app_server: Some cleanup of the new clipping code.

* Fixed some coding style issues and use regular pointers like everywhere
   else in app_server code.
 * Moved _RenderPicture() from View to AlphaMask.

src/servers/app/AlphaMask.cpp

@@ -1,16 +1,22 @@
 /*
  * Copyright 2014, Haiku, Inc.
  * Distributed under the terms of the MIT License.
+ *
+ * Authors:
+ *		Adrien Destugues <[email protected]>
  */
 
 
 #include "AlphaMask.h"
 
+#include "BitmapHWInterface.h"
+#include "BitmapManager.h"
+#include "DrawingEngine.h"
 #include "ServerBitmap.h"
 #include "View.h"
 
 
-AlphaMask::AlphaMask(View& view, ServerPicture& picture, bool inverse,
+AlphaMask::AlphaMask(View* view, ServerPicture* picture, bool inverse,
 		BPoint origin)
 	:
 	fPicture(picture),
@@ -22,13 +28,13 @@ AlphaMask::AlphaMask(View& view, ServerPicture& picture, bool inverse,
 	fCachedMask(),
 	fScanline(fCachedMask)
 {
-	fPicture.AcquireReference();
+	fPicture->AcquireReference();
 }
 
 
 AlphaMask::~AlphaMask()
 {
-	fPicture.ReleaseReference();
+	fPicture->ReleaseReference();
 	if (fCachedBitmap)
 		fCachedBitmap->ReleaseReference();
 }
@@ -37,23 +43,87 @@ AlphaMask::~AlphaMask()
 scanline_unpacked_masked_type*
 AlphaMask::Generate()
 {
-	// If rendering the picture fails, we will draw without any clipping.
-	ServerBitmap* bitmap = fView._RenderPicture(&fPicture, fInverse);
-	if (!bitmap)
-		return NULL;
+//	if (fCachedBitmap != NULL) {
+//		// TODO: See if cached bitmap can actually be used. Don't use it
+//		// when view scrolling offset has changed, for example. Generate()
+//		// could be passed a current offset
+//		return &fScanline;
+//	}
 
-	// FIXME actually use the cached bitmap whenever possible, instead of
-	// rendering the BPicture again and again.
-	if (fCachedBitmap)
+	if (fCachedBitmap != NULL)
 		fCachedBitmap->ReleaseReference();
+	
+	// If rendering the picture fails, we will draw without any clipping.
+	ServerBitmap* bitmap = _RenderPicture(fPicture, fInverse);
+	if (bitmap == NULL) {
+		fCachedBitmap = NULL;
+		fBuffer.attach(NULL, 0, 0, 0);
+		return NULL;
+	}
+
 	fCachedBitmap = bitmap;
 
 	fBuffer.attach(fCachedBitmap->Bits(), fCachedBitmap->Width(),
 		fCachedBitmap->Height(), fCachedBitmap->BytesPerRow());
 
 	BPoint offset(B_ORIGIN);
-	fView.ConvertToScreen(&offset);
+	fView->ConvertToScreen(&offset);
+
 	fCachedMask.attach(fBuffer, offset.x + fOrigin.x, offset.y + fOrigin.y,
 		fInverse ? 255 : 0);
+
 	return &fScanline;
 }
+
+
+ServerBitmap*
+AlphaMask::_RenderPicture(ServerPicture* picture, bool inverse) const
+{
+	BRect bounds(fView->Bounds());
+
+	// TODO: Only the alpha channel is relevant, but there is no B_ALPHA8
+	// color space, so we use 300% more memory than needed.
+	UtilityBitmap* bitmap = new(std::nothrow) UtilityBitmap(bounds, B_RGBA32,
+		0);
+	if (bitmap == NULL)
+		return NULL;
+
+	// Clear the bitmap with the transparent color
+	memset(bitmap->Bits(), 0, bitmap->BitsLength());
+
+	// Render the picture to the bitmap
+	BitmapHWInterface interface(bitmap);
+	DrawingEngine* engine = interface.CreateDrawingEngine();
+	if (engine == NULL) {
+		delete bitmap;
+		return NULL;
+	}
+
+	// Copy the current state of the client view, so we draw with the right
+	// font, color and everything
+	engine->SetDrawState(fView->CurrentState());
+	OffscreenContext context(engine);
+	if (engine->LockParallelAccess()) {
+		// FIXME ConstrainClippingRegion docs says passing NULL disables
+		// all clipping. This doesn't work and will crash in Painter.
+		BRegion clipping;
+		clipping.Include(bounds);
+		engine->ConstrainClippingRegion(&clipping);
+		picture->Play(&context);
+		engine->UnlockParallelAccess();
+	}
+	delete engine;
+
+	if (!inverse)
+		return bitmap;
+
+	// Compute the inverse of our bitmap. There probably is a better way.
+	uint32 size = bitmap->BitsLength();
+	uint8* bits = (uint8*)bitmap->Bits();
+
+	for(uint32 i = 0; i < size; i++)
+		bits[i] = 255 - bits[i];
+
+	return bitmap;
+}
+

src/servers/app/AlphaMask.h

@@ -17,26 +17,30 @@
 class ServerBitmap;
 
