Legacy ImageMagick Discussions Archive

Compression in jpeg and cr2 is optimised for photographs. Png compression is not optimised for photographs, so I would expect the file size to be larger. You can compare the results from ImageMagick and gthumb: identify -verbose fromIm.png >fromIm.txt identify -verbose fromGthumb.png >fromGthumb.txt...

Yes.

It's fine on 6.4.5. Your version is very old; I suggest you upgrade it and try again.

See http://www.imagemagick.org/script/command-line-processing.php#geometry The format is one of: axb+c+d axb+c-d axb-c+d axb-c-d Where a,b,c,d are integers. Generally: a is width b is height c is x-offset, so it may be negative d is y-offset, so it may be negative I don't suppose c and d would make ...

This will do it:

/usr/bin/convert bild.JPG -alpha set -channel alpha -clip -negate temp.png
/usr/bin/convert temp.png -channel Alpha -negate c.png

Smarter folks than me will simplify it.

Edit: +trim +repage after the final -negate, if you want.

Yes, when used in a batch file, %~dp0 will be translated by the Windows command shell into the directory and path of the batch file. You could then use convert to expand the "*" thus (in a batch file): convert %~dp0*.bmp %~dp0thing%%03d.jpg and you will get thing000.jpg, thing001.jpg etc. ...

I think IM's globbing is limited to "*" and "?". "%~dp" is a Windows construct for FOR loops. Even if this globbing worked, it wouldn't do what you wanted, as convert can't take a list of filenames and convert each one to a different output. (Well, it could, but with a ...

I don't really understand the problem. Why not pad all the uploaded images to 3:2 aspect ratio? Trying to get ImageMagick (or other software) to determine whether trimming an image would make it "look awful" sounds like a hard problem. Can you post examples of images that can, or shouldn't...

Constructs like may also be useful

If you post a URL to your image, we can try to come up with something. When levels works in RGB space (which I think it always does), setting "white" must set the maximum value in the three channels. similarly black. So white or black will lose the hue information. I suspect the way to do ...

That's a very old version of IM. fmw's script works fine for me in a slightly less old 6.4.5 on Ubuntu.

I suggest you update IM.

What OS? What version of IM? Can you provide the URL of your image?

Image viewers may not use the same assumed DPI for your screen.

You might use the "-verbose" option of identify to get the density, and hence the physical dimensions.

Then "acroread foo.pdf", File, Properties, Description will tell you if the physical dimensions are the same.

I suspect you are comparing apples with oranges, "judging by eye". What is the density of your png file? identify -verbose foo.png You might get something like: Geometry: 1280x720+0+0 Resolution: 72x72 Print size: 17.77x10.00 Units: PixelsPerInch Then I would expect convert foo.png foo.pdf...

Those are questions about ghostscript, not ImageMagick. I suggest you ask in ghostscript forums.

(Hint: you might search for "ghostscript Unable to substitute for font".)