(svn r19723) -Add: a simple sprite alignment helper. It does not store the new offsets anywhere so as soon as the sprite is reloaded the offsets are gone (use a bigger sprite cache if this happens). Also anything that reloads NewGRFs (new games, loading games or (re)applying NewGRFs) clears the sprite cache and as such resets the offsets.

src/spritecache.h

@@ -28,6 +28,11 @@ extern uint _sprite_cache_size;
 void *GetRawSprite(SpriteID sprite, SpriteType type);
 bool SpriteExists(SpriteID sprite);
 
+SpriteType GetSpriteType(SpriteID sprite);
+uint GetOriginFileSlot(SpriteID sprite);
+uint GetMaxSpriteID();
+
+
 static inline const Sprite *GetSprite(SpriteID sprite, SpriteType type)
 {
 	assert(type != ST_RECOLOUR);