[flexcoders] Re: Drawing in a Canvas subclass

Wed, 24 May 2006 10:30:31 -0700

Thanks for the tip. The issue is that I also need the "container"
features from the Canvas.  I'm trying to build a control that has a
mixture of drawn elements with other components that are sited in the
control.

So if I subclass the UIComponent I think I will loose the ability to
add child controls (although I haven't try).

I was not aware of the fact that the Canvas will add a child
component for the background.  I guess it must be related to the
rawChildren property.  I'm going to try also to override the
createChildren method to avoid this.

As a side note.  I feel that this hidden hierarchy of controls (i.e.
background child) may be a misfeature in Flex.  They should probably
consider removing it from the public API.

thanks,
-Sergio



--- In [email protected], "Gordon Smith" <[EMAIL PROTECTED]> wrote:
>
> Try subclassing UIComponent instead of Canvas. That should avoid the
> problems of having a background child.
>
> - Gordon
>
>
> -----Original Message-----
> From: [email protected]
[mailto:[EMAIL PROTECTED] On
> Behalf Of sergio_trejo_r
> Sent: Tuesday, May 23, 2006 4:37 PM
> To: [email protected]
> Subject: [flexcoders] Drawing in a Canvas subclass
>
> Hi, I ran into a problem while trying to use the drawing API in a
> subclass of the Canvas container.  See the code include below.
>
> The class TestCanvasDrawing extends the Canvas container.  I attempt
> to draw a line in the updateDisplayList method.  However when I see
> the output only a small portion of the line is drawn in the top-left
> corner.  The rest of the line seems to be clip by the background.
>
> If I then set the alpha property to 0.5 and then I can see the full
> line drawn underneath the background.
>
> So it seems that I'm getting a wrong graphics instance or I'm
missing
> some background configuration of the canvas.  Has anybody seen this
> behavior or know what's the right usage?
>
> thanks!
> -Sergio
>
>
> public class TestCanvasDrawing extends Canvas
> {
>  private var _canvas : Canvas;
>
>  public function TestCanvasDrawing()
>  {
>   super();
>  }
>
> protected override function updateDisplayList(unscaledWidth:Number,
> unscaledHeight:Number):void {
>  super.updateDisplayList(unscaledWidth, unscaledHeight);
>  //this.alpha = 0.5;  //Uncomment to see the line below.
>  this.graphics.lineStyle(5, 0xFF0000);
>  this.graphics.moveTo(0, 0)
>  this.graphics.lineTo(20, 20);
> }
>
> }
>
>
>
>
>
>
>
> --
> Flexcoders Mailing List
> FAQ:
http://groups.yahoo.com/group/flexcoders/files/flexcodersFAQ.txt
> Search Archives:
> http://www.mail-archive.com/flexcoders%40yahoogroups.com
> Yahoo! Groups Links
>







--
Flexcoders Mailing List
FAQ: http://groups.yahoo.com/group/flexcoders/files/flexcodersFAQ.txt
Search Archives: http://www.mail-archive.com/flexcoders%40yahoogroups.com



SPONSORED LINKS
Web site design development Computer software development Software design and development
Macromedia flex Software development best practice

YAHOO! GROUPS LINKS



Reply via email to