[gtk+] reftest: Split out some functionality into own file

[Benjamin Otte <otte src gnome org>]

commit 0182d1ed381f489d4fcde851212bc836174b2ef5
Author: Benjamin Otte <otte redhat com>
Date:   Sun Sep 21 18:18:38 2014 +0200

    reftest: Split out some functionality into own file
    
    Comparing two surfaces is something that can be nicely factored out.

 testsuite/reftests/Makefile.am       |    2 +
 testsuite/reftests/gtk-reftest.c     |  151 +-----------------------------
 testsuite/reftests/reftest-compare.c |  172 ++++++++++++++++++++++++++++++++++
 testsuite/reftests/reftest-compare.h |   30 ++++++
 4 files changed, 206 insertions(+), 149 deletions(-)
---
diff --git a/testsuite/reftests/Makefile.am b/testsuite/reftests/Makefile.am
index 0853a00..61135b2 100644
--- a/testsuite/reftests/Makefile.am
+++ b/testsuite/reftests/Makefile.am
@@ -30,6 +30,8 @@ gtk_reftest_LDADD = \
        $(NULL)
 
 gtk_reftest_SOURCES = \
+       reftest-compare.c               \
+       reftest-compare.h               \
        reftest-module.c                \
        reftest-module.h                \
        gtk-reftest.c                   \
diff --git a/testsuite/reftests/gtk-reftest.c b/testsuite/reftests/gtk-reftest.c
index ed0e634..89cd2ad 100644
--- a/testsuite/reftests/gtk-reftest.c
+++ b/testsuite/reftests/gtk-reftest.c
@@ -20,6 +20,7 @@
 
 #include "config.h"
 
+#include "reftest-compare.h"
 #include "reftest-module.h"
 
 #include <string.h>
@@ -464,154 +465,6 @@ save_image (cairo_surface_t *surface,
 }
 
 static void
-get_surface_size (cairo_surface_t *surface,
-                  int             *width,
-                  int             *height)
-{
-  GdkRectangle area;
-  cairo_t *cr;
-
-  cr = cairo_create (surface);
-  if (!gdk_cairo_get_clip_rectangle (cr, &area))
-    {
-      g_assert_not_reached ();
-    }
-
-  g_assert (area.x == 0 && area.y == 0);
-  g_assert (area.width > 0 && area.height > 0);
-
-  *width = area.width;
-  *height = area.height;
-}
-
-static cairo_surface_t *
-coerce_surface_for_comparison (cairo_surface_t *surface,
-                               int              width,
-                               int              height)
-{
-  cairo_surface_t *coerced;
-  cairo_t *cr;
-
-  coerced = cairo_image_surface_create (CAIRO_FORMAT_ARGB32,
-                                        width,
-                                        height);
-  cr = cairo_create (coerced);
-  
-  cairo_set_source_surface (cr, surface, 0, 0);
-  cairo_set_operator (cr, CAIRO_OPERATOR_SOURCE);
-  cairo_paint (cr);
-
-  cairo_destroy (cr);
-  cairo_surface_destroy (surface);
-
-  g_assert (cairo_surface_status (coerced) == CAIRO_STATUS_SUCCESS);
-
-  return coerced;
-}
-
-/* Compares two CAIRO_FORMAT_ARGB32 buffers, returning NULL if the
- * buffers are equal or a surface containing a diff between the two
- * surfaces.
- *
- * This function should be rewritten to compare all formats supported by
- * cairo_format_t instead of taking a mask as a parameter.
- *
- * This function is originally from cairo:test/buffer-diff.c.
- * Copyright © 2004 Richard D. Worth
- */
-static cairo_surface_t *
-buffer_diff_core (const guchar *buf_a,
