Fixed wallpaper prescaling issues

Image::SDLgetScaledImage was changed so that it tries to find an existing
scaled version of the image first, and generates it when none exists.
When it needs to generate one, this resource is added to the resource
manager, partly to avoid duplicating the work later but mainly to keep
memory management straightforward.

This function also used to leak the scaled SDL_Surface since it wrongly
assumed that Image::load would free it.

To avoid filling up the memory with scaled wallpapers that are waiting
30 seconds until they will be deleted, the Resource::decRef function was
extended with a parameter that allows telling it what to do with orphans.
Calling decRef with Resource::DeleteImmediately will delete the resource
immediately in case the resource is orphaned.

Reviewed-by: Yohann Ferreira

1 files changed, 5 insertions, 4 deletions

diff --git a/src/resources/image.h b/src/resources/image.h
index b826112d..7df74c3f 100644
--- a/src/resources/image.h
+++ b/src/resources/image.h
@@ -147,14 +147,15 @@ class Image : public Resource
         { return mDisableTransparency; }
 
         /**
-         * Gets an scaled instance of an image.
+         * Gets an scaled instance of an image. The returned image is managed
+         * by the ResourceManager.
          *
-         * @param width The desired width of the scaled image.
+         * @param width  The desired width of the scaled image.
          * @param height The desired height of the scaled image.
          *
-         * @return A new Image* object.
+         * @return An Image resource, or 0 on failure.
          */
-        Image* SDLgetScaledImage(int width, int height);
+        Image *SDLgetScaledImage(int width, int height);
 
         /**
          * Get the alpha Channel of a SDL surface.