Table of Contents

Class Widget

Namespace
Myra.Graphics2D.UI
Assembly
Myra.dll

The base class for all UI widgets in the Myra framework.

public class Widget : BaseObject, IItemWithId, INotifyAttachedPropertyChanged
Inheritance
Widget
Implements
Derived
Inherited Members

Constructors

Widget()

Initializes a new instance of the Widget class.

public Widget()

Fields

AfterRender

Gets or sets an action to be invoked after the widget is rendered.

[Browsable(false)]
public Action<RenderContext> AfterRender

Field Value

Action<RenderContext>

BeforeRender

Gets or sets an action to be invoked before the widget is rendered.

[Browsable(false)]
public Action<RenderContext> BeforeRender

Field Value

Action<RenderContext>

Properties

AcceptsKeyboardFocus

Gets or sets a value indicating whether the widget can accept keyboard focus.

[Browsable(false)]
public bool AcceptsKeyboardFocus { get; set; }

Property Value

bool

AcceptsMouseWheel

Gets a value indicating whether this widget accepts mouse wheel input.

protected virtual bool AcceptsMouseWheel { get; }

Property Value

bool

ActualBounds

Gets the actual bounds of the widget's content area, excluding margin, border, and padding.

[Browsable(false)]
public Rectangle ActualBounds { get; }

Property Value

Rectangle

Background

Gets or sets the brush used to draw the background of the widget in its normal state.

public IBrush Background { get; set; }

Property Value

IBrush

BackgroundBounds

Gets the bounds of the widget's background area, excluding the border.

[Browsable(false)]
protected Rectangle BackgroundBounds { get; }

Property Value

Rectangle

Border

Gets or sets the brush used for the widget's border in its normal state.

public IBrush Border { get; set; }

Property Value

IBrush

BorderThickness

Gets or sets the thickness of the border around the widget.

public Thickness BorderThickness { get; set; }

Property Value

Thickness

Bounds

Zero-based bounds

[Browsable(false)]
public Rectangle Bounds { get; }

Property Value

Rectangle

Children

Gets the collection of child widgets.

[Browsable(false)]
protected ObservableCollection<Widget> Children { get; }

Property Value

ObservableCollection<Widget>

ChildrenCopy

Gets a copy of the children collection sorted by Z-index.

protected IEnumerable<Widget> ChildrenCopy { get; }

Property Value

IEnumerable<Widget>

ChildrenLayout

Gets or sets the layout that arranges this widget's child widgets.

[Browsable(false)]
public ILayout ChildrenLayout { get; set; }

Property Value

ILayout

ClipToBounds

Gets or sets a value indicating whether the widget's content is clipped to its bounds.

public virtual bool ClipToBounds { get; set; }

Property Value

bool

ContainerBounds

Gets the bounds of the widget's container area.

[Browsable(false)]
public Rectangle ContainerBounds { get; }

Property Value

Rectangle

Desktop

Gets or sets the desktop that this widget is attached to.

[Browsable(false)]
public virtual Desktop Desktop { get; }

Property Value

Desktop

DisabledBackground

Gets or sets the brush used to draw the background of the widget when it is disabled.

public IBrush DisabledBackground { get; set; }

Property Value

IBrush

DisabledBorder

Gets or sets the brush used for the widget's border when it is disabled.

public IBrush DisabledBorder { get; set; }

Property Value

IBrush

DragDirection

Gets or sets the direction(s) in which the widget can be dragged.

public virtual DragDirection DragDirection { get; set; }

Property Value

DragDirection

DragHandle

Gets or sets a widget that should be used as the drag handle for this widget. If set, dragging this handle widget will move the parent widget.

[Browsable(false)]
public Widget DragHandle { get; set; }

Property Value

Widget

Enabled

Gets or sets a value indicating whether the widget is enabled and can receive user input.

public bool Enabled { get; set; }

Property Value

bool

FocusedBackground

Gets or sets the brush used to draw the background of the widget when it has keyboard focus.

public IBrush FocusedBackground { get; set; }

Property Value

IBrush

FocusedBorder

Gets or sets the brush used for the widget's border when it has focus.

public IBrush FocusedBorder { get; set; }

Property Value

IBrush

Height

Gets or sets the height of the widget in pixels.

public int? Height { get; set; }

Property Value

int?

