Started implementing the server side of BScreen()->ReadBitmap().

Colorspace conversion is not done yet so that it only works correct in 32bit modes.
Also drawCursor is not respected yet. Partially fixes bug 197.

git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@16573 a95241bf-73f2-0310-859d-f6bbb57e9c96

headers/private/servers/app/DrawingEngine.h

@@ -59,7 +59,8 @@ public:
 			// for screen shots
 			bool			DumpToFile(const char *path);
 			ServerBitmap*	DumpToBitmap();
-
+			status_t		ReadBitmap(ServerBitmap *bitmap, bool drawCursor,
+								BRect bounds);
 
 			// clipping for all drawing functions, passing a NULL region
 			// will remove any clipping (drawing allowed everywhere)

src/servers/app/ServerApp.cpp

@@ -2439,8 +2439,11 @@ ServerApp::_DispatchMessage(int32 code, BPrivate::LinkReceiver& link)
 
 			ServerBitmap *bitmap = FindBitmap(bitmapToken);
 			if (bitmap != NULL) {
+				if (fDesktop->GetDrawingEngine()->ReadBitmap(bitmap,
+					drawCursor, bounds) == B_OK) {
 					fLink.StartMessage(B_OK);
-				// TODO: Implement for real
+				} else
+					fLink.StartMessage(B_BAD_VALUE);
 			} else
 				fLink.StartMessage(B_BAD_VALUE);
 

src/servers/app/drawing/DrawingEngine.cpp

@@ -16,6 +16,7 @@
 #include "DrawState.h"
 #include "Painter.h"
 #include "PNGDump.h"
+#include "ServerBitmap.h"
 #include "RenderingBuffer.h"
 
 #include "frame_buffer_support.h"
@@ -1135,6 +1136,39 @@ DrawingEngine::DumpToBitmap()
 	return NULL;
 }
 
+status_t
+DrawingEngine::ReadBitmap(ServerBitmap *bitmap, bool drawCursor, BRect bounds)
+{
+	if (Lock()) {
+		RenderingBuffer *buffer = fGraphicsCard->DrawingBuffer();
+		if (!buffer)
+			return B_ERROR;
+
+		BRect clip(0, 0, buffer->Width() - 1, buffer->Height() - 1);
+		bounds = bounds & clip;
+
+		uint32 width = (bounds.IntegerWidth() + 1) * 4;
+		uint32 height = bounds.IntegerHeight() + 1;
+		uint32 srcBytesPerRow = buffer->BytesPerRow();
+		uint32 dstBytesPerRow = bitmap->BytesPerRow();
+		uint8 *dst = (uint8 *)bitmap->Bits();
+		uint8 *src = (uint8 *)buffer->Bits();
+		src += (uint32)bounds.top * srcBytesPerRow + (uint32)bounds.left * 4;
+
+		/* ToDo: handle color conversion */
+		for (uint32 i = 0; i < height; i++) {
+			memcpy(dst, src, width);
+			dst += dstBytesPerRow;
+			src += srcBytesPerRow;
+		}
+
+		Unlock();
+		return B_OK;
+	}
+
+	return B_ERROR;
+}
+
 // #pragma mark -
 
 BRect