDC * dc, bool selected, bool highlight)
{
   if (!inited)
      Init();
   int index = (int) selected;
   auto &brush = highlight ? AColor::uglyBrush : lightBrush[index];
   dc->SetBrush( brush );
   auto &pen = highlight ? AColor::uglyPen : lightPen[index];
   dc->SetPen( pen );
}

void AColor::Medium(wxDC * dc, bool selected)
{
   if (!inited)
      Init();
   int index = (int) selected;
   dc->SetBrush(mediumBrush[index]);
   dc->SetPen(mediumPen[index]);
}

void AColor::MediumTrackInfo(wxDC * dc, bool selected)
{
#ifdef EXPERIMENTAL_THEMING
   UseThemeColour( dc, selected ? clrTrackInfoSelected : clrTrackInfo );
#else
   Medium( dc, selected );
#endif
}


void AColor::Dark(wxDC * dc, bool selected, bool highlight)
{
   if (!inited)
      Init();
   int index = (int) selected;
   auto &brush = highlight ? AColor::uglyBrush : darkBrush[index];
   dc->SetBrush( brush );
   auto &pen = highlight ? AColor::uglyPen : darkPen[index];
   dc->SetPen( pen );
}

void AColor::TrackPanelBackground(wxDC * dc, bool selected)
{
#ifdef EXPERIMENTAL_THEMING
   UseThemeColour( dc, selected ? clrMediumSelected : clrTrackBackground );
#else
   Dark( dc, selected );
#endif
}

void AColor::CursorColor(wxDC * dc)
{
   if (!inited)
      Init();

   dc->SetLogicalFunction(wxCOPY);
   dc->SetPen(cursorPen);
}

void AColor::IndicatorColor(wxDC * dc, bool bIsNotRecording)
{
   if (!inited)
      Init();
   int index = (int) bIsNotRecording;
   dc->SetPen(indicatorPen[index]);
   dc->SetBrush(indicatorBrush[index]);
}

void AColor::TrackFocusPen(wxDC * dc, int level)
{
   if (!inited)
      Init();
   dc->SetPen(trackFocusPens[level]);
}

void AColor::SnapGuidePen(wxDC * dc)
{
   if (!inited)
      Init();
   dc->SetPen(snapGuidePen);
}

void AColor::Mute(wxDC * dc, bool on, bool selected, bool soloing)
{
   if (!inited)
      Init();
   int index = (int) selected;
   if (on) {
      dc->SetPen(*wxBLACK_PEN);
      dc->SetBrush(muteBrush[(int) soloing]);
   }
   else {
      dc->SetPen(*wxTRANSPARENT_PEN);
      dc->SetBrush(mediumBrush[index]);
   }
}

void AColor::Solo(wxDC * dc, bool on, bool selected)
{
   if (!inited)
      Init();
   int index = (int) selected;
   if (on) {
      dc->SetPen(*wxBLACK_PEN);
      dc->SetBrush(soloBrush);
   }
   else {
      dc->SetPen(*wxTRANSPARENT_PEN);
      dc->SetBrush(mediumBrush[index]);
   }
}

bool AColor::gradient_inited = 0;

void AColor::ReInit()
{
   inited=false;
   Init();
   gradient_inited=0;
   PreComputeGradient();
}

wxColour InvertOfColour( const wxColour & c )
{
   return wxColour( 255-c.Red(), 255-c.Green(), 255-c.Blue() );
}

// Fix up the cursor colour, if it is 'unacceptable'.
// Unacceptable if it is too close to the background colour.
wxColour CursorColour( )
{
   wxColour cCursor = theTheme.Colour( clrCursorPen );
   wxColour cBack = theTheme.Colour( clrMedium );

   int d = theTheme.ColourDistance( cCursor, cBack );

   // Pen colour is fine, if there is plenty of contrast.
   if( d  > 200 )
      return theTheme.Colour( clrCursorPen );

