Skip to content

F
Front-End
Commit 069fc6dd authored by Adam Barth's avatar Adam Barth
Browse files
Options

Add some dartdoc to basic widgets 

These docs are largely duplicated from the cooresponding rendering classes. I'm
not sure how we can avoid repeating ourselves.
parent 1d8bea0a
Hide whitespace changes
Inline Side-by-side
Showing with 298 additions and 75 deletions
packages/flutter/lib/src/rendering/custom_layout.dart
View file @ 069fc6dd
...@@ -6,6 +6,7 @@ import 'box.dart'; ...@@ -6,6 +6,7 @@ import 'box.dart';
import 'object.dart'; import 'object.dart';
class MultiChildLayoutParentData extends ContainerBoxParentDataMixin<RenderBox> { class MultiChildLayoutParentData extends ContainerBoxParentDataMixin<RenderBox> {
/// An object representing the identity of this child.
Object id; Object id;
void merge(MultiChildLayoutParentData other) { void merge(MultiChildLayoutParentData other) {
...@@ -17,6 +18,7 @@ class MultiChildLayoutParentData extends ContainerBoxParentDataMixin<RenderBox> ...@@ -17,6 +18,7 @@ class MultiChildLayoutParentData extends ContainerBoxParentDataMixin<RenderBox>
String toString() => '${super.toString()}; id=$id'; String toString() => '${super.toString()}; id=$id';
} }
/// A delegate that controls the layout of multiple children.
abstract class MultiChildLayoutDelegate { abstract class MultiChildLayoutDelegate {
Map<Object, RenderBox> _idToChild; Map<Object, RenderBox> _idToChild;
Set<RenderBox> _debugChildrenNeedingLayout; Set<RenderBox> _debugChildrenNeedingLayout;
...@@ -94,6 +96,12 @@ abstract class MultiChildLayoutDelegate { ...@@ -94,6 +96,12 @@ abstract class MultiChildLayoutDelegate {
void performLayout(Size size, BoxConstraints constraints); void performLayout(Size size, BoxConstraints constraints);
} }
/// Defers the layout of multiple children to a delegate.
///
/// The delegate can determine the layout constraints for each child and can
/// decide where to position each child. The delegate can also determine the
/// size of the parent, but the size of the parent cannot depend on the sizes of
/// the children.
class RenderCustomMultiChildLayoutBox extends RenderBox class RenderCustomMultiChildLayoutBox extends RenderBox
with ContainerRenderObjectMixin<RenderBox, MultiChildLayoutParentData>, with ContainerRenderObjectMixin<RenderBox, MultiChildLayoutParentData>,
RenderBoxContainerDefaultsMixin<RenderBox, MultiChildLayoutParentData> { RenderBoxContainerDefaultsMixin<RenderBox, MultiChildLayoutParentData> {
...@@ -110,6 +118,7 @@ class RenderCustomMultiChildLayoutBox extends RenderBox ...@@ -110,6 +118,7 @@ class RenderCustomMultiChildLayoutBox extends RenderBox
child.parentData = new MultiChildLayoutParentData(); child.parentData = new MultiChildLayoutParentData();
} }
/// The delegate that controls the layout of the children.
MultiChildLayoutDelegate get delegate => _delegate; MultiChildLayoutDelegate get delegate => _delegate;
MultiChildLayoutDelegate _delegate; MultiChildLayoutDelegate _delegate;
void set delegate (MultiChildLayoutDelegate newDelegate) { void set delegate (MultiChildLayoutDelegate newDelegate) {
......
packages/flutter/lib/src/rendering/proxy_box.dart
View file @ 069fc6dd
...@@ -21,7 +21,7 @@ export 'package:flutter/gestures.dart' show ...@@ -21,7 +21,7 @@ export 'package:flutter/gestures.dart' show
PointerUpEvent, PointerUpEvent,
PointerCancelEvent; PointerCancelEvent;
/// A base class for render objects that resemble their children /// A base class for render objects that resemble their children.
/// ///
/// A proxy box has a single child and simply mimics all the properties of that /// A proxy box has a single child and simply mimics all the properties of that
/// child by calling through to the child for each function in the render box /// child by calling through to the child for each function in the render box
...@@ -87,15 +87,16 @@ class RenderProxyBox extends RenderBox with RenderObjectWithChildMixin<RenderBox ...@@ -87,15 +87,16 @@ class RenderProxyBox extends RenderBox with RenderObjectWithChildMixin<RenderBox
} }
} }
/// A render object that imposes additional constraints on its child /// Imposes additional constraints on its child.
/// ///
/// A render constrained box proxies most functions in the render box protocol /// A render constrained box proxies most functions in the render box protocol
/// to its child, except that when laying out its child, it tightens the /// to its child, except that when laying out its child, it tightens the
/// constraints provided by its parent by enforcing the [additionalConstraints] /// constraints provided by its parent by enforcing the [additionalConstraints]
/// as well. /// as well.
/// ///
/// For example, if you wanted [child] to have a minimum height, you could use /// For example, if you wanted [child] to have a minimum height of 50.0 logical
/// `const BoxConstraints(minHeight: 50.0)`` as the [additionalConstraints]. /// pixels, you could use `const BoxConstraints(minHeight: 50.0)`` as the
/// [additionalConstraints].
class RenderConstrainedBox extends RenderProxyBox { class RenderConstrainedBox extends RenderProxyBox {
RenderConstrainedBox({ RenderConstrainedBox({
RenderBox child, RenderBox child,
...@@ -260,7 +261,7 @@ class RenderFractionallySizedBox extends RenderProxyBox { ...@@ -260,7 +261,7 @@ class RenderFractionallySizedBox extends RenderProxyBox {
} }
} }
/// Forces child to layout at a specific aspect ratio /// Forces child to layout at a specific aspect ratio.
/// ///
/// The width of this render object is the largest width permited by the layout /// The width of this render object is the largest width permited by the layout
/// constraints. The height of the render object is determined by applying the /// constraints. The height of the render object is determined by applying the
...@@ -284,7 +285,7 @@ class RenderAspectRatio extends RenderProxyBox { ...@@ -284,7 +285,7 @@ class RenderAspectRatio extends RenderProxyBox {
assert(_aspectRatio != null); assert(_aspectRatio != null);
} }
/// The aspect ratio to use when computing the height from the width /// The aspect ratio to use when computing the height from the width.
/// ///
/// The aspect ratio is expressed as a ratio of width to height. For example, /// The aspect ratio is expressed as a ratio of width to height. For example,
/// a 16:9 width:height aspect ratio would have a value of 16.0/9.0. /// a 16:9 width:height aspect ratio would have a value of 16.0/9.0.
...@@ -329,18 +330,18 @@ class RenderAspectRatio extends RenderProxyBox { ...@@ -329,18 +330,18 @@ class RenderAspectRatio extends RenderProxyBox {
} }
} }
/// Sizes its child to the child's intrinsic width /// Sizes its child to the child's intrinsic width.
