[gtk+] icon theme: Improve loading of unthemed files

[Matthias Clasen <matthiasc src gnome org>]

commit 001598a8211e02dbbebd1bf71c51d4b96bdb9bef
Author: Matthias Clasen <mclasen redhat com>
Date:   Fri Jan 29 17:27:35 2016 -0500

    icon theme: Improve loading of unthemed files
    
    When creating icon info objects for unthemed files, we don't
    really have a nominal size, so we pass 0 to mean 'load at
    original size'. However, this is not what was happening.
    To make this possible, add variants of some pixbuf loading
    functions that take a scale factor instead of a desired size,
    and use those when we don't have a nominal size.

 gtk/Makefile.am             |    6 +-
 gtk/gdkpixbufutils.c        |  132 +++++++++++++++++++++++++++++++++++++++++++
 gtk/gdkpixbufutilsprivate.h |   35 +++++++++++
 gtk/gtkicontheme.c          |   27 +++++++--
 4 files changed, 191 insertions(+), 9 deletions(-)
---
diff --git a/gtk/Makefile.am b/gtk/Makefile.am
index 7ed75b3..7b130e3 100644
--- a/gtk/Makefile.am
+++ b/gtk/Makefile.am
@@ -561,7 +561,8 @@ gtk_private_h_sources =             \
        gtkwidgetprivate.h      \
        gtkwin32themeprivate.h  \
        gtkwindowprivate.h      \
-       gtktreemenu.h
+       gtktreemenu.h           \
+       gdkpixbufutilsprivate.h
 
 # GTK+ C sources to build the library from
 gtk_base_c_sources =           \
@@ -916,7 +917,8 @@ gtk_base_c_sources =                \
        gtkwidgetpath.c         \
        gtkwindow.c             \
        gtkwindowgroup.c        \
-       gtkwin32theme.c
+       gtkwin32theme.c         \
+       gdkpixbufutils.c
 
 if USE_QUARTZ
 gtk_base_c_sources +=          \
diff --git a/gtk/gdkpixbufutils.c b/gtk/gdkpixbufutils.c
new file mode 100644
index 0000000..3da0323
--- /dev/null
+++ b/gtk/gdkpixbufutils.c
@@ -0,0 +1,132 @@
+/* Copyright (C) 2016 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/>.
+ */
+
+#include "config.h"
+
+#include "gdkpixbufutilsprivate.h"
+
+static GdkPixbuf *
+load_from_stream (GdkPixbufLoader  *loader,
+                  GInputStream     *stream,
+                  GCancellable     *cancellable,
+                  GError          **error)
+{
+  GdkPixbuf *pixbuf;
+  gssize n_read;
+  guchar buffer[65536];
+  gboolean res;
+
+  res = TRUE;
+  while (1)
+    {
+      n_read = g_input_stream_read (stream, buffer, sizeof (buffer), cancellable, error);
+      if (n_read < 0)
+        {
+          res = FALSE;
+          error = NULL; /* Ignore further errors */
+          break;
+        }
+
+      if (n_read == 0)
+        break;
+
+      if (!gdk_pixbuf_loader_write (loader, buffer, n_read, error))
+        {
+          res = FALSE;
+          error = NULL;
+          break;
+        }
+    }
+
+  if (!gdk_pixbuf_loader_close (loader, error))
+    {
+      res = FALSE;
+      error = NULL;
+    }
+
+  pixbuf = NULL;
+
+  if (res)
+    {
+      pixbuf = gdk_pixbuf_loader_get_pixbuf (loader);
+      if (pixbuf)
+        g_object_ref (pixbuf);
+    }
+
+  return pixbuf;
+}
+
+static void
+size_prepared_cb (GdkPixbufLoader *loader,
+                  gint             width,
+                  gint             height,
+                  gpointer         data)
+{
+  gdouble *scale = data;
+
+  width = MAX (*scale * width, 1);
+  height = MAX (*scale * height, 1);
+
+  gdk_pixbuf_loader_set_size (loader, width, height);
+}
+
+/* Like gdk_pixbuf_new_from_stream_at_scale, but
+ * load the image at its original size times the
+ * given scale.
+ */
+GdkPixbuf *
+_gdk_pixbuf_new_from_stream_scaled (GInputStream  *stream,
+                                    gdouble        scale,
+                                    GCancellable  *cancellable,
+                                    GError       **error)
+{
+  GdkPixbufLoader *loader;
+  GdkPixbuf *pixbuf;
+
+  loader = gdk_pixbuf_loader_new ();
+
+  g_signal_connect (loader, "size-prepared",
+                    G_CALLBACK (size_prepared_cb), &scale);
+
+  pixbuf = load_from_stream (loader, stream, cancellable, error);
+
+  g_object_unref (loader);
+
+  return pixbuf;
+}
+
+/* Like gdk_pixbuf_new_from_resource_at_scale, but
+ * load the image at its original size times the
+ * given scale.
+ */
+GdkPixbuf *
+_gdk_pixbuf_new_from_resource_scaled (const gchar  *resource_path,
+                                      gdouble       scale,
+                                      GError      **error)
+{
+  GInputStream *stream;
+  GdkPixbuf *pixbuf;
+
+  stream = g_resources_open_stream (resource_path, 0, error);
+  if (stream == NULL)
+    return NULL;
+
+  pixbuf = _gdk_pixbuf_new_from_stream_scaled (stream, scale, NULL, error);
+  g_object_unref (stream);
+
+  return pixbuf;
+}
+
diff --git a/gtk/gdkpixbufutilsprivate.h b/gtk/gdkpixbufutilsprivate.h
new file mode 100644
index 0000000..f01f177
--- /dev/null
+++ b/gtk/gdkpixbufutilsprivate.h
@@ -0,0 +1,35 @@
+/* GTK - The GIMP Toolkit
+ * Copyright (C) 2016 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 __GDK_PIXBUF_UTILS_PRIVATE_H__
+#define __GDK_PIXBUF_UTILS_PRIVATE_H__
+
+#include <gdk-pixbuf/gdk-pixbuf.h>
+
+G_BEGIN_DECLS
+
+GdkPixbuf *_gdk_pixbuf_new_from_stream_scaled   (GInputStream  *stream,
+                                                 gdouble        scale,
+                                                 GCancellable  *cancellable,
+                                                 GError       **error);
+GdkPixbuf *_gdk_pixbuf_new_from_resource_scaled (const gchar   *resource_path,
+                                                 gdouble        scale,
+                                                 GError       **error);
+
+G_END_DECLS
+
+#endif  /* __GDK_PIXBUF_UTILS_PRIVATE_H__ */
diff --git a/gtk/gtkicontheme.c b/gtk/gtkicontheme.c
index 6de7f33..0a04258 100644
--- a/gtk/gtkicontheme.c
+++ b/gtk/gtkicontheme.c
@@ -49,6 +49,7 @@
 #include "gtksettingsprivate.h"
 #include "gtkstylecontextprivate.h"
 #include "gtkprivate.h"
+#include "gdkpixbufutilsprivate.h"
 
