[gimp] app: add gimp_image_estimate_memsize()

[Michael Natterer <mitch src gnome org>]

commit 57ef7a29598ee42c73d2dc20149d041779a9cf60
Author: Michael Natterer <mitch gimp org>
Date:   Sun Jun 15 21:40:05 2014 +0200

    app: add gimp_image_estimate_memsize()
    
    to be used to estimate an image's memory size at another precision or
    size.

 app/core/gimpimage.c |   77 ++++++++++++++++++++++++++++++++++++++++++++++++++
 app/core/gimpimage.h |    5 +++
 2 files changed, 82 insertions(+), 0 deletions(-)
---
diff --git a/app/core/gimpimage.c b/app/core/gimpimage.c
index 664fa13..c4108e9 100644
--- a/app/core/gimpimage.c
+++ b/app/core/gimpimage.c
@@ -48,6 +48,7 @@
 #include "gimpimage.h"
 #include "gimpimage-colormap.h"
 #include "gimpimage-guides.h"
+#include "gimpimage-item-list.h"
 #include "gimpimage-metadata.h"
 #include "gimpimage-sample-points.h"
 #include "gimpimage-preview.h"
@@ -75,6 +76,7 @@
 
 #include "vectors/gimpvectors.h"
 
+#include "gimp-log.h"
 #include "gimp-intl.h"
 
 
@@ -1630,6 +1632,81 @@ gimp_image_new (Gimp              *gimp,
                        NULL);
 }
 
+gint64
+gimp_image_estimate_memsize (const GimpImage   *image,
+                             GimpComponentType  component_type,
+                             gint               width,
+                             gint               height)
+{
+  GList  *drawables;
+  GList  *list;
+  gint    current_width;
+  gint    current_height;
+  gint64  current_size;
+  gint64  scalable_size = 0;
+  gint64  scaled_size   = 0;
+  gint64  new_size;
+
+  g_return_val_if_fail (GIMP_IS_IMAGE (image), 0);
+
+  current_width  = gimp_image_get_width (image);
+  current_height = gimp_image_get_height (image);
+  current_size   = gimp_object_get_memsize (GIMP_OBJECT (image), NULL);
+
+  /*  the part of the image's memsize that scales linearly with the image  */
+  drawables = gimp_image_item_list_get_list (image, NULL,
+                                             GIMP_ITEM_TYPE_LAYERS |
+                                             GIMP_ITEM_TYPE_CHANNELS,
+                                             GIMP_ITEM_SET_ALL);
+
+  gimp_image_item_list_filter (NULL, drawables, TRUE, FALSE);
+
+  drawables = g_list_prepend (drawables, gimp_image_get_mask (image));
+
+  for (list = drawables; list; list = g_list_next (list))
+    {
+      GimpDrawable *drawable = list->data;
+      gdouble       drawable_width;
+      gdouble       drawable_height;
+
+      drawable_width  = gimp_item_get_width  (GIMP_ITEM (drawable));
+      drawable_height = gimp_item_get_height (GIMP_ITEM (drawable));
+
+      scalable_size += gimp_drawable_estimate_memsize (drawable,
+                                                       gimp_drawable_get_component_type (drawable),
+                                                       drawable_width,
+                                                       drawable_height);
+
+      scaled_size += gimp_drawable_estimate_memsize (drawable,
+                                                     component_type,
+                                                     drawable_width * width /
+                                                     current_width,
+                                                     drawable_height * height /
+                                                     current_height);
+    }
+
+  g_list_free (drawables);
+
+  scalable_size +=
+    gimp_projection_estimate_memsize (gimp_image_get_base_type (image),
+                                      gimp_image_get_component_type (image),
+                                      gimp_image_get_width (image),
+                                      gimp_image_get_height (image));
+
+  scaled_size +=
+    gimp_projection_estimate_memsize (gimp_image_get_base_type (image),
+                                      component_type,
+                                      width, height);
+
+  GIMP_LOG (IMAGE_SCALE,
+            "scalable_size = %"G_GINT64_FORMAT"  scaled_size = %"G_GINT64_FORMAT,
+            scalable_size, scaled_size);
+
+  new_size = current_size - scalable_size + scaled_size;
+
+  return new_size;
+}
+
 GimpImageBaseType
 gimp_image_get_base_type (const GimpImage *image)
 {
diff --git a/app/core/gimpimage.h b/app/core/gimpimage.h
index 68c6edf..6a3cfeb 100644
--- a/app/core/gimpimage.h
+++ b/app/core/gimpimage.h
@@ -110,6 +110,11 @@ GimpImage     * gimp_image_new                   (Gimp               *gimp,
                                                   GimpImageBaseType   base_type,
                                                   GimpPrecision       precision);
 
+gint64          gimp_image_estimate_memsize      (const GimpImage    *image,
+                                                  GimpComponentType   component_type,
+                                                  gint                width,
+                                                  gint                height);
+
 GimpImageBaseType  gimp_image_get_base_type      (const GimpImage    *image);
 GimpComponentType  gimp_image_get_component_type (const GimpImage    *image);
 GimpPrecision      gimp_image_get_precision      (const GimpImage    *image);