在HTML5 canvas上用鼠标点击两次绘制一条线? [英] Draw a line with two mouse clicks on HTML5 canvas?
本文介绍了在HTML5 canvas上用鼠标点击两次绘制一条线?的处理方法,对大家解决问题具有一定的参考价值,需要的朋友们下面随着小编来一起学习吧!
问题描述
如何在画布上用两次鼠标点击绘制一条线?
How do I draw a line with two mouse clicks on canvas?
推荐答案
代码很简单,以获得良好的基础:
The code is quite simple, but you have to get a good foundation:
演示: http ://jsfiddle.net/NpDdt/10/
JavaScript :
var clicks = 0;
var lastClick = [0, 0];
document.getElementById('canvas').addEventListener('click', drawLine, false);
function getCursorPosition(e) {
var x;
var y;
if (e.pageX != undefined && e.pageY != undefined) {
x = e.pageX;
y = e.pageY;
} else {
x = e.clientX + document.body.scrollLeft + document.documentElement.scrollLeft;
y = e.clientY + document.body.scrollTop + document.documentElement.scrollTop;
}
return [x, y];
}
function drawLine(e) {
context = this.getContext('2d');
x = getCursorPosition(e)[0] - this.offsetLeft;
y = getCursorPosition(e)[1] - this.offsetTop;
if (clicks != 1) {
clicks++;
} else {
context.beginPath();
context.moveTo(lastClick[0], lastClick[1]);
context.lineTo(x, y, 6);
context.strokeStyle = '#000000';
context.stroke();
clicks = 0;
}
lastClick = [x, y];
};
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