HorizontalAlignment

Gets or sets the horizontal alignment of the widget within its parent container.

public virtual HorizontalAlignment HorizontalAlignment { get; set; }

Property Value

HorizontalAlignment

IsKeyboardFocused

Gets a value indicating whether the widget currently has keyboard focus.

[Browsable(false)]
public bool IsKeyboardFocused { get; }

Property Value

bool

IsModal

Gets or sets a value indicating whether this widget is modal and blocks interaction with other widgets.

[Browsable(false)]
public bool IsModal { get; set; }

Property Value

bool

IsMouseInside

Gets a value indicating whether the mouse pointer is currently inside this widget.

[Browsable(false)]
public bool IsMouseInside { get; }

Property Value

bool

IsPlaced

Determines whether the widget had been placed on Desktop

[Browsable(false)]
public bool IsPlaced { get; }

Property Value

bool

IsPressed

Gets or sets a value indicating whether the button is currently in the pressed state.

[Browsable(false)]
public virtual bool IsPressed { get; set; }

Property Value

bool

IsTouchInside

Gets a value indicating whether a touch point is currently inside this widget.

[Browsable(false)]
public bool IsTouchInside { get; }

Property Value

bool

Left

Gets or sets the left position of the widget in pixels.

public int Left { get; set; }

Property Value

int

LocalMousePosition

Gets or sets the local coordinates of the mouse pointer relative to this widget, or null if the mouse is not over the widget. Setting this property automatically queues MouseEntered, MouseLeft, or MouseMoved events as appropriate.

[Browsable(false)]
public Point? LocalMousePosition { get; }

Property Value

Point?

LocalTouchPosition

Gets or sets the local coordinates of the touch point relative to this widget, or null if there is no active touch on the widget. Setting this property automatically queues TouchDown, TouchUp, TouchEntered, TouchLeft, or TouchMoved events as appropriate.

[Browsable(false)]
public Point? LocalTouchPosition { get; }

Property Value

Point?

MBPHeight

Gets the total height consumed by margin, border, and padding (MBP = Margin + Border + Padding).

[Browsable(false)]
public int MBPHeight { get; }

Property Value

int

MBPWidth

Gets the total width consumed by margin, border, and padding (MBP = Margin + Border + Padding).

[Browsable(false)]
public int MBPWidth { get; }

Property Value

int

Margin

Gets or sets the outer margin around the widget.

public Thickness Margin { get; set; }

Property Value

Thickness

MaxHeight

Gets or sets the maximum height of the widget in pixels.

public int? MaxHeight { get; set; }

Property Value

int?

MaxWidth

Gets or sets the maximum width of the widget in pixels.

public int? MaxWidth { get; set; }

Property Value

int?

MinHeight

Gets or sets the minimum height of the widget in pixels.

public int? MinHeight { get; set; }

Property Value

int?

MinWidth

Gets or sets the minimum width of the widget in pixels.

public int? MinWidth { get; set; }

Property Value

int?

MouseCursor

Gets or sets the mouse cursor type displayed when the mouse is over the widget.

public virtual MouseCursorType? MouseCursor { get; set; }

Property Value

MouseCursorType?

Opacity

Gets or sets the opacity of the widget, where 0.0 is fully transparent and 1.0 is fully opaque.

[Range(0, 1)]
public float Opacity { get; set; }

Property Value

float

OverBackground

Gets or sets the brush used to draw the background of the widget when the mouse is hovering over it.

public IBrush OverBackground { get; set; }

Property Value

IBrush

OverBorder

Gets or sets the brush used for the widget's border when the mouse is over it.

public IBrush OverBorder { get; set; }

Property Value

IBrush

Padding

Gets or sets the inner padding inside the widget's borders.

public Thickness Padding { get; set; }

Property Value

Thickness

Parent

Gets the parent widget in the widget hierarchy.

