Created
July 9, 2019 23:53
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Alpha blending calculator
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| <!DOCTYPE html> | |
| <html> | |
| <head> | |
| <meta charset="utf-8"> | |
| <meta name="viewport" content="width=device-width"> | |
| <title>JS Bin</title> | |
| </head> | |
| <body> | |
| <p> | |
| <label> | |
| Base color | |
| <input id="base"> | |
| </label> | |
| </p> | |
| <p> | |
| <label> | |
| Overlay color | |
| <input id="overlay"> | |
| </label> | |
| </p> | |
| <p> | |
| <label> | |
| Overlay alpha | |
| <input id="alpha" type="number"> | |
| </label> | |
| </p> | |
| <p> | |
| <button type="button"> | |
| Compute | |
| </button> | |
| </p> | |
| <p id="result"></p> | |
| <script id="jsbin-javascript"> | |
| const button = document.querySelector('button'); | |
| button.addEventListener('click', compute); | |
| const baseInput = document.getElementById('base'); | |
| const overlayInput = document.getElementById('overlay'); | |
| const alphaInput = document.getElementById('alpha'); | |
| function getRgbFromHex(hex) { | |
| if (hex[0] === '#') { | |
| hex = hex.slice(1); | |
| } | |
| console.log({ | |
| r: parseInt(hex[0] + hex[1], 16), | |
| g: parseInt(hex[2] + hex[3], 16), | |
| b: parseInt(hex[4] + hex[5], 16), | |
| }) | |
| return { | |
| r: parseInt(hex[0] + hex[1], 16), | |
| g: parseInt(hex[2] + hex[3], 16), | |
| b: parseInt(hex[4] + hex[5], 16), | |
| }; | |
| } | |
| function blend(baseValue, overlayValue, alpha) { | |
| return Math.round((overlayValue * alpha) + (baseValue * (1 - alpha))); | |
| } | |
| function compute() { | |
| const base = getRgbFromHex(baseInput.value); | |
| const overlay = getRgbFromHex(overlayInput.value); | |
| const alpha = alphaInput.valueAsNumber; | |
| const blended = { | |
| r: blend(base.r, overlay.r, alpha), | |
| g: blend(base.g, overlay.g, alpha), | |
| b: blend(base.b, overlay.b, alpha), | |
| }; | |
| document.getElementById('result').textContent = | |
| '#' + | |
| blended.r.toString(16) + | |
| blended.g.toString(16) + | |
| blended.b.toString(16); | |
| } | |
| </script> | |
| <script id="jsbin-source-javascript" type="text/javascript">const button = document.querySelector('button'); | |
| button.addEventListener('click', compute); | |
| const baseInput = document.getElementById('base'); | |
| const overlayInput = document.getElementById('overlay'); | |
| const alphaInput = document.getElementById('alpha'); | |
| function getRgbFromHex(hex) { | |
| if (hex[0] === '#') { | |
| hex = hex.slice(1); | |
| } | |
| console.log({ | |
| r: parseInt(hex[0] + hex[1], 16), | |
| g: parseInt(hex[2] + hex[3], 16), | |
| b: parseInt(hex[4] + hex[5], 16), | |
| }) | |
| return { | |
| r: parseInt(hex[0] + hex[1], 16), | |
| g: parseInt(hex[2] + hex[3], 16), | |
| b: parseInt(hex[4] + hex[5], 16), | |
| }; | |
| } | |
| function blend(baseValue, overlayValue, alpha) { | |
| return Math.round((overlayValue * alpha) + (baseValue * (1 - alpha))); | |
| } | |
| function compute() { | |
| const base = getRgbFromHex(baseInput.value); | |
| const overlay = getRgbFromHex(overlayInput.value); | |
| const alpha = alphaInput.valueAsNumber; | |
| const blended = { | |
| r: blend(base.r, overlay.r, alpha), | |
| g: blend(base.g, overlay.g, alpha), | |
| b: blend(base.b, overlay.b, alpha), | |
| }; | |
| document.getElementById('result').textContent = | |
| '#' + | |
| blended.r.toString(16) + | |
| blended.g.toString(16) + | |
| blended.b.toString(16); | |
| } | |
| </script></body> | |
| </html> |
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| const button = document.querySelector('button'); | |
| button.addEventListener('click', compute); | |
| const baseInput = document.getElementById('base'); | |
| const overlayInput = document.getElementById('overlay'); | |
| const alphaInput = document.getElementById('alpha'); | |
| function getRgbFromHex(hex) { | |
| if (hex[0] === '#') { | |
| hex = hex.slice(1); | |
| } | |
| console.log({ | |
| r: parseInt(hex[0] + hex[1], 16), | |
| g: parseInt(hex[2] + hex[3], 16), | |
| b: parseInt(hex[4] + hex[5], 16), | |
| }) | |
| return { | |
| r: parseInt(hex[0] + hex[1], 16), | |
| g: parseInt(hex[2] + hex[3], 16), | |
| b: parseInt(hex[4] + hex[5], 16), | |
| }; | |
| } | |
| function blend(baseValue, overlayValue, alpha) { | |
| return Math.round((overlayValue * alpha) + (baseValue * (1 - alpha))); | |
| } | |
| function compute() { | |
| const base = getRgbFromHex(baseInput.value); | |
| const overlay = getRgbFromHex(overlayInput.value); | |
| const alpha = alphaInput.valueAsNumber; | |
| const blended = { | |
| r: blend(base.r, overlay.r, alpha), | |
| g: blend(base.g, overlay.g, alpha), | |
| b: blend(base.b, overlay.b, alpha), | |
| }; | |
| document.getElementById('result').textContent = | |
| '#' + | |
| blended.r.toString(16) + | |
| blended.g.toString(16) + | |
| blended.b.toString(16); | |
| } |
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Nice! Thanks!