使用Fabric.js选择画布上的所有对象

Question

Is there a way to explicitly select all the objects present at a particular instance of time. This can be easily done using mouse to select all. Is there a code-solution like a button named Select All so that clicking it would make all the fabric type objects being selected and then I could apply the changes to whole of that ActiveGroup using canvas.getActiveGroup(); and iterate over.

Answer 1

Good question.

There's no built-in method for this, but you would need to do something along these lines:

var objs = canvas.getObjects().map(function(o) {
  return o.set('active', true);
});

var group = new fabric.Group(objs, {
  originX: 'center', 
  originY: 'center'
});

canvas._activeObject = null;

canvas.setActiveGroup(group.setCoords()).renderAll();

The code should be self-explanatory, and it's pretty much what's happening under the hood when you use mouse, shift+click, etc.

Answer 2

Using the current version of fabric.js (2.3.1) you can do this:

canvas.discardActiveObject();
var sel = new fabric.ActiveSelection(canvas.getObjects(), {
  canvas: canvas,
});
canvas.setActiveObject(sel);
canvas.requestRenderAll();

This is an quote from the demo page: http://fabricjs.com/manage-selection

Answer 3

canvas.setActiveGroup it's no longer an option. It was erased as a function in version 2.0

Answer 4

这是一个更紧凑的形式：

canvas.setActiveGroup(new fabric.Group(canvas.getObjects())).renderAll();

Answer 5

selectAllObjects() {
    this.canvas.discardActiveObject();
    this.canvas.discardActiveGroup();

    let objects: Fabric.Object[] = this.canvas.getObjects().map(function (object: Fabric.Object) {
        return object.set('active', true);
    });

    if (objects.length === 1) {
        this.canvas.setActiveObject(objects[0]);
    } else if (objects.length > 1) {
        let group: Fabric.Group = new Fabric.Group(objects.reverse(), {
            canvas: this.canvas
        } as any);
        group.addWithUpdate(null);
        this.canvas.setActiveGroup(group);
        group.saveCoords();
        this.canvas.trigger("selection:created", {
            target: group
        });
    }

    this.canvas.renderAll();
}