Add TiledImage.fitInBounds method.

[avandecreme]

I added a new "enum" Placement which is very similar to OverlayPlacement but with the added functionality to have handy boolean values.
I am thinking of replacing https://github.com/openseadragon/openseadragon/blob/master/src/overlay.js#L54-L64 by $.OverlayPlacement = $.Placement. It should be backward compatible provided people did not use the previously assigned numbers.

It would be nice to be able to set the bounds directly from the constructor (and consequently from viewer.addTiledImage) but it doesn't look easily doable. Suggestions welcome :)

[iangilman]

Looks lovely! I'm down with updating OverlayPlacement as you suggest. I suppose the only risk is if people have serialized the values (or plan to in the future, since the new values don't lend themselves to that)... not sure if that's a likely scenario.

As for adding it to addTiledImage, I suppose we can have new image spec properties: fitBounds and fitBoundsPlacement and pass those through (making sure along the way that people don't pass both x and fitBounds, for instance). Of course the image spec options are already plentiful, so I'm hesitant to add more. On the other hand, it does seem like a common scenario.

[avandecreme]

Looks lovely! I'm down with updating OverlayPlacement as you suggest. I suppose the only risk is if people have serialized the values (or plan to in the future, since the new values don't lend themselves to that)... not sure if that's a likely scenario.

Good point. I found that post http://stijndewitt.com/2014/01/26/enums-in-javascript/ to have the best of both worlds. And it will be 100% compatible with the current implementation.
We could also use Object.freeze when available (IE>8) for extra safety.

As for adding it to addTiledImage, I suppose we can have new image spec properties: fitBounds and fitBoundsPlacement and pass those through (making sure along the way that people don't pass both x and fitBounds, for instance). Of course the image spec options are already plentiful, so I'm hesitant to add more. On the other hand, it does seem like a common scenario.

I am willing to add it. Right now, I am adding the images at an approximate location before fixing it in the add-item event. Not very elegant.

[iangilman]

That sounds like a great plan for the enums!

... and sure, let's add the new properties to addTiledImage.

[dwrogers]

I suppose the only risk is if people have serialized the values (or plan to in the future, since the new values don't lend themselves to that)... not sure if that's a likely scenario.

Serializing overlay placement is something that I am planning on doing and seems like it would be a common requirement. I don’t know about current uses. Couldn’t you just assign the indicated values to the placement objects, as in:

18, 36, 24, 12, 10, 9, 11, 21, 22 for CENTER through LEFT and then add functions to the placement object, as in isLeft(placement), isHorizontallyCentered(placement), isRight(... These functions could use a simple bitwise and to return the desired binary result.

That way you can easily serialze the overlay placement value and also get your binary values. You could also put a quick check for the old values before the “bitwise and” so that those functions could also handle the old values 0-9.

[dwrogers]

Sorry: “old values 0-9.” s/b “old values 0-8.”

David W. Rogers
Software Developer / Collaborative Data Services / 206.667.7089 / drogers@fredhutch.org / Fred Hutch / Cures Start Here

From: Rogers, David W
Sent: Tuesday, March 22, 2016 10:59 AM
To: 'openseadragon/openseadragon'
Subject: RE: [openseadragon] Add TiledImage.fitInBounds method. (#888)

Ø I suppose the only risk is if people have serialized the values (or plan to in the future, since the new values don't lend themselves to that)... not sure if that's a likely scenario.

Serializing overlay placement is something that I am planning on doing and seems like it would be a common requirement. I don’t know about current uses. Couldn’t you just assign the indicated values to the placement objects, as in:

18, 36, 24, 12, 10, 9, 11, 21, 22 for CENTER through LEFT and then add functions to the placement object, as in isLeft(placement), isHorizontallyCentered(placement), isRight(... These functions could use a simple bitwise and to return the desired binary result.

That way you can easily serialze the overlay placement value and also get your binary values. You could also put a quick check for the old values before the “bitwise and” so that those functions could also handle the old values 0-9.

David

David W. Rogers
Software Developer / Collaborative Data Services / 206.667.7089 / drogers@fredhutch.org / Fred Hutch / Cures Start Here

From: Ian Gilman [mailto:notifications@github.com]
Sent: Tuesday, March 22, 2016 10:04 AM
To: openseadragon/openseadragon
Subject: Re: [openseadragon] Add TiledImage.fitInBounds method. (#888)

Looks lovely! I'm down with updating OverlayPlacement as you suggest. I suppose the only risk is if people have serialized the values (or plan to in the future, since the new values don't lend themselves to that)... not sure if that's a likely scenario.

As for adding it to addTiledImage, I suppose we can have new image spec properties: fitBounds and fitBoundsPlacement and pass those through (making sure along the way that people don't pass both x and fitBounds, for instance). Of course the image spec options are already plentiful, so I'm hesitant to add more. On the other hand, it does seem like a common scenario.

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Reply to this email directly or view it on GitHubhttps://github.com//pull/888#issuecomment-199909191

[avandecreme]

That is an option as well. However, I am pretty bad with bitwise operations. How do you go about choosing the values and the operators?

Note that it will break again any serialization people currently may have been doing but I am planning on doing so anyway because OverlayPlacement.CENTER is currently 0. This is dangerous because in the following example, if placement is set to CENTER, it will be overwritten by TOP_LEFT.

function myFunc(placement) {
    placement = placement || OverlayPlacement.TOP_LEFT;
}

[dwrogers]

My bitwise operators are good - my javascript is newbie... :-)

The bitwise operations would be done against a "private" set of constants:

  {...
    placementMask: {
      isLeft: 0x20,
      isHorizontalCenter: 0x10,
      isRight: 0x08,
      isTop: 0x04,
      isVerticalCenter: 0x02,
      isBottom: 0x01
  }
(etc)
  isLeft: function(placement) { return placement & placementMask.isLeft; }
  isHorizontalCenter: function(placement) { return placement & placementMask.isHorizontalCenter; }
  isRight: function(placement) { return placement & placementMask.isright; }
 (etc).
}

[dwrogers]

The constants would be more like they are now - just with different values:

    $.OverlayPlacement = { 
      CENTER:       0x12, 
      TOP_LEFT:     0x24, 
      TOP:          0x14, 
      TOP_RIGHT:    0x0c, 
      RIGHT:        0x0a, 
      BOTTOM_RIGHT: 0x09, 
      BOTTOM:       0x11, 
      BOTTOM_LEFT:  0x21, 
      LEFT:         0x22 
      }; 

[avandecreme]

I added the clipping handling. It should be ready to merge.

[iangilman]

@avandecreme Awesome, looks great!