Re: [GD-DEVEL] Using brushes with alpha transparency...

Hi Steve,

On 7/11/07, Steve Lime <[email protected]> wrote:
> Hi Pierre: I created a little test program and some brushes. You can nab them at:
>
>   ftp://ftp.dnr.state.mn.us/pub/brushtest.zip
>
> The archive contains 3 variable opacity brushes, test C program and one output image. The output image (test.png) is the result of;
>
>    ./testbrush -brush brush_op10.png -output test.png -blend
>
> Basically it draws a brushed line using a 10% opaque brush. It also copies the brush into the image so you can see how it looks alone. Checkout the ends of the line and you'll see the issue. I would expect (or was hoping) that the whole line would be a uniform thick line, a blended version of the brush and the black background. Kinda like you'd see with a paint brush tool in Gimp. That's not the case, the resulting line far more opaque than I would expect. I imagine pixels are getting set and blended over and over. The ends of the line are closer to the appearance I would expect.

Sorry for the late reply, I was busy lately.

I have created a new issue in bugs.libgd.org:

http://bugs.libgd.org/?do=details&task_id=99


It is definitively a (old) bug and I'm not sure if there is an easy
way to fix to fix it. It will certainly require a true brush based
drawing tools (with masks and all other requirements).

A common usage for such tool is to draw thick lines (or outlines for
shapes) with custom line ending. Is it what you try to achieve?

Cheers,
--Pierre