From: Sophie Herold <sophie@hemio.de>
Date: Fri, 26 May 2023 13:35:57 +0000 (+0200)
Subject: gdk: Support gray/alpha in PNG loader
X-Git-Tag: archive/raspbian/4.12.3+ds-1+rpi1~1^2^2^2~22^2~1^2~200^2~7
X-Git-Url: https://dgit.raspbian.org/?a=commitdiff_plain;h=894a4bda852a9b0a1f1612ff7cd4758fb729b38f;p=gtk4.git

gdk: Support gray/alpha in PNG loader
---

diff --git a/gdk/loaders/gdkpng.c b/gdk/loaders/gdkpng.c
index d5991fde38..2f6d55d1f9 100644
--- a/gdk/loaders/gdkpng.c
+++ b/gdk/loaders/gdkpng.c
@@ -183,8 +183,7 @@ gdk_load_png (GBytes  *bytes,
   if (color_type == PNG_COLOR_TYPE_PALETTE)
     png_set_palette_to_rgb (png);
 
-  if (color_type == PNG_COLOR_TYPE_GRAY ||
-      color_type == PNG_COLOR_TYPE_GRAY_ALPHA)
+  if (color_type == PNG_COLOR_TYPE_GRAY)
     png_set_expand_gray_1_2_4_to_8 (png);
 
   if (png_get_valid (png, info, PNG_INFO_tRNS))
@@ -193,10 +192,6 @@ gdk_load_png (GBytes  *bytes,
   if (depth < 8)
     png_set_packing (png);
 
-  if (color_type == PNG_COLOR_TYPE_GRAY ||
-      color_type == PNG_COLOR_TYPE_GRAY_ALPHA)
-    png_set_gray_to_rgb (png);
-
   if (interlace != PNG_INTERLACE_NONE)
     png_set_interlace_handling (png);
 
@@ -239,6 +234,26 @@ gdk_load_png (GBytes  *bytes,
           format = GDK_MEMORY_R16G16B16;
         }
       break;
+    case PNG_COLOR_TYPE_GRAY:
+      if (depth == 8)
+        {
+          format = GDK_MEMORY_G8;
+        }
+      else if (depth == 16)
+        {
+          format = GDK_MEMORY_G16;
+        }
+      break;
+    case PNG_COLOR_TYPE_GRAY_ALPHA:
+      if (depth == 8)
+        {
+          format = GDK_MEMORY_G8A8;
+        }
+      else if (depth == 16)
+        {
+          format = GDK_MEMORY_G16A16;
+        }
+      break;
     default:
       png_destroy_read_struct (&png, &info, NULL);
       g_set_error (error,
@@ -349,6 +364,34 @@ gdk_save_png (GdkTexture *texture)
       depth = 16;
       break;
 
+    case GDK_MEMORY_G8:
+      format = GDK_MEMORY_G8;
+      png_format = PNG_COLOR_TYPE_GRAY;
+      depth = 8;
+      break;
+
+    case GDK_MEMORY_G8A8_PREMULTIPLIED:
+    case GDK_MEMORY_G8A8:
+    case GDK_MEMORY_A8:
+      format = GDK_MEMORY_G8A8;
+      png_format = PNG_COLOR_TYPE_GRAY_ALPHA;
+      depth = 8;
+      break;
+
+    case GDK_MEMORY_G16:
+      format = GDK_MEMORY_G16;
+      png_format = PNG_COLOR_TYPE_GRAY;
+      depth = 16;
+      break;
+
+    case GDK_MEMORY_G16A16_PREMULTIPLIED:
+    case GDK_MEMORY_G16A16:
+    case GDK_MEMORY_A16:
+      format = GDK_MEMORY_G16A16;
+      png_format = PNG_COLOR_TYPE_GRAY_ALPHA;
+      depth = 16;
+      break;
+
     case GDK_MEMORY_N_FORMATS:
     default:
       g_assert_not_reached ();