本文實例為大家分享了HTML5 Canvas實現(xiàn)的一個畫板代碼，供大家參考，具體內(nèi)容如下
<!DOCTYPE html><html><head> <meta charset="utf-8"> <title>DEMO6：自定義畫板</title></head><body><canvas id="canvas" width="600" height="300"> 瀏覽器不支持canvas <!-- 如果不支持會顯示這段文字 --></canvas><br/><button style="width:80px;background-color:yellow;" onclick='linecolor="yellow";'>YELLOW</button><button style="width:80px ;background-color:red;" onclick='linecolor="red";'>RED</button><button style="width:80px ;background-color:blue;" onclick='linecolor="blue";'>BLUE</button><button style="width:80px ;background-color:green;" onclick='linecolor="green";'>GREEN</button><button style="width:80px ;background-color:white;" onclick='linecolor="white";'>WHITE</button><button style="width:80px ;background-color:black;" onclick='linecolor="black";'>BLACK</button><br/> <button style="width: 80px;background-color: white;" onclick="linw=4;">4PX</button><button style="width: 80px;background-color: white;" onclick="linw=8;">8PX</button><button style="width: 80px;background-color: white;" onclick="linw=16;">16PX</button><br/> <button style="width: 80px;background-color: white;" onclick="copyimage();">EXPORT</button> <br/><img src="" id="image_png" width="600px" height="300px"><br/> <script type="text/javascript"> var canvas = document.getElementById('canvas'); //獲取標簽 var ctx = canvas.getContext("2d"); var fillStyle = "black"; ctx.fillRect(0,0,600,300); var onoff = false; //按下標記 var oldx = -10; var oldy = -10; //設(shè)置顏色 var linecolor = "white"; var linw = 4; canvas.addEventListener("mousemove",draw,true); //鼠標移動事件 canvas.addEventListener("mousedown",down,false); //鼠標按下事件 canvas.addEventListener("mouseup",up,false); //鼠標彈起事件 function down(event){ onoff = true; oldx = event.pageX - 10; oldy = event.pageY - 10; } function up(){ onoff = false; } function draw(event){ if (onoff==true) { var newx = event.pageX - 10; var newy = event.pageY - 10 ctx.beginPath(); ctx.moveTo(oldx,oldy); ctx.lineTo(newx,newy); ctx.strokeStyle = linecolor; ctx.lineWidth = linw; ctx.lineCap = "round"; ctx.stroke(); oldx = newx; oldy = newy; } } function copyimage(event) { var img_png_src = canvas.toDataURL("image/png"); //將畫板保存為圖片格式的函數(shù) document.getElementById("image_png").src = img_png_src; } </script> </body></html>以上就是本文的全部內(nèi)容，希望對大家的學習有所幫助。
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