gl-vis/regl-error2d

Draw performant error bars

regl-error2d

Draw error bars for a set of points with regl.

Remake on gl-error2d:

• color may define per-bar colors.
• max number of points extended 40 times (from 1e5 to 4e6) via instanced draw.
• lineWidth and capSize are adjusted to actual pixels.
• enhanced performance via vertex shader.

Demo.

Usage

let regl = require('regl')({extensions: 'angle_instanced_arrays'})
let createError2d = require('regl-error2d')

let error2d = createError2d(regl)

error2d({
  positions: [0,0, .5,0, ...],
  errors: [.5,.5,.5,.6, .2,.3,.4,.1, ...],
  color: 'rgba(0, 100, 200, .75)'
})

createError2d(regl, options?)

Create new error2d instance from regl and initial options. Note that regl instance should have ANGLE_instanced_arrays extension enabled.

error2d(options|list?)

Draw errors, update options.

Option	Default	Description
positions, points, data	[]	An array of unrolled xy coordinates of the points as [x,y, x,y, ...] or array of points [[x,y], [x,y], ...].
errors, error	[]	Array with error values corresponding to the points [e0l,e0r,e0b,e0t, e1l,e1r,e1b,e1t, ...]
capSize, cap	5	Error bar cap size, in pixels
lineWidth, thickness	1	Error bar line width, in pixels
color, colors	'red'	Color or array with colors. Each color can be a css color string or an array with float 0..1 values.
opacity	1	Error bars opacity.
range, dataBox	null	Visible data range.
viewport, viewBox	null	Output area within the canvas.

A list of options can be passed for batch rendering:

error2d([options1, options2, ...])

error2d.update(options|list)

Update options, not incurring redraw.

error2d.draw(id?)

Draw errors based on last options. id integer can specify a list item to redraw from batch update.

error2d.destroy()

Dispose error2d and associated resources.

License

(c) 2017 Dima Yv. MIT License

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