/// ///
/// This class will size its child's width to the child's maximum intrinsic /// Sizes its child's width to the child's maximum intrinsic width. If
/// width. If [stepWidth] is non-null, the child's width will be snapped to a /// [stepWidth] is non-null, the child's width will be snapped to a multiple of
/// multiple of the [stepWidth]. Similarly, if [stepHeight] is non-null, the /// the [stepWidth]. Similarly, if [stepHeight] is non-null, the child's height
/// child's height will be snapped to a multiple of the [stepHeight]. /// will be snapped to a multiple of the [stepHeight].
/// ///
/// This class is useful, for example, when unlimited width is available and /// This class is useful, for example, when unlimited width is available and
/// you would like a child that would otherwise attempt to expand infinitely to /// you would like a child that would otherwise attempt to expand infinitely to
/// instead size itself to a more reasonable width. /// instead size itself to a more reasonable width.
/// ///
/// Note: This class is relatively expensive. Avoid using it where possible. /// This class is relatively expensive. Avoid using it where possible.
class RenderIntrinsicWidth extends RenderProxyBox { class RenderIntrinsicWidth extends RenderProxyBox {
RenderIntrinsicWidth({ RenderIntrinsicWidth({
...@@ -349,7 +350,7 @@ class RenderIntrinsicWidth extends RenderProxyBox { ...@@ -349,7 +350,7 @@ class RenderIntrinsicWidth extends RenderProxyBox {
RenderBox child RenderBox child
}) : _stepWidth = stepWidth, _stepHeight = stepHeight, super(child); }) : _stepWidth = stepWidth, _stepHeight = stepHeight, super(child);
/// If non-null, force the child's width to be a multiple of this value /// If non-null, force the child's width to be a multiple of this value.
double get stepWidth => _stepWidth; double get stepWidth => _stepWidth;
double _stepWidth; double _stepWidth;
void set stepWidth(double newStepWidth) { void set stepWidth(double newStepWidth) {
...@@ -359,7 +360,7 @@ class RenderIntrinsicWidth extends RenderProxyBox { ...@@ -359,7 +360,7 @@ class RenderIntrinsicWidth extends RenderProxyBox {
markNeedsLayout(); markNeedsLayout();
} }
/// If non-null, force the child's height to be a multiple of this value /// If non-null, force the child's height to be a multiple of this value.
double get stepHeight => _stepHeight; double get stepHeight => _stepHeight;
double _stepHeight; double _stepHeight;
void set stepHeight(double newStepHeight) { void set stepHeight(double newStepHeight) {
...@@ -428,16 +429,13 @@ class RenderIntrinsicWidth extends RenderProxyBox { ...@@ -428,16 +429,13 @@ class RenderIntrinsicWidth extends RenderProxyBox {
} }
} }
/// Sizes its child to the child's intrinsic height /// Sizes its child to the child's intrinsic height.
///
/// This class will size its child's height to the child's maximum intrinsic
/// height.
/// ///
/// This class is useful, for example, when unlimited height is available and /// This class is useful, for example, when unlimited height is available and
/// you would like a child that would otherwise attempt to expand infinitely to /// you would like a child that would otherwise attempt to expand infinitely to
/// instead size itself to a more reasonable height. /// instead size itself to a more reasonable height.
/// ///
/// Note: This class is relatively expensive. Avoid using it where possible. /// This class is relatively expensive. Avoid using it where possible.
class RenderIntrinsicHeight extends RenderProxyBox { class RenderIntrinsicHeight extends RenderProxyBox {
RenderIntrinsicHeight({ RenderIntrinsicHeight({
...@@ -486,20 +484,20 @@ class RenderIntrinsicHeight extends RenderProxyBox { ...@@ -486,20 +484,20 @@ class RenderIntrinsicHeight extends RenderProxyBox {
} }
/// Makes its child partially transparent /// Makes its child partially transparent.
/// ///
/// This class paints its child into an intermediate buffer and then blends the /// This class paints its child into an intermediate buffer and then blends the
/// child back into the scene partially transparent. /// child back into the scene partially transparent.
/// ///
/// Note: This class is relatively expensive because it requires painting the /// This class is relatively expensive because it requires painting the child
/// child into an intermediate buffer. /// into an intermediate buffer.
class RenderOpacity extends RenderProxyBox { class RenderOpacity extends RenderProxyBox {
RenderOpacity({ RenderBox child, double opacity }) RenderOpacity({ RenderBox child, double opacity })
: this._opacity = opacity, super(child) { : this._opacity = opacity, super(child) {
assert(opacity >= 0.0 && opacity <= 1.0); assert(opacity >= 0.0 && opacity <= 1.0);
} }
/// The fraction to scale the child's alpha value /// The fraction to scale the child's alpha value.
/// ///
/// An opacity of 1.0 is fully opaque. An opacity of 0.0 is fully transparent /// An opacity of 1.0 is fully opaque. An opacity of 0.0 is fully transparent
/// (i.e., invisible). /// (i.e., invisible).
...@@ -566,7 +564,10 @@ class RenderShaderMask extends RenderProxyBox { ...@@ -566,7 +564,10 @@ class RenderShaderMask extends RenderProxyBox {
} }
} }
/// A class that provides custom clips.
abstract class CustomClipper<T> { abstract class CustomClipper<T> {
/// Returns a description of the clip given that the render object being
/// clipped is of the given size.
T getClip(Size size); T getClip(Size size);
bool shouldRepaint(CustomClipper oldClipper); bool shouldRepaint(CustomClipper oldClipper);
} }
...@@ -577,6 +578,7 @@ abstract class _RenderCustomClip<T> extends RenderProxyBox { ...@@ -577,6 +578,7 @@ abstract class _RenderCustomClip<T> extends RenderProxyBox {
CustomClipper<T> clipper CustomClipper<T> clipper
}) : _clipper = clipper, super(child); }) : _clipper = clipper, super(child);
/// If non-null, determines which clip to use on the child.
CustomClipper<T> get clipper => _clipper; CustomClipper<T> get clipper => _clipper;
CustomClipper<T> _clipper; CustomClipper<T> _clipper;
void set clipper (CustomClipper<T> newClipper) { void set clipper (CustomClipper<T> newClipper) {
...@@ -598,7 +600,7 @@ abstract class _RenderCustomClip<T> extends RenderProxyBox { ...@@ -598,7 +600,7 @@ abstract class _RenderCustomClip<T> extends RenderProxyBox {
T get _clip => _clipper?.getClip(size) ?? _defaultClip; T get _clip => _clipper?.getClip(size) ?? _defaultClip;
} }
/// Clips its child using a rectangle /// Clips its child using a rectangle.
/// ///
/// Prevents its child from painting outside its bounds. /// Prevents its child from painting outside its bounds.
class RenderClipRect extends _RenderCustomClip<Rect> { class RenderClipRect extends _RenderCustomClip<Rect> {
...@@ -624,7 +626,7 @@ class RenderClipRect extends _RenderCustomClip<Rect> { ...@@ -624,7 +626,7 @@ class RenderClipRect extends _RenderCustomClip<Rect> {
} }
} }
/// Clips its child using a rounded rectangle /// Clips its child using a rounded rectangle.
