javascript - 使用 todataurl 时输入错误

Question

每当我尝试运行此程序时，我都会在 chrome 中收到类型错误:代码更新

// Get the drawing canvas
canvas = $('#drawing');
context = canvas[0].getContext('2d');

function resizeCanvas() {

    canvas.attr({'width' : $(window).width()});
    canvas.attr({'height' : $(window).height() - 158});

    var dataURL = canvas[0].toDataURL('image/png');
    context.drawImage(dataURL, 0, 0);

}

$(window).resize(function() {
    resizeCanvas();
}); resizeCanvas();

// Various event handlers after this.

为什么!？

Answer 1

drawImage 接受图像或 Canvas 引用，您向其传递一个字符串。

例如:

var a = document.createElement("canvas");
a.getContext("2d").drawImage("asdasdasd", 0, 0 )
//TypeError: Type error

你可以尝试:

context.drawImage(canvas[0], 0, 0);

或者

var image = new Image();
image.src = dataURL;
context.drawImage( image, 0, 0 );