python-pillow/Pillow
1
1
Fork 0
mirror of https://github.com/python-pillow/Pillow.git synced 2024-12-26 18:06:18 +03:00
Code Issues Packages Projects Releases Wiki Activity

Merge pull request #6838 from radarhere/premultiplied_alpha

Browse Source 
Document the meaning of "premultiplied alpha"
This commit is contained in:
Hugo van Kemenade 2022-12-29 12:02:40 +02:00 committed by GitHub
commit cea6c1e86c
No known key found for this signature in database
GPG Key ID: 4AEE18F83AFDEB23
1 changed files with 6 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

6
docs/handbook/concepts.rst
View File

@ -64,6 +64,12 @@ Pillow also provides limited support for a few additional modes, including:
* ``BGR;24`` (24-bit reversed true colour)
* ``BGR;32`` (32-bit reversed true colour)
Premultiplied alpha is where the values for each other channel have been
multiplied by the alpha. For example, an RGBA pixel of ``(10, 20, 30, 127)``
would convert to an RGBa pixel of ``(5, 10, 15, 127)``. The values of the R,
G and B channels are halved as a result of the half transparency in the alpha
channel.
Apart from these additional modes, Pillow doesn't yet support multichannel
images with a depth of more than 8 bits per channel.