   // otherwise return same colour as a selection.
   return theTheme.Colour( clrSelected );
}

void AColor::Init()
{
   if (inited)
      return;

   wxColour light = theTheme.Colour( clrLight );
   // wxSystemSettings::GetColour(wxSYS_COLOUR_3DHIGHLIGHT);
   wxColour med = theTheme.Colour( clrMedium );
   // wxSystemSettings::GetColour(wxSYS_COLOUR_3DFACE);
   wxColour dark = theTheme.Colour( clrDark );
   // wxSystemSettings::GetColour(wxSYS_COLOUR_3DSHADOW);

   wxColour lightSelected = theTheme.Colour( clrLightSelected );
   wxColour medSelected = theTheme.Colour( clrMediumSelected );
   wxColour darkSelected = theTheme.Colour( clrDarkSelected );


   clippingPen.SetColour(0xCC, 0x11, 0x00);

   theTheme.SetPenColour(   envelopePen,     clrEnvelope );
   theTheme.SetPenColour(   WideEnvelopePen, clrEnvelope );
   theTheme.SetBrushColour( envelopeBrush,   clrEnvelope );

   WideEnvelopePen.SetWidth( 3 );

   theTheme.SetBrushColour( labelTextNormalBrush,  clrLabelTextNormalBrush );
   theTheme.SetBrushColour( labelTextEditBrush,    clrLabelTextEditBrush );
   theTheme.SetBrushColour( labelUnselectedBrush,  clrLabelUnselectedBrush );
   theTheme.SetBrushColour( labelSelectedBrush,    clrLabelSelectedBrush );
   theTheme.SetBrushColour( labelSyncLockSelBrush, clrSyncLockSel );
   theTheme.SetPenColour( labelUnselectedPen,   clrLabelUnselectedPen );
   theTheme.SetPenColour( labelSelectedPen,     clrLabelSelectedPen );
   theTheme.SetPenColour( labelSyncLockSelPen,  clrSyncLockSel );
   theTheme.SetPenColour( labelSurroundPen,     clrLabelSurroundPen );

   // These colors were modified to avoid using reserved colors red and green
   // for the buttons.
   theTheme.SetBrushColour( muteBrush[0],      clrMuteButtonActive);
   theTheme.SetBrushColour( muteBrush[1],      clrMuteButtonVetoed);
   theTheme.SetBrushColour( soloBrush,         clrMuteButtonActive);

   cursorPen.SetColour( CursorColour()  );
   theTheme.SetPenColour(   indicatorPen[0],   clrRecordingPen);
   theTheme.SetPenColour(   indicatorPen[1],   clrPlaybackPen);
   theTheme.SetBrushColour( indicatorBrush[0], clrRecordingBrush);
   theTheme.SetBrushColour( indicatorBrush[1], clrPlaybackBrush);

   theTheme.SetBrushColour( playRegionBrush[0],clrRulerRecordingBrush);
   // theTheme.SetPenColour(   playRegionPen[0],  clrRulerRecordingPen);
   // theTheme.SetBrushColour( playRegionBrush[1],clrRulerPlaybackBrush);
   // theTheme.SetPenColour(   playRegionPen[1],  clrRulerPlaybackPen);

   //Determine tooltip color
   tooltipPen.SetColour( wxSystemSettingsNative::GetColour(wxSYS_COLOUR_INFOTEXT) );
   tooltipBrush.SetColour( wxSystemSettingsNative::GetColour(wxSYS_COLOUR_INFOBK) );

   uglyPen.SetColour( wxColour{ 0, 255, 0 } ); // saturated green
   uglyBrush.SetColour( wxColour{ 255, 0, 255 } ); // saturated magenta

   // A tiny gradient of yellow surrounding the current focused track
   theTheme.SetPenColour(   trackFocusPens[0],  clrTrackFocus0);
   theTheme.SetPenColour(   trackFocusPens[1],  clrTrackFocus1);
   theTheme.SetPenColour(   trackFocusPens[2],  clrTrackFocus2);

   // A vertical line indicating that the selection or sliding has
   // been snapped to the nearest boundary.
   theTheme.SetPenColour(   snapGuidePen,      clrSnapGuide);

   // unselected
   lightBrush[0].SetColour(light);
   mediumBrush[0].SetColour(med);
   darkBrush[0].SetColour(dark);
   lightPen[0].SetColour(light);
   mediumPen[0].SetColour(med);
   darkPen[0].SetColour(dark);

