Base(3) User Contributed Perl Documentation Base(3)NAMEImage::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
package Image::Base ; # Switch to this class to build on it.
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().
}
package main ; # Switch back to the default package.
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.
DESCRIPTIONnew_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.
perl v5.14.2 2000-05-26 Base(3)
