#2337 NORM Trial-3: Switching between activities

[Zarro Boogs per Child]

#2337: Switching between activities
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  Reporter:  bert         |       Owner:  marco  
      Type:  enhancement  |      Status:  new    
  Priority:  normal       |   Milestone:  Trial-3
 Component:  sugar        |     Version:         
Resolution:               |    Keywords:         
  Verified:  0            |  
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Changes (by Eben):

 * cc: tomeu, marco, christianmarc (added)
  * owner:  Eben => marco
  * component:  interface-design => sugar

Comment:

 '''Activity Switcher:''' We need to change alt-n & alt-p to something more
 intelligible, if not more discoverable.  Traditionally, alt-tab and
 command-tab are used for this purpose, with the shift modifier being used
 to go in the reverse direction.  I think it makes a lot of sense to uphold
 these standards, and use alt-tab and alt-shift-tab for our purposes as
 well.

 Traditionally such an application switcher brings up a temporary on screen
 overlay with a list of running apps, with the selected app being focused
 when alt is released.  On our platform, that sounds suspiciously like the
 current design for the Home screen already, and we want to leverage that.
 Pressing alt-tab should immediately teleport one to the Home screen, and
 the highlighted ring segment should be used to indicate the selected
 activity as tab is pressed.  When alt is released, we should either a)
 jump to the activity view for the newly selected activity or b) jump to
 the view that was previously selected.  I lean towards (a).

 Unfortunately, the use of the ring has one drawback: Unlike other designs
 where the relative positions of the objects in the overlay change, it
 won't act like a stack.  It's a circular queue, which means you can't use
 it to jump quickly to the "last activity used", but only to the "next in
 the ring."  Still, I think this is acceptable for us, and keeps the ring
 metaphor strong.

 It will also be extremely important that we allow alt-tab to function
 while a drag is in progress.  This would allow me to drag an image from
 the web, press alt-tab to switch to paint, and drop it in immediately.
 This use, of course, is lower priority since the clipboard can easily
 mediate this as designed.

 I think that it's necessary to have alt-tab cycle through all instances.
 We've essentially elevated the "window" to the level of an "application"
 and each instance really is its own self-contained space.  If there are
 more than one instance of an activity open, then there is a good reason
 for that and providing the ability to cycle through all is quite logical.
 It also, again, makes the best use of the ring.  Note that, while cycling,
 we shouldn't actually be focusing each activity; there should only be one
 context switch with regards to the activities once the alt key is
 released.

 '''Activity Bar:''' I think that we want to maintain the purity of the
 idea behind the icons within the activity bar.  They are outlines, and
 they represent "new" (uninstantiated) activities.  They are wholly
 separate from those which have been started and sit in the ring.  The
 instances in the ring, on the other hand, are at once applications and
 windows (since every activity runs fullscreen in a single window).  It's
 wholly reasonable to think that a child may want to have two drawings, two
 text documents, or two  or more of anything open at once.  It's even more
 reasonable to assume this, since each instance can have a separate scope.

 Therefore, we absolutely need to make these launch new instances by
 default; it's quite essential to the model.  It also wouldn't work to use
 them as drop targets for active activities, since there may be more than
 one.  On the other hand, I ''do'' see potential in upholding the metaphor
 by creating a new instance when they are used as drop targets.  Dragging
 an image from browse to the paint activity would create a painting entry
 in the journal with the image already embedded inside it.  As a visual
 design recommendation, I would say that activities which support the mime
 type of the object being dragged should light up in the XO colors to
 indicate their acceptance of the object.

 I think that the visual clipboard itself will actually be a really usable
 alternative.  It was designed specifically for these cases, specifically
 because of the fullscreen nature of the activities.  I think beyond the
 advanced alt-tab dragging mentioned above, the clipboard should be
 highlighted as much as possible.  That said, there is a lot of work needed
 to make it truly usable.  In my experiences I still cannot drag images or
 text to the clipboard.  It doesn't appear via either the frame key or via
 hitting the corner of the screen, and that needs to be fixed (It's filed
 in #2574)

 '''Action items:'''

  - Convert alt-n, alt-p to alt-tab and alt-shift-tab
  - Implement visual design for alt-tab, using the home screen activity
 ring
  - Consider implementing drop targets on activities in the frame

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Ticket URL: <https://dev.laptop.org/ticket/2337#comment:2>
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