Save a popout’s position

The screen position of a caplin.popout.Popout is not automatically persisted between sessions. It does, however expose the geometric data required to do so. This enables implementation code to choose its own persistance strategy.

Example

Here is a simple example of how to persist the position of a popout using local storage.

First of all we get the geometric data from the popout object, and persist it to local storage (this would generally be done on window.onunload):

var geometrics = popout.getWindowGeometrics();

localStorage.myPopoutGeometrics = JSON.stringify(geometrics);

Then we can update the code that launches our popout to use the persisted geometric data:

var geometrics = { left : 10, top : 10, width : 200, height : 100 };

if(localStorage.myPopoutGeometrics !== undefined) {
    geometrics = JSON.parse(localStorage.myPopoutGeometrics);
}

var popout = new caplin.popout.Popout('popout', geometrics);

popout.open(geometrics.width, geometrics.height);

A note on window positioning

All browsers position new windows relative to the top left of the OS’s main screen, but still have widely different behaviours in regards to positioning:

  • Firefox: Works as expected, even for negative positioning.

  • IE: Same as Firefox, except does not allow negative positioning. This means a popout cannot be placed above or to the left of the OS’s main screen.

  • Chrome: Can handle negative positioning like Firefox, but always places popouts on the same screen as the window that opened the popout. If a popout would be opened on another screen, it will instead appear at the edge of the screen containing the parent window.

See also: