Faster Paint on Flex Mobile
I am trying to build an app that tracks touchpoints and draws circles at those points using Flash Builder. The following works perfectly, but after a while, it begins to lag and the touch will be well ahead of the drawn circles. Is there a way of drawing the circles that does not produce lag as more and more of them are added?
In declarations, I have:
<fx:Component className="Circle">
<s:Ellipse>
<s:stroke>
<s:SolidColorStroke alpha="0"/>
</s:stroke>
</s:Ellipse>
开发者_开发知识库 </fx:Component>
And this is the drawing function:
var c:Circle = new Circle();
c.x = somex;
c.y = somey;
c.fill = new SolidColor(somecolorint);
c.height = somesize;
c.width = somesize;
c.alpha = 1;
addElement(c);
c = null;
Try taking a look at doing a fullscreen Bitmap created with a BitmapData class. As the touch points are moved, update the bitmap data at the coordinates where the touch occured. Modifying and blitting a screen-sized bitmap is extremely fast and will probably work great for what you're trying to do.
Another performance trade off often done is to make a series of lines instead of continuous circles. You create a new line segment only when a certain distance has been traveled, this lets you limit the number of nodes in the segment thereby keeping performance high.
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