From 59575fa5c228308a41d7f5028390be2083aaaf6d Mon Sep 17 00:00:00 2001
From: glennrp <glennrp@git.imagemagick.org>
Date: Sat, 31 Dec 2011 21:31:39 +0000
Subject: [PATCH] Fix "-quality" handling in the JNG encoder.

---
 coders/png.c | 57 ++++++++++++++++++++++++++++++++++------------------
 1 file changed, 37 insertions(+), 20 deletions(-)

diff --git a/coders/png.c b/coders/png.c
index 650acb345..e9938612a 100644
--- a/coders/png.c
+++ b/coders/png.c
@@ -11625,6 +11625,7 @@ static MagickBooleanType WriteOneJNGImage(MngInfo *mng_info,
     transparent;
 
   size_t
+    jng_alpha_quality,
     jng_quality;
 
   logging=LogMagickEvent(CoderEvent,GetMagickModule(),
@@ -11636,19 +11637,17 @@ static MagickBooleanType WriteOneJNGImage(MngInfo *mng_info,
 
   status=MagickTrue;
   transparent=image_info->type==GrayscaleMatteType ||
-     image_info->type==TrueColorMatteType;
-  jng_color_type=10;
-  jng_alpha_sample_depth=0;
-  jng_quality=image_info->quality == 0UL ? 75UL : image_info->quality;
-  jng_alpha_compression_method=0;
+     image_info->type==TrueColorMatteType || image->matte != MagickFalse;
 
-  if (image->matte != MagickFalse)
-    {
-      /* if any pixels are transparent */
-      transparent=MagickTrue;
-      if (image_info->compression==JPEGCompression)
-        jng_alpha_compression_method=8;
-    }
+  jng_quality=image_info->quality == 0UL ? 75UL : image_info->quality%1000;
+
+  jng_alpha_compression_method=image->compression==JPEGCompression? 8 : 0;
+
+  jng_alpha_quality=image_info->quality == 0UL ? 75UL : 
+      image_info->quality;
+
+  if (jng_alpha_quality >= 1000)
+    jng_alpha_quality /= 1000;
 
   if (transparent)
     {
@@ -11681,19 +11680,19 @@ static MagickBooleanType WriteOneJNGImage(MngInfo *mng_info,
       status=SeparateImage(jpeg_image,exception);
       (void) SetPixelChannelMapMask(jpeg_image,channel_mask);
       jpeg_image->matte=MagickFalse;
-
-      if (jng_quality >= 1000)
-        jpeg_image_info->quality=jng_quality/1000;
-
-      else
-        jpeg_image_info->quality=jng_quality;
-
+      jpeg_image->quality=jng_alpha_quality;
       jpeg_image_info->type=GrayscaleType;
       (void) SetImageType(jpeg_image,GrayscaleType,exception);
       (void) AcquireUniqueFilename(jpeg_image->filename);
       (void) FormatLocaleString(jpeg_image_info->filename,MaxTextExtent,
         "%s",jpeg_image->filename);
     }
+  else
+    {
+      jng_alpha_compression_method=0;
+      jng_color_type=10;
+      jng_alpha_sample_depth=0;
+    }
 
   /* To do: check bit depth of PNG alpha channel */
 
@@ -11702,6 +11701,23 @@ static MagickBooleanType WriteOneJNGImage(MngInfo *mng_info,
     TrueColorType && ImageIsGray(image,exception))
     jng_color_type-=2;
 
+  if (logging != MagickFalse)
+    {
+        (void) LogMagickEvent(CoderEvent,GetMagickModule(),
+          "    JNG Quality           = %d",(int) jng_quality);
+        (void) LogMagickEvent(CoderEvent,GetMagickModule(),
+          "    JNG Color Type        = %d",jng_color_type);
+        if (transparent)
+          {
+            (void) LogMagickEvent(CoderEvent,GetMagickModule(),
+              "    JNG Alpha Compression = %d",jng_alpha_compression_method);
+            (void) LogMagickEvent(CoderEvent,GetMagickModule(),
+              "    JNG Alpha Depth       = %d",jng_alpha_sample_depth);
+            (void) LogMagickEvent(CoderEvent,GetMagickModule(),
+              "    JNG Alpha Quality     = %d",(int) jng_alpha_quality);
+          }
+    }
+
   if (transparent)
     {
       if (jng_alpha_compression_method==0)
@@ -12078,7 +12094,8 @@ static MagickBooleanType WriteOneJNGImage(MngInfo *mng_info,
   if (jng_color_type == 8 || jng_color_type == 12)
     jpeg_image_info->type=GrayscaleType;
 
-  jpeg_image_info->quality=jng_quality % 1000;
+  jpeg_image_info->quality=jng_quality;
+  jpeg_image->quality=jng_quality;
   (void) CopyMagickString(jpeg_image_info->magick,"JPEG",MaxTextExtent);
   (void) CopyMagickString(jpeg_image->magick,"JPEG",MaxTextExtent);
 
-- 
2.40.0