[Browsable(false)]
public Widget Parent { get; }

Property Value

Widget

PressedBackground

Gets or sets the brush used for the widget's background when it is pressed.

public IBrush PressedBackground { get; set; }

Property Value

IBrush

PressedBorder

Gets or sets the brush used for the widget's border when it is pressed.

public IBrush PressedBorder { get; set; }

Property Value

IBrush

Rotation

Gets or sets the rotation angle of the widget in degrees, applied around the TransformOrigin point.

public float Rotation { get; set; }

Property Value

float

Scale

Gets or sets the scale factor applied to the widget. A value of (1, 1) is the original size.

public Vector2 Scale { get; set; }

Property Value

Vector2

StyleName

Internal use only. (MyraPad)

public string StyleName { get; set; }

Property Value

string

SuppressInvalidateMeasure

Gets or sets a value indicating whether layout invalidation is temporarily suppressed. When set to true, calls to InvalidateMeasure() have no effect, allowing batch updates without triggering repeated layout passes.

protected bool SuppressInvalidateMeasure { get; set; }

Property Value

bool

Tag

Gets or sets a custom object associated with the widget for application-specific use.

[Browsable(false)]
public object Tag { get; set; }

Property Value

object

Tooltip

Gets or sets the tooltip text to display when the mouse hovers over the widget.

public string Tooltip { get; set; }

Property Value

string

Top

Gets or sets the top position of the widget in pixels.

public int Top { get; set; }

Property Value

int

TransformOrigin

Gets or sets the origin point for transformations (scale and rotation), in normalized coordinates where (0, 0) is top-left and (1, 1) is bottom-right.

public Vector2 TransformOrigin { get; set; }

Property Value

Vector2

UseOverBackground

Gets a value indicating whether the over background should be used for the widget's current state.

protected virtual bool UseOverBackground { get; }

Property Value

bool

VerticalAlignment

Gets or sets the vertical alignment of the widget within its parent container.

public virtual VerticalAlignment VerticalAlignment { get; set; }

Property Value

VerticalAlignment

Visible

Gets or sets a value indicating whether the widget is visible and should be rendered.

public bool Visible { get; set; }

Property Value

bool

Width

Gets or sets the width of the widget in pixels.

public int? Width { get; set; }

Property Value

int?

ZIndex

Gets or sets the z-order (depth) of the widget for rendering. Widgets with higher z-index values are rendered on top.

public int ZIndex { get; set; }

Property Value

int

Methods

ApplyStyle(WidgetStyle)

Applies the specified widget style to this widget.

protected virtual void ApplyStyle(WidgetStyle style)

Parameters

style WidgetStyle

The widget style to apply.

ApplyWidgetStyle(WidgetStyle)

Applies the specified widget style to this widget, copying its sizing, background, border, and margin properties.

public void ApplyWidgetStyle(WidgetStyle style)

Parameters

style WidgetStyle

The widget style to apply.

Arrange(Rectangle)

Arranges the widget within the specified container bounds.

public void Arrange(Rectangle containerBounds)

Parameters

containerBounds Rectangle

The bounds of the container in which to arrange the widget.

BringToBack()

Sends the widget to the back (bottom of the z-order) within its parent or desktop.

public void BringToBack()

BringToFront()

Brings the widget to the front (top of the z-order) within its parent or desktop.

public void BringToFront()

CalculateTotalChildCount(bool)

Calculates the total number of child widgets, optionally including only visible children and their descendants.

public int CalculateTotalChildCount(bool visibleOnly)

Parameters

visibleOnly bool

If true, only counts visible widgets; if false, counts all widgets.

Returns

int

The total count of child widgets.

Clone()

Creates a deep copy of this widget with all its properties and attached properties.

public Widget Clone()

Returns

Widget

A new widget instance that is a copy of this widget.

ContainsGlobalPoint(Point)

Determines whether the specified global position is within the widget's bounds.

public bool ContainsGlobalPoint(Point globalPos)

Parameters

globalPos Point

The position in global coordinates.

Returns

bool

True if the position is within the widget's bounds; otherwise, false.

CopyFrom(Widget)

Copies all properties from another widget to this widget.

protected virtual void CopyFrom(Widget w)

Parameters

w Widget

The widget to copy properties from.

EnsureWidgetById(string)

Finds a child widget by its id, throwing an exception if not found.

public Widget EnsureWidgetById(string id)

Parameters

id string

The id of the widget to find.

Returns

Widget

The widget with the specified id.

Exceptions

Exception

Thrown when a widget with the specified id is not found.