/// ///
/// Creates a rounded rectangle from its layout dimensions and the given x and /// Creates a rounded rectangle from its layout dimensions and the given x and
/// y radius values and prevents its child from painting outside that rounded /// y radius values and prevents its child from painting outside that rounded
...@@ -639,7 +641,7 @@ class RenderClipRRect extends RenderProxyBox { ...@@ -639,7 +641,7 @@ class RenderClipRRect extends RenderProxyBox {
assert(_yRadius != null); assert(_yRadius != null);
} }
/// The radius of the rounded corners in the horizontal direction in logical pixels /// The radius of the rounded corners in the horizontal direction in logical pixels.
/// ///
/// Values are clamped to be between zero and half the width of the render /// Values are clamped to be between zero and half the width of the render
/// object. /// object.
...@@ -653,7 +655,7 @@ class RenderClipRRect extends RenderProxyBox { ...@@ -653,7 +655,7 @@ class RenderClipRRect extends RenderProxyBox {
markNeedsPaint(); markNeedsPaint();
} }
/// The radius of the rounded corners in the vertical direction in logical pixels /// The radius of the rounded corners in the vertical direction in logical pixels.
/// ///
/// Values are clamped to be between zero and half the height of the render /// Values are clamped to be between zero and half the height of the render
/// object. /// object.
...@@ -676,7 +678,7 @@ class RenderClipRRect extends RenderProxyBox { ...@@ -676,7 +678,7 @@ class RenderClipRRect extends RenderProxyBox {
} }
} }
/// Clips its child using an oval /// Clips its child using an oval.
/// ///
/// Inscribes an oval into its layout dimensions and prevents its child from /// Inscribes an oval into its layout dimensions and prevents its child from
/// painting outside that oval. /// painting outside that oval.
...@@ -717,16 +719,16 @@ class RenderClipOval extends _RenderCustomClip<Rect> { ...@@ -717,16 +719,16 @@ class RenderClipOval extends _RenderCustomClip<Rect> {
} }
} }
/// Where to paint a box decoration /// Where to paint a box decoration.
enum BoxDecorationPosition { enum BoxDecorationPosition {
/// Paint the box decoration behind the children /// Paint the box decoration behind the children.
background, background,
/// Paint the box decoration in front of the children /// Paint the box decoration in front of the children.
foreground, foreground,
} }
/// Paints a [BoxDecoration] either before or after its child paints /// Paints a [BoxDecoration] either before or after its child paints.
class RenderDecoratedBox extends RenderProxyBox { class RenderDecoratedBox extends RenderProxyBox {
RenderDecoratedBox({ RenderDecoratedBox({
...@@ -740,7 +742,7 @@ class RenderDecoratedBox extends RenderProxyBox { ...@@ -740,7 +742,7 @@ class RenderDecoratedBox extends RenderProxyBox {
assert(position != null); assert(position != null);
} }
/// Where to paint the box decoration /// Where to paint the box decoration.
BoxDecorationPosition get position => _position; BoxDecorationPosition get position => _position;
BoxDecorationPosition _position; BoxDecorationPosition _position;
void set position (BoxDecorationPosition newPosition) { void set position (BoxDecorationPosition newPosition) {
...@@ -750,7 +752,7 @@ class RenderDecoratedBox extends RenderProxyBox { ...@@ -750,7 +752,7 @@ class RenderDecoratedBox extends RenderProxyBox {
markNeedsPaint(); markNeedsPaint();
} }
/// What decoration to paint /// What decoration to paint.
BoxDecoration get decoration => _painter.decoration; BoxDecoration get decoration => _painter.decoration;
void set decoration (BoxDecoration newDecoration) { void set decoration (BoxDecoration newDecoration) {
assert(newDecoration != null); assert(newDecoration != null);
...@@ -820,7 +822,7 @@ class RenderDecoratedBox extends RenderProxyBox { ...@@ -820,7 +822,7 @@ class RenderDecoratedBox extends RenderProxyBox {
} }
} }
/// Applies a transformation before painting its child /// Applies a transformation before painting its child.
class RenderTransform extends RenderProxyBox { class RenderTransform extends RenderProxyBox {
RenderTransform({ RenderTransform({
Matrix4 transform, Matrix4 transform,
...@@ -836,7 +838,7 @@ class RenderTransform extends RenderProxyBox { ...@@ -836,7 +838,7 @@ class RenderTransform extends RenderProxyBox {
} }
/// The origin of the coordinate system (relative to the upper left corder of /// The origin of the coordinate system (relative to the upper left corder of
/// this render object) in which to apply the matrix /// this render object) in which to apply the matrix.
/// ///
/// Setting an origin is equivalent to conjugating the transform matrix by a /// Setting an origin is equivalent to conjugating the transform matrix by a
/// translation. This property is provided just for convenience. /// translation. This property is provided just for convenience.
...@@ -866,7 +868,7 @@ class RenderTransform extends RenderProxyBox { ...@@ -866,7 +868,7 @@ class RenderTransform extends RenderProxyBox {
// Note the lack of a getter for transform because Matrix4 is not immutable // Note the lack of a getter for transform because Matrix4 is not immutable
Matrix4 _transform; Matrix4 _transform;
/// The matrix to transform the child by during painting /// The matrix to transform the child by during painting.
void set transform(Matrix4 newTransform) { void set transform(Matrix4 newTransform) {
assert(newTransform != null); assert(newTransform != null);
if (_transform == newTransform) if (_transform == newTransform)
...@@ -875,37 +877,37 @@ class RenderTransform extends RenderProxyBox { ...@@ -875,37 +877,37 @@ class RenderTransform extends RenderProxyBox {
markNeedsPaint(); markNeedsPaint();
} }
/// Sets the transform to the identity matrix /// Sets the transform to the identity matrix.
void setIdentity() { void setIdentity() {
_transform.setIdentity(); _transform.setIdentity();
markNeedsPaint(); markNeedsPaint();
} }
/// Concatenates a rotation about the x axis into the transform /// Concatenates a rotation about the x axis into the transform.
void rotateX(double radians) { void rotateX(double radians) {
_transform.rotateX(radians); _transform.rotateX(radians);
markNeedsPaint(); markNeedsPaint();
} }
/// Concatenates a rotation about the y axis into the transform /// Concatenates a rotation about the y axis into the transform.
void rotateY(double radians) { void rotateY(double radians) {
_transform.rotateY(radians); _transform.rotateY(radians);
markNeedsPaint(); markNeedsPaint();
} }
/// Concatenates a rotation about the z axis into the transform /// Concatenates a rotation about the z axis into the transform.
void rotateZ(double radians) { void rotateZ(double radians) {
_transform.rotateZ(radians); _transform.rotateZ(radians);
markNeedsPaint(); markNeedsPaint();
} }
/// Concatenates a translation by (x, y, z) into the transform /// Concatenates a translation by (x, y, z) into the transform.