-                  int           stride_a,
-                 const guchar *buf_b,
-                  int           stride_b,
-                 int           width,
-                 int           height)
-{
-  int x, y;
-  guchar *buf_diff = NULL;
-  int stride_diff = 0;
-  cairo_surface_t *diff = NULL;
-
-  for (y = 0; y < height; y++)
-    {
-      const guint32 *row_a = (const guint32 *) (buf_a + y * stride_a);
-      const guint32 *row_b = (const guint32 *) (buf_b + y * stride_b);
-      guint32 *row = (guint32 *) (buf_diff + y * stride_diff);
-
-      for (x = 0; x < width; x++)
-        {
-          int channel;
-          guint32 diff_pixel = 0;
-
-          /* check if the pixels are the same */
-          if (row_a[x] == row_b[x])
-            continue;
-        
-          if (diff == NULL)
-            {
-              diff = cairo_image_surface_create (CAIRO_FORMAT_RGB24,
-                                                 width,
-                                                 height);
-              g_assert (cairo_surface_status (diff) == CAIRO_STATUS_SUCCESS);
-              buf_diff = cairo_image_surface_get_data (diff);
-              stride_diff = cairo_image_surface_get_stride (diff);
-              row = (guint32 *) (buf_diff + y * stride_diff);
-            }
-
-          /* calculate a difference value for all 4 channels */
-          for (channel = 0; channel < 4; channel++)
-            {
-              int value_a = (row_a[x] >> (channel*8)) & 0xff;
-              int value_b = (row_b[x] >> (channel*8)) & 0xff;
-              guint diff;
-
-              diff = ABS (value_a - value_b);
-              diff *= 4;  /* emphasize */
-              if (diff)
-                diff += 128; /* make sure it's visible */
-              if (diff > 255)
-                diff = 255;
-              diff_pixel |= diff << (channel*8);
-            }
-
-          if ((diff_pixel & 0x00ffffff) == 0)
-            {
-              /* alpha only difference, convert to luminance */
-              guint8 alpha = diff_pixel >> 24;
-              diff_pixel = alpha * 0x010101;
-            }
-          
-          row[x] = diff_pixel;
-      }
-  }
-
-  return diff;
-}
-
-static cairo_surface_t *
-compare_surfaces (cairo_surface_t *surface1,
-                  cairo_surface_t *surface2)
-{
-  int w1, h1, w2, h2, w, h;
-  cairo_surface_t *diff;
-  
-  get_surface_size (surface1, &w1, &h1);
-  get_surface_size (surface2, &w2, &h2);
-  w = MAX (w1, w2);
-  h = MAX (h1, h2);
-  surface1 = coerce_surface_for_comparison (surface1, w, h);
-  surface2 = coerce_surface_for_comparison (surface2, w, h);
-
-  diff = buffer_diff_core (cairo_image_surface_get_data (surface1),
-                           cairo_image_surface_get_stride (surface1),
-                           cairo_image_surface_get_data (surface2),
-                           cairo_image_surface_get_stride (surface2),
-                           w, h);
-
-  return diff;
-}
-
-static void
 test_ui_file (GFile *file)
 {
   char *ui_file, *reference_file;
@@ -635,7 +488,7 @@ test_ui_file (GFile *file)
     }
   g_free (reference_file);
 
