TODO.txt

BUGS
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- set_cursor() must be set in draw? hittest? where?
- grid drawing is stateful (awaiting impl. of secondary cmd streams)
- toolbox move by all sides, with all alignment combinations
- toolbox dynamic z-index

THINK

- solve the IMGUI achilles heel:
	widgets depending on the state of other widgets that appear later in the frame.
		solutions:
			- cmd record buffers
			- events
			- forced re-layouting without redrawing
			- update callback when reading state(id)

- bb on text
- bb on scrollbox?
- negative margins?

- separate available APIs for each phase
- make drawing phase stateless
-

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GOALS

* drag & drop UI designer
	- templates with conditionals, repeats and sub-templates
		- template-based widgets
* IMGUI with popups and layouting
* remote screen sharing
	* with input routing
	- with client-side themes

IMGUI

- drawing
	* z-index
	* text
	* bg-color
	* border
	* box-shadow
	- images (incl. svg?)
- layouting
	* min width & height
	* flexbox fr stretch
	* flexbox min-w/h grow
	* flexbox align
	* flexbox gap
	* stack
	* padding
	* margin
	* text min-w/h
	* popup layouting
	* word-wrapping
	- grid fr stretch
	- grid min-w/h grow
	- grid align
	- grid gap
	- transition animations
- mouse
	* hit-test rect
	* hit state
	* hit parents
	* capturing
	* capture state
	* drag & drop
- keyboard
	* focused state
	- tab focusing
	- event bubbling
- text selection
	- drag-select with mouse
- text(area) input
	* put it behind the canvas with correct width & height
		- route keyboard events to it
		* redraw it on canvas with offset and selection

CHALLENGES

* input on a canvas
- textarea on a canvas
* webgl2 canvas on a 2d canvas
* word wrapping (our layout algo supports word-wrapping for horizontal text)
- rich text on a canvas (inline box model)

PROS vs WEB
- stateless i.e. reactive / IMGUI (but with layouting and z-index and no frame lag)
- simpler and far more productive layouting and styling models
- global z-index, allowing for:
	- relatively-positioned but painted-last popups
	- painted-last focus ring
- transition animations for in-layout objects, allowing for:
	- animated element moving, drag/drop and selection under/overlays
- streamable and replayable rendering, for sreen-sharing and remote interaction
- super-fast and memory-efficient with very low gc pressure between frames.
- complex widgets built with a combination of box-stacking and custom-drawing.

CONS vs WEB
- must reimplement:
	* scrollbox
	- text selection
	- clipboard ops
	* word-wrapping
	- inline layouting with:
		- u, b, i, strike, sub, sup, h1..6, p, br, hr, float
- no fancy typography:
	- no smart word-wrapping (Thai, auto-hyphenation)
	- no BiDi
	- no smart underline (interrupted by letter descenders)