Move the save and restore background routines into generic code...

...so it can be used at other parts (the listbox will need it).

src/gui/widgets/control.cpp

@@ -16,6 +16,7 @@
 
 #include "font.hpp"
 #include "foreach.hpp"
+#include "gui/widgets/helper.hpp"
 #include "gui/widgets/window.hpp"
 #include "log.hpp"
 #include "marked-up_text.hpp"
@@ -269,32 +270,9 @@ void tcontrol::draw(surface& surface)
 //! @param src          background to save.
 void tcontrol::save_background(const surface& src)
 {
-	assert(src);
 	assert(!restorer_);
 
-	const SDL_Rect rect = get_rect();
-
-	restorer_.assign(SDL_CreateRGBSurface(SDL_SWSURFACE, 
-		rect.w, rect.h, 32, 0xFF0000, 0xFF00, 0xFF, 0xFF000000));
-
-	{
-		// Extra scoping used for the surface_lock.
-		surface_lock src_lock(src);
-		surface_lock dst_lock(restorer_);
-
-		Uint32* src_pixels = reinterpret_cast<Uint32*>(src_lock.pixels());
-		Uint32* dst_pixels = reinterpret_cast<Uint32*>(dst_lock.pixels());
-
-		unsigned offset = rect.y * src->w + rect.x;
-		for(unsigned y = 0; y < rect.h; ++y) {
-			for(unsigned x = 0; x < rect.w; ++x) {
-
-				*dst_pixels++ = src_pixels[offset + x];
-			
-			}
-		offset += src->w;
-		}
-	}
+	restorer_ = gui2::save_background(src, get_rect());
 }
 
 //! Restores a portion of the background.
@@ -304,29 +282,7 @@ void tcontrol::save_background(const surface& src)
 //! @param dst          Background to restore.
 void tcontrol::restore_background(surface& dst)
 {
-	assert(restorer_);
-	assert(dst);
-
-	const SDL_Rect rect = get_rect();
-
-	{
-		// Extra scoping used for the surface_lock.
-		surface_lock src_lock(restorer_);
-		surface_lock dst_lock(dst);
-
-		Uint32* src_pixels = reinterpret_cast<Uint32*>(src_lock.pixels());
-		Uint32* dst_pixels = reinterpret_cast<Uint32*>(dst_lock.pixels());
-
-		unsigned offset = rect.y * dst->w + rect.x;
-		for(unsigned y = 0; y < rect.h; ++y) {
-			for(unsigned x = 0; x < rect.w; ++x) {
-
-				dst_pixels[offset + x] = *src_pixels++;
-
-			}
-		offset += dst->w;
-		}
-	}
+	gui2::restore_background(restorer_, dst, get_rect());
 }
 
 //! Inherited from twidget.

src/gui/widgets/helper.cpp

@@ -13,9 +13,10 @@
 */
 
 #include "gui/widgets/helper.hpp"
-#include "gui/widgets/settings.hpp"
-#include "serialization/string_utils.hpp"
 
+#include "gui/widgets/settings.hpp"
+#include "sdl_utils.hpp"
+#include "serialization/string_utils.hpp"
 #include "log.hpp"
 
 #include "SDL_ttf.h"
@@ -111,5 +112,67 @@ Uint32 decode_colour(const std::string& colour)
 	return result;
 }
 
+surface save_background(const surface& background, const SDL_Rect& rect)
+{
+	assert(background);
+	assert((background->flags & SDL_RLEACCEL) == 0);
+	assert(rect.x + rect.w < background->w);
+	assert(rect.y + rect.h < background->h);
+
+	surface result(SDL_CreateRGBSurface(SDL_SWSURFACE, 
+		rect.w, rect.h, 32, 0xFF0000, 0xFF00, 0xFF, 0xFF000000));
+
+	{
+		// Extra scoping used for the surface_lock.
+		surface_lock src_lock(background);
+		surface_lock dst_lock(result);
+
+		Uint32* src_pixels = reinterpret_cast<Uint32*>(src_lock.pixels());
+		Uint32* dst_pixels = reinterpret_cast<Uint32*>(dst_lock.pixels());
+
+		unsigned offset = rect.y * background->w + rect.x;
+		for(unsigned y = 0; y < rect.h; ++y) {
+			for(unsigned x = 0; x < rect.w; ++x) {
+
+				*dst_pixels++ = src_pixels[offset + x];
+			
+			}
+			offset += background->w;
+		}
+	}
+
+	return result;
+}
+
+void restore_background(const surface& restorer, 
+		surface& background, const SDL_Rect& rect)
+{
+	assert(background);
+	assert(restorer);
+	assert((background->flags & SDL_RLEACCEL) == 0);
+	assert((restorer->flags & SDL_RLEACCEL) == 0);
+	assert(rect.x + rect.w < background->w);
+	assert(rect.y + rect.h < background->h);
+
+	{
+		// Extra scoping used for the surface_lock.
+		surface_lock src_lock(restorer);
+		surface_lock dst_lock(background);
+
+		Uint32* src_pixels = reinterpret_cast<Uint32*>(src_lock.pixels());
+		Uint32* dst_pixels = reinterpret_cast<Uint32*>(dst_lock.pixels());
+
+		unsigned offset = rect.y * background->w + rect.x;
+		for(unsigned y = 0; y < rect.h; ++y) {
+			for(unsigned x = 0; x < rect.w; ++x) {
+
+				dst_pixels[offset + x] = *src_pixels++;
+
+			}
+			offset += background->w;
+		}
+	}
+}
+
 } // namespace gui2
 

src/gui/widgets/helper.hpp

@@ -19,6 +19,8 @@
 
 #include <string>
 
+class surface;
+
 namespace gui2 {
 
 // init needs a cfg object later to init the subsystem
@@ -65,6 +67,33 @@ Uint32 decode_colour(const std::string& colour);
 
 int decode_font_style(const std::string& style);
 
+
+/**
+ * Copies a portion of a surface.
+ *
+ * Unlike get_surface_portion it copies rather then using SDL_Blit. Using 
+ * SDL_Blit gives problems with transparent surfaces.
+ *
+ * @param background              The surface to safe a portion from, this
+ *                                surface shouldn't be a RLE surface.
+ * @param rect                    The part of the surface to copy, the part of
+ *                                the rect should be entirely on the surface.
+ *
+ * @returns                       A copy of the wanted part of the background.
+ */
+surface save_background(const surface& background, const SDL_Rect& rect);
+
+
+/**
+ * Copies one surface unto another one.
+ *
+ * @param restore                The surface to copy to the background.
+ * @param background             The surface to copy unto.
+ * @param rect                   The area to copy to on the background.
+ */
+void restore_background(const surface& restorer, 
+		surface& background,const SDL_Rect& rect);
+
 } // namespace gui2
 
 #endif