[gdk-pixbuf] Fix denisty unit reading during incremental loading. Add tests for reading density units.

[Robert Ancell <rancell src gnome org>]

commit de9338004126415873d2db41d0fb9b41858c2d31
Author: Robert Ancell <robert ancell canonical com>
Date:   Wed Oct 22 12:06:30 2014 -0400

    Fix denisty unit reading during incremental loading. Add tests for reading density units.

 gdk-pixbuf/io-jpeg.c |   22 ++++++++++
 gdk-pixbuf/io-png.c  |   16 ++++++++
 tests/Makefile.am    |    9 ++++
 tests/dpi.jpeg       |  Bin 0 -> 1890 bytes
 tests/dpi.png        |  Bin 0 -> 2723 bytes
 tests/pixbuf-dpi.c   |  106 ++++++++++++++++++++++++++++++++++++++++++++++++++
 6 files changed, 153 insertions(+), 0 deletions(-)
---
diff --git a/gdk-pixbuf/io-jpeg.c b/gdk-pixbuf/io-jpeg.c
index c43aee6..4fefb8c 100644
--- a/gdk-pixbuf/io-jpeg.c
+++ b/gdk-pixbuf/io-jpeg.c
@@ -923,6 +923,7 @@ gdk_pixbuf__jpeg_image_load_increment (gpointer data,
        gint             width, height;
        char             otag_str[5];
        gchar           *icc_profile_base64;
+       char            *density_str;
        JpegExifContext  exif_context = { 0, };
        gboolean         retval;
 
@@ -1060,6 +1061,27 @@ gdk_pixbuf__jpeg_image_load_increment (gpointer data,
                                 retval = FALSE;
                                goto out;
                        }
+
+                       switch (cinfo->density_unit) {
+                       case 1:
+                               /* Dots per inch (no conversion required) */
+                               density_str = g_strdup_printf ("%d", cinfo->X_density);
+                               gdk_pixbuf_set_option (context->pixbuf, "x-dpi", density_str);
+                               g_free (density_str);
+                               density_str = g_strdup_printf ("%d", cinfo->Y_density);
+                               gdk_pixbuf_set_option (context->pixbuf, "y-dpi", density_str);
+                               g_free (density_str);
+                               break;
+                       case 2:
+                               /* Dots per cm - convert into dpi */
+                               density_str = g_strdup_printf ("%d", DPCM_TO_DPI (cinfo->X_density));
+                               gdk_pixbuf_set_option (context->pixbuf, "x-dpi", density_str);
+                               g_free (density_str);
+                               density_str = g_strdup_printf ("%d", DPCM_TO_DPI (cinfo->Y_density));
+                               gdk_pixbuf_set_option (context->pixbuf, "y-dpi", density_str);
+                               g_free (density_str);
+                               break;
+                       }
                
                        /* if orientation tag was found set an option to remember its value */
                        if (exif_context.orientation != 0) {
diff --git a/gdk-pixbuf/io-png.c b/gdk-pixbuf/io-png.c
index c1e6bcd..7099f82 100644
--- a/gdk-pixbuf/io-png.c
+++ b/gdk-pixbuf/io-png.c
@@ -632,6 +632,10 @@ png_info_callback   (png_structp png_read_ptr,
         const gchar *icc_profile_title;
         const gchar *icc_profile;
         png_uint_32 icc_profile_size;
+        png_uint_32 x_resolution;
+        png_uint_32 y_resolution;
+        int unit_type;
+        gchar *density_str;
         guint32 retval;
         gint compression_type;
 
@@ -711,6 +715,18 @@ png_info_callback   (png_structp png_read_ptr,
         }
 #endif
 
+#ifdef PNG_pHYs_SUPPORTED
+        retval = png_get_pHYs (png_read_ptr, png_info_ptr, &x_resolution, &y_resolution, &unit_type);
+        if (retval != 0 && unit_type == PNG_RESOLUTION_METER) {
+                density_str = g_strdup_printf ("%d", DPM_TO_DPI (x_resolution));
+                gdk_pixbuf_set_option (lc->pixbuf, "x-dpi", density_str);
+                g_free (density_str);
+                density_str = g_strdup_printf ("%d", DPM_TO_DPI (y_resolution));
+                gdk_pixbuf_set_option (lc->pixbuf, "y-dpi", density_str);
+                g_free (density_str);
+        }
+#endif
+
         /* Notify the client that we are ready to go */
 
         if (lc->prepare_func)
diff --git a/tests/Makefile.am b/tests/Makefile.am
index 1c17877..868da9d 100644
--- a/tests/Makefile.am
+++ b/tests/Makefile.am
@@ -28,6 +28,7 @@ test_programs =                       \
        pixbuf-randomly-modified        \
        pixbuf-threads                  \
        pixbuf-icc                      \
+       pixbuf-dpi                      \
        pixbuf-stream                   \
        pixbuf-resource                 \
        pixbuf-scale                    \
@@ -41,6 +42,8 @@ dist_installed_test_data =            \
        test-animation.ani              \
        icc-profile.jpeg                \
        icc-profile.png                 \
+       dpi.jpeg                                \
+       dpi.png                                 \
        $(wildcard $(srcdir)/test-images/*)
 
 pixbuf_icc_SOURCES =                   \
@@ -49,6 +52,12 @@ pixbuf_icc_SOURCES =                         \
        test-common.h                   \
        $(NULL)
 
