Legacy ImageMagick Discussions Archive

Can you be more specific about what you are trying to do? Ideally with before/after images. For example: an image could be distorted so that every horizontal line in the original followed a given bezier curve in the output. I would do this with a displacement map. See http://www.imagemagick.org/Usag...

Your shell command "convert stock.pdf -colorspace RGB stock.jpg" converts the image to the colorspace RGB, instead of the usual sRGB. Then it stores the image with a flag that says it is sRGB. You need to find the equivalent wand-python commands that do this. I know nothing about wand-pyth...

"-color-matrix" will do this. See http://www.imagemagick.org/script/command-line-options.php#color-matrix For example, the following Windows command will increase the green channel by 25% of the red, and increase blue by 75% of the red, and zero the red. convert ^ in.png ^ -color-matrix ^ ...

1. There is a single collection of global settings, referred to as the settings, which affect the behavior of operators.

Some setting affect things that aren't operators. Eg "-density" affects the image formed by reading a PDF file.

Good stuff. I do like it when a wild guess turns out to be correct.

Ah, sorry. "-remap" can dither, and can use the colours from your Sample2: Is Sample3.png what you want?

This may be a problem with DIB headers. These come in different flavours: seven, at the last count. See http://en.wikipedia.org/wiki/BMP_file_format If I understand correctly (and I probably don't), IM understands three of them; see "convert -list format". Maybe your program implicitly exp...

For PDFs that are a single raster image in a vector wrapper, as this one is, I open it in Adobe Reader and control-C the image, which copies it to the clipboard. Then ... convert clipboard: info: ... tells me how many pixels it has. Then I try a simple convert (at 72 ppi)... convert test.pdf info: ....

I cross-posted with fmw42. His "+level colors" is far more elegant, and probably quicker, than my version that messes around with alpha. My "-density 150" is what you need for readable text.

For example, green text on a white background: convert -density 150 test.pdf lecture2.png convert lecture2.png -alpha Copy -fuzz 100% -fill White -opaque Gray -background Green -alpha Remove lecture3.png convert lecture3.png lecture3.pdf I've shown it as three stages, but you could combine them into...

A good description. A couple of observations: The IM "convert" language is essentially postfix, although (for historical reasons) many operators can also work in the prefix position. Example: "convert -resize 800% rose: bigrose.png". I expect (and hope) these anomonlies will be p...

convert Sample.png -colors 16 Sample2.png

Get a scanner. Life will be so much easier. If that isn't feasible (perhaps horrible images like this come from clients), use an interactive editor to square up the image, crop it and curve it. Automated processing is possible for this particular image, of course. But a generic solution for dodgy ph...

The source image has gone away. Can you re-post it?

If this is the only re-save you are doing, it shouldn't harm the visual quality much. If you are doing multiple changes and saving as jpeg each time, then you shouldn't. Instead, use a lossless compression for intermediate files. IM can't get a jpeg quality setting from non-jpeg files. I don't know ...