[gthumb] image viewer: some image loading optimizations

[Paolo Bacchilega <paobac src gnome org>]

commit c3686f3b8c7bc7ee492d636fc0f1b132618e9f95
Author: Paolo Bacchilega <paobac src gnome org>
Date:   Tue Nov 5 17:53:58 2013 +0100

    image viewer: some image loading optimizations

 extensions/image_viewer/gth-image-viewer-page.c |  172 ++++++++++++++++------
 1 files changed, 125 insertions(+), 47 deletions(-)
---
diff --git a/extensions/image_viewer/gth-image-viewer-page.c b/extensions/image_viewer/gth-image-viewer-page.c
index 9d47258..f743cdc 100644
--- a/extensions/image_viewer/gth-image-viewer-page.c
+++ b/extensions/image_viewer/gth-image-viewer-page.c
@@ -28,7 +28,7 @@
 #include "preferences.h"
 
 
-#define UPDATE_QUALITY_DELAY 100
+#define UPDATE_QUALITY_DELAY 500
 #define N_HEADER_BAR_BUTTONS 2
 
 
@@ -85,7 +85,7 @@ struct _GthImageViewerPagePrivate {
        gboolean           loading_image;
        GFile             *last_loaded;
        gboolean           can_paste;
-       guint              update_quality_event;
+       guint              update_quality_id;
        GtkWidget         *buttons[N_HEADER_BAR_BUTTONS];
        gboolean           pointer_on_viewer;
        gboolean           pointer_on_overview;
@@ -109,14 +109,30 @@ gth_image_viewer_page_file_loaded (GthImageViewerPage *self,
 
 
 static int
-_gth_image_preloader_get_requested_size (GthImageViewerPage *self)
+get_viewer_size (GthImageViewerPage *self)
 {
-       int    requested_size;
-       int    original_width;
-       int    original_height;
-       double zoom;
-       int    window_width;
-       int    window_height;
+       GtkAllocation allocation;
+       int           size;
+
+       gtk_widget_get_allocation (GTK_WIDGET (self->priv->viewer), &allocation);
+       size = MAX (allocation.width, allocation.height);
+       if (size <= 1) {
+               int window_width;
+               int window_height;
+               gtk_window_get_size (GTK_WINDOW (self->priv->browser),
+                                    &window_width,
+                                    &window_height);
+               size = MAX (window_width, window_height);;
+       }
+
+       return size;
+}
+
+
+static int
+_gth_image_preloader_get_requested_size_for_next_images (GthImageViewerPage *self)
+{
+       int requested_size;
 
        requested_size = -1;
 
@@ -126,29 +142,45 @@ _gth_image_preloader_get_requested_size (GthImageViewerPage *self)
                break;
 
        case GTH_ZOOM_CHANGE_KEEP_PREV:
-               if (gth_image_viewer_get_fit_mode (GTH_IMAGE_VIEWER (self->priv->viewer)) == GTH_FIT_NONE) {
-                       gth_image_viewer_get_original_size (GTH_IMAGE_VIEWER (self->priv->viewer),
-                                                           &original_width,
-                                                           &original_height);
-                       zoom = gth_image_viewer_get_zoom (GTH_IMAGE_VIEWER (self->priv->viewer));
-                       requested_size = (zoom < 1.0) ? MAX (original_width, original_height) * zoom : -1;
-               }
-               else {
-                       gtk_window_get_size (GTK_WINDOW (self->priv->browser),
-                                            &window_width,
-                                            &window_height);
-                       requested_size = MAX (window_width, window_height);
-               }
-               break;
-
        case GTH_ZOOM_CHANGE_FIT_SIZE:
        case GTH_ZOOM_CHANGE_FIT_SIZE_IF_LARGER:
        case GTH_ZOOM_CHANGE_FIT_WIDTH:
        case GTH_ZOOM_CHANGE_FIT_WIDTH_IF_LARGER:
-               gtk_window_get_size (GTK_WINDOW (self->priv->browser),
-                                    &window_width,
-                                    &window_height);
-               requested_size = MAX (window_width, window_height);
+               requested_size = get_viewer_size (self);
+               break;
+       }
+
+       return requested_size;
+}
+
+
+static int
+_gth_image_preloader_get_requested_size_for_current_image (GthImageViewerPage *self)
+{
+       int     requested_size;
+       double  zoom;
+
+       requested_size = -1;
+
+       switch (gth_image_viewer_get_fit_mode (GTH_IMAGE_VIEWER (self->priv->viewer))) {
+       case GTH_FIT_NONE:
+               zoom = gth_image_viewer_get_zoom (GTH_IMAGE_VIEWER (self->priv->viewer));
+               if (zoom < 1.0) {
+                       int original_width;
+                       int original_height;
+
+                       gth_image_viewer_get_original_size (GTH_IMAGE_VIEWER (self->priv->viewer), 
&original_width, &original_height);
+                       requested_size = MAX (original_width * zoom, original_height * zoom);
+               }
+               else
+                       requested_size = -1;
+               break;
+
+       case GTH_FIT_SIZE:
+       case GTH_FIT_SIZE_IF_LARGER:
+       case GTH_FIT_WIDTH:
+       case GTH_FIT_WIDTH_IF_LARGER:
+               requested_size = get_viewer_size (self);
                break;
        }
 
