fabricjs delete backgroundImage

问题

Is it possible to delete the backgroundImage in a fabric.Canvas after setting with:

canvas.setBackgroundImage('img_url',function() { 
    canvas.renderAll();

Or just go back to the standard background? To set the backgroundColor to white isn't working.

Thanks for helping! Greetings Max

回答1:

This is a snippet from renderAll function of fabric.Canvas;

...
if (this.backgroundColor) {
    canvasToDrawOn.fillStyle = this.backgroundColor;
    canvasToDrawOn.fillRect(0, 0, this.width, this.height);
}

if (typeof this.backgroundImage === 'object') {
    this._drawBackroundImage(canvasToDrawOn);
}
...

Clearly, the background color is, in fact, being set to white when you do canvas.backgroundColor = white;. But, since canvas.backgroundImage is still an Image object, it is drawn over whatever color you fill the background with.

So, when you don't want the backgroundImage to be drawn, you need to set it to 0. It doesn't work with null, since typeof this.backgroundImage === 'object' still evaluates to true in renderAll, prompting backgroundImage to be drawn. It works with canvas.backgroundImage = 0;, though.

Example.

来源：https://stackoverflow.com/questions/14171378/fabricjs-delete-backgroundimage