FindChild(Func<Widget, bool>)

Finds the first child found by predicate.

public Widget FindChild(Func<Widget, bool> predicate)

Parameters

predicate Func<Widget, bool>

Predicate to match on widget

Returns

Widget

Widget instance if found otherwise null

FindChildById(string)

Finds the first widget with matching Id

public Widget FindChildById(string Id)

Parameters

Id string

Id to match on

Returns

Widget

Widget instance if found otherwise null

FindChildById<WidgetT>(string)

Finds first child widget of type WidgetT with specified Id

public WidgetT FindChildById<WidgetT>(string Id) where WidgetT : Widget

Parameters

Id string

Id of widget

Returns

WidgetT

Widget instance if found otherwise null

Type Parameters

WidgetT

Widget type

FindChild<WidgetT>(Func<WidgetT, bool>)

Finds first child widget of type WidgetT. If predicate is null - the first widget of WidgetT is returned, otherwise the first widget of WidgetT matching predicate is returned.

public WidgetT FindChild<WidgetT>(Func<WidgetT, bool> predicate = null) where WidgetT : Widget

Parameters

predicate Func<WidgetT, bool>

Predicate to match on widget

Returns

WidgetT

Widget instance if found otherwise null

Type Parameters

WidgetT

Widget type

FireKeyDown(Keys)

Fires the KeyDown event for the specified key.

protected void FireKeyDown(Keys k)

Parameters

k Keys

The key that was pressed.

GetChildren(bool, Func<Widget, bool>)

Gets all children in Widget matching on optional predicate.

public IEnumerable<Widget> GetChildren(bool recursive = false, Func<Widget, bool> predicate = null)

Parameters

recursive bool

If true, indicates that child Widgets will also be iterated.

predicate Func<Widget, bool>

Predicate to filter children

Returns

IEnumerable<Widget>

Children found

GetCurrentBackground()

Gets the brush to use for the widget's background based on its current state.

public IBrush GetCurrentBackground()

Returns

IBrush

The current background brush appropriate for the widget's state.

GetCurrentBorder()

Gets the brush to use for the widget's border based on its current state.

public IBrush GetCurrentBorder()

Returns

IBrush

The current border brush appropriate for the widget's state.

GetCurrentVisual<T>(T[])

Gets the current visual element based on the widget's state, selecting from the provided array of visual values.

protected T GetCurrentVisual<T>(T[] values)

Parameters

values T[]

Array of visual values indexed by WidgetVisualState constants.

Returns

T

The current visual element appropriate for the widget's current state.

Type Parameters

T

The type of visual element.

HitTest(Point)

Performs hit testing to determine which widget at the given global position should receive input events.

public virtual Widget HitTest(Point p)

Parameters

p Point

The position in global coordinates to test.

Returns

Widget

The widget at the specified position, or null if no widget is there or this widget is not visible.

InputFallsThrough(Point)

Determines whether input at the specified local position should fall through to widgets behind this widget.

public virtual bool InputFallsThrough(Point localPos)

Parameters

localPos Point

The position in the widget's local coordinates.

Returns

bool

True if input should fall through; false if this widget should handle it.

InternalArrange()

Arranges the child widgets within this widget's bounds.

protected virtual void InternalArrange()

InternalMeasure(Point)

Measures the widget and its children to determine the required size.

protected virtual Point InternalMeasure(Point availableSize)

Parameters

availableSize Point

The available size for this widget and its children.

Returns

Point

The measured size of this widget.

InternalRender(RenderContext)

Renders the widget's content (called after backgrounds and borders are rendered). Default implementation renders all child widgets.

public virtual void InternalRender(RenderContext context)

Parameters

context RenderContext

The render context to draw to.

InvalidateArrange()

Marks the widget's arrangement as dirty, requiring a recalculation on the next update.

public void InvalidateArrange()

InvalidateChildren()

Invalidates the child layout, marking it as needing recalculation.

protected virtual void InvalidateChildren()

InvalidateMeasure()

Marks the widget's measurement as dirty, requiring a recalculation on the next update. This cascades up to parent widgets.

public virtual void InvalidateMeasure()

Measure(Point)

Measures the widget to determine its desired size based on available space.

public Point Measure(Point availableSize)

Parameters

availableSize Point

The available space for the widget.