 
-class AlphaMask
-{
-	public:
-										AlphaMask(View& view,
-											ServerPicture& mask, bool inverse,
-											BPoint origin);
-										~AlphaMask();
-		scanline_unpacked_masked_type*	Generate();
+class AlphaMask {
+public:
+								AlphaMask(View* view, ServerPicture* mask,
+									bool inverse, BPoint origin);
+								~AlphaMask();
 
-	private:
-		ServerPicture&					fPicture;
-		const bool						fInverse;
-		const BPoint					fOrigin;
-		View&							fView;
+			scanline_unpacked_masked_type* Generate();
 
-		ServerBitmap*					fCachedBitmap;
-		agg::rendering_buffer			fBuffer;
-		agg::clipped_alpha_mask			fCachedMask;
-		scanline_unpacked_masked_type	fScanline;
+private:
+			ServerBitmap*		_RenderPicture(ServerPicture* picture,
+									bool inverse) const;
+
+
+private:
+			ServerPicture*		fPicture;
+			const bool			fInverse;
+			BPoint				fOrigin;
+			View*				fView;
+
+			ServerBitmap*		fCachedBitmap;
+			agg::rendering_buffer fBuffer;
+			agg::clipped_alpha_mask fCachedMask;
+			scanline_unpacked_masked_type fScanline;
 };
 
 
-#endif
+#endif // ALPHA_MASK_H

src/servers/app/View.cpp

@@ -16,8 +16,6 @@
 #include <stdio.h>
 
 #include "AlphaMask.h"
-#include "BitmapHWInterface.h"
-#include "BitmapManager.h"
 #include "Desktop.h"
 #include "DrawingEngine.h"
 #include "DrawState.h"
@@ -1596,79 +1594,13 @@ View::SetAlphaMask(ServerPicture* picture, bool inverse, BPoint origin)
 
 	delete fAlphaMask;
 	if (picture != NULL) {
-		fAlphaMask = new(std::nothrow) AlphaMask(*this, *picture, inverse,
+		fAlphaMask = new(std::nothrow) AlphaMask(this, picture, inverse,
 			origin);
 	} else
 		fAlphaMask = NULL;
 }
 
 
-ServerBitmap*
-View::_RenderPicture(ServerPicture* picture, bool inverse)
-{
-	BRect bounds(Bounds());
-
-	// TODO: Only the alpha channel is relevant, but there is no B_ALPHA8
-	// color space, so we use 300% more memory than needed.
-	UtilityBitmap* bitmap = new(std::nothrow) UtilityBitmap(bounds, B_RGBA32,
-		0);
-	if (bitmap == NULL)
-		return NULL;
-
-#if 0
-	/*
-	 * TODO stippi says we could use OffscreenWindow to do this, but there
-	 * doesn't seem to be a way to create a View without a BView on
-	 * application side (the constructor wants a token).
-	 * This would be better, as it would avoid the DrawingContext abstraction
-	 * above View and OffscreenContext and allow for inlining more methods.
-	 */
-	OffscreenWindow window(bitmap, "ClipToPicture", Window());
-	View view(bounds, IntPoint(0, 0), "ClipToPicture");
-	window->SetTopView(view);
-#endif
-
-	// Clear the bitmap with the transparent color
-	memset(bitmap->Bits(), 0, bitmap->BitsLength());
-
-	// Render the picture to the bitmap
-	BitmapHWInterface interface(bitmap);
-	DrawingEngine* engine = interface.CreateDrawingEngine();
-	if (engine == NULL) {
-		delete bitmap;
-		return NULL;
-	}
-
-	// Copy the current state of the client view, so we draw with the right
-	// font, color and everything
-	engine->SetDrawState(CurrentState());
-	OffscreenContext context(engine);
-	if (engine->LockParallelAccess())
-	{
-		// FIXME ConstrainClippingRegion docs says passing NULL disables
-		// all clipping. This doesn't work and will crash in Painter.
-		BRegion clipping;
-		clipping.Include(bounds);
-		engine->ConstrainClippingRegion(&clipping);
-		picture->Play(&context);
-		engine->UnlockParallelAccess();
-	}
-	delete engine;
-
-	if (!inverse)
-		return bitmap;
-
-	// Compute the inverse of our bitmap. There probably is a better way.
-	uint32 size = bitmap->BitsLength();
-	uint8* bits = (uint8*)bitmap->Bits();
-
-	for(uint32 i = 0; i < size; i++)
-		bits[i] = 255 - bits[i];
-
-	return bitmap;
-}
-
-
 BRegion&
 View::_ScreenClipping(BRegion* windowContentClipping, bool force) const
 {

src/servers/app/View.h

@@ -39,7 +39,7 @@ class ServerPicture;
 class BGradient;
 
 class View: public DrawingContext {
-	public:
+public:
 							View(IntRect frame, IntPoint scrollingOffset,
 								const char* name, int32 token,
 								uint32 resizeMode, uint32 flags);
@@ -232,10 +232,7 @@ class View: public DrawingContext {
 								int32 level = 0);
 #endif
 
-	protected:
-			friend class	AlphaMask;
-			ServerBitmap*	_RenderPicture(ServerPicture* picture,
-								bool inverse);
+protected:
 			BRegion&		_ScreenClipping(BRegion* windowContentClipping,
 								bool force = false) const;
 			void			_MoveScreenClipping(int32 x, int32 y,