Actionscript 3.0 drawRect works weird

Question

I have a BitmapData object named myBitmapData. It was loaded of PNG of size 104x104. This PNG represents a red circle on the transparent background. There is also a Sprite object named myBackground. I want render that red circle into myBackground.

myBackground.graphics.beginBitmapFill(myBitmapData);
myBackground.graphics.drawRect(0, 0, myBitmapData.width, myBitmapData.height);
myBackground.graphics.endFill();
addChild(myBackground);

Everything is fine. I see a red circle in the left top of myBackground.

But when I change the third line to

myBackground.graphics.drawRect(0, 52, myBitmapData.width, myBitmapData.height);

and expect my circle to be translated 52 pixels down, I actually obtain something strange (for me :)): there are two red half-circles (they form like hourglass).

So, the question is: how do I render myBitmapData into the random position of myBackground?

P.S. In the case of

myBackground.graphics.drawRect(0, 104, myBitmapData.width, myBitmapData.height);

it is circle again :)

kapex · Accepted Answer · 2011-09-13T12:47:03.933

This is caused by beginBitmapFill's default repeat = true parameter. There's an example in the docs. Disabling the repetition won't work though, you'd just get a half circle then.

There are several ways to fix this:

Use a Matrix with a translation (displacement) as argument in beginBitmapFill.
Draw the rectangle at 0,0 on another Sprite, and move that sprite to where you want it on the background.
Don't draw directly to the background, but to another bitmap using copyPixels. Then fill the background with that bitmap.

Actionscript 3.0 drawRect works weird

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