dany/libwebp
1
0
Fork 0
mirror of https://github.com/webmproject/libwebp.git synced 2025-07-13 06:24:27 +02:00
Code Issues Actions Packages Projects Releases Wiki Activity

add WebPBlendAlpha() function to blend colors against background

Browse Source 
new option: -blend_alpha 0xrrggbb
also: don't force picture.use_argb value for lossless. Instead,
delay the YUVA<->ARGB conversion till WebPEncode() is called.
This make the blending more accurate when source is ARGB
and lossy compression is used (YUVA).
This has an effect on cropping/rescaling. E.g. for PNG, these
are now done in ARGB colorspace instead of YUV when lossy compression
is used.

Change-Id: I18571f1b1179881737a8dbd23ad0aa8cddae3c6b
This commit is contained in:
Pascal Massimino
2013-04-02 19:14:14 -07:00
parent df4a406d8d
commit e7d9548c9b
8 changed files with 121 additions and 6 deletions
Download Patch File Download Diff File Expand all files Collapse all files

4
README
View File

@ -170,6 +170,10 @@ options:
-alpha_filter <string> . predictive filtering for alpha plane.
One of: none, fast (default) or best.
-alpha_cleanup ......... Clean RGB values in transparent area.
-blend_alpha <hex> ..... Blend colors against background color
expressed as RGB values written in
hexadecimal, e.g. 0xc0e0d0 for red=0xc0
green=0xe0 and blue=0xd0.
-noalpha ............... discard any transparency information.
-lossless .............. Encode image losslessly.
-hint <string> ......... Specify image characteristics hint.