[sc-users] scwindow .refresh clear

[Till Bovermann]

On 04 Dec 2006, at 17:43, Fredrik Olofsson wrote:

> hi list,
> is there any way to _not clear a SCWindow completely when  
> calling .refresh?  i think not but please prove me wrong.

Unfortunately you're right... :-/
It would require to have an NSImage (I think thats the name) to draw  
in which currently is not available...

> i'd like to clear it manually by drawing a full-sized rectangle  
> alpha 0.5 or something.  this'd let you do cool and efficient trail  
> effects with the Pen class.
>
> i know i can store the trails in an fifo buffer and thereby let  
> them survive a .refresh but that's really not realtime friendly.
> so something like this but without the need to run all the 50  
> frames all at once.
>

neat, but you have to do it like this currently:

(
	var width= 640, height= 480, run= true, w, theta= 0, i = 1;
	w= SCWindow("trail test", Rect(128, 64, width, height));
	w.view.background= Color.black;
	w.front;
	w.drawHook= {
		//i would like to sequence these 25 frames. but routine not allowed  
inside drawHook
		//and refresh clears the window completely
		i.do{
			var x= 60*sin(theta), y= 40*cos(theta);
			theta= theta+0.015;
			
			//--clear with alpha
			Color.grey(0, 0.1).set;
			Pen.fillRect(Rect(0, 0, width, height));
			
			//--rects
			Color.white.set;
			Pen.push;
			Pen.translate(width*0.6, height*0.6);
			5.do{|i|
				Pen.scale(i+0.6, i+0.6);
				Pen.rotate(theta);
				Pen.strokeRect(Rect.aboutPoint(x at y, 60, 40));
			};
			Pen.pop;
		}
	};

	// awful:
	{
	25.do{|j|
		i = j+1;
		0.125.wait;
		{w.refresh;}.defer
	}
	}.fork
)