Tell the display manager whenever a given logical display
contains interesting windows. If so, then the display
manager arranges to show that content on a physical display,
otherwise it ignores the logical display and makes its
associated primary physical display mirror the default
display.
Assign DisplayContents when Displays are added, remove them when
Displays are removed, and update the DisplayInfo when Displays
change.
Change-Id: I36e08ec538055acabe1e24cdd12c40de4e47a158
This change is the initial check in of the screen magnification
feature. This feature enables magnification of the screen via
global gestures (assuming it has been enabled from settings)
to allow a low vision user to efficiently use an Android device.
Interaction model:
1. Triple tap toggles permanent screen magnification which is magnifying
the area around the location of the triple tap. One can think of the
location of the triple tap as the center of the magnified viewport.
For example, a triple tap when not magnified would magnify the screen
and leave it in a magnified state. A triple tapping when magnified would
clear magnification and leave the screen in a not magnified state.
2. Triple tap and hold would magnify the screen if not magnified and enable
viewport dragging mode until the finger goes up. One can think of this
mode as a way to move the magnified viewport since the area around the
moving finger will be magnified to fit the screen. For example, if the
screen was not magnified and the user triple taps and holds the screen
would magnify and the viewport will follow the user's finger. When the
finger goes up the screen will clear zoom out. If the same user interaction
is performed when the screen is magnified, the viewport movement will
be the same but when the finger goes up the screen will stay magnified.
In other words, the initial magnified state is sticky.
3. Pinching with any number of additional fingers when viewport dragging
is enabled, i.e. the user triple tapped and holds, would adjust the
magnification scale which will become the current default magnification
scale. The next time the user magnifies the same magnification scale
would be used.
4. When in a permanent magnified state the user can use two or more fingers
to pan the viewport. Note that in this mode the content is panned as
opposed to the viewport dragging mode in which the viewport is moved.
5. When in a permanent magnified state the user can use three or more
fingers to change the magnification scale which will become the current
default magnification scale. The next time the user magnifies the same
magnification scale would be used.
6. The magnification scale will be persisted in settings and in the cloud.
Note: Since two fingers are used to pan the content in a permanently magnified
state no other two finger gestures in touch exploration or applications
will work unless the uses zooms out to normal state where all gestures
works as expected. This is an intentional tradeoff to allow efficient
panning since in a permanently magnified state this would be the dominant
action to be performed.
Design:
1. The window manager exposes APIs for setting accessibility transformation
which is a scale and offsets for X and Y axis. The window manager queries
the window policy for which windows will not be magnified. For example,
the IME windows and the navigation bar are not magnified including windows
that are attached to them.
2. The accessibility features such a screen magnification and touch
exploration are now impemented as a sequence of transformations on the
event stream. The accessibility manager service may request each
of these features or both. The behavior of the features is not changed
based on the fact that another one is enabled.
3. The screen magnifier keeps a viewport of the content that is magnified
which is surrounded by a glow in a magnified state. Interactions outside
of the viewport are delegated directly to the application without
interpretation. For example, a triple tap on the letter 'a' of the IME
would type three letters instead of toggling magnified state. The viewport
is updated on screen rotation and on window transitions. For example,
when the IME pops up the viewport shrinks.
4. The glow around the viewport is implemented as a special type of window
that does not take input focus, cannot be touched, is laid out in the
screen coordiates with width and height matching these of the screen.
When the magnified region changes the root view of the window draws the
hightlight but the size of the window does not change - unless a rotation
happens. All changes in the viewport size or showing or hiding it are
animated.
5. The viewport is encapsulated in a class that knows how to show,
hide, and resize the viewport - potentially animating that.
This class uses the new animation framework for animations.
6. The magnification is handled by a magnification controller that
keeps track of the current trnasformation to be applied to the screen
content and the desired such. If these two are not the same it is
responsibility of the magnification controller to reconcile them by
potentially animating the transition from one to the other.
7. A dipslay content observer wathces for winodw transitions, screen
rotations, and when a rectange on the screen has been reqeusted. This
class is responsible for handling interesting state changes such
as changing the viewport bounds on IME pop up or screen rotation,
panning the content to make a requested rectangle visible on the
screen, etc.
8. To implement viewport updates the window manger was updated with APIs
to watch for window transitions and when a rectangle has been requested
on the screen. These APIs are protected by a signature level permission.
Also a parcelable and poolable window info class has been added with
APIs for getting the window info given the window token. This enables
getting some useful information about a window. There APIs are also
signature protected.
bug:6795382
Change-Id: Iec93da8bf6376beebbd4f5167ab7723dc7d9bd00
The inner loop that ran over each display had a few problems:
- The Surface transaction was starting and stopping between each
display.
- The layout change bits were being applied globally so all
displays were layed out when only individual displays needed to be.
- Wallpaper and input actions were being applied each time through
the display loop rather than once only for the default display.
Change-Id: I924252bab28c426222a4bb73693accc4b21cecbe
- Refactor DragState to take Display instead of DisplayContent.
- Rename xxxAnimationLw methods in WindowManagerPolicy to xxxPostLayout
to reflect animation refactoring.
Change-Id: I502f2aa45a699ad395a249a12abf9843294623f0
Make better use of Display object by saving it in DisplayContent.
Only use layerStack when referring to Surfaces. Get displayId from
default Display or default DisplayContent. Remove warnings.
Fixes bug 7038151.
Change-Id: Ie493f0f5e755dc9b91ee969ff561c2a098283ead
Preloaded drawables now have a density associated with them, so we
can load the correct drawable if we are using a different density.
Window manager now formally keeps track of the density for each
screen, allowing it to be overridden like you can already do with
size, and relies on this density to drive itself internally and
the configurations it reports.
There are a new set of Bitmap constructors where you provide a
DisplayMetrics so they can be constructed with the correct density.
(This will be for when you can have different windows in the same
app running at different densities.)
ActivityThread now watches for density changes, and pushes them
to the DENSITY_DEVICE and Bitmap global density values for that
process.
A new am command allows you to change the density.
Fix a couple of bugs that turned up.
Remove touch/focus from display. Add iterators for access.
Respond to comments. Remove TODOs, and some deviceId parameters.
Change-Id: Idcdb4f1979aa7b14634d450fd0333d6eff26994d