void translate(x, [double y = 0.0, double z = 0.0]) { void translate(x, [double y = 0.0, double z = 0.0]) {
_transform.translate(x, y, z); _transform.translate(x, y, z);
markNeedsPaint(); markNeedsPaint();
} }
/// Concatenates a scale into the transform /// Concatenates a scale into the transform.
void scale(x, [double y, double z]) { void scale(x, [double y, double z]) {
_transform.scale(x, y, z); _transform.scale(x, y, z);
markNeedsPaint(); markNeedsPaint();
...@@ -963,13 +965,13 @@ class RenderTransform extends RenderProxyBox { ...@@ -963,13 +965,13 @@ class RenderTransform extends RenderProxyBox {
} }
} }
/// Called when a size changes /// Called when a size changes.
typedef void SizeChangedCallback(Size newSize); typedef void SizeChangedCallback(Size newSize);
/// Calls [onSizeChanged] whenever the child's layout size changes /// Calls [onSizeChanged] whenever the child's layout size changes
/// ///
/// Note: Size observer calls its callback during layout, which means you cannot /// Because size observer calls its callback during layout, you cannot modify
/// dirty layout information during the callback. /// layout information during the callback.
class RenderSizeObserver extends RenderProxyBox { class RenderSizeObserver extends RenderProxyBox {
RenderSizeObserver({ RenderSizeObserver({
this.onSizeChanged, this.onSizeChanged,
...@@ -1007,13 +1009,13 @@ abstract class CustomPainter { ...@@ -1007,13 +1009,13 @@ abstract class CustomPainter {
/// current canvas and then paints its children. After painting its children, /// current canvas and then paints its children. After painting its children,
/// custom paint asks foregroundPainter to paint. The coodinate system of the /// custom paint asks foregroundPainter to paint. The coodinate system of the
/// canvas matches the coordinate system of the custom paint object. The /// canvas matches the coordinate system of the custom paint object. The
/// painters are expected to paint with in a rectangle starting at the origin /// painters are expected to paint within a rectangle starting at the origin
/// and encompassing a region of the given size. If the painters paints outside /// and encompassing a region of the given size. If the painters paints outside
/// those bounds, there might be insufficient memory allocated to rasterize the /// those bounds, there might be insufficient memory allocated to rasterize the
/// painting commands and the resulting behavior is undefined. /// painting commands and the resulting behavior is undefined.
/// ///
/// Note: Custom paint calls its painters during paint, which means you cannot /// Because custom paint calls its painters during paint, you cannot dirty
/// dirty layout or paint information during the callback. /// layout or paint information during the callback.
class RenderCustomPaint extends RenderProxyBox { class RenderCustomPaint extends RenderProxyBox {
RenderCustomPaint({ RenderCustomPaint({
CustomPainter painter, CustomPainter painter,
......
packages/flutter/lib/src/rendering/shifted_box.dart
View file @ 069fc6dd
...@@ -72,15 +72,24 @@ abstract class RenderShiftedBox extends RenderBox with RenderObjectWithChildMixi ...@@ -72,15 +72,24 @@ abstract class RenderShiftedBox extends RenderBox with RenderObjectWithChildMixi
} }
/// Insets its child by the given padding.
///
/// When passing layout constraints to its child, padding shrinks the
/// constraints by the given padding, causing the child to layout at a smaller
/// size. Padding then sizes itself to its child's size, inflated by the
/// padding, effectively creating empty space around the child.
class RenderPadding extends RenderShiftedBox { class RenderPadding extends RenderShiftedBox {
RenderPadding({
RenderPadding({ EdgeDims padding, RenderBox child }) : super(child) { EdgeDims padding,
RenderBox child
}) : _padding = padding, super(child) {
assert(padding != null); assert(padding != null);
this.padding = padding; assert(padding.isNonNegative);
} }
EdgeDims _padding; /// The amount to pad the child in each dimension.
EdgeDims get padding => _padding; EdgeDims get padding => _padding;
EdgeDims _padding;
void set padding (EdgeDims value) { void set padding (EdgeDims value) {
assert(value != null); assert(value != null);
assert(value.isNonNegative); assert(value.isNonNegative);
...@@ -143,14 +152,12 @@ class RenderPadding extends RenderShiftedBox { ...@@ -143,14 +152,12 @@ class RenderPadding extends RenderShiftedBox {
} }
} }
/// Aligns its child box within itself.
///
/// For example, to align a box at the bottom right, you would pass this box a
/// tight constraint that is bigger than the child's natural size,
/// with horizontal and vertical set to 1.0.
class RenderPositionedBox extends RenderShiftedBox { class RenderPositionedBox extends RenderShiftedBox {
// This box aligns a child box within itself. It's only useful for
// children that don't always size to fit their parent. For example,
// to align a box at the bottom right, you would pass this box a
// tight constraint that is bigger than the child's natural size,
// with horizontal and vertical set to 1.0.
RenderPositionedBox({ RenderPositionedBox({
RenderBox child, RenderBox child,
FractionalOffset alignment: const FractionalOffset(0.5, 0.5), FractionalOffset alignment: const FractionalOffset(0.5, 0.5),
...@@ -160,9 +167,20 @@ class RenderPositionedBox extends RenderShiftedBox { ...@@ -160,9 +167,20 @@ class RenderPositionedBox extends RenderShiftedBox {
_widthFactor = widthFactor, _widthFactor = widthFactor,
_heightFactor = heightFactor, _heightFactor = heightFactor,
super(child) { super(child) {
assert(alignment != null); assert(alignment != null && alignment.x != null && alignment.y != null);
} assert(widthFactor == null || widthFactor >= 0.0);
assert(heightFactor == null || heightFactor >= 0.0);
}
/// How to align the child.
///
/// The x and y values of the alignment control the horizontal and vertical
/// alignment, respectively. An x value of 0.0 means that the left edge of
/// the child is aligned with the left edge of the parent whereas an x value
/// of 1.0 means that the right edge of the child is aligned with the right
/// edge of the parent. Other values interpolate (and extrapolate) linearly.
/// For example, a value of 0.5 means that the center of the child is aligned
/// with the center of the parent.
FractionalOffset get alignment => _alignment; FractionalOffset get alignment => _alignment;
FractionalOffset _alignment; FractionalOffset _alignment;
void set alignment (FractionalOffset newAlignment) { void set alignment (FractionalOffset newAlignment) {
...@@ -173,18 +191,26 @@ class RenderPositionedBox extends RenderShiftedBox { ...@@ -173,18 +191,26 @@ class RenderPositionedBox extends RenderShiftedBox {
markNeedsLayout(); markNeedsLayout();
} }
double _widthFactor; /// If non-null, sets its width to the child's width multipled by this factor.