 #undef GDK_DEPRECATED
 #undef GDK_DEPRECATED_FOR
@@ -3880,9 +3881,15 @@ icon_info_ensure_scale_and_pixbuf (GtkIconInfo *icon_info)
             size = scaled_desired_size;
           else
             size = icon_info->dir_size * dir_scale * icon_info->scale;
-          source_pixbuf = gdk_pixbuf_new_from_resource_at_scale (icon_info->filename,
-                                                                 size, size, TRUE,
-                                                                 &icon_info->load_error);
+
+          if (size == 0)
+            source_pixbuf = _gdk_pixbuf_new_from_resource_scaled (icon_info->filename,
+                                                                  icon_info->desired_scale,
+                                                                  &icon_info->load_error);
+          else
+            source_pixbuf = gdk_pixbuf_new_from_resource_at_scale (icon_info->filename,
+                                                                   size, size, TRUE,
+                                                                   &icon_info->load_error);
         }
       else
         source_pixbuf = gdk_pixbuf_new_from_resource (icon_info->filename,
@@ -3910,10 +3917,16 @@ icon_info_ensure_scale_and_pixbuf (GtkIconInfo *icon_info)
                 size = scaled_desired_size;
               else
                 size = icon_info->dir_size * dir_scale * icon_info->scale;
-              source_pixbuf = gdk_pixbuf_new_from_stream_at_scale (stream,
-                                                                   size, size,
-                                                                   TRUE, NULL,
-                                                                   &icon_info->load_error);
+              if (size == 0)
+                source_pixbuf = _gdk_pixbuf_new_from_stream_scaled (stream,
+                                                                    icon_info->desired_scale,
+                                                                    NULL,
+                                                                    &icon_info->load_error);
+              else
+                source_pixbuf = gdk_pixbuf_new_from_stream_at_scale (stream,
+                                                                     size, size,
+                                                                     TRUE, NULL,
+                                                                     &icon_info->load_error);
             }
           else
             source_pixbuf = gdk_pixbuf_new_from_stream (stream,