function drawPixel(x, y, fillArray) {
fill = "rgb(" + fillArray.join() + ")" || "black";
context.beginPath();
context.rect(x, y, 1, 1);
context.fillStyle = fill;
context.fill();
}
var canvas = document.getElementById("primary");
var context = canvas.getContext("2d");
var grad1 = [ [255, 255, 255], [0, 0, 0] ];
fillPrimary([255, 0, 0]);
$("#secondary").on("input", function() {
var hue = parseInt(this.value, 10);
var clr = hsl2rgb(hue, 100, 50);
fillPrimary(clr);
});
function fillPrimary(rgb) {
var grad2 = [ [255, 255, 255], rgb ];
for (var x = 0; x < canvas.width; x++) {
for (var y = 0; y < canvas.height; y++) {
var grad1Change = [
grad1[0][0] - grad1[1][0],
grad1[0][1] - grad1[1][1],
grad1[0][2] - grad1[1][2],
];
var currentGrad1Color = [
grad1[0][0] - (grad1Change[0] * y / 255),
grad1[0][1] - (grad1Change[1] * y / 255),
grad1[0][2] - (grad1Change[2] * y / 255)
];
var grad2Change = [
grad2[0][0] - grad2[1][0],
grad2[0][1] - grad2[1][1],
grad2[0][2] - grad2[1][2],
];
var currentGrad2Color = [
grad2[0][0] - (grad2Change[0] * x / 255),
grad2[0][1] - (grad2Change[1] * x / 255),
grad2[0][2] - (grad2Change[2] * x / 255)
];
var multiplied = [
Math.floor(currentGrad1Color[0] * currentGrad2Color[0] / 255),
Math.floor(currentGrad1Color[1] * currentGrad2Color[1] / 255),
Math.floor(currentGrad1Color[2] * currentGrad2Color[2] / 255),
];
drawPixel(x, y, multiplied);
}
}
}
function hsl2rgb(h, s, l) {
h /= 360;
s /= 100;
l /= 100;
var r, g, b;
if (s == 0) {
r = g = b = l;
} else {
var hue2rgb = function hue2rgb(p, q, t) {
if (t < 0) t += 1;
if (t > 1) t -= 1;
if (t < 1 / 6) return p + (q - p) * 6 * t;
if (t < 1 / 2) return q;
if (t < 2 / 3) return p + (q - p) * (2 / 3 - t) * 6;
return p;
}
var q = l < 0.5 ? l * (1 + s) : l + s - l * s;
var p = 2 * l - q;
r = hue2rgb(p, q, h + 1 / 3);
g = hue2rgb(p, q, h);
b = hue2rgb(p, q, h - 1 / 3);
}
return [
Math.round(r * 255),
Math.round(g * 255),
Math.round(b * 255),
];
}
#primary {
display: block;
border: 1px solid gray;
}
#secondary {
width: 256px;
height: 15px;
margin-top: 15px;
outline: 0;
display: block;
border: 1px solid gray;
box-sizing: border-box;
-webkit-appearance: none;
background-image: linear-gradient(to right, red 0%, yellow 16.66%, lime 33.33%, cyan 50%, blue 66.66%, violet 83.33%, red 100%);
}
#secondary::-webkit-slider-thumb {
-webkit-appearance: none;
height: 25px;
width: 10px;
border-radius: 10px;
background-color: rgb(230, 230, 230);
border: 1px solid gray;
box-shadow: inset 0 0 2px rgba(255, 255, 255, 1), 0 0 2px rgba(255, 255, 255, 1);
}
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<canvas id="primary" width="256" height="256"></canvas>
<input type="range" min="0" max="360" step="1" value="0" id="secondary" />
x,y
来计算聚焦的颜色(费力的方式),或者我可以直接读取位于x,y
位置的像素。有什么建议吗?我可能很快会发布另一个关于此问题的问题。 - akinuri