[gimp] app: add support for a preview rectangle to GimpImageMap

[Michael Natterer <mitch src gnome org>]

commit b5bc15c9b9980c315d7daa1218af44772040707d
Author: Michael Natterer <mitch gimp org>
Date:   Tue Feb 16 21:25:44 2016 +0100

    app: add support for a preview rectangle to GimpImageMap

 app/core/gimpimagemap.c |  107 +++++++++++++++++++++++++++++++++++++++++++++-
 app/core/gimpimagemap.h |   49 +++++++++++----------
 2 files changed, 130 insertions(+), 26 deletions(-)
---
diff --git a/app/core/gimpimagemap.c b/app/core/gimpimagemap.c
index acc1baa..3e7c183 100644
--- a/app/core/gimpimagemap.c
+++ b/app/core/gimpimagemap.c
@@ -27,6 +27,7 @@
 
 #include "config.h"
 
+#include <cairo.h>
 #include <gdk-pixbuf/gdk-pixbuf.h>
 #include <gegl.h>
 
@@ -62,6 +63,8 @@ struct _GimpImageMap
   gchar                *icon_name;
 
   GimpImageMapRegion    region;
+  GimpOrientationType   preview_orientation;
+  gdouble               preview_percent;
   gdouble               opacity;
   GimpLayerModeEffects  paint_mode;
   gboolean              gamma_hack;
@@ -81,6 +84,9 @@ static void       gimp_image_map_dispose         (GObject             *object);
 static void       gimp_image_map_finalize        (GObject             *object);
 
 static void       gimp_image_map_sync_region     (GimpImageMap        *image_map);
+static void       gimp_image_map_sync_preview    (GimpImageMap        *image_map,
+                                                  GimpOrientationType  old_orientation,
+                                                  gdouble              old_percent);
 static void       gimp_image_map_sync_mode       (GimpImageMap        *image_map);
 static void       gimp_image_map_sync_affect     (GimpImageMap        *image_map);
 static void       gimp_image_map_sync_gamma_hack (GimpImageMap        *image_map);
@@ -125,9 +131,11 @@ gimp_image_map_class_init (GimpImageMapClass *klass)
 static void
 gimp_image_map_init (GimpImageMap *image_map)
 {
-  image_map->region     = GIMP_IMAGE_MAP_REGION_SELECTION;
-  image_map->opacity    = GIMP_OPACITY_OPAQUE;
-  image_map->paint_mode = GIMP_REPLACE_MODE;
+  image_map->region              = GIMP_IMAGE_MAP_REGION_SELECTION;
+  image_map->preview_orientation = GIMP_ORIENTATION_HORIZONTAL;
+  image_map->preview_percent     = 1.0;
+  image_map->opacity             = GIMP_OPACITY_OPAQUE;
+  image_map->paint_mode          = GIMP_REPLACE_MODE;
 }
 
 static void
@@ -229,6 +237,28 @@ gimp_image_map_set_region (GimpImageMap       *image_map,
 }
 
 void
+gimp_image_map_set_preview (GimpImageMap        *image_map,
+                            GimpOrientationType  orientation,
+                            gdouble              percent)
+{
+  g_return_if_fail (GIMP_IS_IMAGE_MAP (image_map));
+
+  percent = CLAMP (percent, 0.0, 1.0);
+
+  if (orientation != image_map->preview_orientation ||
+      percent     != image_map->preview_percent)
+    {
+      GimpOrientationType old_orientation = image_map->preview_orientation;
+      gdouble             old_percent     = image_map->preview_percent;
+
+      image_map->preview_orientation = orientation;
+      image_map->preview_percent     = percent;
+
+      gimp_image_map_sync_preview (image_map, old_orientation, old_percent);
+    }
+}
+
+void
 gimp_image_map_set_mode (GimpImageMap         *image_map,
                          gdouble               opacity,
                          GimpLayerModeEffects  paint_mode)
@@ -344,6 +374,9 @@ gimp_image_map_apply (GimpImageMap        *image_map,
                                                    NULL);
 
       gimp_image_map_sync_region (image_map);
+      gimp_image_map_sync_preview (image_map,
+                                   image_map->preview_orientation,
+                                   image_map->preview_percent);
       gimp_image_map_sync_mode (image_map);
       gimp_image_map_sync_gamma_hack (image_map);
 
