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Wenn Sie mit der Maus zeichnen, nehmen Sie den Farbwert des aktuellen Bereichs der Maus und stellen Sie dann die Farbe des Pinsels ein. Allerdings ist die Farbauswahl immer sehr unterschiedlich mit meiner Berechnung Bitte helfen Sie!
<!DOCTYPE html>
<html>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<meta name="viewport" content="width=device-width,user-scalable=no,initial-scale=1,maximum-scale=1" />
<title></title>
<head>
<style>
*{
margin: 0;
padding: 0;
}
.box {
position: fixed;
top: 300px;
}
img {
vertical-align: middle;
}
</style>
</head>
<body>
<p class="box">
<button id="create">生成</button>
<button id="clear">清除</button>
</p>
<canvas id="canvas"></canvas>
<script src="js/jquery-1.9.1.js"></script>
<script>
// 本地图片路径
var imgSrc = 'img/aaa.png';
var height = 300;
var width = 480;
//将图片分成100份
var xW = width / 100;
var yH = height / 100;
var clip = new mosaic(height, width, imgSrc);
function mosaic(height, width, src) {
var img = new Image();
var canvas = $('#canvas')[0];
var ctx = canvas.getContext('2d');
img.addEventListener('load', function (e) {
var mousedown = false,
offsetX = canvas.offsetLeft,
offsetY = canvas.offsetTop;
canvas.width = width;
canvas.height = height;
ctx.drawImage(img, 0, 0, width, height, 0, 0, width, height);
$('#clear').on('click', function () {
ctx.drawImage(img, 0, 0, width, height, 0, 0, width, height);
});
$('#create').on('click', function () {
var images = new Image();
images.onload = function () {
$('body').append(images);
}
images.src = canvas.toDataURL()
});
// 计算当前鼠标坐标值在这个100份格子中的位置
function getPos(x, y){
var px, py;
var result = {x, y};
var posArr = createPosArr();
for(var i = 0; i < posArr.length; i++){
px = posArr[i].x;
py = posArr[i].y;
if(x >= px){
result.x = posArr[i].x;
continue;
}
}
for(var i = 0; i < posArr.length; i++){
px = posArr[i].x;
py = posArr[i].y;
if(y >= py){
result.y = posArr[i].y;
continue;
}
}
return result;
}
function createPosArr(){
var arr = [];
for(var i = 0; i < 100; i++){
arr.push({
x: i * xW,
y: i * yH
});
}
return arr;
}
function down(e) {
e.preventDefault();
mousedown = true;
}
function up(e) {
e.preventDefault();
mousedown = false;
}
function move(e) {
if(!mousedown){return;}
e.preventDefault();
// 如果鼠标按下
if (mousedown) {
var pos = getPos(e.clientX, e.clientY);
console.log(pos);
var imgData = ctx.getImageData(pos.x, pos.y, 5, 5);
var red = imgData.data[0];
var green = imgData.data[1];
var blue = imgData.data[2];
var alpha = imgData.data[3] / 255;
ctx.fillStyle = 'rgba(' + red + ',' + green + ',' + blue + ',' + alpha / 2 + ')'
ctx.fillRect(pos.x, pos.y, 10, 10);
}
}
// 在源图像外显示目标图像。只有源图像外的目标图像部分会被显示,源图像是透明的。
// ctx.globalCompositeOperation = 'destination-out';
canvas.addEventListener('mousedown', down);
canvas.addEventListener('mousemove', move);
canvas.addEventListener('mouseup', up);
});
img.src = src;
}
</script>
</body>
</html>
漂亮男人2017-06-08 11:05:00
取当前坐标颜色的时候将宽高设为1PX呢?
var imgData = ctx.getImageData(pos.x, pos.y, 1, 1);
刚好我也在弄这块,
https://github.com/S-mohan/ca...