canvas_ity port

[p0nce]

The goal is to have before 1.0.0

• Use colors library instead of passing 4 floats, deprecate old method
• gamma-space yes or no? => assuming gamma 2.0 is almost the same but much faster than sRGB conversions
• premultiplied yes or no? => yes always
• Integrate into dplug:canvas, allows to use HTML colors, ImageRef!RGBA, ImageRef!L16 => no, separate library
• a slower but more featureful Canvas, named Canvasity (ISC licence) which borrow from canvas_ity.h
• make it work, no gradients
• without allocations
• resembling HTML5 Canvas even more
• remove fonts... for now, since the API not good
• remove gradients... for now, since the API not good
• getImageData must work => no, removed, dithering removed
• putImageData must work => no, removed
• backing buffer can be any PixelType

Decisions:

• should the canvas backing store be owned by the canvas, or external like in dplug:canvas? The latter uses less memory, but also it's lesser quality. => external
• Perhaps more something that could be integrated in Gamut? => no, and doesn't need a dep on that either

[p0nce]

Current port can already do that

[p0nce]

• colors package define a single, monomorphic, Color type (no dependencies apart libc), based upon CSS Color recommendation
• gamut package define a single, monomorphic, Image type (depend on intel-intrinsics and soon colors), loosely based upon FreeImage design
• canvasity package define a single, monomorphic, Canvasity type (depend on gamut and colors and intel-intrinsics and dplug:core for Vec and sorting), based upon Canvasity and made faster. This canvas can have any image type as underlying buffer!

[p0nce]

kinda functional, but need Dplug integration

• Take vec2f and vec2i
• Take box2f and box2i => no, later
• take RGBA is possible => OK
• take ImageRef!RGBA is possible => no, quite hard. Example in distort/levelmeter.d for how to use in Dplug

[p0nce]

• v1.0.0 for canvasity => Leaks canvasity#1
• Udpate distort example to use it.
• turtle should have both canvas ready to use by user
• trying on more important widget with curves, make visual comparisons
• dplug:canvas should depends on colors and take a Color where possible.
• More Wiki documentation, especially a case for when to use one or the other
• pretty sure there are bugs when save/restore and matrices are involved => LATER
• Minor tag and release
• Update turtle to use colors for color parsing

[p0nce]

Comparison that highlight difference in integration.

Left is dplug:canvas, right is canvasity
alpha values needs to be boosted in canvasity to match, because of the gamma-aware blending.

[p0nce]

https://github.com/AuburnSounds/Dplug/wiki/Using-dplug-canvas-or-canvasity