[gimp/soc-2013-n-point-deformation-tool: 17/22] app: add canvas buffer preview

[Marek Dvoroznak <dvoromar src gnome org>]

commit a7cba2a251c5e5d76fe5c1e9be13d2887d4047c2
Author: Marek Dvoroznak <dvoromar gmail com>
Date:   Tue Sep 10 17:50:29 2013 +0200

    app: add canvas buffer preview
    
    It is used by n-point deformation tool to preview a deformation process.

 app/display/Makefile.am               |    2 +
 app/display/gimpcanvasbufferpreview.c |  247 +++++++++++++++++++++++++++++++++
 app/display/gimpcanvasbufferpreview.h |   56 ++++++++
 3 files changed, 305 insertions(+), 0 deletions(-)
---
diff --git a/app/display/Makefile.am b/app/display/Makefile.am
index f04ea1b..a755af2 100644
--- a/app/display/Makefile.am
+++ b/app/display/Makefile.am
@@ -23,6 +23,8 @@ libappdisplay_a_sources = \
        gimpcanvasarc.h                         \
        gimpcanvasboundary.c                    \
        gimpcanvasboundary.h                    \
+       gimpcanvasbufferpreview.c               \
+       gimpcanvasbufferpreview.h               \
        gimpcanvascorner.c                      \
        gimpcanvascorner.h                      \
        gimpcanvascursor.c                      \
diff --git a/app/display/gimpcanvasbufferpreview.c b/app/display/gimpcanvasbufferpreview.c
new file mode 100644
index 0000000..9623204
--- /dev/null
+++ b/app/display/gimpcanvasbufferpreview.c
@@ -0,0 +1,247 @@
+/* GIMP - The GNU Image Manipulation Program
+ * Copyright (C) 1995 Spencer Kimball and Peter Mattis
+ *
+ * gimpcanvasbufferpreview.c
+ * Copyright (C) 2013 Marek Dvoroznak <dvoromar gmail com>
+ *
+ * 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 3 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/>.
+ */
+
+#include "config.h"
+
+#include <gegl.h>
+#include <gtk/gtk.h>
+#include <cairo/cairo.h>
+
+#include "libgimpbase/gimpbase.h"
+
+#include "display/display-types.h"
+
+#include "gimpcanvas.h"
+#include "gimpcanvasbufferpreview.h"
+#include "gimpdisplayshell.h"
+#include "gimpdisplayshell-scroll.h"
+
+
+enum
+{
+  PROP_0,
+  PROP_BUFFER
+};
+
+typedef struct _GimpCanvasBufferPreviewPrivate GimpCanvasBufferPreviewPrivate;
+
+struct _GimpCanvasBufferPreviewPrivate
+{
+  GeglBuffer      *buffer;
+};
+
+#define GET_PRIVATE(transform_preview) \
+        G_TYPE_INSTANCE_GET_PRIVATE (transform_preview, \
+                                     GIMP_TYPE_CANVAS_BUFFER_PREVIEW, \
+                                     GimpCanvasBufferPreviewPrivate)
+
+
+/*  local function prototypes  */
+
+static void             gimp_canvas_buffer_preview_set_property   (GObject               *object,
+                                                                   guint                  property_id,
+                                                                   const GValue          *value,
+                                                                   GParamSpec            *pspec);
+static void             gimp_canvas_buffer_preview_get_property   (GObject               *object,
+                                                                   guint                  property_id,
+                                                                   GValue                *value,
+                                                                   GParamSpec            *pspec);
+
+static void             gimp_canvas_buffer_preview_draw           (GimpCanvasItem        *item,
+                                                                   cairo_t               *cr);
+static cairo_region_t * gimp_canvas_buffer_preview_get_extents    (GimpCanvasItem        *item);
+static void             gimp_canvas_buffer_preview_compute_bounds (GimpCanvasItem        *item,
+                                                                   cairo_rectangle_int_t *bounds);
+
+
+G_DEFINE_TYPE (GimpCanvasBufferPreview, gimp_canvas_buffer_preview,
+               GIMP_TYPE_CANVAS_ITEM)
+
+#define parent_class gimp_canvas_buffer_preview_parent_class
+
+
+static void
+gimp_canvas_buffer_preview_class_init (GimpCanvasBufferPreviewClass *klass)
+{
