A few very minor changes seemed to small to commit separately:
- Fix typo postive -> positive
- Remove swap(start, end) FIXME, that is the correct thing to do
- Add FIXME for start_radius == end_radius case
- Formatting tweaks
Previously, it was assumed the focal point was the center of the start
circle. This is only the case if the start radius is zero or the centers
of the start and end circle are the same.
This was pretty hard to spot until repeating SVG radial gradients where
added, where the maths broke near the focal point.
The current implementation assumes the focal point is the center of the
start circle, for most cases the difference this makes is very subtle,
but becomes more apparent with spreadMethod=repeat/reflect.
This also slightly refactors things to share more implementation with
the SVG linear gradients, and improve accuracy (which fixes some banding
issues).
This fixes a few rendering bugs especially where the first or last
color stop had a zero alpha value. Note we can't just set the first
and last values on the gradient line to the first/last colors since
that might not be correct (e.g. have a transition hint).
This implements the gradients for:
- CanvasRenderingContext2D.createLinearGradient()
- CanvasRenderingContext2D.createConicGradient()
- CanvasRenderingContext2D.createRadialGradient()
As loosely defined in: https://html.spec.whatwg.org/multipage/canvas.html#fill-and-stroke-styles
(It's really not very well defined for radial gradients)
Actual implementation (for radial gradients) was done with a lot
of trial and error, then visually comparing to other browsers.
This moves the CSS gradient painting to the painter creating:
- Painter::fill_rect_with_linear_gradient()
- Painter::fill_rect_with_conic_gradient()
- Painter::fill_rect_with_radial_gradient()
This has a few benefits:
- The gradients can now easily respect the painter scale
- The Painter::fill_pixels() escape hatch can be removed
- We can remove the old fixed color stop gradient code
- The old functions are now just a shim
- Anywhere can now easily use this gradient painting code!
This only leaves the color stop resolution in LibWeb (which is fine).
Just means in LibGfx you have to actually specify color stop positions.
(Also while here add a small optimization to avoid generating
excessively long gradient lines)
