Adds a HomogeneousViewport class that works like MixedViewport but
handles only children that have all the same height.
Converts ScrollableWidgetList to use that, so that we don't waste a
frame looking at the size of the contents each time we change size.
This allows a number of seemingly pointless double-pumps in the tests
to be removed.
Other changes that were necessary to support the above:
- RenderBlock now supports minExtent (think 'min-height' in CSS)
- RenderBlock now supports itemExtent (forces the height of each
child to be the same, so that the itemExtent passed to the fixed-
height scrollables are all authoritative instead of a source of
bugs when they don't match)
- RenderBlockViewport now supports horizontal scrolling
- improved the style of the isInfinite assert in box.dart
- fixed the position of a comment in mixed_viewport.dart
- added a test
- made the logic for how many items to show be more precise
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.
Widgets that want to receive drops should include a DropTarget in their build.
Currently there's no widget for initiating a drag. Components can use the
DragController directly. In the future, we'll probably want to add a Draggable
that knows how to do some of this work automatically.
Fixes#612
This widget lets you mimic one of its children in an overlay. The overlay
starts out as the same size of the child and then grows to fill the overlay. In
the future, the mimic will start at the same visual position as the child.
Wrap widgets you want to reparent in a Mimicable widget and assign the
Mimicable widget a global key. Then, given the same global key to a Mimic
widget to make it appear elsewhere in the view hierarchy.
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.
