javascript - 将canvas转换为pdf:黑色背景

我想将html canvas导出为pdf并下载，我进行了一些搜索，以下脚本对我来说效果很好：

<script language = "JAVASCRIPT">
var canvas = document.getElementById('mycanvas');

var context = canvas.getContext('2d');

// draw a blue cloud
context.beginPath();
context.moveTo(170, 80);
context.bezierCurveTo(130, 100, 130, 150, 230, 150);
context.bezierCurveTo(250, 180, 320, 180, 340, 150);
context.bezierCurveTo(420, 150, 420, 120, 390, 100);
context.bezierCurveTo(430, 40, 370, 30, 340, 50);
context.bezierCurveTo(320, 5, 250, 20, 250, 50);
context.bezierCurveTo(200, 5, 150, 20, 170, 80);
context.closePath();
context.lineWidth = 5;
context.fillStyle = '#8ED6FF';
context.fill();
context.strokeStyle = '#0000ff';
context.stroke();

download.addEventListener("click", function() {
// only jpeg is supported by jsPDF
var imgData = canvas.toDataURL("image/jpeg", 1.0);
var pdf = new jsPDF();

pdf.addImage(imgData, 'JPEG', 0, 0);
var download = document.getElementById('download');

pdf.save("download.pdf");
}, false);
</script>

但是我的画布有黑色背景！

我尝试了其他代码和许多在Internet上找到的解决方案，尝试更改canvas标签中的背景颜色，但没有进行..

有什么帮助吗？

最佳答案

代替以JPEG的方式下载，请尝试以PNG的方式下载：

download.addEventListener("click", function() {
// only jpeg is supported by jsPDF
var imgData = canvas.toDataURL("image/png", 1.0);
var pdf = new jsPDF();

pdf.addImage(imgData, 'PNG', 0, 0);
var download = document.getElementById('download');

pdf.save("download.pdf");
}, false);

关于javascript - 将canvas转换为pdf:黑色背景，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/37244994/