Legacy ImageMagick Discussions Archive

Thanks for your confirmations! Another example with the color reduction.. I always wondered why it's so difficult to write 8 bit per pixel BMPs (when there are already less than 256 colors). Well, that's off-topic.. But the thing is: I can use "-colors 256" to force it to 8bpp - but then s...

anthony wrote:PNG8 Image file format and GIF are handled and treated in exactly the same way!!!!

Not in the above examples.

The filesize should stay about the same with supersampling. Anyway, this method is mainly for vectorial elements that can be rasterized at a higher density and then get downsized (and the downsizing does some sort of antialiasing). But this last PDF is solely made out of images (already rasterized, ...

If the input happens to already have GenericCMYK.icc embedded, the first "-profile" will have no effect The documentation says something different: http://www.imagemagick.org/Usage/formats/#color_profile_changing If the original image already contains a profile, for example a CMYK profile...

But what hinders you from using the supersampling method? I think the only disadvantages are an increased processing time - and a bit of blurriness (if the upsampling/downsampling size is not ideal). But the jagged edges of the text will be gone. If you have problems with specific PDFs, you could up...

This affects the storage of GIFs, but also manual color reductions. (And it may be the origin of the problem of that thread .) As example - a command that produces a 258x1 stripe with only 3 colors in it, once stored as BMP, once stored as GIF. The GIF has still 3 distinct colors, but some pixels ha...

I think Anthony's GIF test is successful with version 6.6.1-6 (or newer). But this won't change the result of your commands. I believe there is a problem with the GIF format. In the meantime you could use e.g. PNG8 (if you have pictures with max. 256 colors) and convert to GIF only as a last step.

After updating ImageMagick, I now get 256 colors for the second GIF test, too. So that works.
But I'm still getting reduced colors for the 'B156074' GIF. I'll have to do some more tests for that...

magick wrote:6.6.1-8 Beta

That goes fast! Thanks!

OK. Thanks again!
(It seems the documentation has a bit changed now.)

The rounding of the density values is better now (IM v6.6.1-6), thanks! But it doesn't work for all cases.. An example with a 96dpi PNG.. "identify -verbose" shows for that file: Resolution: 37.8x37.8 Print size: 21.5873x30.291 Units: PixelsPerCentimeter "identify -verbose -units Pixe...

Thanks! (The list in the documentation is now also identical to my "convert -list list" output.)

Drarakel what version of libtiff you are use? I'm using the regular Win32 Q16 binary of v6.6.1-5. The libtiff version here seems to be 3.9.2. I've now updated to ImageMagick v6.6.1.6 - not sure about the libtiff version, sorry. It's still workin' (with the warnings, but the output is fine): convert...

I don't think that there is an alternative to the supersampling method. Ghostscript makes the rasterization. You can change the handling of the elements that are antialiased. But some things are simply not antialiased at all with Ghostscript. (I think that normal fonts are antialiased. But other vec...

I think that "RGB" is correct. It always shows "RGB" for type grayscale. (But I hate to say that you can't take 'Type' and 'Base Type' as a clear indicator whether it's really stored as e.g. Grayscale or Truecolor.)