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pixelbuffer.mdx

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PixelBuffer

A 1D color vector to support color manipulation of LED strips. All colors are 24bit RGB colors.

The pixel buffer is typically accessed through a Led client.

import { Led } from "@devicescript/core"
import "@devicescript/runtime"

const led = new Led()
// highlight-next-line
const pixels = await led.buffer()

It can also be allocated using pixelBuffer.

import { PixelBuffer } from "@devicescript/runtime"

// highlight-next-line
const pixels = PixelBuffer.alloc(32)

Usage

at, setAt

Indexing functions similar to Array.at, they allow to set color of individual LEDs and support negative indices.

const c0 = pixels.at(0)
pixels.setAt(1, c0)

clear

Clears all colors to #000000.

pixels.clear()

view

Creates a aliased range view of the buffer so that you can apply operations on a subset of the colors.

const view = pixels.view(5, 10)
view.clear()

correctGamma

Applies gamma correction to compensate LED and eye perception

// highlight-next-line
pixels.correctGamma()

rotate

Shifts the colors in the buffer by the given offset. Use a negative offset to shift right.

pixels.rotate(-1)

Helpers

Here are a few helpers built for PixelBuffer, but many others could be added!

fillSolid

This helper function assigns the given color to the entire range.

import { Led } from "@devicescript/core"
import { fillSolid } from "@devicescript/runtime"

const led = new Led()
const pixels = await led.buffer()

// highlight-next-line
fillSolid(pixels, 0x00_ff_00)

await led.show()

fillRainbow

Fills the buffer by interpolating the hue of hsv colors.

import { Led } from "@devicescript/core"
import { fillRainbow } from "@devicescript/runtime"

const led = new Led()
const pixels = await led.buffer()

// highlight-next-line
fillRainbow(pixels)

await led.show()

By default, the helper interpolates between 0 and 0xff, but this can be changed with optional parameters.

fillGradient

Fills with a linear interpolation of two colors across the RGB space.

import { Led } from "@devicescript/core"
import { fillGradient } from "@devicescript/runtime"

const led = new Led()
const pixels = await led.buffer()

// highlight-next-line
fillGradient(pixels, 0x00_ff_00, 0x00_00_ff, { circular: true })

await led.show()

fillPalette

Fills by interpolating the colors of a palette.

import { Led } from "@devicescript/core"
import { Palette } from "@devicescript/graphics"
import { fillPalette } from "@devicescript/runtime"

const led = new Led()
const pixels = await led.buffer()
const palette = Palette.arcade()

// highlight-next-line
fillPalette(pixels, palette)

await led.show()

fillBarGraph

A tiny bar chart engine to render on a value on a LED strip

import { Led } from "@devicescript/core"
import { fillBarGraph } from "@devicescript/runtime"

const led = new Led()
const pixels = await led.buffer()

const current = 25
const max = 100

// highlight-next-line
fillBarGraph(pixels, current, max)

await led.show()