1=head1 NAME
2
3Image::Base - base class for loading, manipulating and saving images.
4
5=head1 SYNOPSIS
6
7This class should not be used directly. Known inheritors are Image::Xbm and
8Image::Xpm.
9
10 use Image::Xpm ;
11
12 my $i = Image::Xpm->new( -file => 'test.xpm' ) ;
13 $i->line( 1, 1, 3, 7, 'red' ) ;
14 $i->ellipse( 3, 3, 6, 7, '#ff00cc' ) ;
15 $i->rectangle( 4, 2, 9, 8, 'blue' ) ;
16
17If you want to create your own algorithms to manipulate images in terms of
18(x,y,colour) then you could extend this class (without changing the file),
19like this:
20
21 # Filename: mylibrary.pl
22 package Image::Base ; # Switch to this class to build on it.
23
24 sub mytransform {
25 my $self = shift ;
26 my $class = ref( $self ) || $self ;
27
28 # Perform your transformation here; might be drawing a line or filling
29 # a rectangle or whatever... getting/setting pixels using $self->xy().
30 }
31
32 package main ; # Switch back to the default package.
33
34Now if you C<require> mylibrary.pl after you've C<use>d Image::Xpm or any
35other Image::Base inheriting classes then all these classes will inherit your
36C<mytransform()> method.
37
38=head1 DESCRIPTION
39
40=head2 new_from_image()
41
42 my $bitmap = Image::Xbm->new( -file => 'bitmap.xbm' ) ;
43 my $pixmap = $bitmap->new_from_image( 'Image::Xpm', -cpp => 1 ) ;
44 $pixmap->save( 'pixmap.xpm' ) ;
45
46Note that the above will only work if you've installed Image::Xbm and
47Image::Xpm, but will work correctly for any image object that inherits from
48Image::Base and respects its API.
49
50You can use this method to transform an image to another image of the same
51type but with some different characteristics, e.g.
52
53 my $p = Image::Xpm->new( -file => 'test1.xpm' ) ;
54 my $q = $p->new_from_image( ref $p, -cpp => 2, -file => 'test2.xpm' ) ;
55 $q->save ;
56
57=head2 line()
58
59 $i->line( $x0, $y0, $x1, $y1, $colour ) ;
60
61Draw a line from point ($x0,$y0) to point ($x1,$y1) in colour $colour.
62
63=head2 ellipse()
64
65 $i->ellipse( $x0, $y0, $x1, $y1, $colour ) ;
66
67Draw an oval enclosed by the rectangle whose top left is ($x0,$y0) and bottom
68right is ($x1,$y1) using a line colour of $colour.
69
70=head2 rectangle()
71
72 $i->rectangle( $x0, $y0, $x1, $y1, $colour, $fill ) ;
73
74Draw a rectangle whose top left is ($x0,$y0) and bottom right is ($x1,$y1)
75using a line colour of $colour. If C<$fill> is true then the rectangle will be
76filled.
77
78=head2 new()
79
80Virtual - must be overridden.
81
82Recommend that it at least supports C<-file> (filename), C<-width> and
83C<-height>.
84
85=head2 new_from_serialised()
86
87Not implemented. Recommended for inheritors. Should accept a string serialised
88using serialise() and return an object (reference).
89
90=head2 serialise()
91
92Not implemented. Recommended for inheritors. Should return a string
93representation (ideally compressed).
94
95=head2 get()
96
97 my $width = $i->get( -width ) ;
98 my( $hotx, $hoty ) = $i->get( -hotx, -hoty ) ;
99
100Get any of the object's attributes. Multiple attributes may be requested in a
101single call.
102
103See C<xy> get/set colours of the image itself.
104
105=head2 set()
106
107Virtual - must be overridden.
108
109Set any of the object's attributes. Multiple attributes may be set in a single
110call; some attributes are read-only.
111
112See C<xy> get/set colours of the image itself.
113
114=head2 xy()
115
116Virtual - must be overridden. Expected to provide the following functionality:
117
118 $i->xy( 4, 11, '#123454' ) ; # Set the colour at point 4,11
119 my $v = $i->xy( 9, 17 ) ; # Get the colour at point 9,17
120
121Get/set colours using x, y coordinates; coordinates start at 0.
122
123When called to set the colour the value returned is class specific; when
124called to get the colour the value returned is the colour name, e.g. 'blue' or
125'#f0f0f0', etc, e.g.
126
127 $colour = xy( $x, $y ) ; # e.g. #123456
128 xy( $x, $y, $colour ) ; # Return value is class specific
129
130We don't normally pick up the return value when setting the colour.
131
132=head2 load()
133
134Virtual - must be overridden. Expected to provide the following functionality:
135
136 $i->load ;
137 $i->load( 'test.xpm' ) ;
138
139Load the image whose name is given, or if none is given load the image whose
140name is in the C<-file> attribute.
141
142=head2 save()
143
144Virtual - must be overridden. Expected to provide the following functionality:
145
146 $i->save ;
147 $i->save( 'test.xpm' ) ;
148
149Save the image using the name given, or if none is given save the image using
150the name in the C<-file> attribute. The image is saved in xpm format.
151
152=head1 CHANGES
153
1542000/05/05
155
156Added some basic drawing methods. Minor documentation changes.
157
158
1592000/05/04
160
161Created.
162
163
164=head1 AUTHOR
165
166Mark Summerfield. I can be contacted as <summer@perlpress.com> -
167please include the word 'imagebase' in the subject line.
168
169=head1 COPYRIGHT
170
171Copyright (c) Mark Summerfield 2000. All Rights Reserved.
172
173This module may be used/distributed/modified under the LGPL.
174
175=cut
176
177