[squeak-dev] Erase when drawing

Ricardo Moran richi.moran at gmail.com
Wed Aug 18 20:38:58 UTC 2010


Hi, I don't know if this will help you but I started working on a drawing
app for Etoys and I'm using a Pen for the paintbrush. This way I can change
its sourceForm and use different shapes and stuff. And when I need to erase
I simply change its combination rule to #erase1bitShape, otherwise I use the
#paint combination rule and I change the pen's color to whatever color I
want.
Maybe this is not the right way of doing it but it works :)

Richo

On Wed, Aug 18, 2010 at 4:15 PM, J.F. Rick <self at je77.com> wrote:

> Hi,
>
> I'm building a drawing application for the iPad and I'm having some
> problems building erase into it. I'm using fillOval:fillStyle:
> and drawPolygon:fillStyle: for drawing normally and I'd like to use the same
> methods for erasing. Unfortunately, when I put in (Color transparent) as the
> fillStyle, it doesn't do anything. I believe this is because it is acting as
> a paint over combination rule. So, original + transparent = original. What I
> want is that the transparent color takes the place of the original color.
> Any advice on how to do this?
>
> Thanks,
>
> Jeff
>
> --
> Jochen "Jeff" Rick, Ph.D.
> http://www.je77.com/
> +44(0)1908 332 451 (work)
> Skype ID: jochenrick
>
>
>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://lists.squeakfoundation.org/pipermail/squeak-dev/attachments/20100818/99a04339/attachment.htm


More information about the Squeak-dev mailing list