Prepare shape objects for a group without having them on screen...yet about two.js

[jonobr1]

Glad you like it! I'm not at a computer right this second.., but have you
tried setting group.visible = false;

Groups and shapes all have the visible property, a Boolean.

On Monday, May 13, 2013, Richard Shaw wrote:

I hope this is the right place for this! Using two.js, what could be the
best approach to properly create shape objects (like using makeLine,
makeRectangle, etc) without having them appear in the scene immediately,
add them to a group, then have the shapes appear in the scene thereafter?
I'm sure that question in a bit unclear, so here is an example:

/.../function: buildShape(){
this.shape = two.makeGroup();
this.shape.translation.set(this.X,this.Y);

var unitBody = two.makeRectangle(0,0,28,16);
var pod = two.makeCirucle(0,0,this.podSize);
var barrel = two.makeLine(0,0,this.barrelLen,0);

this.shape.add(unitBody,pod,barrel);}/.../

While the above works just fine in code and eventual outcome, there is a
split second that the three shape objects appear at the top left of the
screen (0px, 0px) since that's what I have to do for them to appear
properly in the group after adding them.

Without having to copy/paste your make functions so that I can manipulate
them to not place the shape on the screen, is there any other way to do
this?

Thanks in advance for an awesome library!

—
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[blitzxion]

As a matter of fact I have! I dove into the source just to see if you did implement some sort of feature like that (and you have!).

I actually created a little "twoExt.js" file of my own that adds some feature like "hide, show, toggle":

/*...*/
var VisualFuncs = {
  show: function(){ this.visible = true; if(this) return this; },
  hide: function(){ this.visible = false; if(this) return this; },
  toggle: function(){ this.visible = !this.visible; if(this) return this; }
};

_.extend(Two.Polygon.prototype, VisualFuncs);
_.extend(Two.Group.prototype, VisualFuncs);
/*...*/

I decided to so some chaining in there so I could do something like:

this.shape = two.makeGroup().hide();
var b = two.makeRectangle(0,0,24,16).hide();
b.fill = 'red';
b.stroke = 'green';
this.shape.add(b);
this.shape.show(); // Would setting this to "visible = true" make its children visible too?

I guess with that kind of implementation, would you automatically show "b" above once the parent group's "visible" property is set to true (using show())?

Thanks for getting back to me so quickly!

[jonobr1]

You're exactly right. As a result you'd have to modify your VisualFuncs a bit:

/*...*/
var PolygonFuncs = {
  show: function(){ this.visible = true; if(this) return this; },
  hide: function(){ this.visible = false; if(this) return this; },
  toggle: function(){ this.visible = !this.visible; if(this) return this; }
};

var GroupFuncs = {
  show: function() { _.each(this.children, function(child) { child.show(); }); return this; },
  hide: function() { _.each(this.children, function(child) { child.hide(); }); return this; },
  toggle: function() { _.each(this.children, function(child) { child.toggle(); }); return this; }
};

_.extend(Two.Polygon.prototype, PolygonFuncs);
_.extend(Two.Group.prototype, GroupFuncs);
/*...*/

Nice work!

[blitzxion]

Thanks for the update (especially on my existing code)! Completely skipped my mind about using the _.each method to work on all the child objects in a group in this context.

I'll use this and see what I can do. Thanks again!