+  GObjectClass        *object_class = G_OBJECT_CLASS (klass);
+  GimpCanvasItemClass *item_class   = GIMP_CANVAS_ITEM_CLASS (klass);
+
+  object_class->set_property = gimp_canvas_buffer_preview_set_property;
+  object_class->get_property = gimp_canvas_buffer_preview_get_property;
+
+  item_class->draw           = gimp_canvas_buffer_preview_draw;
+  item_class->get_extents    = gimp_canvas_buffer_preview_get_extents;
+
+  g_object_class_install_property (object_class, PROP_BUFFER,
+                                   g_param_spec_object ("buffer",
+                                                        NULL, NULL,
+                                                        GEGL_TYPE_BUFFER,
+                                                        GIMP_PARAM_READWRITE));
+
+  g_type_class_add_private (klass, sizeof (GimpCanvasBufferPreviewPrivate));
+}
+
+static void
+gimp_canvas_buffer_preview_init (GimpCanvasBufferPreview *transform_preview)
+{
+}
+
+static void
+gimp_canvas_buffer_preview_set_property (GObject      *object,
+                                            guint         property_id,
+                                            const GValue *value,
+                                            GParamSpec   *pspec)
+{
+  GimpCanvasBufferPreviewPrivate *private = GET_PRIVATE (object);
+
+  switch (property_id)
+    {
+    case PROP_BUFFER:
+      private->buffer = g_value_get_object (value); /* don't ref */
+      break;
+
+    default:
+      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, property_id, pspec);
+      break;
+    }
+}
+
+static void
+gimp_canvas_buffer_preview_get_property (GObject    *object,
+                                            guint       property_id,
+                                            GValue     *value,
+                                            GParamSpec *pspec)
+{
+  GimpCanvasBufferPreviewPrivate *private = GET_PRIVATE (object);
+
+  switch (property_id)
+    {
+    case PROP_BUFFER:
+      g_value_set_object (value, private->buffer);
+      break;
+
+    default:
+      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, property_id, pspec);
+      break;
+    }
+}
+
+static void
+gimp_canvas_buffer_preview_draw (GimpCanvasItem *item,
+                                 cairo_t        *cr)
+{
+  GimpDisplayShell      *shell  = gimp_canvas_item_get_shell (item);
+  GeglBuffer            *buffer = GET_PRIVATE (item)->buffer;
+  cairo_surface_t       *area;
+  guchar                *data;
+  cairo_rectangle_int_t  rectangle;
+  gint                   viewport_offset_x, viewport_offset_y;
+  gint                   viewport_width,    viewport_height;
+
+  gimp_display_shell_scroll_get_scaled_viewport (shell,
+                                                 &viewport_offset_x,
+                                                 &viewport_offset_y,
+                                                 &viewport_width,
+                                                 &viewport_height);
+
+  gimp_canvas_buffer_preview_compute_bounds (item, &rectangle);
+
+  area = cairo_image_surface_create (CAIRO_FORMAT_ARGB32,
+                                     rectangle.width,
+                                     rectangle.height);
+
+  data = cairo_image_surface_get_data (area);
+  gegl_buffer_get (buffer,
+                   GEGL_RECTANGLE ((viewport_offset_x < 0 ? 0 : viewport_offset_x),
+                                   (viewport_offset_y < 0 ? 0 : viewport_offset_y),
+                                   rectangle.width,
+                                   rectangle.height),
+                   shell->scale_x,
+                   gegl_buffer_get_format (buffer), /* has to be cairo-ARGB32 */
+                   data,
+                   cairo_image_surface_get_stride (area),
+                   GEGL_ABYSS_NONE);
+
+  cairo_surface_flush (area);
+  cairo_surface_mark_dirty (area);
+
+  cairo_set_source_surface (cr, area, rectangle.x, rectangle.y);
+  cairo_rectangle (cr, rectangle.x, rectangle.y, rectangle.width, rectangle.height);
+  cairo_fill (cr);
+
+  cairo_surface_destroy (area);
+}
+
+static void
