GLK: Add picture scaling

engines/glk/picture.cpp

@@ -126,6 +126,21 @@ Picture *Pictures::load(uint32 id) {
     return pic;
 }
 
+Picture *Pictures::scale(Picture *src, size_t sx, size_t sy) {
+	// Check for the presence of an already scaled version of that size
+	Picture *dst = retrieve(src->_id, true);
+	if (dst && dst->w == sx && dst->h == sy)
+		return dst;
+
+	// Create a new picture of the destination size and rescale the source picture
+	dst = new Picture(sx, sy, src->format);
+	dst->_id = src->_id;
+	dst->_scaled = true;
+	dst->transBlitFrom(*src, src->getBounds(), dst->getBounds(), (uint)-1);
+
+	storeScaled(dst);
+}
+
 /*--------------------------------------------------------------------------*/
 
 void Picture::increment() {
@@ -139,11 +154,6 @@ void Picture::decrement() {
 	}
 }
 
-Picture *Picture::scale(int sx, int sy) {
-	// TODO: gli_picture_scale
-	return nullptr;
-}
-
 void Picture::drawPicture(int x0, int y0, int dx0, int dy0, int dx1, int dy1) {
 	// TODO: drawPicture
 }

engines/glk/picture.h

@@ -40,7 +40,13 @@ public:
 	/**
 	 * Constructor
 	 */
-	Picture() : Graphics::ManagedSurface(), _refCount(0), _id(0), _scaled(0) {}
+	Picture() : Graphics::ManagedSurface(), _refCount(0), _id(0), _scaled(false) {}
+
+	/**
+	 * Constructor
+	 */
+	Picture(int width, int height, const Graphics::PixelFormat &format) :
+		Graphics::ManagedSurface(width, height, format), _refCount(0), _id(0), _scaled(false) {}
 
 	/**
 	 * Increment reference counter
@@ -52,11 +58,6 @@ public:
 	 */
 	void decrement();
 
-	/**
-	 * Rescale the picture to a new picture of a given size
-	 */
-	Picture *scale(int sx, int sy);
-
 	/**
 	 * Draw the picture
 	 */
@@ -134,6 +135,11 @@ public:
 	 * Load a given picture
 	 */
 	Picture *load(uint32 id);
+
+	/**
+	 * Rescale the passed picture to a new picture of a given size
+	 */
+	Picture *scale(Picture *src, size_t sx, size_t sy);
 };
 
 } // End of namespace Glk

engines/glk/window_graphics.cpp

@@ -186,7 +186,7 @@ void GraphicsWindow::drawPicture(Picture *src,  int x0, int y0, int width, int h
 	int w, h;
 
 	if (width != src->w || height != src->h) {
-		src = src->scale(width, height);
+		src = g_vm->_pictures->scale(src, width, height);
 		if (!src)
 			return;
 	}

engines/glk/window_text_buffer.cpp

@@ -286,7 +286,7 @@ glui32 TextBufferWindow::drawPicture(glui32 image, glui32 align, glui32 scaled,
 
 	if (scaled) {
 		Picture *tmp;
-		tmp = pic->scale(width, height);
+		tmp = g_vm->_pictures->scale(pic, width, height);
 		pic = tmp;
 	}