add png_compression_level parameter for writing PNG files

diff --git a/PNG/PNG.pm b/PNG/PNG.pm
index 954e964179202cd3d28cb453d8328ad7e9b52af0..f145d0ee4d87d67b462c73841c69096954645905 100644 (file)
--- a/PNG/PNG.pm
+++ b/PNG/PNG.pm
@@ -4,7 +4,7 @@ use Imager;
 use vars qw($VERSION @ISA);
 
 BEGIN {
-  $VERSION = "0.92";
+  $VERSION = "0.93";
 
   require XSLoader;
   XSLoader::load('Imager::File::PNG', $VERSION);

diff --git a/PNG/impng.c b/PNG/impng.c
index ac3f9fe1d61f29962cd8b1a7ebf0fb4d9b847dd2..c7a7b8e4ce68aafe1b34fc0e1df0dddd07369a66 100644 (file)
--- a/PNG/impng.c
+++ b/PNG/impng.c
@@ -2,6 +2,7 @@
 #include "png.h"
 #include <stdlib.h>
 #include <string.h>
+#include <zlib.h>
 
 /* this is a way to get number of channels from color space 
  * Color code to channel number */
@@ -1137,6 +1138,19 @@ set_png_tags(i_img *im, png_structp png_ptr, png_infop info_ptr) {
     }
   }
 
+  {
+    int level;
+    if (i_tags_get_int(&im->tags, "png_compression_level", 0, &level)) {
+      if (level >= Z_NO_COMPRESSION && level <= Z_BEST_COMPRESSION) 
+       png_set_compression_level(png_ptr, level);
+      else {
+       i_push_errorf(0, "png_compression_level must be between %d and %d",
+                     Z_NO_COMPRESSION, Z_BEST_COMPRESSION);
+       return 0;
+      }
+    }
+  }
+
   {
     /* no bKGD support yet, maybe later
        it may be simpler to do it in the individual writers

diff --git a/PNG/t/10png.t b/PNG/t/10png.t
index b1915075039cff26106e52c99393ca499853ed4e..2892a56d0251910d96e26dfce36d378bedb6b1b4 100644 (file)
--- a/PNG/t/10png.t
+++ b/PNG/t/10png.t
@@ -10,7 +10,7 @@ my $debug_writes = 1;
 
 init_log("testout/t102png.log",1);
 
-plan tests => 251;
+plan tests => 256;
 
 # this loads Imager::File::PNG too
 ok($Imager::formats{"png"}, "must have png format");
@@ -799,6 +799,23 @@ SKIP:
   }
 }
 
+{
+  # png_compression_level
+  my $im = test_image();
+  my $out1;
+  ok($im->write(data => \$out1, type => "png"), "write default compression");
+  my $out2;
+  ok($im->write(data => \$out2, type => "png", png_compression_level => 9),
+     "write best compression");
+  cmp_ok(length($out1), '>', length($out2), "best compression smaller than default");
+  note "went from ", length($out1), " to ", length($out2);
+  # error handling
+  ok(!$im->write(data => \$out1, type => "png", png_compression_level => -1),
+     "fail with compression level -1");
+  ok(!$im->write(data => \$out1, type => "png", png_compression_level => 10),
+     "fail with compression level 10");
+}
+
 sub limited_write {
   my ($limit) = @_;
 

diff --git a/lib/Imager/Files.pod b/lib/Imager/Files.pod
index 0c3c16d289697fd93f5e9ff2c3c7882d3a671ae5..e19a68f51ea29861187383afa1d2651e80ddf791 100644 (file)
--- a/lib/Imager/Files.pod
+++ b/lib/Imager/Files.pod
@@ -1449,7 +1449,7 @@ C<adam7>.
 X<tags, png_srgb_intent>C<png_srgb_intent> - the sRGB rendering intent
 for the image. an integer from 0 to 3, per the PNG specification.  If
 this chunk is found in the PNG file the C<gAMA> and C<cHRM> are
-ignored and the C<png_gamme> and C<png_chroma_...> tags are not set.
+ignored and the C<png_gamma> and C<png_chroma_...> tags are not set.
 Similarly when writing if C<png_srgb_intent> is set the C<gAMA> and
 C<cHRM> chunks are not written.
 
@@ -1492,6 +1492,11 @@ C<i_background> - set from the C<sBKG> when reading an image file.
 
 =back
 
+X<compression>X<png_compression_level>You can control the level of
+F<zlib> compression used when writing with the
+C<png_compression_level> parameter.  This can be an integer between 0
+(uncompressed) and 9 (best compression).
+
 =for stopwords
 CRC