Legacy ImageMagick Discussions Archive

Looks like it is fixed in 6.7.4

> C:\dev\ImageMagick-6.7.3-5\identify.exe -version Version: ImageMagick 6.7.3-6 2011-10-29 Q16 http://www.imagemagick.org Copyright: Copyright (C) 1999-2011 ImageMagick Studio LLC Features: OpenMP (yes, for some reason it prints that it has version 6.7.3-6) When i try to run identify or convert on ...

Whoa! Nice. It works. I haven't event thought in that direction. Thank you very much.

In case there is some misunderstanding: the source are 32bpp PNGs (24bpp color + 8 bit alpha, but alpha is either 0 or 255 for each pixel). I want 16bpp raw files (so in each two bytes three 5-bit color components and 1-bit alpha is packed as on image in first post), so the output file size is ...

I have a bunch of PNG files with each pixel either completely transparent or completely opaque. I want to convert them to raw binaries (containing only pixel data - no headers, no other stuff) so each pixel is represented by two bytes containing R, G, B values 5 bit per channel and single bit alpha ...

fmw42 wrote:what is "a" in your formula?

Docs on -fx you linked above say

a = alpha

, and it works.

Thanks, doing convert input.png -channel alpha -fx "a*31/255" output.png before stream does the trick, still I don't like that "*31/255" part: I'd rather use >> operation (thinking I'm working with integer channel values), but since I got a real number in range [0..1] as input, I can't.

I have a png file with alpha channel. I'm extracting it's alpha channel as raw bytes with this command: Is there any way to reduce alpha values range from 0-255 to 0-31 (so for example 255 becomes 31, and 127 becomes 15) in this process?

Thanks, I've come to this command line: convert "%INPUT_FILE%" "(" +clone -fill "%RENDER_ON%" -colorize 100 ")" -compose dst-over -composite -alpha off "(" -clone 0 -alpha extract -level 0,1 -alpha off ")" -compose copy-opacity -composite -background "%COLOR_KEY%" -alpha background -alpha off ...

I have images with alpha channel (PNG and TGA) that I want to transform in following way: all pixels that are not fully transparent (alpha > 0) must be blended with given color, after that all pixels that are fully transparent (alpha == 0) must be set to another color and set fully opaque. I made ...