raster fillRect

[mbostock]

Alternative to #2414 and #2145; bypass color parsing and color space conversion entirely by using context.fillRect to set colors. Unblocks #2143.

[Fil]

I've tested this together with #2143 and it works well.

The ramp opacity legend, which is currently based on d3.rgb, does not support CSS4 color strings; solvable with a SVG filter.

SSR (and snapshot tests) do not work when the colors are defined using a CSS4 string such as color(display-p3 1 0 0). Using a CSS4 color string parser would solve this, but I don't think it's a blocker. I'll add a test that is not "all black".

Here's how it looks: on the left, the test as it runs in the browser with everything p3; on the right, the snapshot test (in dull sRGB).

[mbostock]

SSR (and snapshot tests) do not work when the colors are defined using a CSS4 string

Are you saying this is a limitation of Plot? Or a limitation of the node-canvas library we are using for snapshot testing? I don’t think that node-canvas supports colorSpace currently, so that’s fine, but I would want to know if you’re saying we have some limitation in Plot.

[mbostock]

Also, are you aware that this is generally slower than the previous implementation?

test	main	mbostock/raster-fill-rect
rasterCa55Barycentric	148,123	257,264
rasterCa55Color	194,181	271,273
rasterCa55Nearest	132,142	228,234
rasterCa55None	33,44	38,36
rasterCa55RandomWalk	232,235	325,332
rasterFacet	94,96	144,142
rasterPenguinsBarycentric	100,90	136,134
rasterPenguinsBarycentricBlur	101,114	143,149
rasterPenguinsBlur	133,136	171,191
rasterPenguinsRandomWalk	121,124	165,175
rasterPrecision	111,102	141,171
rasterVapor	102,114	100,116
rasterVapor2	133,149	152,158
rasterVaporEqualEarth	127,138	151,150
rasterVaporEqualEarthBarycentric	139,133	169,176
rasterVaporPeters	123,125	159,153
rasterWalmartBarycentric	211,218	276,281
rasterWalmartBarycentricOpacity	102,87	183,159
rasterWalmartRandomWalk	250,249	287,320
rasterWalmartRandomWalkOpacity	163,148	246,247

[mbostock]

Superseded by #2417.