好吧,它比你的一个衬里长得多,但你可以更改上下文矩形的背景颜色。
printCanvas (renderer.domElement.toDataURL ("image/png"), width, height,
function (url) { window.open (url, '_blank'); });
// from THREEx.screenshot.js
function printCanvas (srcUrl, dstW, dstH, callback)
{
// to compute the width/height while keeping aspect
var cpuScaleAspect = function (maxW, maxH, curW, curH)
{
var ratio = curH / curW;
if (curW >= maxW && ratio <= 1)
{
curW = maxW;
curH = maxW * ratio;
}
else if (curH >= maxH)
{
curH = maxH;
curW = maxH / ratio;
}
return { width: curW, height: curH };
}
// callback once the image is loaded
var onLoad = function ()
{
// init the canvas
var canvas = document.createElement ('canvas');
canvas.width = dstW;
canvas.height = dstH;
var context = canvas.getContext ('2d');
context.fillStyle = "black";
context.fillRect (0, 0, canvas.width, canvas.height);
// scale the image while preserving the aspect
var scaled = cpuScaleAspect (canvas.width, canvas.height, image.width, image.height);
// actually draw the image on canvas
var offsetX = (canvas.width - scaled.width ) / 2;
var offsetY = (canvas.height - scaled.height) / 2;
context.drawImage (image, offsetX, offsetY, scaled.width, scaled.height);
// notify the url to the caller
callback && callback (canvas.toDataURL ("image/png")); // dump the canvas to an URL
}
// Create new Image object
var image = new Image();
image.onload = onLoad;
image.src = srcUrl;
}