我有一个问题,我在画布上实现了一个裁剪自定义矩形我在Javascript中做了一个函数,当裁剪函数被称为在现有画布上创建一个孩子,然后与我绘制矩形的JQuery侦听器。当侦听器不工作时,childNode被正确创建,他们没有得到事件。这是我的代码:在画布上的JQuery监听器孩子不工作
var dragging = false;
var xstart = 0;
var ystart = 0;
var width = 0;
var height = 0;
var ctxotmp = null;
var ctxtmp = null;
var canvastmp = null;
var mycanvas = null;
function draw() {
ctxtmp.fillRect(xstart, ystart, width, height);
}
function init() {
mycanvas = $('#mycanvas')[0];
// create temp canvas
canvastmp = document.createElement('canvas');
canvastmp.id = "mycanvastmp";
canvastmp.width = mycanvas.width;
canvastmp.height = mycanvas.height;
mycanvas.parentNode.appendChild(canvastmp);
$("#mycanvastmp").css({position:"absolute",top:$("#mycanvas").css("top"),left:$("#mycanvas").css("left")});
canvastmp = $('#mycanvastmp')[0];
ctxtmp = canvastmp.getContext('2d');
ctxtmp.lineWidth = 1;
ctxtmp.fillStyle = "rgba(0, 0, 0, 0.5)";
}
//listener
$('#mycanvastmp').mousedown(function(e) {
var xoffs = $(this).offset().left;
var yoffs = $(this).offset().top;
xstart = e.pageX - xoffs;
ystart = e.pageY - yoffs;
dragging = true;
});
$('#mycanvastmp').mousemove(function(e) {
if(dragging) {
var xoffs = $(this).offset().left;
var yoffs = $(this).offset().top;
width = e.pageX - xoffs - xstart;
height = e.pageY - yoffs - ystart;
ctxtmp.clearRect(0, 0, $(this).width(), $(this).height());
draw();
}
});
$('#mycanvastmp').mouseup(function() {
dragging=false;
alert('The rectangle for crop (x, y, width, height): ' + xstart + ', ' + ystart + ', ' + width + ', ' + height);
});
有人可以帮我吗?
你应该设定听众之前调用初始化。 – Musa