dany/libwebp
1
0
Fork 0
mirror of https://github.com/webmproject/libwebp.git synced 2025-07-16 05:49:51 +02:00
Code Issues Actions Packages Projects Releases Wiki Activity

add alpha dithering for lossy

Browse Source 
new options:
 dwebp -alpha_dither
 vwebp -noalphadither

When the source was marked as quantized, we use a threshold-averaging
filter to smooth the decoded alpha plane.
Note: this option forces the decoding of alpha data in one pass, and
might slow the decoding a bit.

The new field in WebPDecoderOptions struct is 'alpha_dithering_strength'
(0 by default, means: off). Max strength value is '100'.

Change-Id: I218e21af96360d4781587fede95f8ea4e2b7287a
This commit is contained in:
skal
2014-06-14 00:06:16 +02:00
parent 790207679d
commit bbe32df1e3
11 changed files with 308 additions and 21 deletions
Download Patch File Download Diff File Expand all files Collapse all files

3
src/dec/vp8i.h
View File

@ -296,7 +296,8 @@ struct VP8Decoder {
const uint8_t* alpha_data_; // compressed alpha data (if present)
size_t alpha_data_size_;
int is_alpha_decoded_; // true if alpha_data_ is decoded in alpha_plane_
uint8_t* alpha_plane_; // output. Persistent, contains the whole data.
uint8_t* alpha_plane_; // output. Persistent, contains the whole data.
int alpha_dithering_; // derived from decoding options (0=off, 100=full).
};
//------------------------------------------------------------------------------