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mscostimscosti
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make example web app not depend on externally hosted assets, to support AP without internet
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‎examples/server/static/index.html

Lines changed: 1 addition & 5 deletions
Original file line numberDiff line numberDiff line change
@@ -1,14 +1,10 @@
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<!DOCTYPE html>
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<html>
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<head>
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<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.4.1/jquery.min.js"></script>
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<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery-minicolors/2.3.4/jquery.minicolors.min.js"></script>
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<script async src="led_color_picker_example.js"></script>
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<link rel="stylesheet" type="text/css" href="https://cdnjs.cloudflare.com/ajax/libs/jquery-minicolors/2.3.4/jquery.minicolors.css" />
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<link rel="stylesheet" type="text/css" href="https://cdnjs.cloudflare.com/ajax/libs/twitter-bootstrap/4.3.1/css/bootstrap.min.css" />
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</head>
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<body>
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<h1>LED color picker demo!</h1>
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<input id="colorPicker" type=text/>
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<canvas id="colorPicker" height="300px" width="300px"></canvas>
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</body>
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</html>

‎examples/server/static/led_color_picker_example.js

Lines changed: 125 additions & 22 deletions
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@@ -1,23 +1,126 @@
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console.log("initializing color picker")
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var colorPicker = $('input#colorPicker');
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colorPicker.minicolors({
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format: "rgb",
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changeDelay: 200,
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change: function (value, opacity) {
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rgbObject = colorPicker.minicolors("rgbObject");
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console.log(rgbObject);
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$.ajax({
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type: "POST",
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url: "/ajax/ledcolor",
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data: JSON.stringify(rgbObject),
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contentType: "application/json; charset=utf-8",
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dataType: "json",
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success: function(data){
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console.log("success!");
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},
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failure: function(errMsg) {
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console.log("error! " + errMsg);
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}
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});
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let canvas = document.getElementById('colorPicker');
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let ctx = canvas.getContext("2d");
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ctx.width = 300;
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ctx.height = 300;
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function drawColorPicker() {
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/**
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* Color picker inspired by:
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* https://medium.com/@bantic/hand-coding-a-color-wheel-with-canvas-78256c9d7d43
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*/
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let radius = 150;
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let image = ctx.createImageData(2*radius, 2*radius);
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let data = image.data;
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for (let x = -radius; x < radius; x++) {
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for (let y = -radius; y < radius; y++) {
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let [r, phi] = xy2polar(x, y);
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if (r > radius) {
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// skip all (x,y) coordinates that are outside of the circle
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continue;
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}
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let deg = rad2deg(phi);
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// Figure out the starting index of this pixel in the image data array.
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let rowLength = 2*radius;
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let adjustedX = x + radius; // convert x from [-50, 50] to [0, 100] (the coordinates of the image data array)
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let adjustedY = y + radius; // convert y from [-50, 50] to [0, 100] (the coordinates of the image data array)
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let pixelWidth = 4; // each pixel requires 4 slots in the data array
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let index = (adjustedX + (adjustedY * rowLength)) * pixelWidth;
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let hue = deg;
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let saturation = r / radius;
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let value = 1.0;
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let [red, green, blue] = hsv2rgb(hue, saturation, value);
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let alpha = 255;
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data[index] = red;
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data[index+1] = green;
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data[index+2] = blue;
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data[index+3] = alpha;
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}
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}
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});
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ctx.putImageData(image, 0, 0);
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}
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function xy2polar(x, y) {
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let r = Math.sqrt(x*x + y*y);
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let phi = Math.atan2(y, x);
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return [r, phi];
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}
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// rad in [-π, π] range
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// return degree in [0, 360] range
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function rad2deg(rad) {
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return ((rad + Math.PI) / (2 * Math.PI)) * 360;
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}
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// hue in range [0, 360]
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// saturation, value in range [0,1]
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// return [r,g,b] each in range [0,255]
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// See: https://en.wikipedia.org/wiki/HSL_and_HSV#From_HSV
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function hsv2rgb(hue, saturation, value) {
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let chroma = value * saturation;
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let hue1 = hue / 60;
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let x = chroma * (1- Math.abs((hue1 % 2) - 1));
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let r1, g1, b1;
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if (hue1 >= 0 && hue1 <= 1) {
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([r1, g1, b1] = [chroma, x, 0]);
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} else if (hue1 >= 1 && hue1 <= 2) {
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([r1, g1, b1] = [x, chroma, 0]);
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} else if (hue1 >= 2 && hue1 <= 3) {
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([r1, g1, b1] = [0, chroma, x]);
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} else if (hue1 >= 3 && hue1 <= 4) {
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([r1, g1, b1] = [0, x, chroma]);
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} else if (hue1 >= 4 && hue1 <= 5) {
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([r1, g1, b1] = [x, 0, chroma]);
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} else if (hue1 >= 5 && hue1 <= 6) {
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([r1, g1, b1] = [chroma, 0, x]);
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}
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let m = value - chroma;
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let [r,g,b] = [r1+m, g1+m, b1+m];
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// Change r,g,b values from [0,1] to [0,255]
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return [255*r,255*g,255*b];
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}
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function onColorPick(event) {
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coords = getCursorPosition(canvas, event)
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imageData = ctx.getImageData(coords[0],coords[1],1,1)
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rgbObject = {
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r: imageData.data[0],
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g: imageData.data[1],
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b: imageData.data[2]
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}
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console.log(`r: ${rgbObject.r} g: ${rgbObject.g} b: ${rgbObject.b}`);
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data = JSON.stringify(rgbObject);
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window.fetch("/ajax/ledcolor", {
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method: "POST",
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body: data,
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headers: {
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'Content-Type': 'application/json; charset=utf-8',
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},
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}).then(response => {
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console.log("sucess!: " + response)
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}, error => {
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console.log("error!: " + error)
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})
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}
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function getCursorPosition(canvas, event) {
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const rect = canvas.getBoundingClientRect()
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const x = event.clientX - rect.left
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const y = event.clientY - rect.top
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console.log("x: " + x + " y: " + y)
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return [x,y]
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}
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drawColorPicker();
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canvas.addEventListener('mousedown', onColorPick);
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