Cannot get ImageMagick to trim wasted alpha space around PNG image

[StainlessStlRat]

Image In Question: https://imgur.com/XwgIzXL

I'm writing some backend server stuff in Golang and wanted to automatically trim +repage incoming PNG data to remove wasted space, make images line up better, etc...

But I couldn't get it working in code. I then moved onto command line:
convert 8_0_1587588173.png -trim +repage rose_a_trim.png

BUT the resulting image is never cropped! I tried messing with fuzz values, order of operations, etc... always the same results. But I can open it in GIMP and use "Crop To Content" no problem, so I don't think the file is the issue.

Am I doing something wrong?

NOTE: I'm using ImageMagick installed via brew (version 7+) and the matching golang branch of v3

[fmw42]

Works for me on IM 7.0.10.7 Q16 Mac OSX.

magick two.png -fuzz 15% -trim +repage x.png
magick identify two.png x.png

two.png PNG 400x216 400x216+0+0 8-bit sRGB 61934B 0.000u 0:00.000
x.png PNG 386x154 386x154+0+0 8-bit sRGB 61067B 0.000u 0:00.000

[StainlessStlRat]

Thanks for the help! When I run the commands and use identify as you said, it does in fact report those dimensions. But when I open it, the image still has the bordering alpha. Do I need to call vacuum or something?

[fmw42]

-trim only removes constant colored regions around the outside. It does not remove transparency. If you want to remove transparency then turn alpha off using -alpha off. On the Mac in Preview, the window background color is gray and the window has a minimum size for which you cannot make it smaller. The window background color outside the image will be the same color as the transparent regions. It does not show a checkerboard pattern like some other tools. So it is hard to know where the image ends and window background starts, if the image is smaller than the minimum windows size. Perhaps that is your issue?

[StainlessStlRat]

Maybe that is it! I will check with GIMP

[StainlessStlRat]

Thanks for your help!