Mathis/sharp
1
0
Fork 0
mirror of https://github.com/lovell/sharp.git synced 2025-07-10 11:00:14 +02:00
Code Issues Packages Projects Releases Wiki Activity
344 Commits 2 Branches 175 Tags
Commit Graph

2 Commits

Author SHA1 Message Date
Daniel Gasienica
ef8db1eebf Premultiply alpha channel to avoid dark artifacts during tranformation 
Add `Sharp.compare(file1, file2, callback)` function for comparing images
using mean squared error (MSE). This is useful for unit tests.

See:
- https://github.com/jcupitt/libvips/issues/291
- http://entropymine.com/imageworsener/resizealpha/
 2015-06-01 14:21:02 +01:00
Daniel Gasienica
64f7f1d662 Add experimental overlayWith API 
Composites an overlay image with alpha channel into the input image (which
must have alpha channel) using ‘over’ alpha compositing blend mode. This API
requires both images to have the same dimensions.

References:
- http://en.wikipedia.org/wiki/Alpha_compositing#Alpha_blending
- https://github.com/jcupitt/ruby-vips/issues/28#issuecomment-9014826

See #97.
 2015-06-01 14:21:01 +01:00