Returns

Point

The desired size of the widget.

OnChar(char)

Called when a character is entered while this widget has focus.

public virtual void OnChar(char c)

Parameters

c char

The character that was entered.

OnChildAdded(Widget)

Called when a child widget is added to this widget.

protected virtual void OnChildAdded(Widget w)

Parameters

w Widget

The child widget that was added.

OnChildRemoved(Widget)

Called when a child widget is removed from this widget.

protected virtual void OnChildRemoved(Widget w)

Parameters

w Widget

The child widget that was removed.

OnGotKeyboardFocus()

Called when the widget receives keyboard focus.

public virtual void OnGotKeyboardFocus()

OnKeyDown(Keys)

Called when a keyboard key is pressed while this widget has focus.

public virtual void OnKeyDown(Keys k)

Parameters

k Keys

The key that was pressed.

OnKeyUp(Keys)

Called when a keyboard key is released while this widget has focus.

public virtual void OnKeyUp(Keys k)

Parameters

k Keys

The key that was released.

OnLostKeyboardFocus()

Called when the widget loses keyboard focus.

public virtual void OnLostKeyboardFocus()

OnMouseEntered()

Called when the mouse pointer enters the widget.

public virtual void OnMouseEntered()

OnMouseLeft()

Called when the mouse pointer leaves the widget.

public virtual void OnMouseLeft()

OnMouseMoved()

Called when the mouse pointer moves within the widget.

public virtual void OnMouseMoved()

OnMouseWheel(float)

Called when the mouse wheel is scrolled while over the widget.

public virtual void OnMouseWheel(float delta)

Parameters

delta float

The scroll delta value.

OnPlacedChanged()

Called when the widget's placement (position or size) has changed.

protected virtual void OnPlacedChanged()

OnPressedChanged()

Raises the PressedChanged event.

public virtual void OnPressedChanged()

OnTouchDoubleClick()

Called when the widget receives a double-tap touch event.

public virtual void OnTouchDoubleClick()

OnTouchDown()

Called when a touch point is pressed on the widget.

public virtual void OnTouchDown()

OnTouchEntered()

Called when a touch point enters the widget.

public virtual void OnTouchEntered()

OnTouchLeft()

Called when a touch point leaves the widget.

public virtual void OnTouchLeft()

OnTouchMoved()

Called when a touch point moves within the widget.

public virtual void OnTouchMoved()

OnTouchUp()

Called when a touch point is released on the widget.

public virtual void OnTouchUp()

OnVisibleChanged()

Called when the widget's visibility state changes.

public virtual void OnVisibleChanged()

ProcessInput(InputContext)

Processes input events for this widget, including mouse and touch input. Performs hit-testing, updates input positions, and recursively processes children. Marks input as handled if widget consumes it, preventing propagation to parent widgets.

protected virtual void ProcessInput(InputContext inputContext)

Parameters

inputContext InputContext

The input context containing the current input state and handling flags.

RemoveFromDesktop()

Removes this widget from the desktop's widgets collection.

public void RemoveFromDesktop()

RemoveFromParent()

Removes this widget from its parent widget's children collection.

public void RemoveFromParent()

Render(RenderContext)

Renders the widget and its children to the specified render context.

public void Render(RenderContext context)

Parameters

context RenderContext

The render context to draw to.

SetIsPressedByUser(bool)

Sets the IsPressed state as a result of user interaction, raising the PressedChangingByUser event first.

protected void SetIsPressedByUser(bool value)

Parameters

value bool

The new pressed state value.

SetKeyboardFocus()

Sets this widget to have keyboard focus.

public void SetKeyboardFocus()

SetStyle(Stylesheet, string)

Sets the style for this widget by name from the specified stylesheet.

public void SetStyle(Stylesheet stylesheet, string name)

Parameters

stylesheet Stylesheet

The stylesheet containing the style to apply.

name string

The name of the style to apply.

ToGlobal(Point)

Converts a position from the widget's local coordinates to global (screen) coordinates.

public Point ToGlobal(Point pos)

Parameters

pos Point

The position in local coordinates.

Returns

Point

The position in global coordinates.

