Add a handy utility class that provides a DrawingEngine directly attached to a

server side UtilityBitmap of a certain size. It sets up the DrawingEngine, the
UtilityBitmap and the BitmapHWInterface necessary so that one can directly
do drawing to a bitmap using the normal DrawingEngine interface. It provides
an ExportToBitmap method that allocates an output UtilityBitmap of a specified
size and color space where the content is put into, so a single instance of a
BitmapDrawingEngine can be reused for various drawing.

git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@25951 a95241bf-73f2-0310-859d-f6bbb57e9c96

src/servers/app/BitmapDrawingEngine.cpp

@@ -0,0 +1,85 @@
+#include "BitmapDrawingEngine.h"
+#include "BitmapHWInterface.h"
+#include "ServerBitmap.h"
+#include <new>
+
+
+BitmapDrawingEngine::BitmapDrawingEngine()
+	:	DrawingEngine(),
+		fHWInterface(NULL),
+		fBitmap(NULL)
+{
+}
+
+
+BitmapDrawingEngine::~BitmapDrawingEngine()
+{
+	SetSize(0, 0);
+}
+
+
+status_t
+BitmapDrawingEngine::SetSize(int32 newWidth, int32 newHeight)
+{
+	if (fBitmap != NULL && newWidth > 0 && newHeight > 0
+		&& fBitmap->Bounds().IntegerWidth() >= newWidth
+		&& fBitmap->Bounds().IntegerHeight() >= newHeight) {
+		return B_OK;
+	}
+
+	SetHWInterface(NULL);
+	if (fHWInterface) {
+		fHWInterface->LockExclusiveAccess();
+		fHWInterface->Shutdown();
+		fHWInterface->UnlockExclusiveAccess();
+		delete fHWInterface;
+		fHWInterface = NULL;
+	}
+
+	delete fBitmap;
+	fBitmap = NULL;
+
+	if (newWidth <= 0 || newHeight <= 0)
+		return B_OK;
+
+	fBitmap = new(std::nothrow) UtilityBitmap(BRect(0, 0, newWidth - 1,
+		newHeight - 1), B_RGB32, 0);
+	if (fBitmap == NULL)
+		return B_NO_MEMORY;
+
+	fHWInterface = new(std::nothrow) BitmapHWInterface(fBitmap);
+	if (fHWInterface == NULL)
+		return B_NO_MEMORY;
+
+	status_t result = fHWInterface->Initialize();
+	if (result != B_OK)
+		return result;
+
+	// we have to set a valid clipping first
+	fClipping.Set(fBitmap->Bounds());
+	ConstrainClippingRegion(&fClipping);
+	SetHWInterface(fHWInterface);
+	return B_OK;
+}
+
+
+UtilityBitmap *
+BitmapDrawingEngine::ExportToBitmap(int32 width, int32 height,
+	color_space space)
+{
+	if (width <= 0 || height <= 0)
+		return NULL;
+
+	UtilityBitmap *result = new(std::nothrow) UtilityBitmap(BRect(0, 0,
+		width - 1, height - 1), space, 0);
+	if (result == NULL)
+		return NULL;
+
+	if (result->ImportBits(fBitmap->Bits(), fBitmap->BitsLength(),
+		fBitmap->BytesPerRow(), fBitmap->ColorSpace()) != B_OK) {
+		delete result;
+		return NULL;
+	}
+
+	return result;
+}

src/servers/app/BitmapDrawingEngine.h

@@ -0,0 +1,25 @@
+#ifndef BITMAP_DRAWING_ENGINE_H
+#define BITMAP_DRAWING_ENGINE_H
+
+#include "DrawingEngine.h"
+#include <Region.h>
+
+class BitmapHWInterface;
+class UtilityBitmap;
+
+class BitmapDrawingEngine : public DrawingEngine {
+public:
+								BitmapDrawingEngine();
+virtual							~BitmapDrawingEngine();
+
+			status_t			SetSize(int32 newWidth, int32 newHeight);
+			UtilityBitmap *		ExportToBitmap(int32 width, int32 height,
+									color_space space);
+
+private:
+			BitmapHWInterface *	fHWInterface;
+			UtilityBitmap *		fBitmap;
+			BRegion				fClipping;
+};
+
+#endif // BITMAP_DRAWING_ENGINE_H

src/servers/app/Jamfile

@@ -12,6 +12,7 @@ Server app_server :
 	Angle.cpp
 	AppServer.cpp
 	#BitfieldRegion.cpp
+	BitmapDrawingEngine.cpp
 	BitmapManager.cpp
 	ClientMemoryAllocator.cpp
 	CursorData.cpp