ImageBuffer ib(image);
// .. here's the manipulation of the ib
image=ib;

void SetSurface(HDC dc, Rect &dest, Point &srcoff, Size &bufsz, const RGBA *pixels){
	GuiLock __;
	BitmapInfo32__ bi(bufsz.cx, bufsz.cy);
	::SetDIBitsToDevice(dc,dest.left,dest.top,dest.Width(),dest.Height(),srcoff.x,-srcoff.y-dest.Height()+bufsz.cy,0,bufsz.cy,pixels, bi, DIB_RGB_COLORS);
}

void SetSurface(SystemDraw &w, Rect &dest, Point &srcoff, Size &bufsz, const RGBA *pixels){
	SetSurface(w.GetHandle(),dest,srcoff,bufsz,pixels);
}

virtual void Paint(Draw &draw){
  // The image to draw is in ImageBuffer ib;
  Rect paintrect=draw.GetPaintRect();
  SetSurface(draw,paintrect,ib,ib.GetSize(),Point(paintrect.left,paintrect.top));
}

#include <CtrlLib/CtrlLib.h>

using namespace Upp;

struct MyApp : TopWindow {
	RGBA pixels[65536];

	virtual void Paint(Draw& w) {
		Rect r = w.GetPaintRect();
		w.DrawRect(r, LtGray());
		Point p = r.TopLeft();
		if(p.x < 256 && p.y < 256)
			SetSurface(w, r, pixels, Size(256, 256), p);
	}

	MyApp() {
		RGBA *t = pixels;
		for(int x = 0; x < 256; x++)
			for(int y = 0; y < 256; y++) {
				int d = (x - 128) * (x - 128) + (y - 128) * (y - 128);
				RGBA c = Black();
				if(d > 120 * 120)
					c = White();
				if(d < 120 * 120)
					c.r = 255 - min(255 * d / (120 * 120), 255);
				*t++ = c;
			}
	}
};

GUI_APP_MAIN
{
	MyApp().Run();
}

virtual void Paint(Draw &draw){
  // The image to draw is in ImageBuffer ib;
  Rect paintrect=draw.GetPaintRect();
  SetSurface(draw,paintrect,ib,ib.GetSize(),Point(paintrect.left,paintrect.top));
}

#include <CtrlLib/CtrlLib.h>
#include <Painter/Painter.h>

using namespace Upp;

class PainterCtrl : public Ctrl {
	ImageBuffer ib;

public:
	virtual void Paint(Painter &pntr,Size &sz)=0;

	virtual void Layout(){
		Size sz=GetSize();
		ib.Clear();
		ib.Create(sz);
		BufferPainter pntr(ib);
		Paint(pntr,sz);
	}

	virtual void Paint(Draw &draw) {
		Rect paintrect=draw.GetPaintRect();
		
		Point p = paintrect.TopLeft();
		if(p.x < ib.GetSize().cx && p.y < ib.GetSize().cy) 
			SetSurface(draw, paintrect, ib, ib.GetSize(), p);
	}
	
};

struct ExampleCtrl : PainterCtrl {
	
	virtual void Paint(Painter &pntr,Size &sz){
		pntr.Move(0,0).Line(sz.cx,0).Line(sz.cx,sz.cy).Line(0,sz.cy).Close().Fill(White()).Stroke(5,Black());
		pntr.Move(0,0).Line(sz.cx,sz.cy).Stroke(5,Black());           
	}
};

class ExampleTopWindow: public TopWindow{
public:
	ExampleCtrl ec;
	
	virtual void Layout(){
		ec.SetRect(20,0,GetSize().cx-20,GetSize().cy);
	}

	ExampleTopWindow(){
		Add(ec);
	}
};

GUI_APP_MAIN
{
   ExampleTopWindow win;
   win.Sizeable();
   win.Open();
   win.Run();
}