viewbox values get rounded to nearest int

RiedleroD commented 1 month ago

Not much to explain here, the issue is quite simple. I hope the fix will be simple too 🤞🏻 I've attached some renders of a test image. I tested in resvg 0.41 and 0.43

<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 1.5 1.5">
    <rect fill="green" width="1.7" height="1.7"/>
    <rect fill="blue" width="1.5" height="1.5"/>
    <rect fill="red" width="1.2" height="1.2"/>
</svg>

Impl	viewbox size	command
Your Browser	-	-
rsvg	1.5x1.5	`rsvg-convert test.svg -w 100 -o test_rsvg.png`
inkscape	1.5x1.5	`inkscape "/home/riedler/Downloads/test.svg" --export-filename="test_inkscape.png" -w 100`
resvg	2x2	`resvg test.svg -w 100 test_resvg.png`

note that this is less of an issue when rounded up, but quite a big issue when rounded down, since some SVGs are perfectly cut to their contents. I feel that a suitable hotfix would be always rounding up, and cutting the resulting bitmap image to the proper size afterwards.

I didn't test whether aspect ratio is preserved e.g. when viewBox="0 0 1.5 2", but I assume that's also an issue.

RazrFalcon commented 1 month ago

Not sure if the SVG spec specifies this behavior to begin with. Will see what we can do about it.

RiedleroD commented 1 month ago

I would say so, considering what they say here: https://www.w3.org/TR/SVG11/types.html#Precision

edit: equivalent SVG 2 spec: https://www.w3.org/TR/SVG2/types.html#Precision

RazrFalcon commented 1 month ago

Yes, I'm familiar with it, but it doesn't describe that case in particular. Once again, I will look into it eventually.

linebender / resvg

viewbox values get rounded to nearest int #810