canvas 畫圖，能夠選中所畫的圖片並且能夠隨意移動圖片 ...
canvas 畫圖，能夠選中所畫的圖片並且能夠隨意移動圖片
<html xmlns="http://www.w3.org/1999/xhtml"> <head runat="server"> <meta http-equiv="Content-Type" content="text/html; charset=utf-8"/> <title></title> <script type="text/javascript" src="JS/jquery.min.js"></script> </head> <body> <canvas id="myCanvas" width="500" height="400" style="border:1px solid #000000; background-color: #CCCCCC;"></canvas> <input id="Button1" type="button" value="畫矩形" onclick="DrawingRec()" /> <input id="Button2" type="button" value="畫線" onclick="Drawline()"/> <p></p> </body> </html> <script> var c = document.getElementById("myCanvas"); var ctx = c.getContext("2d"); var list = []; var currentImag; var ax, ay, x, y; var startmove = false; var c = document.getElementById("myCanvas"); c.onmousedown = function (e) { for (var i = 0; i < list.length; i++) { var w = list[i].x + list[i].width; var h = list[i].y + list[i].height; if (e.clientX < w && e.clientX > list[i].x && e.clientY < h && e.clientY > list[i].y) { currentImag = list[i]; startmove = true; console.log("select: true"); } } }; c.onmousemove = function (e) { console.log("x:" + e.pageX + " y:" + e.pageY); if (currentImag == null) return; console.log("moveselect:true"); x = e.clientX; y = e.clientY; //限制移動不能超出畫布 (x < 40) ? ax = 20 : ax = 480; (y < 40) ? ay = 20 : ay = 380; (x < 480 && x > 20) ? x = e.clientX : x = ax; (y < 380 && y > 20) ? y = e.clientY : y = ay; //清除之前圖片然後重新繪製 ctx.clearRect(0, 0, c.width, c.height); currentImag.x = x; currentImag.y = y; Piant(); ctx.drawImage(currentImag, x - 20, y - 20, currentImag.width, currentImag.height); }; c.onmouseup = function () { //c.onmousemove = null; //c.onmouseup = null; currentImag = null; startmove = false; }; function Piant() { if (startmove) { for (var i = 0; i < list.length; i++) { ctx.drawImage(list[i], list[i].x - 20, list[i].y - 20, list[i].width, list[i].height); } } } function DrawingRec() { //ctx.beginPath(); //ctx.fillStyle = "#000000"; //ctx.fillRect(200, 100, 150, 75); //ctx.closePath(); var img = new Image(); img.src = "default/images/panel_tools.png"; img.x = 50; img.y = 50; img.width = 40; img.height = 40; ctx.drawImage(img, 50, 50, img.width, img.height); list.push(img); } </script>
