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v7 read or write problem
Posted: 2014-01-11T13:28:53-07:00
by snibgo
Windows 8.1, IM v7 downloaded today, ImageMagick-7.0.0-0~beta20140110-Q16-x64-dll.exe.
There is a problem reading or writing a greyscale image.
Create a greyscale image using IM v6.8.8-0:
Code: Select all
%IM%convert -size 100x200 gradient: ^
-rotate 90 ^
hdri_grad.png
Read it and write it with v7:
Code: Select all
%IMGF%magick ^
hdri_grad.png ^
hdri_gradSv.png
The result is red where I would expect grey. It has populated just the red channel instead of all three.
Re: v7 read or write problem
Posted: 2014-01-11T14:45:33-07:00
by fmw42
Grayscale images in IM 7 have only one channel. That may be the issue. In IM 6 they have 3 channels. So there may be an import issue between IM 6 grayscale images to IM 7.
Re: v7 read or write problem
Posted: 2014-01-11T15:02:19-07:00
by snibgo
The same problem occurs when v7 creates the first file.
Yes, I guess the problem arises from v7 storing greyscale as a single channel.
A simpler demo of (probably) the same problem:
Code: Select all
F:\web\im>%IMGF%magick -size 2x1 gradient: g.png
F:\web\im>%IMGF%magick g.png txt:
# ImageMagick pixel enumeration: 2,1,255,srgb
0,0: (255,255,255) #FFFFFF white
1,0: (0,0,0) #000000 black
F:\web\im>%IMGF%magick -size 3x1 gradient: g.png
F:\web\im>%IMGF%magick g.png txt:
# ImageMagick pixel enumeration: 3,1,65535,srgb
0,0: (100%,0%,0%) #FFFF00000000 red
1,0: (50.0008%,0%,0%) #800000000000 srgb(50.0008%,0%,0%)
2,0: (0%,0%,0%) #000000000000 black
The 2x1 gradient gives the corect greyscale result. The 3x1 gradient populates (or or writes to txt) just the red channel.
Re: v7 read or write problem
Posted: 2014-01-11T15:38:18-07:00
by fmw42
Now that is really odd (pardon the pun)