Modify rasterizer to support non-square X,Y axes scaling. #274
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Add new function nsvgRasterizeXY() similar to nsvgRasterize() but with separate scaling factors for x-axis and y-axis.
memononen
requested changes
Sep 23, 2025
src/nanosvgrast.h
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| NSVGimage* image, float tx, float ty, float scale, | ||
| unsigned char* dst, int w, int h, int stride); | ||
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| // As above, but allow X and Y axes to scale independently for non-square aspects |
src/nanosvgrast.h
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| * | ||
| */ | ||
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| /* Modified by FLTK to support non-square X,Y axes scaling. |
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This should go to the commit message instead.
| } | ||
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| static void nsvg__flattenShapeStroke(NSVGrasterizer* r, NSVGshape* shape, float scale) | ||
| static void nsvg__flattenShapeStroke(NSVGrasterizer* r, NSVGshape* shape, float sx, float sy) |
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This function does not seem correct. When scaling non-proportionally, the stroke should scale non-proportionally too.
I think the correct way could be to:
- flatten the paths, but adjust the tessellation so that it takes scaling into account
- expand strokes, including dashing
- scale paths
It should be possible to implement pt 1 by multiplying dx and dy in nsvg__flattenCubicBez() by the scale factors. This needs to be verified, though.
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I agree that this is a bit hacky at the moment.
I'll try taking a crack at it later, but if I'm being honest, this might be a bit beyond me right now, given that I don't understand bezier math yet 😅
Since this is going upstream, this message is no longer needed.
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Add new function nsvgRasterizeXY() similar to nsvgRasterize() but with separate scaling factors for x-axis and y-axis.
This is a forward-port of fltk@abcd277 to the current master branch. It is applied on the nanosvg Debian package, and the new
nsvgRasterizeXY()function is used by thefltkandslic3r-prusapackages.It also seems to be more widely used by a number of other projects (many of them are being Slic3r forks), so it would be really good to have this in the main repo.