-  diff_image = compare_surfaces (ui_image, reference_image);
+  diff_image = reftest_compare_surfaces (ui_image, reference_image);
 
   save_image (ui_image, ui_file, ".out.png");
   save_image (reference_image, ui_file, ".ref.png");
diff --git a/testsuite/reftests/reftest-compare.c b/testsuite/reftests/reftest-compare.c
new file mode 100644
index 0000000..84c560c
--- /dev/null
+++ b/testsuite/reftests/reftest-compare.c
@@ -0,0 +1,172 @@
+/*
+ * Copyright (C) 2011 Red Hat Inc.
+ *
+ * Author:
+ *      Benjamin Otte <otte gnome org>
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Library General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Library General Public License for more details.
+ *
+ * You should have received a copy of the GNU Library General Public
+ * License along with this library. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "config.h"
+
+#include "reftest-compare.h"
+
+static void
+get_surface_size (cairo_surface_t *surface,
+                  int             *width,
+                  int             *height)
+{
+  GdkRectangle area;
+  cairo_t *cr;
+
+  cr = cairo_create (surface);
+  if (!gdk_cairo_get_clip_rectangle (cr, &area))
+    {
+      g_assert_not_reached ();
+    }
+
+  g_assert (area.x == 0 && area.y == 0);
+  g_assert (area.width > 0 && area.height > 0);
+
+  *width = area.width;
+  *height = area.height;
+}
+
+static cairo_surface_t *
+coerce_surface_for_comparison (cairo_surface_t *surface,
+                               int              width,
+                               int              height)
+{
+  cairo_surface_t *coerced;
+  cairo_t *cr;
+
+  coerced = cairo_image_surface_create (CAIRO_FORMAT_ARGB32,
+                                        width,
+                                        height);
+  cr = cairo_create (coerced);
+  
+  cairo_set_source_surface (cr, surface, 0, 0);
+  cairo_set_operator (cr, CAIRO_OPERATOR_SOURCE);
+  cairo_paint (cr);
+
+  cairo_destroy (cr);
+  cairo_surface_destroy (surface);
+
+  g_assert (cairo_surface_status (coerced) == CAIRO_STATUS_SUCCESS);
+
+  return coerced;
+}
+
+/* Compares two CAIRO_FORMAT_ARGB32 buffers, returning NULL if the
+ * buffers are equal or a surface containing a diff between the two
+ * surfaces.
+ *
+ * This function should be rewritten to compare all formats supported by
+ * cairo_format_t instead of taking a mask as a parameter.
+ *
+ * This function is originally from cairo:test/buffer-diff.c.
+ * Copyright © 2004 Richard D. Worth
+ */
+static cairo_surface_t *
+buffer_diff_core (const guchar *buf_a,
+                  int           stride_a,
+                 const guchar *buf_b,
+                  int           stride_b,
+                 int           width,
+                 int           height)
+{
+  int x, y;
+  guchar *buf_diff = NULL;
+  int stride_diff = 0;
+  cairo_surface_t *diff = NULL;
+
+  for (y = 0; y < height; y++)
+    {
+      const guint32 *row_a = (const guint32 *) (buf_a + y * stride_a);
+      const guint32 *row_b = (const guint32 *) (buf_b + y * stride_b);
+      guint32 *row = (guint32 *) (buf_diff + y * stride_diff);
+
+      for (x = 0; x < width; x++)
+        {
+          int channel;
+          guint32 diff_pixel = 0;
+
+          /* check if the pixels are the same */
+          if (row_a[x] == row_b[x])
+            continue;
+        
+          if (diff == NULL)
+            {
+              diff = cairo_image_surface_create (CAIRO_FORMAT_RGB24,
+                                                 width,
+                                                 height);
+              g_assert (cairo_surface_status (diff) == CAIRO_STATUS_SUCCESS);
+              buf_diff = cairo_image_surface_get_data (diff);
+              stride_diff = cairo_image_surface_get_stride (diff);
+              row = (guint32 *) (buf_diff + y * stride_diff);
+            }
+
+          /* calculate a difference value for all 4 channels */
+          for (channel = 0; channel < 4; channel++)
+            {
+              int value_a = (row_a[x] >> (channel*8)) & 0xff;
+              int value_b = (row_b[x] >> (channel*8)) & 0xff;
+              guint diff;
+
+              diff = ABS (value_a - value_b);
+              diff *= 4;  /* emphasize */
+              if (diff)
+                diff += 128; /* make sure it's visible */
+              if (diff > 255)
+                diff = 255;
+              diff_pixel |= diff << (channel*8);
+            }
+
+          if ((diff_pixel & 0x00ffffff) == 0)
+            {
+              /* alpha only difference, convert to luminance */
+              guint8 alpha = diff_pixel >> 24;
+              diff_pixel = alpha * 0x010101;
+            }
+          
+          row[x] = diff_pixel;
+      }
+  }
+
+  return diff;
+}
+
+cairo_surface_t *
+reftest_compare_surfaces (cairo_surface_t *surface1,
+                          cairo_surface_t *surface2)
+{
+  int w1, h1, w2, h2, w, h;
+  cairo_surface_t *diff;
+  
+  get_surface_size (surface1, &w1, &h1);
+  get_surface_size (surface2, &w2, &h2);
+  w = MAX (w1, w2);
+  h = MAX (h1, h2);
+  surface1 = coerce_surface_for_comparison (surface1, w, h);
+  surface2 = coerce_surface_for_comparison (surface2, w, h);
+
+  diff = buffer_diff_core (cairo_image_surface_get_data (surface1),
+                           cairo_image_surface_get_stride (surface1),
+                           cairo_image_surface_get_data (surface2),
+                           cairo_image_surface_get_stride (surface2),
+                           w, h);
+
+  return diff;
+}
+
diff --git a/testsuite/reftests/reftest-compare.h b/testsuite/reftests/reftest-compare.h
new file mode 100644
index 0000000..b889e16
--- /dev/null
+++ b/testsuite/reftests/reftest-compare.h
@@ -0,0 +1,30 @@
+/* GTK - The GIMP Toolkit
+ * Copyright (C) 2014 Red Hat, Inc.
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef __REFTEST_COMPARE_H__
+#define __REFTEST_COMPARE_H__
+
+#include <gtk/gtk.h>
+
+G_BEGIN_DECLS
+
+cairo_surface_t *       reftest_compare_surfaces        (cairo_surface_t        *surface1,
+                                                         cairo_surface_t        *surface2);
+
+G_END_DECLS
+
+#endif /* __REFTEST_COMPARE_H__ */