[PATCH] shell: moving drag surface refine

[Kristian Høgsberg]

On Fri, Jul 27, 2012 at 4:26 PM, Bill Spitzak <spitzak at gmail.com> wrote:
>
>
> Kristian Høgsberg wrote:
>>
>> On Fri, Jul 27, 2012 at 02:58:50AM -0700, juan.j.zhao at linux.intel.com
>> wrote:
>>>
>>> From: Juan Zhao <juan.j.zhao at linux.intel.com>
>>>
>>> When applications not directly based on toytoolkit, like simple-egl, efl
>>> applications is grabbed and moved, they may be moved to the place under
>>> the panel. Then they could not be grabbed again.
>>> Don't allow the pointer's bounding box move across the desktop's
>>> viewport.
>>
>>
>> This is good, but it doesn't work for multiple monitors.  I think we
>> need a different strategy for supporting multiple outputs.  The
>> outputs are rectangles laid out in the global coordinate system
>> (output->x/y and output->current->width/height).  Here's what I think
>> should work: we add a new shell->active_region to weston_compositor,
>> and pixman_region32_union all the outputs into that union and then
>> subtract all the panel rectangles.  It won't change very often so we
>> can just keep that in desktop_shell and update it on monitor hotplug
>> or resolution changes.
>>
>> To see if we can move a surface, we intersect the bounding box for the
>> surface with shell->active_region and look at the boxes in the
>> intersection.  If all boxes are below a minimum width we cancel the
>> horizontal movement (set dx = es->geometry.x).  If all boxes are below
>> a certain height we cancel the vertical movement.
>>
>> It's a slightly different heuristics than the bounding box you
>> implemented below, but I think it works better.  The bounding box
>> approach will restrict motion event though there may be plenty of
>> surface left on the screen to grab later.  The region intersect
>> approach just makes sure there's always a minimum amount of surface on
>> the screen.
>>
>> Kristian
>
>
> I don't think the surface boundaries enter into this at all. All that is
> required is that a very small square around the cursor be prevented from
> being moved off-screen or behind a panel. This square should be what is
> intersected with the non-obscured area.
>
> In addition it may be a lot easier for the shell to just offer a "is this
> rectangle visible" call, rather than having it update a region. They are
> both running in the same process. I would use regions only to communicate
> information asynchronously between client/server.

I don't think you understood what I proposed at all.

Kristian