@@ -477,6 +510,74 @@ gimp_image_map_sync_region (GimpImageMap *image_map)
 }
 
 static void
+gimp_image_map_get_preview_rect (GimpImageMap        *image_map,
+                                 GimpOrientationType  orientation,
+                                 gdouble              percent,
+                                 GeglRectangle       *rect)
+{
+  rect->x = 0;
+  rect->y = 0;
+  rect->width  = gimp_item_get_width  (GIMP_ITEM (image_map->drawable));
+  rect->height = gimp_item_get_height (GIMP_ITEM (image_map->drawable));
+
+  if (orientation == GIMP_ORIENTATION_HORIZONTAL)
+    rect->width *= percent;
+  else
+    rect->height *= percent;
+ }
+
+static void
+gimp_image_map_sync_preview (GimpImageMap        *image_map,
+                             GimpOrientationType  old_orientation,
+                             gdouble              old_percent)
+{
+  if (image_map->applicator)
+    {
+      GeglRectangle old_rect;
+      GeglRectangle new_rect;
+
+      gimp_image_map_get_preview_rect (image_map,
+                                       old_orientation,
+                                       old_percent,
+                                       &old_rect);
+
+      gimp_image_map_get_preview_rect (image_map,
+                                       image_map->preview_orientation,
+                                       image_map->preview_percent,
+                                       &new_rect);
+
+      gimp_applicator_set_preview (image_map->applicator, TRUE, &new_rect);
+
+      if (old_rect.width  != new_rect.width ||
+          old_rect.height != new_rect.height)
+        {
+          cairo_region_t *region;
+          gint            n_rects;
+          gint            i;
+
+          region = cairo_region_create_rectangle ((cairo_rectangle_int_t *)
+                                                  &old_rect);
+          cairo_region_xor_rectangle (region,
+                                      (cairo_rectangle_int_t *) &new_rect);
+
+          n_rects = cairo_region_num_rectangles (region);
+
+          for (i = 0; i < n_rects; i++)
+            {
+              cairo_rectangle_int_t rect;
+
+              cairo_region_get_rectangle (region, i, &rect);
+
+              gimp_image_map_update_drawable (image_map,
+                                              (const GeglRectangle *) &rect);
+            }
+
+          cairo_region_destroy (region);
+        }
+    }
+}
+
+static void
 gimp_image_map_sync_mode (GimpImageMap *image_map)
 {
   if (image_map->applicator)
diff --git a/app/core/gimpimagemap.h b/app/core/gimpimagemap.h
index b40ae06..003a7cc 100644
--- a/app/core/gimpimagemap.h
+++ b/app/core/gimpimagemap.h
@@ -47,29 +47,32 @@ struct _GimpImageMapClass
  *  both of which will remove the live filter from the drawable.
  */
 
-GType          gimp_image_map_get_type   (void) G_GNUC_CONST;
-
-GimpImageMap * gimp_image_map_new        (GimpDrawable         *drawable,
-                                          const gchar          *undo_desc,
-                                          GeglNode             *operation,
-                                          const gchar          *icon_name);
-
-void           gimp_image_map_set_region (GimpImageMap         *image_map,
-                                          GimpImageMapRegion    region);
-void           gimp_image_map_set_mode   (GimpImageMap         *image_map,
-                                          gdouble               opacity,
-                                          GimpLayerModeEffects  paint_mode);
-
-void       gimp_image_map_set_gamma_hack (GimpImageMap         *image_map,
-                                          gboolean              gamma_hack);
-
-void           gimp_image_map_apply      (GimpImageMap         *image_map,
-                                          const GeglRectangle  *area);
-
-gboolean       gimp_image_map_commit     (GimpImageMap         *image_map,
-                                          GimpProgress         *progress,
-                                          gboolean              cancellable);
-void           gimp_image_map_abort      (GimpImageMap         *image_map);
+GType          gimp_image_map_get_type    (void) G_GNUC_CONST;
+
+GimpImageMap * gimp_image_map_new         (GimpDrawable         *drawable,
+                                           const gchar          *undo_desc,
+                                           GeglNode             *operation,
+                                           const gchar          *icon_name);
+
+void           gimp_image_map_set_region  (GimpImageMap         *image_map,
+                                           GimpImageMapRegion    region);
+void           gimp_image_map_set_preview (GimpImageMap         *image_map,
+                                           GimpOrientationType   orienatnios,
+                                           gdouble               percent_visible);
+void           gimp_image_map_set_mode    (GimpImageMap         *image_map,
+                                           gdouble               opacity,
+                                           GimpLayerModeEffects  paint_mode);
+
+void        gimp_image_map_set_gamma_hack (GimpImageMap         *image_map,
+                                           gboolean              gamma_hack);
+
+void           gimp_image_map_apply       (GimpImageMap         *image_map,
+                                           const GeglRectangle  *area);
+
+gboolean       gimp_image_map_commit      (GimpImageMap         *image_map,
+                                           GimpProgress         *progress,
+                                           gboolean              cancellable);
+void           gimp_image_map_abort       (GimpImageMap         *image_map);
 
 
 #endif /* __GIMP_IMAGE_MAP_H__ */