///
/// Can be both greater and less than 1.0 but must be positive.
double get widthFactor => _widthFactor; double get widthFactor => _widthFactor;
double _widthFactor;
void set widthFactor (double value) { void set widthFactor (double value) {
assert(value == null || value >= 0.0);
if (_widthFactor == value) if (_widthFactor == value)
return; return;
_widthFactor = value; _widthFactor = value;
markNeedsLayout(); markNeedsLayout();
} }
double _heightFactor; /// If non-null, sets its height to the child's height multipled by this factor.
///
/// Can be both greater and less than 1.0 but must be positive.
double get heightFactor => _heightFactor; double get heightFactor => _heightFactor;
double _heightFactor;
void set heightFactor (double value) { void set heightFactor (double value) {
assert(value == null || value >= 0.0);
if (_heightFactor == value) if (_heightFactor == value)
return; return;
_heightFactor = value; _heightFactor = value;
...@@ -226,6 +252,12 @@ class OneChildLayoutDelegate { ...@@ -226,6 +252,12 @@ class OneChildLayoutDelegate {
Point getPositionForChild(Size size, Size childSize) => Point.origin; Point getPositionForChild(Size size, Size childSize) => Point.origin;
} }
/// Defers the layout of its single child to a delegate.
///
/// The delegate can determine the layout constraints for the child and can
/// decide where to position the child. The delegate can also determine the size
/// of the parent, but the size of the parent cannot depend on the size of the
/// child.
class RenderCustomOneChildLayoutBox extends RenderShiftedBox { class RenderCustomOneChildLayoutBox extends RenderShiftedBox {
RenderCustomOneChildLayoutBox({ RenderCustomOneChildLayoutBox({
RenderBox child, RenderBox child,
...@@ -234,6 +266,7 @@ class RenderCustomOneChildLayoutBox extends RenderShiftedBox { ...@@ -234,6 +266,7 @@ class RenderCustomOneChildLayoutBox extends RenderShiftedBox {
assert(delegate != null); assert(delegate != null);
} }
/// A delegate that controls this object's layout.
OneChildLayoutDelegate get delegate => _delegate; OneChildLayoutDelegate get delegate => _delegate;
OneChildLayoutDelegate _delegate; OneChildLayoutDelegate _delegate;
void set delegate (OneChildLayoutDelegate newDelegate) { void set delegate (OneChildLayoutDelegate newDelegate) {
......
packages/flutter/lib/src/rendering/viewport.dart
View file @ 069fc6dd
...@@ -21,13 +21,15 @@ enum ScrollDirection { ...@@ -21,13 +21,15 @@ enum ScrollDirection {
both both
} }
/// A render object that's bigger on the inside /// A render object that's bigger on the inside.
/// ///
/// A viewport is the core scrolling primitive in the render tree. The child of /// The child of a viewport can layout to a larger size than the viewport
/// a viewport can layout to a larger size than the viewport itself. If that /// itself. If that happens, only a portion of the child will be visible through
/// happens, only a portion of the child will be visible through the viewport. /// the viewport. The portion of the child that is visible is controlled by the
/// The portiion of the child that is visible is controlled by the scroll /// scroll offset.
/// offset. ///
/// Viewport is the core scrolling primitive in the system, but it can be used
/// in other situations.
class RenderViewport extends RenderBox with RenderObjectWithChildMixin<RenderBox> { class RenderViewport extends RenderBox with RenderObjectWithChildMixin<RenderBox> {
RenderViewport({ RenderViewport({
...@@ -51,7 +53,7 @@ class RenderViewport extends RenderBox with RenderObjectWithChildMixin<RenderBox ...@@ -51,7 +53,7 @@ class RenderViewport extends RenderBox with RenderObjectWithChildMixin<RenderBox
} }
} }
/// The offset at which to paint the child /// The offset at which to paint the child.
/// ///
/// The offset can be non-zero only in the [scrollDirection]. /// The offset can be non-zero only in the [scrollDirection].
Offset get scrollOffset => _scrollOffset; Offset get scrollOffset => _scrollOffset;
...@@ -64,7 +66,7 @@ class RenderViewport extends RenderBox with RenderObjectWithChildMixin<RenderBox ...@@ -64,7 +66,7 @@ class RenderViewport extends RenderBox with RenderObjectWithChildMixin<RenderBox
markNeedsPaint(); markNeedsPaint();
} }
/// In which direction the child is permitted to be larger than the viewport /// The direction in which the child is permitted to be larger than the viewport
/// ///
/// If the viewport is scrollable in a particular direction (e.g., vertically), /// If the viewport is scrollable in a particular direction (e.g., vertically),
/// the child is given layout constraints that are fully unconstrainted in /// the child is given layout constraints that are fully unconstrainted in
......
packages/flutter/lib/src/widgets/basic.dart
View file @ 069fc6dd
...@@ -72,12 +72,23 @@ export 'package:flutter/rendering.dart' show ...@@ -72,12 +72,23 @@ export 'package:flutter/rendering.dart' show
// PAINTING NODES // PAINTING NODES
/// Makes its child partially transparent.
///
/// This class paints its child into an intermediate buffer and then blends the
/// child back into the scene partially transparent.
///
/// This class is relatively expensive because it requires painting the child
/// into an intermediate buffer.
class Opacity extends OneChildRenderObjectWidget { class Opacity extends OneChildRenderObjectWidget {
Opacity({ Key key, this.opacity, Widget child }) Opacity({ Key key, this.opacity, Widget child })
: super(key: key, child: child) { : super(key: key, child: child) {
assert(opacity >= 0.0 && opacity <= 1.0); assert(opacity >= 0.0 && opacity <= 1.0);
} }
/// The fraction to scale the child's alpha value.
///
/// An opacity of 1.0 is fully opaque. An opacity of 0.0 is fully transparent
/// (i.e., invisible).
final double opacity; final double opacity;
RenderOpacity createRenderObject() => new RenderOpacity(opacity: opacity); RenderOpacity createRenderObject() => new RenderOpacity(opacity: opacity);
...@@ -119,6 +130,7 @@ class ShaderMask extends OneChildRenderObjectWidget { ...@@ -119,6 +130,7 @@ class ShaderMask extends OneChildRenderObjectWidget {
} }
} }
/// Paints a [BoxDecoration] either before or after its child paints.
class DecoratedBox extends OneChildRenderObjectWidget { class DecoratedBox extends OneChildRenderObjectWidget {
DecoratedBox({ DecoratedBox({
Key key, Key key,
...@@ -130,10 +142,13 @@ class DecoratedBox extends OneChildRenderObjectWidget { ...@@ -130,10 +142,13 @@ class DecoratedBox extends OneChildRenderObjectWidget {
assert(position != null); assert(position != null);
} }
/// What decoration to paint.
final BoxDecoration decoration; final BoxDecoration decoration;
/// Where to paint the box decoration.
final BoxDecorationPosition position; final BoxDecorationPosition position;
RenderObject createRenderObject() => new RenderDecoratedBox(decoration: decoration, position: position); RenderDecoratedBox createRenderObject() => new RenderDecoratedBox(decoration: decoration, position: position);
void updateRenderObject(RenderDecoratedBox renderObject, DecoratedBox oldWidget) { void updateRenderObject(RenderDecoratedBox renderObject, DecoratedBox oldWidget) {
renderObject.decoration = decoration; renderObject.decoration = decoration;
...@@ -141,11 +156,27 @@ class DecoratedBox extends OneChildRenderObjectWidget { ...@@ -141,11 +156,27 @@ class DecoratedBox extends OneChildRenderObjectWidget {
} }
} }
/// Delegates its painting.
