我用 image() 画了一个画布(又名画布 1),然后将其旋转 25 度。然后我用旋转的画布为另一个画布(又名画布 2)制作图案。然后我画这个。并用新创建的图案填充填充样式。我注意到下面代码中间是否有警报
finalsleeve_ctx.globalCompositeOperation = "source-atop";
/*****************************************
alert(sleeve.toDataURL('image/png'));
*****************************************/
var pattern = finalsleeve_ctx.createPattern(sleeve, 'repeat');
然后 Firefox 给出正确的输出,但如果我不发出警报,它不会给我正确的输出。crom 没有显示正确的输出。
我需要延迟吗?
这是我尝试过的。
HTML
<div >
<canvas id="sleeve" width=436 height=567></canvas>
<canvas id="finalsleeve" width=436 height=567 ></canvas>
</div>
JS
var sleeve = document.getElementById('sleeve');
var sleeve_ctx = sleeve.getContext('2d');
var finalsleeve = document.getElementById('finalsleeve');
var finalsleeve_ctx = finalsleeve.getContext('2d');
function rotator2(var2,var3)
{
sleeve.width=sleeve.width;
var imageObj_rotator2 = new Image();
imageObj_rotator2.onload = function ()
{
var pattern_rotator2 = sleeve_ctx.createPattern(imageObj_rotator2, "repeat");
sleeve_ctx.fillStyle = pattern_rotator2;
sleeve_ctx.rect(0, 0, sleeve.width, sleeve.height);
sleeve_ctx.rotate(var3 * Math.PI/180);
sleeve_ctx.fill();
}
imageObj_rotator2.src = var2;
}
function drawSleeve()
{
finalsleeve.width = finalsleeve.width;
var imgsleeve = new Image();
imgsleeve.src="http://i.stack.imgur.com/FoqGC.png";
finalsleeve_ctx.drawImage(imgsleeve,0,0);
finalsleeve_ctx.globalCompositeOperation = "source-atop";
alert(sleeve.toDataURL('image/png'));
var pattern = finalsleeve_ctx.createPattern(sleeve, 'repeat');
finalsleeve_ctx.rect(0, 0, sleeve.width, sleeve.height);
finalsleeve_ctx.fillStyle = pattern;
finalsleeve_ctx.fill();
finalsleeve_ctx.globalAlpha = .10;
finalsleeve_ctx.drawImage(imgsleeve, 0, 0);
finalsleeve_ctx.drawImage(imgsleeve, 0, 0);
finalsleeve_ctx.drawImage(imgsleeve, 0, 0);
}
rotator2('http://i.stack.imgur.com/fvpMN.png','25');
drawSleeve();
这是小提琴。 http://jsfiddle.net/EbBHz/