Legacy ImageMagick Discussions Archive

Also, use "-sampling-factor 1x1" (alongside "-quality 100") for the best JPEG output. Subsampling can 'smear' some colors. Perhaps you meant that with "blend surrounding colors".

If you want only 2 colors, you should turn off antialiasing. Try something like that: convert -size 720x576 xc:white -transparent white +antialias -font Helvetica-Bold -pointsize 25 -fill red -draw "text 0,312 'Text for button 1'" -depth 8 -type PaletteMatte out.png This should work for so...

This may be two separate issues. I think, the color reduction is ok here. One gets the expected output (with transparency) when saving to TIFF/MIFF/BMP/etc. But the PNG saving part seems to have problems.. So.. Your original PNG has less than 256 colors and gets read in as PaletteMatte (the file is ...

For more info check: http://www.imagemagick.org/discourse-server/viewtopic.php?f=3&t=16157 Interesting thread! I think you wrote about the same issue (a bias towards half a sample darker). It's just appearing at different places/versions... I'm using the integer versions of ImageMagick (the reg...

whether Nconvert will produce a BMP3 with partially transparent pixels nor whether Xnview could display one properly. Yes (both cases). However, BMP is a Microsoft file format and the documentation that comes with my C compiler, and also what I have found on Microsoft's website, says that the high ...

IrfanView is indeed a good programm - but it can't display transparency.
Free Windows software that is able to handle the alpha channel in BMP V3 files is Gimp or XnView (the latter includes Nconvert).

Nconvert creates ARGB files with a BMP V3 header.

The problem is fixed in ImageMagick 6.6.2-0 Beta available by sometime tomorrow. OK, thanks. But with "the problem", did you mean something with the bit depth reduction - or something with the grayscale conversion? Because my posting was not about the actual grayscale conversion - that wa...

If one has a 16 bit (channel bit depth) image and saves that to a 8 bit quality file format, an implicit bit depth reduction is done. That implicit bit depth reduction should be same as the explicit "-depth 8" operation.. Is that correct? (At least the documentation seems to imply that.) I...

You're probably referring to the line "The high byte in each DWORD is not used." within the biBitCount section. But that line is the same in the BITMAPV4HEADER and BITMAPV5HEADER descriptions. I just don't think much of these details within the Microsoft descriptions - it's not really cons...

That's correct because V3 does not support an alpha layer. In ImageMagick, it's not supported. But a few other programs do create BMP V3 files with alpha layer. when I do so convert 1.png 1.bmp I get a bmp file with alpha channel v1 Most likely, you will get a BMP V4 file. Again: BMP3 with alpha ch...

BMP Version 1 - with alpha channel?? Can't believe that.
I'm not sure what your question is. As I said, with a current version of ImageMagick, you can read/write BMP V4 and V5 files with an alpha layer (not BMP3).

You could upload one of your BMP files - then we can tell you for sure.
It's also possible that your ImageMagick version is simply too old. What version do you use?

At the moment, ImageMagick supports BMP with alpha layer if the BMPs are stored with a Windows V4 or V5 header - but not if it's a BMP with V3 header. So, probably you have BMP V3 files. In that case, you will have to use another software (e.g. Gimp) to convert your files to PNG first.

I don't want to start an argument here 8), but the only exception in this thread where the files would be stored as 'normal' PNG (3x8bit) is my last test: convert B156074.png PNG:- | identify -format %k - 248 convert B156074.png GIF:- | identify -format %k - 248 convert B156074.png -bordercolor whit...