Struct RenderAspectRatio 

pub struct RenderAspectRatio { /* private fields */ }

Attempts to size the child to a specific aspect ratio.

The render object first tries the largest width permitted by the layout constraints. The height of the render object is determined by applying the given aspect ratio to the width, 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. If the maximum width is infinite, the initial width is determined by applying the aspect ratio to the maximum height.

Now consider a second example, this time with an aspect ratio of 2.0 and layout constraints that require the width to be between 0.0 and 100.0 and the height to be between 0.0 and 100.0. The largest width permitted is 100.0, and applying the ratio gives a height of 50.0.

Implementations

impl RenderAspectRatio

pub fn new( app: &mut App, aspect_ratio: f64, child: Option<AnyRenderBox>, ) -> RenderHandle<RenderAspectRatio>

Creates a render object with a specific aspect ratio.

The aspect_ratio argument must be a finite, positive value.

pub fn aspect_ratio(self: RenderHandle<Self>, app: &App) -> f64

The aspect ratio to attempt to use.

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.

pub fn set_aspect_ratio(self: RenderHandle<Self>, app: &mut App, value: f64)

Sets aspect_ratio.

Trait Implementations

impl RenderBox for RenderAspectRatio

fn render_box_data(self: RenderHandle<Self>, app: &App) -> &RenderBoxData

Mixin field access.

fn render_box_data_mut( self: RenderHandle<Self>, app: &mut App, ) -> &mut RenderBoxData

See render_box_data.

fn setup_parent_data( self: RenderHandle<Self>, app: &mut App, child: AnyRenderObject, )

Installs BoxParentData unless the child already has it.

fn apply_paint_transform( self: RenderHandle<Self>, app: &App, child: AnyRenderObject, transform: &mut Matrix4, )

Multiply the transform from the parent’s coordinate system to this box’s coordinate system into the given transform.

fn hit_test_children( self: RenderHandle<Self>, app: &mut App, result: &mut BoxHitTestResult<'_>, position: Offset, ) -> bool

Override this method to check whether any children are located at the given position.

fn compute_min_intrinsic_width( self: RenderHandle<Self>, app: &mut App, height: f64, ) -> f64

Computes the value returned by get_min_intrinsic_width. Do not call this function directly, instead, call get_min_intrinsic_width.

fn compute_max_intrinsic_width( self: RenderHandle<Self>, app: &mut App, height: f64, ) -> f64

Computes the value returned by get_max_intrinsic_width. Do not call this function directly, instead, call get_max_intrinsic_width.

fn compute_min_intrinsic_height( self: RenderHandle<Self>, app: &mut App, width: f64, ) -> f64

Computes the value returned by get_min_intrinsic_height. Do not call this function directly, instead, call get_min_intrinsic_height.

fn compute_max_intrinsic_height( self: RenderHandle<Self>, app: &mut App, width: f64, ) -> f64

Computes the value returned by get_max_intrinsic_height. Do not call this function directly, instead, call get_max_intrinsic_height.

fn compute_distance_to_actual_baseline( self: RenderHandle<Self>, app: &mut App, baseline: TextBaseline, ) -> Option<f64>

Returns the distance from the y-coordinate of the position of the box to the y-coordinate of the first given baseline in the box’s contents, if any, or None otherwise.

fn compute_dry_layout( self: RenderHandle<Self>, app: &mut App, constraints: BoxConstraints, ) -> Size

Computes the value returned by get_dry_layout. Do not call this function directly, instead, call get_dry_layout.

fn compute_dry_baseline( self: RenderHandle<Self>, app: &mut App, constraints: BoxConstraints, baseline: TextBaseline, ) -> Option<f64>

Computes the value returned by get_dry_baseline.

fn constraints(self: RenderHandle<Self>, app: &App) -> BoxConstraints

The box constraints most recently supplied by the parent.

fn get_min_intrinsic_width( self: RenderHandle<Self>, app: &mut App, height: f64, ) -> f64

See AnyRenderBox::get_min_intrinsic_width.

fn get_max_intrinsic_width( self: RenderHandle<Self>, app: &mut App, height: f64, ) -> f64

See AnyRenderBox::get_max_intrinsic_width.

fn get_min_intrinsic_height( self: RenderHandle<Self>, app: &mut App, width: f64, ) -> f64

See AnyRenderBox::get_min_intrinsic_height.

fn get_max_intrinsic_height( self: RenderHandle<Self>, app: &mut App, width: f64, ) -> f64

See AnyRenderBox::get_max_intrinsic_height.

fn get_dry_layout( self: RenderHandle<Self>, app: &mut App, constraints: BoxConstraints, ) -> Size

See AnyRenderBox::get_dry_layout.

fn get_dry_baseline( self: RenderHandle<Self>, app: &mut App, constraints: BoxConstraints, baseline: TextBaseline, ) -> Option<f64>

See AnyRenderBox::get_dry_baseline.

fn debug_cannot_compute_dry_layout( self: RenderHandle<Self>, failure: DryLayoutFailure<'_>, )

