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- add samples/replace_color.pl

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1 parent f323a43 commit 1611d10167d61b427a12ce6ea15eafe5e1481160 Tony Cook committed Oct 10, 2005
Showing with 126 additions and 0 deletions.
  1. +1 −0 Changes
  2. +2 −0 MANIFEST
  3. +2 −0 TODO
  4. +8 −0 samples/README
  5. +113 −0 samples/replace_color.pl
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@@ -1147,6 +1147,7 @@ Revision history for Perl extension Imager.
generated by i_tt_new().
- renamed lib/Imager/Cookbook.pm to lib/Imager/Cookbook.pod - CPANTS
complains about it not having 'use strict;'
+- add samples/replace_color.pl
=================================================================
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@@ -87,6 +87,7 @@ lib/Imager/Transformations.pod
lib/Imager/Tutorial.pod
lib/Imager/interface.pod
lib/Imager/regmach.pod
+limits.c
log.c
log.h
map.c
@@ -107,6 +108,7 @@ rotate.c
samples/README
samples/anaglyph.pl
samples/interleave.pl
+samples/replace_color.pl
samples/samp-form.cgi
samples/samp-image.cgi
samples/samp-scale.cgi Demonstrate image upload via a HTML form
View
2 TODO
@@ -35,6 +35,8 @@ not commitments.
it doesn't need to cover everything - read/write/create/simple drawing
and simple text - other stuff belongs in the cookbook or in sample code
+- rename lib/Imager/Cookbook.pm to lib/Imager/Cookbook.pod (done)
+
- add 5 more recipes to Imager::Cookbook
- implement i_incomplete for png and gif files.
View
@@ -12,6 +12,13 @@ anaglyph.pl
Uses transform2() and convert().
+replace_color.pl
+
+ Example using Imager::transform2() to replace one color with another
+ in an image.
+
+ http://www.perlmonks.org/?node_id=497355
+
interleave.pl
Produce an interleaved image given the left and right images of a
@@ -50,3 +57,4 @@ samp-tags.cgi
See the section "Parsing an image posted via CGI" in Imager::Cookbook
for cautions and details on reading uploaded images.
+
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@@ -0,0 +1,113 @@
+#!perl -w
+use strict;
+use Imager;
+
+=head1 NAME
+
+replace_color - replace one color with another in an image
+
+=head1 SYNOPSIS
+
+ perl replace_color fromcolor tocolor inimage outimage
+
+=head1 DESCRIPTION
+
+This is a simple demonstration of Imager::transform2 that replaces one
+color with another in an image.
+
+Note: this works with full color images, and always produces a 3
+channel output image - the alpha channel (if any) is not preserved.
+
+Most of the work is done in the replace_color() function.
+
+=over
+
+=cut
+
+# extract parameters
+my $from = shift;
+
+my $to = shift;
+
+my $in = shift;
+
+my $out = shift
+ or die "Usage: $0 fromcolor tocolor inimage outimage\n";
+
+# convert the colors into objects
+my $from_color = Imager::Color->new($from)
+ or die "Cannot convert fromcolor $from into a color: ", Imager->errstr, "\n";
+
+my $to_color = Imager::Color->new($to)
+ or die "Cannot convert tocolor $to into a color: ", Imager->errstr, "\n";
+
+# do the work
+my $img = Imager->new;
+$img->read(file=>$in)
+ or die "Cannot read image $in: ", $img->errstr, "\n";
+
+my $result = replace_color($img, $from_color, $to_color)
+ or die "Cannot replace colors: ", Imager->errstr, "\n";
+
+$result->write(file=>$out)
+ or die "Cannot write image $out: ", $result->errstr, "\n";
+
+=item replace_color
+
+Called:
+
+ my $result = replace_color($in_image, $from_color, $to_color);
+
+Returns a new image object with colors replaced.
+
+=cut
+
+sub replace_color {
+ my ($img, $from_color, $to_color) = @_;
+
+ my ($from_red, $from_green, $from_blue) = $from_color->rgba;
+ my ($to_red, $to_green, $to_blue) = $to_color->rgba;
+ my $rpnexpr = <<'EOS';
+# get the pixel
+x y getp1 !pix
+# check against the from_color
+@pix red from_red eq
+@pix green from_green eq
+@pix blue from_blue eq
+and and
+# pick a result
+to_red to_green to_blue rgb @pix ifp
+EOS
+ # rpnexpr doesn't really support comments - remove them
+ $rpnexpr =~ s/^#.*\n//mg;
+ my %constants =
+ (
+ from_red => $from_red,
+ from_green => $from_green,
+ from_blue => $from_blue,
+ to_red => $to_red,
+ to_green => $to_green,
+ to_blue => $to_blue,
+ );
+ return Imager::transform2({ rpnexpr => $rpnexpr,
+ constants => \%constants },
+ $img);
+}
+
+__END__
+
+=back
+
+=head1 REVISION
+
+$Revision$
+
+=head1 AUTHOR
+
+Tony Cook <tony@develop-help.com>
+
+=head1 SEE ALSO
+
+Imager, Imager::Engines, Imager::Color, Imager::Files
+
+=cut

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