function initDrawReact(id, fn) { var drawArear = document.getElementById(id); // 获取画布元素 // 创建矩形框 var drawReact = document.createElement('div'); drawReact.id = id + '_box' drawReact.style.boxSizing = 'border-box' drawReact.style.border = '1px solid red' drawReact.style.position = 'absolute' drawReact.style.display = 'none' drawArear.appendChild(drawReact) // 绑定鼠标事件--onmousedown drawArear.onmousedown = function ($event) { console.log($event.which); if($event.which!='1'){ return ; } drawArear = document.getElementById(id); // 获取画布元素 // 初始化 var drawReact = document.getElementById(id + '_box'); // 获取矩形框元素 var areaInfo = drawArear.getBoundingClientRect(); // 返回元素的大小及其相对于视口的位置 var height = 1000 / areaInfo.height;//分为100分 var width = 1000 / areaInfo.width; var reactWidth, reactHeight, reactTop, reactLeft; // 定义矩形框的宽、高、top、left // xy坐标是以画布的左上角为原点,方向矢量以向下和向右为正方向。 var beginPoint = {}; // 标记起点 var endPoint = {}; // 标记终点 var is3dyun = localStorage.getItem(id + "_3d");//是否开启 if (is3dyun == 'true') { drawReact.style.display = 'block'; // 进入画布按下鼠标显示默认矩形框 } // 鼠标按下的位置作为矩形框的起点,横纵坐标记为 x0, y0 beginPoint = {x: $event.clientX - areaInfo.x, y: $event.clientY - areaInfo.y} // 起点的横坐标 var x0 = $event.clientX - areaInfo.x; // 起点的纵坐标 var y0 = $event.clientY - areaInfo.y; // 绑定鼠标事件--onmousemove document.onmousemove = function ($event) { // 终点的横坐标 var x1 = $event.clientX - areaInfo.x; // 终点的纵坐标 var y1 = $event.clientY - areaInfo.y; // 对终点相对于起点的位置进行分类讨论 if (x1 >= x0 && y1 < y0) { // x 越界处理 reactWidth = $event.clientX >= areaInfo.right ? areaInfo.width - x0 : x1 - x0; reactLeft = x0; // y 越界处理 reactHeight = $event.clientY <= areaInfo.top ? y0 : y0 - y1; reactTop = $event.clientY <= areaInfo.top ? 0 : y1; // 终点 endPoint = {x: x0 + reactWidth, y: y0 - reactHeight}; } else if (x1 < x0 && y1 < y0) { // x 越界处理 reactWidth = $event.clientX <= areaInfo.left ? x0 : x0 - x1; reactLeft = $event.clientX <= areaInfo.left ? 0 : x1; // y 越界处理 reactHeight = $event.clientY <= areaInfo.top ? y0 : y0 - y1; reactTop = $event.clientY <= areaInfo.top ? 0 : y1; // 终点 endPoint = {x: x0 - reactWidth, y: y0 - reactHeight}; } else if (x1 < x0 && y1 >= y0) { // x 越界处理 reactWidth = $event.clientX <= areaInfo.left ? x0 : x0 - x1; reactLeft = $event.clientX <= areaInfo.left ? 0 : x1; // y 越界处理 reactHeight = $event.clientY >= areaInfo.bottom ? areaInfo.height - y0 : y1 - y0; reactTop = y0; // 终点 endPoint = {x: x0 - reactWidth, y: y0 + reactHeight}; } else if (x1 >= x0 && y1 >= y0) { // x 越界处理 reactWidth = $event.clientX >= areaInfo.right ? areaInfo.width - x0 : x1 - x0; reactLeft = x0 // y 越界处理 reactHeight = $event.clientY >= areaInfo.bottom ? areaInfo.height - y0 : y1 - y0; reactTop = y0; // 终点 endPoint = {x: x0 + reactWidth, y: y0 + reactHeight}; } drawReact.style.width = reactWidth + 'px'; // 宽 drawReact.style.height = reactHeight + 'px'; // 高 drawReact.style.top = reactTop + 'px'; drawReact.style.left = reactLeft + 'px'; } // 绑定鼠标事件--onmousedown document.onmouseup = function ($event) { if($event.which!='1'){ return false; } document.onmousemove = null document.onmouseup = null // 回调 var options = {reactWidth, reactHeight, reactTop, reactLeft, beginPoint, endPoint, id, is3dyun} options.beginPoint.x = options.beginPoint.x * width; options.beginPoint.y = options.beginPoint.y * height; options.endPoint.x = options.endPoint.x * width; options.endPoint.y = options.endPoint.y * height; fn(options) } } }