Initial release

engine/vendor/vst3sdk/vstgui4/vstgui/lib/coffscreencontext.h

@@ -0,0 +1,99 @@
+// This file is part of VSTGUI. It is subject to the license terms 
+// in the LICENSE file found in the top-level directory of this
+// distribution and at http://github.com/steinbergmedia/vstgui/LICENSE
+
+#pragma once
+
+#include "vstguifwd.h"
+#include "cdrawcontext.h"
+
+namespace VSTGUI {
+
+//-----------------------------------------------------------------------------
+// COffscreenContext Declaration
+//! @brief A draw context using a bitmap as it's back buffer
+/*! @class COffscreenContext
+There are two usage scenarios :
+@section offscreen_usage1 Drawing into a bitmap and then push the contents into another draw context
+
+@code
+if (auto offscreen = COffscreenContext::create (frame, 100, 100))
+{
+	offscreen->beginDraw ();
+	// ... 
+	// draw into offscreen
+	// ...
+	offscreen->endDraw ();
+	offscreen->copyFrom (otherContext, destRect);
+}
+@endcode
+
+@section offscreen_usage2 Drawing static content into a bitmap and reuse the bitmap for drawing
+
+@code
+if (cachedBitmap == 0)
+{
+	if (auto offscreen = COffscreenContext::create (frame, 100, 100))
+	{
+		offscreen->beginDraw ();
+		// ... 
+		// draw into offscreen
+		// ...
+		offscreen->endDraw ();
+		cachedBitmap = offscreen->getBitmap ();
+		if (cachedBitmap)
+			cachedBitmap->remember ();
+	}
+}
+if (cachedBitmap)
+{
+	// ...
+}
+
+@endcode
+
+ */
+//-----------------------------------------------------------------------------
+class COffscreenContext : public CDrawContext
+{
+public:
+	static SharedPointer<COffscreenContext> create (const CPoint& size, double scaleFactor = 1.);
+	VSTGUI_DEPRECATED (static SharedPointer<COffscreenContext> create (CFrame* frame, CCoord width,
+	                                                                   CCoord height,
+	                                                                   double scaleFactor = 1.);)
+
+	//-----------------------------------------------------------------------------
+	/// @name COffscreenContext Methods
+	//-----------------------------------------------------------------------------
+	//@{
+	/** copy from offscreen to pContext */
+	void copyFrom (CDrawContext *pContext, CRect destRect, CPoint srcOffset = CPoint (0, 0));
+
+	CCoord getWidth () const;
+	CCoord getHeight () const;
+	//@}
+
+	CBitmap* getBitmap () const { return bitmap; }
+
+	COffscreenContext (const PlatformGraphicsDeviceContextPtr device, const CRect& surfaceRect,
+					   const PlatformBitmapPtr& platformBitmap);
+
+protected:
+	explicit COffscreenContext (CBitmap* bitmap);
+	explicit COffscreenContext (const CRect& surfaceRect);
+
+	SharedPointer<CBitmap> bitmap;
+};
+
+//-----------------------------------------------------------------------------
+/** Render a bitmap offscreen
+ *	@param size size of the bitmap
+ *	@param scaleFactor scale factor (bitmap size will be scaled by this)
+ *	@param drawFunction user supplied draw function
+ *	@return bitmap pointer on success and nullptr on failure
+ */
+SharedPointer<CBitmap> renderBitmapOffscreen (
+    const CPoint& size, double scaleFactor,
+    const std::function<void (CDrawContext& drawContext)> drawFunction);
+
+} // VSTGUI