1 files changed, 133 insertions, 0 deletions
diff --git a/app/core/gimpitem-preview.c b/app/core/gimpitem-preview.c
new file mode 100644
index 0000000..f24017b
--- /dev/null
+++ b/app/core/gimpitem-preview.c
@@ -0,0 +1,133 @@
+/* GIMP - The GNU Image Manipulation Program
+ * Copyright (C) 1995 Spencer Kimball and Peter Mattis
+ *
+ * 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 <https://www.gnu.org/licenses/>.
+ */
+
+#include "config.h"
+
+#include <string.h>
+
+#include <gdk-pixbuf/gdk-pixbuf.h>
+#include <gegl.h>
+
+#include "libgimpmath/gimpmath.h"
+
+#include "core-types.h"
+
+#include "config/gimpcoreconfig.h"
+
+#include "gimp.h"
+#include "gimpimage.h"
+#include "gimpitem.h"
+#include "gimpitem-preview.h"
+
+
+/*  public functions  */
+
+void
+gimp_item_get_preview_size (GimpViewable *viewable,
+                            gint          size,
+                            gboolean      is_popup,
+                            gboolean      dot_for_dot,
+                            gint         *width,
+                            gint         *height)
+{
+  GimpItem  *item  = GIMP_ITEM (viewable);
+  GimpImage *image = gimp_item_get_image (item);
+
+  if (image && ! image->gimp->config->layer_previews && ! is_popup)
+    {
+      *width  = size;
+      *height = size;
+      return;
+    }
+
+  if (image && ! is_popup)
+    {
+      gdouble xres;
+      gdouble yres;
+
+      gimp_image_get_resolution (image, &xres, &yres);
+
+      gimp_viewable_calc_preview_size (gimp_image_get_width  (image),
+                                       gimp_image_get_height (image),
+                                       size,
+                                       size,
+                                       dot_for_dot,
+                                       xres,
+                                       yres,
+                                       width,
+                                       height,
+                                       NULL);
+    }
+  else
+    {
+      gimp_viewable_calc_preview_size (gimp_item_get_width  (item),
+                                       gimp_item_get_height (item),
+                                       size,
+                                       size,
+                                       dot_for_dot, 1.0, 1.0,
+                                       width,
+                                       height,
+                                       NULL);
+    }
+}
+
+gboolean
+gimp_item_get_popup_size (GimpViewable *viewable,
+                          gint          width,
+                          gint          height,
+                          gboolean      dot_for_dot,
+                          gint         *popup_width,
+                          gint         *popup_height)
+{
+  GimpItem  *item  = GIMP_ITEM (viewable);
+  GimpImage *image = gimp_item_get_image (item);
+
+  if (image && ! image->gimp->config->layer_previews)
+    return FALSE;
+
+  if (gimp_item_get_width  (item) > width ||
+      gimp_item_get_height (item) > height)
+    {
+      gboolean scaling_up;
+      gdouble  xres = 1.0;
+      gdouble  yres = 1.0;
+
+      if (image)
+        gimp_image_get_resolution (image, &xres, &yres);
+
+      gimp_viewable_calc_preview_size (gimp_item_get_width  (item),
+                                       gimp_item_get_height (item),
+                                       width  * 2,
+                                       height * 2,
+                                       dot_for_dot,
+                                       xres,
+                                       yres,
+                                       popup_width,
+                                       popup_height,
+                                       &scaling_up);
+
+      if (scaling_up)
+        {
+          *popup_width  = gimp_item_get_width  (item);
+          *popup_height = gimp_item_get_height (item);
+        }
+
+      return TRUE;
+    }
+
+  return FALSE;
+}