///
/// When asked to paint, custom paint first asks painter to paint with the
/// current canvas and then paints its children. After painting its children,
/// custom paint asks foregroundPainter to paint. The coodinate system of the
/// canvas matches the coordinate system of the custom paint object. The
/// painters are expected to paint within a rectangle starting at the origin
/// and encompassing a region of the given size. If the painters paints outside
/// those bounds, there might be insufficient memory allocated to rasterize the
/// painting commands and the resulting behavior is undefined.
///
/// Because custom paint calls its painters during paint, you cannot dirty
/// layout or paint information during the callback.
class CustomPaint extends OneChildRenderObjectWidget { class CustomPaint extends OneChildRenderObjectWidget {
CustomPaint({ Key key, this.painter, this.foregroundPainter, Widget child }) CustomPaint({ Key key, this.painter, this.foregroundPainter, Widget child })
: super(key: key, child: child); : super(key: key, child: child);
/// The painter that paints before the children.
final CustomPainter painter; final CustomPainter painter;
/// The painter that paints after the children.
final CustomPainter foregroundPainter; final CustomPainter foregroundPainter;
RenderCustomPaint createRenderObject() => new RenderCustomPaint( RenderCustomPaint createRenderObject() => new RenderCustomPaint(
...@@ -164,9 +195,13 @@ class CustomPaint extends OneChildRenderObjectWidget { ...@@ -164,9 +195,13 @@ class CustomPaint extends OneChildRenderObjectWidget {
} }
} }
/// Clips its child using a rectangle.
///
/// Prevents its child from painting outside its bounds.
class ClipRect extends OneChildRenderObjectWidget { class ClipRect extends OneChildRenderObjectWidget {
ClipRect({ Key key, this.clipper, Widget child }) : super(key: key, child: child); ClipRect({ Key key, this.clipper, Widget child }) : super(key: key, child: child);
/// If non-null, determines which clip to use.
final CustomClipper<Rect> clipper; final CustomClipper<Rect> clipper;
RenderClipRect createRenderObject() => new RenderClipRect(clipper: clipper); RenderClipRect createRenderObject() => new RenderClipRect(clipper: clipper);
...@@ -180,11 +215,25 @@ class ClipRect extends OneChildRenderObjectWidget { ...@@ -180,11 +215,25 @@ class ClipRect extends OneChildRenderObjectWidget {
} }
} }
/// Clips its child using a rounded rectangle.
///
/// Creates a rounded rectangle from its layout dimensions and the given x and
/// y radius values and prevents its child from painting outside that rounded
/// rectangle.
class ClipRRect extends OneChildRenderObjectWidget { class ClipRRect extends OneChildRenderObjectWidget {
ClipRRect({ Key key, this.xRadius, this.yRadius, Widget child }) ClipRRect({ Key key, this.xRadius, this.yRadius, Widget child })
: super(key: key, child: child); : super(key: key, child: child);
/// The radius of the rounded corners in the horizontal direction in logical pixels.
///
/// Values are clamped to be between zero and half the width of the render
/// object.
final double xRadius; final double xRadius;
/// The radius of the rounded corners in the vertical direction in logical pixels.
///
/// Values are clamped to be between zero and half the height of the render
/// object.
final double yRadius; final double yRadius;
RenderClipRRect createRenderObject() => new RenderClipRRect(xRadius: xRadius, yRadius: yRadius); RenderClipRRect createRenderObject() => new RenderClipRRect(xRadius: xRadius, yRadius: yRadius);
...@@ -195,9 +244,14 @@ class ClipRRect extends OneChildRenderObjectWidget { ...@@ -195,9 +244,14 @@ class ClipRRect extends OneChildRenderObjectWidget {
} }
} }
/// Clips its child using an oval.
///
/// Inscribes an oval into its layout dimensions and prevents its child from
/// painting outside that oval.
class ClipOval extends OneChildRenderObjectWidget { class ClipOval extends OneChildRenderObjectWidget {
ClipOval({ Key key, this.clipper, Widget child }) : super(key: key, child: child); ClipOval({ Key key, this.clipper, Widget child }) : super(key: key, child: child);
/// If non-null, determines which clip to use.
final CustomClipper<Rect> clipper; final CustomClipper<Rect> clipper;
RenderClipOval createRenderObject() => new RenderClipOval(clipper: clipper); RenderClipOval createRenderObject() => new RenderClipOval(clipper: clipper);
...@@ -214,14 +268,27 @@ class ClipOval extends OneChildRenderObjectWidget { ...@@ -214,14 +268,27 @@ class ClipOval extends OneChildRenderObjectWidget {
// POSITIONING AND SIZING NODES // POSITIONING AND SIZING NODES
/// Applies a transformation before painting its child.
class Transform extends OneChildRenderObjectWidget { class Transform extends OneChildRenderObjectWidget {
Transform({ Key key, this.transform, this.origin, this.alignment, Widget child }) Transform({ Key key, this.transform, this.origin, this.alignment, Widget child })
: super(key: key, child: child) { : super(key: key, child: child) {
assert(transform != null); assert(transform != null);
} }
/// The matrix to transform the child by during painting.
final Matrix4 transform; final Matrix4 transform;
/// The origin of the coordinate system (relative to the upper left corder of
/// this render object) in which to apply the matrix.
///
/// Setting an origin is equivalent to conjugating the transform matrix by a
/// translation. This property is provided just for convenience.
final Offset origin; final Offset origin;
/// The alignment of the origin, relative to the size of the box.
///
/// This is equivalent to setting an origin based on the size of the box.
/// If it is specificed at the same time as an offset, both are applied.
final FractionalOffset alignment; final FractionalOffset alignment;
RenderTransform createRenderObject() => new RenderTransform(transform: transform, origin: origin, alignment: alignment); RenderTransform createRenderObject() => new RenderTransform(transform: transform, origin: origin, alignment: alignment);
...@@ -233,12 +300,19 @@ class Transform extends OneChildRenderObjectWidget { ...@@ -233,12 +300,19 @@ class Transform extends OneChildRenderObjectWidget {
} }
} }
/// Insets its child by the given padding.
