Refactored out create_optimized_surface

Instead, we simply call adjust_surface_alpha directly. This removes the creation of another temporary surface.
This also removes cases when it's called after creating a surface with create_neutral_surface, since that
function should produce the same result.

src/floating_label.cpp

@@ -179,8 +179,8 @@ surface floating_label::create_surface()
 
 			if (background == nullptr) {
 				ERR_FT << "could not create tooltip box" << std::endl;
-				surf_ = create_optimized_surface(foreground);
-				return surf_;
+				adjust_surface_alpha(foreground, SDL_ALPHA_OPAQUE);
+				return surf_ = foreground;
 			}
 
 			Uint32 color = SDL_MapRGBA(foreground->format, bgcolor_.r,bgcolor_.g, bgcolor_.b, bgalpha_);
@@ -196,7 +196,8 @@ surface floating_label::create_surface()
 			adjust_surface_alpha(foreground, SDL_ALPHA_OPAQUE);
 			blit_surface(foreground, nullptr, background, &r);
 
-			surf_ = create_optimized_surface(background);
+			adjust_surface_alpha(background, SDL_ALPHA_OPAQUE);
+			surf_ = background;
 			// RLE compression seems less efficient for big semi-transparent area
 			// so, remove it for this case, but keep the optimized display format
 			adjust_surface_alpha(surf_, SDL_ALPHA_OPAQUE);
@@ -212,12 +213,13 @@ surface floating_label::create_surface()
 
 			if (background == nullptr) {
 				ERR_FT << "could not create floating label's shadow" << std::endl;
-				surf_ = create_optimized_surface(foreground);
-				return surf_;
+				adjust_surface_alpha(foreground, SDL_ALPHA_OPAQUE);
+				return surf_ = foreground;
 			}
 			adjust_surface_alpha(foreground, SDL_ALPHA_OPAQUE);
 			blit_surface(foreground, nullptr, background, &r);
-			surf_ = create_optimized_surface(background);
+			adjust_surface_alpha(background, SDL_ALPHA_OPAQUE);
+			surf_ = background;
 		}
 	}
 

src/image.cpp

@@ -959,7 +959,7 @@ surface get_image(const image::locator& i_locator, TYPE type)
 
 	// Optimizes surface before storing it
 	if(res)
-		res = create_optimized_surface(res);
+		adjust_surface_alpha(res, SDL_ALPHA_OPAQUE);
 
 #ifdef _OPENMP
 #pragma omp critical(image_cache)
@@ -1112,7 +1112,8 @@ surface get_lighted_image(const image::locator& i_locator, const light_string& l
 	}
 
 	// Optimizes surface before storing it
-	res = create_optimized_surface(res);
+	adjust_surface_alpha(res, SDL_ALPHA_OPAQUE);
+
 	// record the lighted surface in the corresponding variants cache
 	i_locator.access_in_cache(*imap)[ls] = res;
 

src/image_modifications.cpp

@@ -247,8 +247,9 @@ surface crop_modification::operator()(const surface& src) const
 	 * Since it seems to work for most cases, rather change this caller instead
 	 * of the function signature. (The issue was discovered in bug #20876).
 	 */
-	return create_optimized_surface(
-			cut_surface(make_neutral_surface(src), area));
+    surface temp = cut_surface(make_neutral_surface(src), area);
+	adjust_surface_alpha(temp, SDL_ALPHA_OPAQUE);
+	return temp;
 }
 
 const SDL_Rect& crop_modification::get_slice() const