gtk2/testsuite/reftests/reftest-compare.c
Benjamin Otte 58f66ebd07 reftests: Make image-compare use textures
All image comparisons are done on textures now.
2021-09-16 23:59:37 +02:00

136 lines
4.2 KiB
C

/*
* Copyright (C) 2011,2021 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"
/* Compares two GDK_MEMORY_DEFAULT buffers, returning NULL if the
* buffers are equal or a surface containing a diff between the two
* surfaces.
*
* This function is originally from cairo:test/buffer-diff.c.
* Copyright © 2004 Richard D. Worth
*/
static GdkTexture *
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;
GdkTexture *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;
/* even if they're not literally the same, fully-transparent
* pixels are effectively the same regardless of colour */
if ((row_a[x] & 0xff000000) == 0 && (row_b[x] & 0xff000000) == 0)
continue;
if (diff == NULL)
{
GBytes *bytes;
stride_diff = 4 * width;
buf_diff = g_malloc0_n (stride_diff, height);
bytes = g_bytes_new_take (buf_diff, stride_diff * height);
diff = gdk_memory_texture_new (width, height,
GDK_MEMORY_DEFAULT,
bytes,
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 channel_diff;
channel_diff = ABS (value_a - value_b);
channel_diff *= 4; /* emphasize */
if (channel_diff)
channel_diff += 128; /* make sure it's visible */
if (channel_diff > 255)
channel_diff = 255;
diff_pixel |= channel_diff << (channel * 8);
}
if ((diff_pixel & 0x00ffffff) == 0)
{
/* alpha only difference, convert to luminance */
guint8 alpha = diff_pixel >> 24;
diff_pixel = alpha * 0x010101;
}
/* make the pixel fully opaque */
diff_pixel |= 0xff000000;
row[x] = diff_pixel;
}
}
return diff;
}
GdkTexture *
reftest_compare_textures (GdkTexture *texture1,
GdkTexture *texture2)
{
int w, h;
guchar *data1, *data2;
GdkTexture *diff;
w = MAX (gdk_texture_get_width (texture1), gdk_texture_get_width (texture2));
h = MAX (gdk_texture_get_height (texture1), gdk_texture_get_height (texture2));
data1 = g_malloc_n (w * 4, h);
gdk_texture_download (texture1, data1, w * 4);
data2 = g_malloc_n (w * 4, h);
gdk_texture_download (texture2, data2, w * 4);
diff = buffer_diff_core (data1, w * 4,
data2, w * 4,
w, h);
g_free (data1);
g_free (data2);
return diff;
}