   // selected
   lightBrush[1].SetColour(lightSelected);
   mediumBrush[1].SetColour(medSelected);
   darkBrush[1].SetColour(darkSelected);
   lightPen[1].SetColour(lightSelected);
   mediumPen[1].SetColour(medSelected);
   darkPen[1].SetColour(darkSelected);

   inited = true;
}

// These colours are chosen so that black text shows up OK on them.
const int AColor_midicolors[16][3] = {
   {255, 102, 102},             // 1=salmon
   {204, 0, 0},                 // 2=red
   {255, 117, 23},              // 3=orange
   {255, 255, 0},               // 4=yellow
   {0, 204, 0},                 // 5=green
   {0, 204, 204},               // 6=turquoise
   {125, 125, 255},             // 7=blue
   {153, 0, 255},               // 8=blue-violet

   {140, 97, 54},               // 9=brown
   {120, 120, 120},             // 10=gray (drums)
   {255, 175, 40},              // 11=lt orange
   {102, 255, 102},             // 12=lt green
   {153, 255, 255},             // 13=lt turquoise
   {190, 190, 255},             // 14=lt blue
   {204, 102, 255},             // 15=lt blue-violet
   {255, 51, 204}               // 16=lt red-violet
};

void AColor::MIDIChannel(wxDC * dc, int channel /* 1 - 16 */ )
{
   if (channel >= 1 && channel <= 16) {
      const int *colors = AColor_midicolors[channel - 1];

      dc->SetPen(wxPen(wxColour(colors[0],
                                colors[1], colors[2]), 1, wxPENSTYLE_SOLID));
      dc->SetBrush(wxBrush(wxColour(colors[0],
                                    colors[1], colors[2]), wxBRUSHSTYLE_SOLID));
   } else {
      dc->SetPen(wxPen(wxColour(153, 153, 153), 1, wxPENSTYLE_SOLID));
      dc->SetBrush(wxBrush(wxColour(153, 153, 153), wxBRUSHSTYLE_SOLID));
   }

}

void AColor::LightMIDIChannel(wxDC * dc, int channel /* 1 - 16 */ )
{
   if (channel >= 1 && channel <= 16) {
      const int *colors = AColor_midicolors[channel - 1];

      dc->SetPen(wxPen(wxColour(127 + colors[0] / 2,
                                127 + colors[1] / 2,
                                127 + colors[2] / 2), 1, wxPENSTYLE_SOLID));
      dc->SetBrush(wxBrush(wxColour(127 + colors[0] / 2,
                                    127 + colors[1] / 2,
                                    127 + colors[2] / 2), wxBRUSHSTYLE_SOLID));
   } else {
      dc->SetPen(wxPen(wxColour(204, 204, 204), 1, wxPENSTYLE_SOLID));
      dc->SetBrush(wxBrush(wxColour(204, 204, 204), wxBRUSHSTYLE_SOLID));
   }

}

void AColor::DarkMIDIChannel(wxDC * dc, int channel /* 1 - 16 */ )
{
   if (channel >= 1 && channel <= 16) {
      const int *colors = AColor_midicolors[channel - 1];

      dc->SetPen(wxPen(wxColour(colors[0] / 2,
                                colors[1] / 2,
                                colors[2] / 2), 1, wxPENSTYLE_SOLID));
      dc->SetBrush(wxBrush(wxColour(colors[0] / 2,
                                    colors[1] / 2,
                                    colors[2] / 2), wxBRUSHSTYLE_SOLID));
   } else {
      dc->SetPen(wxPen(wxColour(102, 102, 102), 1, wxPENSTYLE_SOLID));
      dc->SetBrush(wxBrush(wxColour(102, 102, 102), wxBRUSHSTYLE_SOLID));
   }

}



unsigned char AColor::gradient_pre[ColorGradientTotal][colorSchemes][gradientSteps][3];

void AColor::PreComputeGradient() {
   if (gradient_inited) return;
   gradient_inited = 1;

   // Keep in correspondence with enum SpectrogramSettings::ColorScheme

   // colorScheme 0: Color (New)
   std::copy_n(&specColormap[0][0], gradientSteps * 3, &gradient_pre[ColorGradientUnselected][0][0][0]);
   std::copy_n(&selColormap[0][0], gradientSteps * 3, &gradient_pre[ColorGradientTimeSelected][0][0][0]);
   std::copy_n(&freqSelColormap[0][0], gradientSteps * 3, &gradient_pre[ColorGradientTimeAndFrequencySelected][0][0][0]);
   std::fill_n(&gradient_pre[ColorGradientEdge][0][0][0], gradientSteps * 3, 0);