@@ -188,6 +220,25 @@ different_quality_ready_cb (GObject                *source_object,
        if (image == NULL)
                goto clear_data;
 
+       /* check whether the image is of different quality */
+       {
+               cairo_surface_t *s1;
+               cairo_surface_t *s2;
+               int              w1, h1, w2, h2;
+
+               s1 = gth_image_get_cairo_surface (image);
+               s2 = gth_image_viewer_get_current_image (GTH_IMAGE_VIEWER (self->priv->viewer));
+               w1 = cairo_image_surface_get_width (s1);
+               h1 = cairo_image_surface_get_height (s1);
+               w2 = cairo_image_surface_get_width (s2);
+               h2 = cairo_image_surface_get_height (s2);
+
+               cairo_surface_destroy (s1);
+
+               if ((w1 == w2) && (h1 == h2))
+                       goto clear_data;
+       }
+
        gth_viewer_page_focus (GTH_VIEWER_PAGE (self));
        gth_image_viewer_set_better_quality (GTH_IMAGE_VIEWER (self->priv->viewer),
                                             image,
@@ -207,31 +258,58 @@ clear_data:
 
 
 static gboolean
+_g_mime_type_can_load_different_quality (const char *mime_type)
+{
+       static const char *supported[] = {
+               "image/jpeg",
+               "image/x-portable-pixmap"
+
+               /* RAW formats: to keep in sync with raw_mime_types in extensions/raw_files/main.c */
+
+               "image/x-adobe-dng",
+               "image/x-canon-cr2",
+               "image/x-canon-crw",
+               "image/x-epson-erf",
+               "image/x-minolta-mrw",
+               "image/x-nikon-nef",
+               "image/x-olympus-orf",
+               "image/x-pentax-pef",
+               "image/x-sony-arw"
+       };
+       int i;
+
+       for (i = 0; i < G_N_ELEMENTS (supported); i++)
+               if (g_strcmp0 (mime_type, supported[i]) == 0)
+                       return TRUE;
+
+       return FALSE;
+}
+
+
+static gboolean
 update_quality_cb (gpointer user_data)
 {
        GthImageViewerPage *self = user_data;
-       int                 old_requested_size;
-       int                 new_requested_size;
 
-       if (self->priv->update_quality_event != 0) {
-               g_source_remove (self->priv->update_quality_event);
-               self->priv->update_quality_event = 0;
+       if (self->priv->update_quality_id != 0) {
+               g_source_remove (self->priv->update_quality_id);
+               self->priv->update_quality_id = 0;
        }
 
        if (self->priv->loading_image)
                return FALSE;
 
-       old_requested_size = gth_image_viewer_get_requested_size (GTH_IMAGE_VIEWER (self->priv->viewer));
-       new_requested_size = _gth_image_preloader_get_requested_size (self);
-       if (old_requested_size != new_requested_size)
-               gth_image_preloader_load (self->priv->preloader,
-                                         self->priv->image_changed ? GTH_MODIFIED_IMAGE : 
self->priv->file_data,
-                                         new_requested_size,
-                                         NULL,
-                                         different_quality_ready_cb,
-                                         self,
-                                         GTH_NO_PRELOADERS,
-                                         NULL);
+       if (! self->priv->image_changed && ! _g_mime_type_can_load_different_quality 
(gth_file_data_get_mime_type (self->priv->file_data)))
+               return FALSE;
+
+       gth_image_preloader_load (self->priv->preloader,
+                                 self->priv->image_changed ? GTH_MODIFIED_IMAGE : self->priv->file_data,
+                                 _gth_image_preloader_get_requested_size_for_current_image (self),
+                                 NULL,
+                                 different_quality_ready_cb,
+                                 self,
+                                 GTH_NO_PRELOADERS,
+                                 NULL);
 
        return FALSE;
 }
@@ -1010,7 +1088,7 @@ gth_image_viewer_page_real_view (GthViewerPage *base,
 
        gth_image_preloader_load (self->priv->preloader,
                                  self->priv->file_data,
-                                 _gth_image_preloader_get_requested_size (self),
+                                 _gth_image_preloader_get_requested_size_for_next_images (self),
                                  NULL,
                                  preloader_load_ready_cb,
                                  self,
@@ -1484,7 +1562,7 @@ gth_image_viewer_page_init (GthImageViewerPage *self)
        self->priv->image_changed = FALSE;
        self->priv->loading_image = FALSE;
        self->priv->can_paste = FALSE;
-       self->priv->update_quality_event = 0;
+       self->priv->update_quality_id = 0;
 }
 
 
@@ -1766,7 +1844,7 @@ gth_image_viewer_page_get_original (GthImageViewerPage     *self,
 
        gth_image_preloader_load (self->priv->preloader,
                                  self->priv->image_changed ? GTH_MODIFIED_IMAGE : self->priv->file_data,
-                                 -1,
+                                 GTH_ORIGINAL_SIZE,
                                  data->cancellable,
                                  original_image_ready_cb,
                                  data,