1Base(3)               User Contributed Perl Documentation              Base(3)
2
3
4

NAME

6       Image::Base - base class for loading, manipulating and saving images.
7

SYNOPSIS

9       This class should not be used directly. Known inheritors are Image::Xbm
10       and Image::Xpm.
11
12           use Image::Xpm ;
13
14           my $i = Image::Xpm->new( -file => 'test.xpm' ) ;
15           $i->line( 1, 1, 3, 7, 'red' ) ;
16           $i->ellipse( 3, 3, 6, 7, '#ff00cc' ) ;
17           $i->rectangle( 4, 2, 9, 8, 'blue' ) ;
18
19       If you want to create your own algorithms to manipulate images in terms
20       of (x,y,colour) then you could extend this class (without changing the
21       file), like this:
22
23           # Filename: mylibrary.pl
24           package Image::Base ; # Switch to this class to build on it.
25
26           sub mytransform {
27               my $self  = shift ;
28               my $class = ref( $self ) || $self ;
29
30               # Perform your transformation here; might be drawing a line or filling
31               # a rectangle or whatever... getting/setting pixels using $self->xy().
32           }
33
34           package main ; # Switch back to the default package.
35
36       Now if you "require" mylibrary.pl after you've "use"d Image::Xpm or any
37       other Image::Base inheriting classes then all these classes will
38       inherit your "mytransform()" method.
39

DESCRIPTION

41   new_from_image()
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
46       Note that the above will only work if you've installed Image::Xbm and
47       Image::Xpm, but will work correctly for any image object that inherits
48       from Image::Base and respects its API.
49
50       You can use this method to transform an image to another image of the
51       same type 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   line()
58           $i->line( $x0, $y0, $x1, $y1, $colour ) ;
59
60       Draw a line from point ($x0,$y0) to point ($x1,$y1) in colour $colour.
61
62   ellipse()
63           $i->ellipse( $x0, $y0, $x1, $y1, $colour ) ;
64
65       Draw an oval enclosed by the rectangle whose top left is ($x0,$y0) and
66       bottom right is ($x1,$y1) using a line colour of $colour.
67
68   rectangle()
69           $i->rectangle( $x0, $y0, $x1, $y1, $colour, $fill ) ;
70
71       Draw a rectangle whose top left is ($x0,$y0) and bottom right is
72       ($x1,$y1) using a line colour of $colour. If $fill is true then the
73       rectangle will be filled.
74
75   new()
76       Virtual - must be overridden.
77
78       Recommend that it at least supports "-file" (filename), "-width" and
79       "-height".
80
81   new_from_serialised()
82       Not implemented. Recommended for inheritors. Should accept a string
83       serialised using serialise() and return an object (reference).
84
85   serialise()
86       Not implemented. Recommended for inheritors. Should return a string
87       representation (ideally compressed).
88
89   get()
90           my $width = $i->get( -width ) ;
91           my( $hotx, $hoty ) = $i->get( -hotx, -hoty ) ;
92
93       Get any of the object's attributes. Multiple attributes may be
94       requested in a single call.
95
96       See "xy" get/set colours of the image itself.
97
98   set()
99       Virtual - must be overridden.
100
101       Set any of the object's attributes. Multiple attributes may be set in a
102       single call; some attributes are read-only.
103
104       See "xy" get/set colours of the image itself.
105
106   xy()
107       Virtual - must be overridden. Expected to provide the following
108       functionality:
109
110           $i->xy( 4, 11, '#123454' ) ;    # Set the colour at point 4,11
111           my $v = $i->xy( 9, 17 ) ;       # Get the colour at point 9,17
112
113       Get/set colours using x, y coordinates; coordinates start at 0.
114
115       When called to set the colour the value returned is class specific;
116       when called to get the colour the value returned is the colour name,
117       e.g. 'blue' or '#f0f0f0', etc, e.g.
118
119           $colour = xy( $x, $y ) ;  # e.g. #123456
120           xy( $x, $y, $colour ) ;   # Return value is class specific
121
122       We don't normally pick up the return value when setting the colour.
123
124   load()
125       Virtual - must be overridden. Expected to provide the following
126       functionality:
127
128           $i->load ;
129           $i->load( 'test.xpm' ) ;
130
131       Load the image whose name is given, or if none is given load the image
132       whose name is in the "-file" attribute.
133
134   save()
135       Virtual - must be overridden. Expected to provide the following
136       functionality:
137
138           $i->save ;
139           $i->save( 'test.xpm' ) ;
140
141       Save the image using the name given, or if none is given save the image
142       using the name in the "-file" attribute. The image is saved in xpm
143       format.
144

CHANGES

146       2000/05/05
147
148       Added some basic drawing methods. Minor documentation changes.
149
150       2000/05/04
151
152       Created.
153

AUTHOR

155       Mark Summerfield. I can be contacted as <summer@perlpress.com> - please
156       include the word 'imagebase' in the subject line.
157

159       Copyright (c) Mark Summerfield 2000. All Rights Reserved.
160
161       This module may be used/distributed/modified under the LGPL.
162
163
164
165perl v5.16.3                      2000-05-26                           Base(3)
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