make cv::imread(..., -1) respect alpha channel in PNG images (Feature #1107)

Added by Markus Schwarzenberg almost 14 years ago. Updated over 13 years ago.

Status:Done Start date:
Priority:High Due date:
Assignee:- % Done:

0%
Category:highgui-images
Target version:-
Difficulty: Pull request:

Description

With this patch cv::imread(const string& filename, int flags)
returns a 4-channel Mat containing the alpha channel, provided

flags = -1
  image(filename) is a RGBA-PNG file.

opencv-png-imload-with-alpha.diff (2.5 kB) Markus Schwarzenberg, 2011-05-31 04:53 pm

Associated revisions

Revision c65c67ef
Added by Vadim Pisarevsky over 13 years ago

preserve alpha channel in PNG, when imread(..., -1) is called (ticket #1107)

Revision 616dbd53
Added by Roman Donchenko over 11 years ago

Merge pull request #1107 from abidrahmank:master

History

#1
Updated by Markus Schwarzenberg over 13 years ago

Side note: In the application where this patch is used the R and B color channel
are swapped when using RGBA-PNG-Files. It's OK for RGB. From the sources (highgui stuff, this patch, libpng sources) it is still not clear why this happens.

#2
Updated by Vadim Pisarevsky over 13 years ago

thanks! your patch was integrated in r6444.

  • Status changed from Open to Done
  • (deleted custom field) set to fixed

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