///
/// When passing layout constraints to its child, padding shrinks the
/// constraints by the given padding, causing the child to layout at a smaller
/// size. Padding then sizes itself to its child's size, inflated by the
/// padding, effectively creating empty space around the child.
class Padding extends OneChildRenderObjectWidget { class Padding extends OneChildRenderObjectWidget {
Padding({ Key key, this.padding, Widget child }) Padding({ Key key, this.padding, Widget child })
: super(key: key, child: child) { : super(key: key, child: child) {
assert(padding != null); assert(padding != null);
} }
/// The amount to pad the child in each dimension.
final EdgeDims padding; final EdgeDims padding;
RenderPadding createRenderObject() => new RenderPadding(padding: padding); RenderPadding createRenderObject() => new RenderPadding(padding: padding);
...@@ -248,6 +322,11 @@ class Padding extends OneChildRenderObjectWidget { ...@@ -248,6 +322,11 @@ class Padding extends OneChildRenderObjectWidget {
} }
} }
/// Aligns its child box within itself.
///
/// For example, to align a box at the bottom right, you would pass this box a
/// tight constraint that is bigger than the child's natural size,
/// with horizontal and vertical set to 1.0.
class Align extends OneChildRenderObjectWidget { class Align extends OneChildRenderObjectWidget {
Align({ Align({
Key key, Key key,
...@@ -255,10 +334,31 @@ class Align extends OneChildRenderObjectWidget { ...@@ -255,10 +334,31 @@ class Align extends OneChildRenderObjectWidget {
this.widthFactor, this.widthFactor,
this.heightFactor, this.heightFactor,
Widget child Widget child
}) : super(key: key, child: child); }) : super(key: key, child: child) {
assert(alignment != null && alignment.x != null && alignment.y != null);
assert(widthFactor == null || widthFactor >= 0.0);
assert(heightFactor == null || heightFactor >= 0.0);
}
/// How to align the child.
///
/// The x and y values of the alignment control the horizontal and vertical
/// alignment, respectively. An x value of 0.0 means that the left edge of
/// the child is aligned with the left edge of the parent whereas an x value
/// of 1.0 means that the right edge of the child is aligned with the right
/// edge of the parent. Other values interpolate (and extrapolate) linearly.
/// For example, a value of 0.5 means that the center of the child is aligned
/// with the center of the parent.
final FractionalOffset alignment; final FractionalOffset alignment;
/// If non-null, sets its width to the child's width multipled by this factor.
///
/// Can be both greater and less than 1.0 but must be positive.
final double widthFactor; final double widthFactor;
/// If non-null, sets its height to the child's height multipled by this factor.
///
/// Can be both greater and less than 1.0 but must be positive.
final double heightFactor; final double heightFactor;
RenderPositionedBox createRenderObject() => new RenderPositionedBox(alignment: alignment, widthFactor: widthFactor, heightFactor: heightFactor); RenderPositionedBox createRenderObject() => new RenderPositionedBox(alignment: alignment, widthFactor: widthFactor, heightFactor: heightFactor);
...@@ -270,11 +370,18 @@ class Align extends OneChildRenderObjectWidget { ...@@ -270,11 +370,18 @@ class Align extends OneChildRenderObjectWidget {
} }
} }
/// Centers its child within itself.
class Center extends Align { class Center extends Align {
Center({ Key key, widthFactor, heightFactor, Widget child }) Center({ Key key, widthFactor, heightFactor, Widget child })
: super(key: key, widthFactor: widthFactor, heightFactor: heightFactor, child: child); : super(key: key, widthFactor: widthFactor, heightFactor: heightFactor, child: child);
} }
/// Defers the layout of its single child to a delegate.
///
/// The delegate can determine the layout constraints for the child and can
/// decide where to position the child. The delegate can also determine the size
/// of the parent, but the size of the parent cannot depend on the size of the
/// child.
class CustomOneChildLayout extends OneChildRenderObjectWidget { class CustomOneChildLayout extends OneChildRenderObjectWidget {
CustomOneChildLayout({ CustomOneChildLayout({
Key key, Key key,
...@@ -304,6 +411,7 @@ class CustomOneChildLayout extends OneChildRenderObjectWidget { ...@@ -304,6 +411,7 @@ class CustomOneChildLayout extends OneChildRenderObjectWidget {
} }
} }
/// Metadata for identifying children in a [CustomMultiChildLayout].
class LayoutId extends ParentDataWidget { class LayoutId extends ParentDataWidget {
LayoutId({ LayoutId({
Key key, Key key,
...@@ -314,6 +422,7 @@ class LayoutId extends ParentDataWidget { ...@@ -314,6 +422,7 @@ class LayoutId extends ParentDataWidget {
assert(id != null); assert(id != null);
} }
/// An object representing the identity of this child.
final Object id; final Object id;
void debugValidateAncestor(Widget ancestor) { void debugValidateAncestor(Widget ancestor) {
...@@ -340,6 +449,12 @@ class LayoutId extends ParentDataWidget { ...@@ -340,6 +449,12 @@ class LayoutId extends ParentDataWidget {
} }
} }
/// Defers the layout of multiple children to a delegate.
///
/// The delegate can determine the layout constraints for each child and can
/// decide where to position each child. The delegate can also determine the
/// size of the parent, but the size of the parent cannot depend on the sizes of
/// the children.
class CustomMultiChildLayout extends MultiChildRenderObjectWidget { class CustomMultiChildLayout extends MultiChildRenderObjectWidget {
CustomMultiChildLayout(List<Widget> children, { CustomMultiChildLayout(List<Widget> children, {
Key key, Key key,
...@@ -349,6 +464,7 @@ class CustomMultiChildLayout extends MultiChildRenderObjectWidget { ...@@ -349,6 +464,7 @@ class CustomMultiChildLayout extends MultiChildRenderObjectWidget {
assert(delegate != null); assert(delegate != null);
} }
/// The delegate that controls the layout of the children.
final MultiChildLayoutDelegate delegate; final MultiChildLayoutDelegate delegate;
final Object token; final Object token;
...@@ -363,11 +479,18 @@ class CustomMultiChildLayout extends MultiChildRenderObjectWidget { ...@@ -363,11 +479,18 @@ class CustomMultiChildLayout extends MultiChildRenderObjectWidget {
} }
} }
/// A box with a specified size.
///
/// Forces its child to have a specific width and/or height and sizes itself to
/// match the size of its child.
class SizedBox extends OneChildRenderObjectWidget { class SizedBox extends OneChildRenderObjectWidget {
SizedBox({ Key key, this.width, this.height, Widget child }) SizedBox({ Key key, this.width, this.height, Widget child })
: super(key: key, child: child); : super(key: key, child: child);
/// If non-null, requires the child to have exactly this width.
final double width; final double width;
/// If non-null, requires the child to have exactly this height.
final double height; final double height;
RenderConstrainedBox createRenderObject() => new RenderConstrainedBox( RenderConstrainedBox createRenderObject() => new RenderConstrainedBox(
...@@ -396,12 +519,18 @@ class SizedBox extends OneChildRenderObjectWidget { ...@@ -396,12 +519,18 @@ class SizedBox extends OneChildRenderObjectWidget {
} }
} }
/// Imposes additional constraints on its child.
