Possible bug in -define for gradient

[fmw42]

ImageMagick version

7.1.1.29

Operating system

MacOS

Operating system, version and so on

Ventura

Description

I am not sure I understand the following define or perhaps there is a bug. It is not working as I might expect. But I could just not understand how it should work.

-define gradient:bounding-box=widthxheight+x+y

I tried:

magick -size 500x500 -define gradient:bounding-box=400x200+50+200 gradient:red-blue x.png

expecting to see a red-blue gradient inside the 500x500 size. But I got a completely red image

Is my syntax correct?

Steps to Reproduce

See above

Images

see above

[snibgo]

I confirm the weirdness.

If we use offsets that are less then the dimensions, we get a gradient. For example:

magick -size 500x500 -define gradient:bounding-box=400x200+150+150 gradient:red-blue x.png

With these parameters, I would expect the top-left of the gradient to be at (150,150), and the gradient would be 400x200 pixels.

The gradient does start at y=150, but nothing else is as expected.

[fmw42]

Besides the lack of x offset, it also does not look like the gradient goes to pure red at the top of the gradient. I would have thought the gradient would be a full gradient inside the bounding box. It looks like a crop of a 500x500 gradient rather than a full gradient in the bounding box. The documentation is not clear on this point.

[urban-warrior]

Gradients theoretically follow the SVG standard. Write an SVG gradient and the magick command-line equivalent. If they do not match, ImageMagick may have a bug which we will investigate further.

[fmw42]

Here is my SVG file that I saved as grad.svg

<?xml version="1.0" standalone="no"?>
<!DOCTYPE svg PUBLIC "-//W3C//DTD SVG 1.1//EN" 
  "http://www.w3.org/Graphics/SVG/1.1/DTD/svg11.dtd">
<svg width="500" height="500" viewBox="0 0 500 500" version="1.1"
     xmlns="http://www.w3.org/2000/svg">
  <g>
    <defs>
      <linearGradient id="MyGradient">
        <stop offset="0%" stop-color="red" />
        <stop offset="100%" stop-color="blue" />
      </linearGradient>
    </defs>

    <!-- The rectangle is filled using a linear gradient paint server -->
    <rect fill="url(#MyGradient)" stroke="none"   
          x="100" y="100" width="300" height="200"/>
  </g>
</svg>

grad.svg.zip

magick grad.svg grad_svg.png

Here is the IM command

magick -size 500x500 -define gradient:direction=east -define gradient:bounding-box=300x200+100+100 gradient:red-blue grad_im.png

It is not respecting the X-offset nor the dimension of the bounding box

[urban-warrior]

Thank you for reporting the issue. We have successfully reproduced it and are actively working on a patch to resolve it. You can expect this patch to be merged into the main GIT branch, later today. As part of our commitment to quality, this fix will also be included in the upcoming beta releases of ImageMagick by tomorrow. Your patience and feedback are greatly appreciated.

[fmw42]

I am still getting a totally red image. No blue gradient. IM 7.1.1.30 Mac OSX Ventura

magick -size 500x500 -define gradient:bounding-box=400x200+50+200 gradient:red-blue x.png

[fmw42]

FYI, still only a solid red output in 7.1.1-31 for

magick -size 500x500 -define gradient:bounding-box=400x200+50+200 gradient:red-blue x.png

[urban-warrior]

Thank you for reporting the issue. We have successfully reproduced it and are actively working on a patch to resolve it. You can expect this patch to be merged into the main GIT branch, later today. As part of our commitment to quality, this fix will also be included in the upcoming beta releases of ImageMagick by tomorrow. Your patience and feedback are greatly appreciated.

[fmw42]

This is still not working correctly at least as I expect in IM 7.1.1.31 Mac OSX Ventura

magick -size 500x500 -define gradient:bounding-box=400x200+150+150 gradient:red-blue x.png

The width is not 400 and height is not 200. It has a width of 250 and height of 50.

magick x.png -format "%@" info:
250x50+150+150