How to zoom all elements pof canvas with one click

问题:

I m using fabric.js in one of my projects. I m using zooming functionalities . I would like to know if there a simple way to zoom all the canvas (with all the elements ) in on click.

回答1:

Try out this jsfiddle demonstrating zoom onclick of a button: http://jsfiddle.net/cmontgomery/H7Utw/1/. In essence you get all objects on the canvas and scale/move them by the same factor, giving the visual appearance of zoom.

var objects = canvas.getObjects();
for (var i in objects) {
    var scaleX = objects[i].scaleX;
    var scaleY = objects[i].scaleY;
    var left = objects[i].left;
    var top = objects[i].top;

    var tempScaleX = scaleX * SCALE_FACTOR;
    var tempScaleY = scaleY * SCALE_FACTOR;
    var tempLeft = left * SCALE_FACTOR;
    var tempTop = top * SCALE_FACTOR;

    objects[i].scaleX = tempScaleX;
    objects[i].scaleY = tempScaleY;
    objects[i].left = tempLeft;
    objects[i].top = tempTop;

    objects[i].setCoords();
}

canvas.renderAll();

回答2:

If you use zoom with fabricjs without modifying all objects use: https://github.com/wojtek-krysiak/fabricjs-viewport.

Example: http://wojtek-krysiak.github.io/fabricjs-viewport/