Draw Targets, Clipping

MoSync graphics operations are always performed to a "draw target". By default, this draw target is the screen, but you can create images that can be drawn to, using maCreateDrawableImage().

These mutable images behave exactly like any other images, and can be used with maDrawImage() or maDrawImageRegion() - the only difference is that they can't be transparent. Also, all drawing operations respect the "clip rectangle", which is a rectangular portion of the screen that is affected by drawing operations. By default, the clipping rectangle is the whole screen.

Draw Targets

  MAHandle myPlaceholder = maCreatePlaceholder(); 

  maCreateDrawableImage(myPlaceholder, 32, 32); 

  maSetDrawTarget(myPlaceholder); 

  maSetDrawTarget(HANDLE_SCREEN); 

 maSetDrawTarget(myPlaceholder); 
 maSetClipRect(0,0,16,16); 

 MARect myRect; 
 maGetClipRect(&myRect); 

#include <MAUtil/Moblet.h>
#include <MAUtil/String.h>
#include <mastdlib.h>
using namespace MAUtil;
#define BORDER 40
class MyMoblet : public Moblet {
public:
	MyMoblet() {
		MAExtent scrSize = maGetScrSize();
		int width  = EXTENT_X(scrSize);
		int height = EXTENT_Y(scrSize);
		
		MAHandle myPlaceholder = maCreatePlaceholder();
		maCreateDrawableImage(myPlaceholder, 32, 32);
		maSetDrawTarget(myPlaceholder);
		// Fill with blue
		maSetColor(0x0000ff);
		maFillRect(0, 0, 32, 32);
		maSetColor(0xff00);
		// draw green triangle
		maLine(0,10,10,0);
		maLine(0,0,0,10);
		maLine(0,0,10,0);
		
		maSetDrawTarget(HANDLE_SCREEN);
		maSetClipRect(BORDER,BORDER,width-BORDER*2, height-BORDER*2);
		// Draw purple background
		maSetColor(0xff00ff);
		maFillRect(0,0, 200, 200);
		for(int i = 0; i < 10; i++) {
			maDrawImage(myPlaceholder, i*40, i*40);
		}
		// Draw white text
		maSetColor(0xffffff);
		maDrawText(0,BORDER, "This text is also clipped");
		maUpdateScreen();
	}
};
extern "C" int MAMain() {
	Moblet::run(new MyMoblet());
	return 0;
};