+gimp_canvas_buffer_preview_compute_bounds (GimpCanvasItem *item,
+                                           cairo_rectangle_int_t *bounds)
+{
+  GimpDisplayShell *shell  = gimp_canvas_item_get_shell (item);
+  GeglBuffer       *buffer = GET_PRIVATE (item)->buffer;
+  gint              x_from, x_to;
+  gint              y_from, y_to;
+  gint              viewport_offset_x, viewport_offset_y;
+  gint              viewport_width,    viewport_height;
+  gint              width, height;
+
+  width  = gegl_buffer_get_width  (buffer);
+  height = gegl_buffer_get_height (buffer);
+
+  gimp_display_shell_scroll_get_scaled_viewport (shell,
+                                                 &viewport_offset_x,
+                                                 &viewport_offset_y,
+                                                 &viewport_width,
+                                                 &viewport_height);
+
+  x_from = (viewport_offset_x < 0 ? -viewport_offset_x : 0);
+  y_from = (viewport_offset_y < 0 ? -viewport_offset_y : 0);
+
+  x_to = width * shell->scale_x - viewport_offset_x;
+  if (x_to > viewport_width) x_to = viewport_width;
+
+  y_to = height * shell->scale_y - viewport_offset_y;
+  if (y_to > viewport_height) y_to = viewport_height;
+
+  bounds->x = x_from;
+  bounds->y = y_from;
+  bounds->width  = x_to - x_from;
+  bounds->height = y_to - y_from;
+}
+
+static cairo_region_t *
+gimp_canvas_buffer_preview_get_extents (GimpCanvasItem *item)
+{
+  cairo_rectangle_int_t rectangle;
+  gimp_canvas_buffer_preview_compute_bounds (item, &rectangle);
+  return cairo_region_create_rectangle (&rectangle);
+}
+
+GimpCanvasItem *
+gimp_canvas_buffer_preview_new (GimpDisplayShell  *shell,
+                                GeglBuffer        *buffer)
+{
+  g_return_val_if_fail (GIMP_IS_DISPLAY_SHELL (shell), NULL);
+  g_return_val_if_fail (GEGL_IS_BUFFER (buffer), NULL);
+
+  return g_object_new (GIMP_TYPE_CANVAS_BUFFER_PREVIEW,
+                       "shell",       shell,
+                       "buffer",      buffer,
+                       NULL);
+}
diff --git a/app/display/gimpcanvasbufferpreview.h b/app/display/gimpcanvasbufferpreview.h
new file mode 100644
index 0000000..50660e9
--- /dev/null
+++ b/app/display/gimpcanvasbufferpreview.h
@@ -0,0 +1,56 @@
+/* GIMP - The GNU Image Manipulation Program
+ * Copyright (C) 1995 Spencer Kimball and Peter Mattis
+ *
+ * gimpcanvasbufferpreview.h
+ * Copyright (C) 2013 Marek Dvoroznak <dvoromar gmail com>
+ *
+ * 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 3 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/>.
+ */
+
+#ifndef __GIMP_CANVAS_BUFFER_PREVIEW_H__
+#define __GIMP_CANVAS_BUFFER_PREVIEW_H__
+
+
+#include "gimpcanvasitem.h"
+
+
+#define GIMP_TYPE_CANVAS_BUFFER_PREVIEW            (gimp_canvas_buffer_preview_get_type ())
+#define GIMP_CANVAS_BUFFER_PREVIEW(obj)            (G_TYPE_CHECK_INSTANCE_CAST ((obj), 
GIMP_TYPE_CANVAS_BUFFER_PREVIEW, GimpCanvasBufferPreview))
+#define GIMP_CANVAS_BUFFER_PREVIEW_CLASS(klass)    (G_TYPE_CHECK_CLASS_CAST ((klass), 
GIMP_TYPE_CANVAS_BUFFER_PREVIEW, GimpCanvasBufferPreviewClass))
+#define GIMP_IS_CANVAS_BUFFER_PREVIEW(obj)         (G_TYPE_CHECK_INSTANCE_TYPE ((obj), 
GIMP_TYPE_CANVAS_BUFFER_PREVIEW))
+#define GIMP_IS_CANVAS_BUFFER_PREVIEW_CLASS(klass) (G_TYPE_CHECK_CLASS_TYPE ((klass), 
GIMP_TYPE_CANVAS_BUFFER_PREVIEW))
+#define GIMP_CANVAS_BUFFER_PREVIEW_GET_CLASS(obj)  (G_TYPE_INSTANCE_GET_CLASS ((obj), 
GIMP_TYPE_CANVAS_BUFFER_PREVIEW, GimpCanvasBufferPreviewClass))
+
+
+typedef struct _GimpCanvasBufferPreview      GimpCanvasBufferPreview;
+typedef struct _GimpCanvasBufferPreviewClass GimpCanvasBufferPreviewClass;
+
+struct _GimpCanvasBufferPreview
+{
+  GimpCanvasItem  parent_instance;
+};
+
+struct _GimpCanvasBufferPreviewClass
+{
+  GimpCanvasItemClass  parent_class;
+};
+
+
+GType            gimp_canvas_buffer_preview_get_type (void) G_GNUC_CONST;
+
+GimpCanvasItem * gimp_canvas_buffer_preview_new      (GimpDisplayShell  *shell,
+                                                      GeglBuffer        *buffer);
+
+
+#endif /* __GIMP_CANVAS_BUFFER_PREVIEW_H__ */