Called from compute_dry_layout or compute_dry_baseline if this box does not support calculating a dry layout.

fn get_distance_to_baseline( self: RenderHandle<Self>, app: &mut App, baseline: TextBaseline, only_real: bool, ) -> Option<f64>

See AnyRenderBox::get_distance_to_baseline.

fn get_distance_to_actual_baseline( self: RenderHandle<Self>, app: &mut App, baseline: TextBaseline, ) -> Option<f64>

See AnyRenderBox::get_distance_to_actual_baseline.

fn mark_needs_layout(self: RenderHandle<Self>, app: &mut App)

Mark this render object’s layout information as dirty.

fn perform_resize(self: RenderHandle<Self>, app: &mut App)

Updates the box’s size using only the constraints.

fn size(self: RenderHandle<Self>, app: &App) -> Size

The size of this box.

fn paint_bounds(self: RenderHandle<Self>, app: &App) -> Rect

An estimate of the bounds within which this render object will paint: the box’s own size.

fn has_size(self: RenderHandle<Self>, app: &App) -> bool

Whether this render object has undergone layout and has a size.

fn handle_event( self: RenderHandle<Self>, app: &mut App, event: &PointerEvent, entry: &BoxHitTestEntry, )

Override this method to handle pointer events that hit this render object.

fn hit_test( self: RenderHandle<Self>, app: &mut App, result: &mut BoxHitTestResult<'_>, position: Offset, ) -> bool

Determines the set of render objects located at the given position.

fn hit_test_self( self: RenderHandle<Self>, _app: &App, _position: Offset, ) -> bool

Override this method if this render object can be hit even if its children were not hit.

fn set_size(self: RenderHandle<Self>, app: &mut App, size: Size)

Sets the size of this box. Call from RenderObject::perform_layout or RenderObject::perform_resize.

fn layout( self: RenderHandle<Self>, app: &mut App, constraints: BoxConstraints, parent_uses_size: bool, )

See AnyRenderBox::layout.

fn as_box(self: RenderHandle<Self>) -> AnyRenderBox

The type-erased RenderBox handle. Free: the vtable is a const, and the id is copied.

fn as_object(self: RenderHandle<Self>) -> AnyRenderObject

The type-erased RenderObject handle, through as_box.

fn adopt_child(self: RenderHandle<Self>, app: &mut App, child: AnyRenderObject)

See AnyRenderObject::adopt_child.

fn drop_child(self: RenderHandle<Self>, app: &mut App, child: AnyRenderObject)

See AnyRenderObject::drop_child.

fn mark_needs_paint(self: RenderHandle<Self>, app: &mut App)

See AnyRenderObject::mark_needs_paint.

fn mark_needs_composited_layer_update(self: RenderHandle<Self>, app: &mut App)

See AnyRenderObject::mark_needs_composited_layer_update.

fn mark_needs_compositing_bits_update(self: RenderHandle<Self>, app: &mut App)

See AnyRenderObject::mark_needs_compositing_bits_update.

fn schedule_initial_layout(self: RenderHandle<Self>, app: &mut App)

See AnyRenderObject::schedule_initial_layout.

fn parent(self: RenderHandle<Self>, app: &App) -> Option<AnyRenderObject>

See AnyRenderObject::parent.

fn owner(self: RenderHandle<Self>, app: &App) -> Option<Handle<PipelineOwner>>

See AnyRenderObject::owner.

fn attached(self: RenderHandle<Self>, app: &App) -> bool

See AnyRenderObject::attached.

fn debug_needs_layout(self: RenderHandle<Self>, app: &App) -> bool

See AnyRenderObject::debug_needs_layout.

impl RenderObject for RenderAspectRatio

fn render_object_data(self: RenderHandle<Self>, app: &App) -> &RenderObjectData

Mixin field access.

fn render_object_data_mut( self: RenderHandle<Self>, app: &mut App, ) -> &mut RenderObjectData

See render_object_data.

fn perform_layout(self: RenderHandle<Self>, app: &mut App)

Do the work of computing the layout for this render object.

fn paint( self: RenderHandle<Self>, app: &mut App, context: &mut PaintingContext, offset: Offset, )

Paint this render object into the given context at the given offset.

fn visit_children( self: RenderHandle<Self>, app: &App, visitor: &mut dyn FnMut(AnyRenderObject), )

Calls visitor for each immediate child.

fn as_render_object(self: RenderHandle<Self>, app: &App) -> AnyRenderObject

Dart’s implicit upcast of a concrete render object to RenderObject: this object’s type-erased handle, through the vtable the protocol recorded when it created it.

fn perform_resize(self: RenderHandle<Self>, _app: &mut App)

Updates the render object’s size using only the constraints.

fn setup_parent_data( self: RenderHandle<Self>, app: &mut App, child: AnyRenderObject, )

Sets up parent data for child if it has none.

fn did_attach( self: RenderHandle<Self>, app: &mut App, owner: Handle<PipelineOwner>, )

The body of Flutter’s attach override after super.attach(owner); the base body has already run. The default attaches the children reported by visit_children.

