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Fill Image with Random Gray
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| height: 300 |
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| <script async src=https://CDN.JSDelivr.net/npm/p5></script> | |
| <script defer src=sketch.js></script> |
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| /** | |
| * Fill Image with Random Gray (v1.1.1) | |
| * GoToLoop (2018-May-26) | |
| * | |
| * https://Discourse.Processing.org/t/ | |
| * pushing-a-7712x960-binary-image-to-p5-js- | |
| * is-super-slow-is-there-a-better-way/371/11 | |
| * | |
| * Bl.ocks.org/GoSubRoutine/dd290c28663ef13aaf2f1b5e8d0adffa | |
| */ | |
| "use strict"; | |
| const WEBCOLOR_RANGE = 0x1000, GRAY_RANGE = 0x100, | |
| NUM_COLOR_BYTES = Int32Array.BYTES_PER_ELEMENT, | |
| ONE_BYTE = 0o10, TWO_BYTES = 0o20, THREE_BYTES = 0o30, MAX_BYTE = 0xff; | |
| let img; | |
| function setup() { | |
| createCanvas(400, 300).mousePressed(redraw); | |
| noLoop(); | |
| img = createImage(width >> 1, height >> 1); | |
| } | |
| function draw() { | |
| background(top.document.title = randomColor()); | |
| fillImgRndGray(img); | |
| set(width - img.width >> 1, height - img.height >> 1, img); | |
| } | |
| function keyPressed() { | |
| return !!redraw(); // returns false as preventDefault() | |
| } | |
| function randomColor() { | |
| return '#' + hex(~~random(WEBCOLOR_RANGE), 3); | |
| } | |
| function fillImgRndGray(img) { | |
| if (!img) img = createImage(width, height); | |
| img.pixels.buffer || img.loadPixels(); | |
| const pix = new DataView(img.pixels.buffer), len = pix.byteLength; | |
| for (let i = 0; i < len; i += NUM_COLOR_BYTES) { | |
| const gray = ~~random(GRAY_RANGE), | |
| RGBa = gray<<THREE_BYTES | gray<<TWO_BYTES | gray<<ONE_BYTE | MAX_BYTE; | |
| pix.setInt32(i, RGBa); | |
| } | |
| img.updatePixels(); | |
| return img; | |
| } |
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