Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

ENH: Non-CG blend modes #7

Open
iccir opened this issue Jan 1, 2012 · 0 comments
Open

ENH: Non-CG blend modes #7

iccir opened this issue Jan 1, 2012 · 0 comments

Comments

@iccir
Copy link
Member

iccir commented Jan 1, 2012

The following blend mode don't have direct mappings to CGBlendModes:
Layer, Add, Subtract, Invert, Alpha, Erase

Add is close to kCGBlendModePlusLighter, but handles the alpha channel differently.
Invert is close to kCGBlendModeDifference, but draws using all black.

Erase and Alpha may have equivalent Porter-Duff modes.

See:
http://www.kaourantin.net/2005/09/some-word-on-blend-modes-in-flash.html

Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment
Labels
None yet
Projects
None yet
Development

No branches or pull requests

1 participant