fn did_detach(self: RenderHandle<Self>, app: &mut App)

The body of Flutter’s detach override after super.detach(). The default detaches the children reported by visit_children.

fn redepth_children(self: RenderHandle<Self>, app: &mut App)

Adjusts the depth of each child reported by visit_children.

fn sized_by_parent(self: RenderHandle<Self>, _app: &App) -> bool

Whether the constraints are the only input to the sizing algorithm.

fn apply_paint_transform( self: RenderHandle<Self>, app: &App, child: AnyRenderObject, transform: &mut Matrix4, )

Applies the transform that would be applied when painting the given child to the given matrix.

fn is_repaint_boundary(self: RenderHandle<Self>, _app: &App) -> bool

Whether this render object repaints separately from its parent.

fn always_needs_compositing(self: RenderHandle<Self>, _app: &App) -> bool

Whether this render object always needs compositing.

fn mouse_tracker_annotation( self: RenderHandle<Self>, _app: &App, ) -> Option<MouseTrackerAnnotation>

Dart’s this is MouseTrackerAnnotation: the annotation this render object implements, read live each time the mouse tracker consults it. None for a render object that is not an annotation, which is the default.

fn update_composited_layer( self: RenderHandle<Self>, app: &mut App, old_layer: Option<AnyOffsetLayer>, ) -> AnyOffsetLayer

Update the composited layer owned by this render object.

fn show_on_screen( self: RenderHandle<Self>, app: &mut App, descendant: Option<AnyRenderObject>, rect: Option<Rect>, duration: Duration, curve: Rc<dyn Curve>, )

Attempt to make (a portion of) this or a descendant RenderObject visible on screen.

fn interface(self: RenderHandle<Self>, id: TypeId) -> Option<Box<dyn Any>>

Dart’s object is RenderAbstractViewport for any interface: the erased handle of the interface id names, if this type implements it.

fn dispose(self: RenderHandle<Self>, app: &mut App)

Release any resources held by this render object.

impl RenderObjectWithChildMixin for RenderAspectRatio

type ChildType = AnyRenderBox

Flutter’s ChildType: the protocol of this render object’s child.

fn child_data( self: RenderHandle<Self>, app: &App, ) -> &RenderObjectWithChildData<AnyRenderBox>

Mixin field access.

fn child_data_mut( self: RenderHandle<Self>, app: &mut App, ) -> &mut RenderObjectWithChildData<AnyRenderBox>

See child_data.

fn child(self: RenderHandle<Self>, app: &App) -> Option<Self::ChildType>

The render object’s unique child.

fn set_child( self: RenderHandle<Self>, app: &mut App, value: Option<Self::ChildType>, )

Sets the unique child, adopting or dropping as Flutter’s setter does.

impl RenderProxyBoxMixin for RenderAspectRatio

fn setup_parent_data( self: RenderHandle<Self>, app: &mut App, child: AnyRenderObject, )

A proxy child gets plain parent data, not crate::BoxParentData.

fn apply_paint_transform( self: RenderHandle<Self>, app: &App, child: AnyRenderObject, transform: &mut Matrix4, )

A proxy paints its child at its own offset: no transform to apply.

fn compute_min_intrinsic_width( self: RenderHandle<Self>, app: &mut App, height: f64, ) -> f64

The child’s minimum intrinsic width, or 0 without a child.

fn compute_max_intrinsic_width( self: RenderHandle<Self>, app: &mut App, height: f64, ) -> f64

The child’s maximum intrinsic width, or 0 without a child.

fn compute_min_intrinsic_height( self: RenderHandle<Self>, app: &mut App, width: f64, ) -> f64

The child’s minimum intrinsic height, or 0 without a child.

fn compute_max_intrinsic_height( self: RenderHandle<Self>, app: &mut App, width: f64, ) -> f64

The child’s maximum intrinsic height, or 0 without a child.

fn compute_distance_to_actual_baseline( self: RenderHandle<Self>, app: &mut App, baseline: TextBaseline, ) -> Option<f64>

The child’s baseline, or none without a child.

fn compute_dry_baseline( self: RenderHandle<Self>, app: &mut App, constraints: BoxConstraints, baseline: TextBaseline, ) -> Option<f64>

The child’s dry baseline, or none without a child.

fn compute_dry_layout( self: RenderHandle<Self>, app: &mut App, constraints: BoxConstraints, ) -> Size

The child’s dry layout at this box’s constraints, or compute_size_for_no_child.

fn perform_layout(self: RenderHandle<Self>, app: &mut App)

Lays the child out with this box’s constraints and takes its size.

fn compute_size_for_no_child( self: RenderHandle<Self>, _app: &App, constraints: BoxConstraints, ) -> Size

Calculate the size the proxy box would have when it has no child.

fn hit_test_children( self: RenderHandle<Self>, app: &mut App, result: &mut BoxHitTestResult<'_>, position: Offset, ) -> bool

Hit tests the child at this box’s position.

fn paint( self: RenderHandle<Self>, app: &mut App, context: &mut PaintingContext, offset: Offset, )

Paints the child at this box’s offset.