Similar to widgets.dart, rendering.dart exports the entire rendering layer.
Also, update the examples to use rendering.dart and widgets.dart. Also clean up
some exports so that the examples have more sensible imports.
Sadly, box.dart has grown much longer than 1000 lines. This patch splits it up
into several files based on the class hierarchy. Fortunately, many of these
classes are loosely coupled to each other.
When given a null image, RenderImage should be as small as possible (isntead of
being NaNxNaN).
Also, plumb ImageFit and ImageRepeat through the various image widgets.
This CL inflates the padding of Container to account for the borders so that
the borders are allocated space in the layout and don't draw behind the
Container's child.
... as long as it doesn't have a child. If it has a child, it should size
according to that child. Essentially, if Container doesn't have a child, it
pretends like it has a child that expands to fill its constraints.
Added a ScrollListener listener to Scrollable. The ScrollListener runs each time the Scrollable's scrollOffset changes. This can be used to keep overlay widgets in sync with a Scrollable below them.
Removed the Scrollable ScrollClient API. It was no longer used and was clumsy to use as a ScrollListener.
Added global function findScrollableAncestor() to scrollable.dart.
Added examples/widgets/overlay_geometry.dart. The app's Scaffold is contained by a Stack. The Stack is used to display green overlay "Markers" at the corners of the most recently selected list item and where the corresponding tap occurred. The app uses widget.localToGlobal() to compute the global overlay positions of the markers. The ScrollListener is used to keep the markers' positions up to date.
Using ImageResource solves two problems:
1) Listeners can be notified synchronously when the sky.Image is already
available. This change removes flash of 0x0 layout when moving an
already-cached image around in the render tree.
2) In the future, when we support animated images, we can notify listeners
multiple times whenever a new image is available.
- Inline -> Pargraph. This class is actually a box, not an inline. It's really
a wrapper for RenderParagraph, so Paragraph is the normal name.
- InlineBase -> RenderInline. The name we used in C++ for the base class of
all inlines was RenderInline, which removes the ugly "Base" suffix.
- InlineText -> RenderText. Aligns this name with C++.
- InlineStyle -> RenderStyled. Matches the foregoing pattern.
Now ScrollableBlock can combine a horizontally scrolling viewport with a
horizontal block.
Also rename ViewportScrollDirection to just ScrollDirection for less verbosity.
This refactors Checkbox to own a RenderObject similar to how Switch was
refactored in https://github.com/domokit/sky_engine/pull/376 and
extracts common functionality for toggleable renderers into a base
class. Switch and Checkbox's render objects derive from this base
class to add their own custom painting and theming logic.
This introduces the notion of event disposition and allows event
targets (widgets and render objects) to consume events that should not
be processed further. This is needed by the Switch component in the
Drawer in the stocks example. The Switch is embedded in a DrawerItem.
The Switch handles the gesture tap event to toggle its state and should
handle pointer events to allow swiping and draw its own radial
reaction. The DrawerItem also handles gesture taps to allow toggling
the switch value when tapping anywhere on the drawer and to draw its
own ink splash. When tapping on the switch, both the switch's render
object and the DrawerItem's listener are in the event dispatch path.
The Switch needs to signal in some fashion that it consumed the event
so the DrawerItem does not also try to toggle the switch's state.
This changes Switch from being a subclass of the Toggleable widget to
being a standalone Component with a custom RenderObject. This is to
enable adding Switch-specific radial reaction animations in a
subsequent patch. The CustomPaint logic that Toggleable was using does
not provide a nice way for a class and its subclass to both participate
in deciding to repaint.
Assert that there are no duplicates.
Export GlobalKey from basic.dart, so that people don't have to import widgets.dart just for that.
Fix the "initialFocus" feature which actually didn't work.
In theory, before, if you had the same image twice in a scrolling container, you'd get an assertion with no way around it.
This makes those nodes not bother making keys by default, which is cheaper and more correct.
This fixes some theoretical bugs whereby we were using hashCode to try
to get unique keys for objects, but really we wanted object identity.
It also lays the groundwork for a new GlobalKey concept.
I tried to keep the impact on the code minimal, which is why the "Key"
constructor is actually a factory that returns a StringKey. The code
has this class hierarchy:
```
KeyBase
|
Key--------------+---------------+
| | |
StringKey ObjectKey UniqueKey
```
...where the constructors are Key and Key.stringify (StringKey),
Key.fromObjectIdentity (ObjectKey), and Key.unique (UniqueKey).
We could instead of factory methods use regular constructors with the
following hierarchy:
```
KeyBase
|
LocalKey---------+---------------+
| | |
Key ObjectIdentityKey UniqueKey
```
...with constructors Key, Key.stringify, ObjectIdentityKey, and
UniqueKey, but I felt that that was maybe a more confusing hierarchy.
I don't have a strong opinion on this.
This change makes it easier to defined only the width or the height of an image
and let the other value be filled in from the image's intrinsic aspect ratio.
Fixes#175