   for (int selected = 0; selected < ColorGradientTotal; selected++) {
      // Get color scheme from Theme
      const int gsteps = 4;
      float gradient[gsteps + 1][3];
      theTheme.Colour( clrSpectro1 ) = theTheme.Colour( clrUnselected );
      theTheme.Colour( clrSpectro1Sel ) = theTheme.Colour( clrSelected );
      int clrFirst = (selected == ColorGradientUnselected ) ? clrSpectro1 : clrSpectro1Sel;
      for(int j=0;j<(gsteps+1);j++){
         wxColour c = theTheme.Colour( clrFirst+j );
         gradient[ j] [0] = c.Red()/255.0;
         gradient[ j] [1] = c.Green()/255.0;
         gradient[ j] [2] = c.Blue()/255.0;
      }

      // colorScheme 1: Color (from theme)
      for (int i = 0; i<gradientSteps; i++) {
         float r, g, b;
         float value = float(i)/gradientSteps;

         int left = (int)(value * gsteps);
         int right = (left == gsteps ? gsteps : left + 1);

         float rweight = (value * gsteps) - left;
         float lweight = 1.0 - rweight;

         r = (gradient[left][0] * lweight) + (gradient[right][0] * rweight);
         g = (gradient[left][1] * lweight) + (gradient[right][1] * rweight);
         b = (gradient[left][2] * lweight) + (gradient[right][2] * rweight);

         switch (selected) {
         case ColorGradientUnselected:
            // not dimmed
            break;

         case ColorGradientTimeAndFrequencySelected:
            float temp;
            temp = r;
            r = g;
            g = b;
            b = temp;
            break;

         case ColorGradientTimeSelected:
            // partly dimmed
            r *= 0.75f;
            g *= 0.75f;
            b *= 0.75f;
            break;


         // For now edge colour is just black (or white if grey-scale)
         // Later we might invert or something else funky.
         case ColorGradientEdge:
            // fully dimmed
            r = 0;
            g = 0;
            b = 0;
            break;
         }
         gradient_pre[selected][1][i][0] = (unsigned char) (255 * r);
         gradient_pre[selected][1][i][1] = (unsigned char) (255 * g);
         gradient_pre[selected][1][i][2] = (unsigned char) (255 * b);
      }

      // colorScheme 3: Inverse Grayscale
      for (int i = 0; i < gradientSteps; i++) {
         float r, g, b;
         float value = float(i) / gradientSteps;

         r = g = b = value;

         switch (selected) {
         case ColorGradientUnselected:
            // not dimmed
            break;

         case ColorGradientTimeAndFrequencySelected:
            // else fall through to SAME grayscale colour as normal selection.
            // The white lines show it up clearly enough.

         case ColorGradientTimeSelected:
            // partly dimmed
            r = r * 0.75f + 0.25f;
            g = g * 0.75f + 0.25f;
            b = b * 0.75f + 0.25f;
            break;

         case ColorGradientEdge:
            r = 1.0f;
            g = 1.0f;
            b = 1.0f;
            break;
         }
         gradient_pre[selected][3][i][0] = (unsigned char)(255 * r);
         gradient_pre[selected][3][i][1] = (unsigned char)(255 * g);
         gradient_pre[selected][3][i][2] = (unsigned char)(255 * b);
      }

      // colorScheme 2: Grayscale (=Old grayscale)
      for (int i = 0; i<gradientSteps; i++) {
         float r, g, b;
         float value = float(i)/gradientSteps;

         r = g = b = 0.84 - 0.84 * value;

         switch (selected) {
         case ColorGradientUnselected:
            // not dimmed
            break;

         case ColorGradientTimeAndFrequencySelected:
            // else fall through to SAME grayscale colour as normal selection.
            // The white lines show it up clearly enough.

         case ColorGradientTimeSelected:
            // partly dimmed
            r *= 0.75f;
            g *= 0.75f;
            b *= 0.75f;
            break;


         // For now edge colour is just black (or white if grey-scale)
         // Later we might invert or something else funky.
         case ColorGradientEdge:
            // fully dimmed
            r = 1.0f;
            g = 1.0f;
            b = 1.0f;
            break;
         }
         gradient_pre[selected][2][i][0] = (unsigned char) (255 * r);
         gradient_pre[selected][2][i][1] = (unsigned char) (255 * g);
         gradient_pre[selected][2][i][2] = (unsigned char) (255 * b);
      }
   }
}