+pixbuf_dpi_SOURCES =                   \
+       pixbuf-dpi.c                    \
+       test-common.c                   \
+       test-common.h                   \
+       $(NULL)
+
 pixbuf_scale_SOURCES =                         \
        pixbuf-scale.c                  \
        test-common.c                   \
diff --git a/tests/dpi.jpeg b/tests/dpi.jpeg
new file mode 100644
index 0000000..b70d167
Binary files /dev/null and b/tests/dpi.jpeg differ
diff --git a/tests/dpi.png b/tests/dpi.png
new file mode 100644
index 0000000..33aaf44
Binary files /dev/null and b/tests/dpi.png differ
diff --git a/tests/pixbuf-dpi.c b/tests/pixbuf-dpi.c
new file mode 100644
index 0000000..51613e0
--- /dev/null
+++ b/tests/pixbuf-dpi.c
@@ -0,0 +1,106 @@
+/* -*- Mode: C; c-basic-offset: 2; -*- */
+/* GdkPixbuf library - test loaders
+ *
+ * Copyright (C) 2014 Canonical Ltd.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program 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 General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <http://www.gnu.org/licenses/>.
+ *
+ * Author: Robert Ancell
+ */
+
+#include <string.h>
+
+#include "config.h"
+#include "gdk-pixbuf/gdk-pixbuf.h"
+#include "test-common.h"
+
+static void
+test_incremental (gconstpointer data)
+{
+  const gchar *filename = data;
+  GdkPixbufLoader *loader;
+  GdkPixbuf *pixbuf;
+  GError *error = NULL;
+  const gchar *x_dpi, *y_dpi;
+  gchar *contents;
+  gsize size;
+
+  if (!format_supported (filename))
+    {
+      g_test_skip ("format not supported");
+      return;
+    }
+
+  g_file_get_contents (g_test_get_filename (G_TEST_DIST, filename, NULL), &contents, &size, &error);
+  g_assert_no_error (error);
+
+  loader = gdk_pixbuf_loader_new ();
+
+  gdk_pixbuf_loader_write (loader, (const guchar*)contents, size, &error);
+  g_assert_no_error (error);
+  
+  gdk_pixbuf_loader_close (loader, &error);
+  g_assert_no_error (error);
+
+  pixbuf = gdk_pixbuf_loader_get_pixbuf (loader);
+  x_dpi = gdk_pixbuf_get_option (pixbuf, "x-dpi");
+  y_dpi = gdk_pixbuf_get_option (pixbuf, "y-dpi");
+  g_assert (x_dpi != NULL);
+  g_assert (y_dpi != NULL);
+  g_assert (strcmp (x_dpi, "300") == 0);
+  g_assert (strcmp (y_dpi, "600") == 0);
+
+  g_object_unref (loader);
+  g_free (contents);
+}
+
+static void
+test_nonincremental (gconstpointer data)
+{
+  const gchar *filename = data;
+  GError *error = NULL;
+  GdkPixbuf *pixbuf;
+  const gchar *x_dpi, *y_dpi;
+
+  if (!format_supported (filename))
+    {
+      g_test_skip ("format not supported");
+      return;
+    }
+
+  pixbuf = gdk_pixbuf_new_from_file (g_test_get_filename (G_TEST_DIST, filename, NULL), &error);
+  g_assert_no_error (error);
+
+  x_dpi = gdk_pixbuf_get_option (pixbuf, "x-dpi");
+  y_dpi = gdk_pixbuf_get_option (pixbuf, "y-dpi");
+  g_assert (x_dpi != NULL);
+  g_assert (y_dpi != NULL);
+  g_assert (strcmp (x_dpi, "300") == 0);
+  g_assert (strcmp (y_dpi, "600") == 0);
+
+  g_object_unref (pixbuf);
+}
+
+int
+main (int argc, char **argv)
+{
+  g_test_init (&argc, &argv, NULL);
+
+  g_test_add_data_func ("/pixbuf/dpi/png", "dpi.png", test_nonincremental);
+  g_test_add_data_func ("/pixbuf/dpi/jpeg", "dpi.jpeg", test_nonincremental);
+  g_test_add_data_func ("/pixbuf/dpi/png/incremental", "dpi.png", test_incremental);
+  g_test_add_data_func ("/pixbuf/dpi/jpeg/incremental", "dpi.jpeg", test_incremental);
+
+  return g_test_run ();
+}