///
/// For example, if you wanted [child] to have a minimum height of 50.0 logical
/// pixels, you could use `const BoxConstraints(minHeight: 50.0)`` as the
/// [additionalConstraints].
class ConstrainedBox extends OneChildRenderObjectWidget { class ConstrainedBox extends OneChildRenderObjectWidget {
ConstrainedBox({ Key key, this.constraints, Widget child }) ConstrainedBox({ Key key, this.constraints, Widget child })
: super(key: key, child: child) { : super(key: key, child: child) {
assert(constraints != null); assert(constraints != null);
} }
/// The additional constraints to impose on the child.
final BoxConstraints constraints; final BoxConstraints constraints;
RenderConstrainedBox createRenderObject() => new RenderConstrainedBox(additionalConstraints: constraints); RenderConstrainedBox createRenderObject() => new RenderConstrainedBox(additionalConstraints: constraints);
...@@ -479,6 +608,9 @@ class SizedOverflowBox extends OneChildRenderObjectWidget { ...@@ -479,6 +608,9 @@ class SizedOverflowBox extends OneChildRenderObjectWidget {
} }
} }
/// Lays the child out as if it was in the tree, but without painting anything,
/// without making the child available for hit testing, and without taking any
/// room in the parent.
class OffStage extends OneChildRenderObjectWidget { class OffStage extends OneChildRenderObjectWidget {
OffStage({ Key key, Widget child }) OffStage({ Key key, Widget child })
: super(key: key, child: child); : super(key: key, child: child);
...@@ -506,11 +638,26 @@ class AspectRatio extends OneChildRenderObjectWidget { ...@@ -506,11 +638,26 @@ class AspectRatio extends OneChildRenderObjectWidget {
} }
} }
/// Sizes its child to the child's intrinsic width.
///
/// Sizes its child's width to the child's maximum intrinsic width. If
/// [stepWidth] is non-null, the child's width will be snapped to a multiple of
/// the [stepWidth]. Similarly, if [stepHeight] is non-null, the child's height
/// will be snapped to a multiple of the [stepHeight].
///
/// This class is useful, for example, when unlimited width is available and
/// you would like a child that would otherwise attempt to expand infinitely to
/// instead size itself to a more reasonable width.
///
/// This class is relatively expensive. Avoid using it where possible.
class IntrinsicWidth extends OneChildRenderObjectWidget { class IntrinsicWidth extends OneChildRenderObjectWidget {
IntrinsicWidth({ Key key, this.stepWidth, this.stepHeight, Widget child }) IntrinsicWidth({ Key key, this.stepWidth, this.stepHeight, Widget child })
: super(key: key, child: child); : super(key: key, child: child);
/// If non-null, force the child's width to be a multiple of this value.
final double stepWidth; final double stepWidth;
/// If non-null, force the child's height to be a multiple of this value.
final double stepHeight; final double stepHeight;
RenderIntrinsicWidth createRenderObject() => new RenderIntrinsicWidth(stepWidth: stepWidth, stepHeight: stepHeight); RenderIntrinsicWidth createRenderObject() => new RenderIntrinsicWidth(stepWidth: stepWidth, stepHeight: stepHeight);
...@@ -521,6 +668,13 @@ class IntrinsicWidth extends OneChildRenderObjectWidget { ...@@ -521,6 +668,13 @@ class IntrinsicWidth extends OneChildRenderObjectWidget {
} }
} }
/// Sizes its child to the child's intrinsic height.
///
/// This class is useful, for example, when unlimited height is available and
/// you would like a child that would otherwise attempt to expand infinitely to
/// instead size itself to a more reasonable height.
///
/// This class is relatively expensive. Avoid using it where possible.
class IntrinsicHeight extends OneChildRenderObjectWidget { class IntrinsicHeight extends OneChildRenderObjectWidget {
IntrinsicHeight({ Key key, Widget child }) : super(key: key, child: child); IntrinsicHeight({ Key key, Widget child }) : super(key: key, child: child);
RenderIntrinsicHeight createRenderObject() => new RenderIntrinsicHeight(); RenderIntrinsicHeight createRenderObject() => new RenderIntrinsicHeight();
...@@ -544,6 +698,15 @@ class Baseline extends OneChildRenderObjectWidget { ...@@ -544,6 +698,15 @@ class Baseline extends OneChildRenderObjectWidget {
} }
} }
/// A widget that's bigger on the inside.
///
/// The child of a viewport can layout to a larger size than the viewport
/// itself. If that happens, only a portion of the child will be visible through
/// the viewport. The portion of the child that is visible is controlled by the
/// scroll offset.
///
/// Viewport is the core scrolling primitive in the system, but it can be used
/// in other situations.
class Viewport extends OneChildRenderObjectWidget { class Viewport extends OneChildRenderObjectWidget {
Viewport({ Viewport({
Key key, Key key,
...@@ -555,7 +718,16 @@ class Viewport extends OneChildRenderObjectWidget { ...@@ -555,7 +718,16 @@ class Viewport extends OneChildRenderObjectWidget {
assert(scrollOffset != null); assert(scrollOffset != null);
} }
/// The direction in which the child is permitted to be larger than the viewport
///
/// If the viewport is scrollable in a particular direction (e.g., vertically),
/// the child is given layout constraints that are fully unconstrainted in
/// that direction (e.g., the child can be as tall as it wants).
final ScrollDirection scrollDirection; final ScrollDirection scrollDirection;
/// The offset at which to paint the child.
///
/// The offset can be non-zero only in the [scrollDirection].
final Offset scrollOffset; final Offset scrollOffset;
RenderViewport createRenderObject() => new RenderViewport(scrollDirection: scrollDirection, scrollOffset: scrollOffset); RenderViewport createRenderObject() => new RenderViewport(scrollDirection: scrollDirection, scrollOffset: scrollOffset);
...@@ -567,12 +739,17 @@ class Viewport extends OneChildRenderObjectWidget { ...@@ -567,12 +739,17 @@ class Viewport extends OneChildRenderObjectWidget {
} }
} }
/// Calls [onSizeChanged] whenever the child's layout size changes
///
/// Because size observer calls its callback during layout, you cannot modify
/// layout information during the callback.
class SizeObserver extends OneChildRenderObjectWidget { class SizeObserver extends OneChildRenderObjectWidget {
SizeObserver({ Key key, this.onSizeChanged, Widget child }) SizeObserver({ Key key, this.onSizeChanged, Widget child })
: super(key: key, child: child) { : super(key: key, child: child) {
assert(onSizeChanged != null); assert(onSizeChanged != null);
} }
/// The callback to call whenever the child's layout size changes
final SizeChangedCallback onSizeChanged; final SizeChangedCallback onSizeChanged;
RenderSizeObserver createRenderObject() => new RenderSizeObserver(onSizeChanged: onSizeChanged); RenderSizeObserver createRenderObject() => new RenderSizeObserver(onSizeChanged: onSizeChanged);
......
Markdown is supported
0% or
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment

HIAST - GitLab