[gthumb] navigator: fixed scrolling when not using the original image

[Paolo Bacchilega <paobac src gnome org>]

commit 955936c46514cf23b8a72add78b871eaa3e07dd8
Author: Paolo Bacchilega <paobac src gnome org>
Date:   Fri Oct 11 17:59:01 2013 +0200

    navigator: fixed scrolling when not using the original image

 gthumb/gth-image-navigator.c |   36 ++++++++++++++++++++++++------------
 1 files changed, 24 insertions(+), 12 deletions(-)
---
diff --git a/gthumb/gth-image-navigator.c b/gthumb/gth-image-navigator.c
index 134c97b..1503591 100644
--- a/gthumb/gth-image-navigator.c
+++ b/gthumb/gth-image-navigator.c
@@ -335,10 +335,12 @@ typedef struct {
        GtkWidget             *preview;
        cairo_surface_t       *image;
        int                    image_width, image_height;
+       int                    original_width, original_height;
        int                    window_max_width, window_max_height;
        int                    popup_x, popup_y, popup_width, popup_height;
        cairo_rectangle_int_t  visible_area;
        double                 zoom_factor;
+       double                 quality_zoom;
 } NavigatorPopup;
 
 
@@ -378,14 +380,14 @@ update_popup_geometry (NavigatorPopup *nav_popup)
        int           scroll_offset_x;
        int           scroll_offset_y;
 
-       zoomed_width = nav_popup->image_width * gth_image_viewer_get_zoom (nav_popup->viewer);
-       zoomed_height = nav_popup->image_height * gth_image_viewer_get_zoom (nav_popup->viewer);
+       zoomed_width = nav_popup->original_width * gth_image_viewer_get_zoom (nav_popup->viewer);
+       zoomed_height = nav_popup->original_height * gth_image_viewer_get_zoom (nav_popup->viewer);
 
        nav_popup->window_max_width = MIN (zoomed_width, POPUP_MAX_WIDTH);
        nav_popup->window_max_height = MIN (zoomed_width, POPUP_MAX_HEIGHT);
-
        nav_popup->zoom_factor = MIN ((double) (nav_popup->window_max_width) / zoomed_width,
-                                   (double) (nav_popup->window_max_height) / zoomed_height);
+                                     (double) (nav_popup->window_max_height) / zoomed_height);
+       nav_popup->quality_zoom = (double) nav_popup->original_width / nav_popup->image_width;
 
        /* popup window size */
 
@@ -411,8 +413,8 @@ update_popup_geometry (NavigatorPopup *nav_popup)
        /* visible area position */
 
        gth_image_viewer_get_scroll_offset (nav_popup->viewer, &scroll_offset_x, &scroll_offset_y);
-       nav_popup->visible_area.x = scroll_offset_x * nav_popup->zoom_factor;
-       nav_popup->visible_area.y = scroll_offset_y * nav_popup->zoom_factor;
+       nav_popup->visible_area.x = scroll_offset_x * (nav_popup->zoom_factor * nav_popup->quality_zoom);
+       nav_popup->visible_area.y = scroll_offset_y * (nav_popup->zoom_factor * nav_popup->quality_zoom);
 
        /* popup window position */
 
@@ -458,8 +460,8 @@ popup_window_event_cb (GtkWidget *widget,
                nav_popup->visible_area.x = (int) x;
                nav_popup->visible_area.y = (int) y;
 
-               mx = (int) (x / nav_popup->zoom_factor);
-               my = (int) (y / nav_popup->zoom_factor);
+               mx = (int) (x / (nav_popup->quality_zoom * nav_popup->zoom_factor));
+               my = (int) (y / (nav_popup->quality_zoom * nav_popup->zoom_factor));
                gth_image_viewer_set_scroll_offset (viewer, mx, my);
 
                gtk_widget_queue_draw (widget);
@@ -540,18 +542,22 @@ navigator_popup_draw_cb (GtkWidget      *widget,
        if (nav_popup->image == NULL)
                return FALSE;
 
-       cairo_set_antialias (cr, CAIRO_ANTIALIAS_NONE);
-
        cairo_save (cr);
+       cairo_set_antialias (cr, CAIRO_ANTIALIAS_NONE);
        cairo_set_source_surface (cr, nav_popup->image, 0, 0);
        cairo_pattern_set_filter (cairo_get_source (cr), CAIRO_FILTER_FAST);
-       cairo_rectangle (cr, 0, 0, nav_popup->image_width, nav_popup->image_height);
+       cairo_rectangle (cr,
+                        0, 0,
+                        cairo_image_surface_get_width (nav_popup->image),
+                        cairo_image_surface_get_height (nav_popup->image));
        cairo_fill (cr);
        cairo_restore (cr);
 
+       cairo_save (cr);
        cairo_set_source_rgba (cr, 0.0, 0.0, 0.0, 0.5);
        cairo_rectangle (cr, 0, 0, nav_popup->popup_width, nav_popup->popup_height);
        cairo_fill (cr);
+       cairo_restore (cr);
 
        if ((nav_popup->visible_area.width < nav_popup->popup_width)
            || (nav_popup->visible_area.height < nav_popup->popup_height))
@@ -565,7 +571,10 @@ navigator_popup_draw_cb (GtkWidget      *widget,
                cairo_clip (cr);
                cairo_set_source_surface (cr, nav_popup->image, 0, 0);
                cairo_pattern_set_filter (cairo_get_source (cr), CAIRO_FILTER_FAST);
-               cairo_rectangle (cr, 0, 0, nav_popup->image_width, nav_popup->image_width);
+               cairo_rectangle (cr,
+                                0, 0,
+                                cairo_image_surface_get_width (nav_popup->image),
+                                cairo_image_surface_get_height (nav_popup->image));
                cairo_fill (cr);
                cairo_restore (cr);
 
@@ -623,6 +632,9 @@ navigator_event_area_button_press_event_cb (GtkWidget      *widget,
 
        nav_popup->image_width = gth_image_viewer_get_image_width (GTH_IMAGE_VIEWER (self->priv->viewer));
        nav_popup->image_height = gth_image_viewer_get_image_height (GTH_IMAGE_VIEWER (self->priv->viewer));
+       gth_image_viewer_get_original_size (GTH_IMAGE_VIEWER (self->priv->viewer),
+                                           &nav_popup->original_width,
+                                           &nav_popup->original_height);
        update_popup_geometry (nav_popup);
 
        g_signal_connect (G_OBJECT (nav_popup->popup_win),