NAME
Image::Base - base class for loading, manipulating and saving images.
SYNOPSIS
This class should not be used directly. Known inheritors are Image::Xbm and Image::Xpm.
use
Image::Xpm ;
my
$i
= Image::Xpm->new(
-file
=>
'test.xpm'
) ;
$i
->line( 1, 1, 3, 7,
'red'
) ;
$i
->ellipse( 3, 3, 6, 7,
'#ff00cc'
) ;
$i
->rectangle( 4, 2, 9, 8,
'blue'
) ;
If you want to create your own algorithms to manipulate images in terms of (x,y,colour) then you could extend this class (without changing the file), like this:
# Filename: mylibrary.pl
sub
mytransform {
my
$self
=
shift
;
my
$class
=
ref
(
$self
) ||
$self
;
# Perform your transformation here; might be drawing a line or filling
# a rectangle or whatever... getting/setting pixels using $self->xy().
}
Now if you require
mylibrary.pl after you've use
d Image::Xpm or any other Image::Base inheriting classes then all these classes will inherit your mytransform()
method.
DESCRIPTION
new_from_image()
my
$bitmap
= Image::Xbm->new(
-file
=>
'bitmap.xbm'
) ;
my
$pixmap
=
$bitmap
->new_from_image(
'Image::Xpm'
,
-cpp
=> 1 ) ;
$pixmap
->save(
'pixmap.xpm'
) ;
Note that the above will only work if you've installed Image::Xbm and Image::Xpm, but will work correctly for any image object that inherits from Image::Base and respects its API.
You can use this method to transform an image to another image of the same type but with some different characteristics, e.g.
my
$p
= Image::Xpm->new(
-file
=>
'test1.xpm'
) ;
my
$q
=
$p
->new_from_image(
ref
$p
,
-cpp
=> 2,
-file
=>
'test2.xpm'
) ;
$q
->save ;
line()
$i
->line(
$x0
,
$y0
,
$x1
,
$y1
,
$colour
) ;
Draw a line from point ($x0,$y0) to point ($x1,$y1) in colour $colour.
ellipse()
$i
->ellipse(
$x0
,
$y0
,
$x1
,
$y1
,
$colour
) ;
Draw an oval enclosed by the rectangle whose top left is ($x0,$y0) and bottom right is ($x1,$y1) using a line colour of $colour.
rectangle()
$i
->rectangle(
$x0
,
$y0
,
$x1
,
$y1
,
$colour
,
$fill
) ;
Draw a rectangle whose top left is ($x0,$y0) and bottom right is ($x1,$y1) using a line colour of $colour. If $fill
is true then the rectangle will be filled.
new()
Virtual - must be overridden.
Recommend that it at least supports -file
(filename), -width
and -height
.
new_from_serialised()
Not implemented. Recommended for inheritors. Should accept a string serialised using serialise() and return an object (reference).
serialise()
Not implemented. Recommended for inheritors. Should return a string representation (ideally compressed).
get()
my
$width
=
$i
->get( -width ) ;
my
(
$hotx
,
$hoty
) =
$i
->get( -hotx, -hoty ) ;
Get any of the object's attributes. Multiple attributes may be requested in a single call.
See xy
get/set colours of the image itself.
set()
Virtual - must be overridden.
Set any of the object's attributes. Multiple attributes may be set in a single call; some attributes are read-only.
See xy
get/set colours of the image itself.
xy()
Virtual - must be overridden. Expected to provide the following functionality:
$i
->xy( 4, 11,
'#123454'
) ; # Set the colour at point 4,11
my
$v
=
$i
->xy( 9, 17 ) ;
# Get the colour at point 9,17
Get/set colours using x, y coordinates; coordinates start at 0.
When called to set the colour the value returned is class specific; when called to get the colour the value returned is the colour name, e.g. 'blue' or '#f0f0f0', etc, e.g.
$colour
= xy(
$x
,
$y
) ;
# e.g. #123456
xy(
$x
,
$y
,
$colour
) ;
# Return value is class specific
We don't normally pick up the return value when setting the colour.
load()
Virtual - must be overridden. Expected to provide the following functionality:
$i
->load ;
$i
->load(
'test.xpm'
) ;
Load the image whose name is given, or if none is given load the image whose name is in the -file
attribute.
save()
Virtual - must be overridden. Expected to provide the following functionality:
$i
->save ;
$i
->save(
'test.xpm'
) ;
Save the image using the name given, or if none is given save the image using the name in the -file
attribute. The image is saved in xpm format.
CHANGES
2000/05/05
Added some basic drawing methods. Minor documentation changes.
2000/05/04
Created.
AUTHOR
Mark Summerfield. I can be contacted as <summer@perlpress.com> - please include the word 'imagebase' in the subject line.
COPYRIGHT
Copyright (c) Mark Summerfield 2000. All Rights Reserved.
This module may be used/distributed/modified under the LGPL.