ToGlobal(Vector2)

Converts a position from the widget's local coordinates to global (screen) coordinates.

public Vector2 ToGlobal(Vector2 pos)

Parameters

pos Vector2

The position in local coordinates.

Returns

Vector2

The position in global coordinates.

ToLocal(Point)

Converts a position from global (screen) coordinates to the widget's local coordinates.

public Point ToLocal(Point pos)

Parameters

pos Point

The position in global coordinates.

Returns

Point

The position in local coordinates.

ToLocal(Vector2)

Converts a position from global (screen) coordinates to the widget's local coordinates.

public Vector2 ToLocal(Vector2 pos)

Parameters

pos Vector2

The position in global coordinates.

Returns

Vector2

The position in local coordinates.

UpdateArrange()

Updates the widget's arrangement if it is marked as dirty.

public void UpdateArrange()

Events

ArrangeUpdated

Occurs when the widget's layout arrangement has been updated.

public event MyraEventHandler ArrangeUpdated

Event Type

MyraEventHandler

Char

Occurs when a character is entered while the widget has keyboard focus.

public event MyraEventHandler<GenericEventArgs<char>> Char

Event Type

MyraEventHandler<GenericEventArgs<char>>

EnabledChanged

Occurs when the widget's enabled state has changed.

public event MyraEventHandler EnabledChanged

Event Type

MyraEventHandler

KeyDown

Occurs when a key is pressed while the widget has keyboard focus.

public event MyraEventHandler<GenericEventArgs<Keys>> KeyDown

Event Type

MyraEventHandler<GenericEventArgs<Keys>>

KeyUp

Occurs when a key is released while the widget has keyboard focus.

public event MyraEventHandler<GenericEventArgs<Keys>> KeyUp

Event Type

MyraEventHandler<GenericEventArgs<Keys>>

KeyboardFocusChanged

Occurs when the keyboard focus on the widget has changed.

public event MyraEventHandler KeyboardFocusChanged

Event Type

MyraEventHandler

LocationChanged

Occurs when the widget's location has changed.

public event MyraEventHandler LocationChanged

Event Type

MyraEventHandler

MouseEntered

Occurs when the mouse pointer enters the widget.

public event MyraEventHandler MouseEntered

Event Type

MyraEventHandler

MouseLeft

Occurs when the mouse pointer leaves the widget.

public event MyraEventHandler MouseLeft

Event Type

MyraEventHandler

MouseMoved

Occurs when the mouse pointer moves within the widget.

public event MyraEventHandler MouseMoved

Event Type

MyraEventHandler

MouseWheelChanged

Occurs when the mouse wheel is scrolled while over the widget.

public event MyraEventHandler<GenericEventArgs<float>> MouseWheelChanged

Event Type

MyraEventHandler<GenericEventArgs<float>>

PlacedChanged

Occurs when the widget's position has changed.

public event MyraEventHandler PlacedChanged

Event Type

MyraEventHandler

PressedChanged

Occurs when the widget's pressed state changes.

public event MyraEventHandler PressedChanged

Event Type

MyraEventHandler

PressedChangingByUser

Occurs when the widget's pressed state is being changed by user interaction, before the change is committed.

public event MyraEventHandler<ValueChangingEventArgs<bool>> PressedChangingByUser

Event Type

MyraEventHandler<ValueChangingEventArgs<bool>>

SizeChanged

Occurs when the widget's size has changed.

public event MyraEventHandler SizeChanged

Event Type

MyraEventHandler

TouchDoubleClick

Occurs when the widget receives a double-tap touch event.

public event MyraEventHandler TouchDoubleClick

Event Type

MyraEventHandler

TouchDown

Occurs when a touch point is pressed on the widget.

public event MyraEventHandler TouchDown

Event Type

MyraEventHandler

TouchEntered

Occurs when a touch point enters the widget.

public event MyraEventHandler TouchEntered

Event Type

MyraEventHandler

TouchLeft

Occurs when a touch point leaves the widget.

public event MyraEventHandler TouchLeft

Event Type

MyraEventHandler

TouchMoved

Occurs when a touch point moves within the widget.

public event MyraEventHandler TouchMoved

Event Type

MyraEventHandler

TouchUp

Occurs when a touch point is released on the widget.

public event MyraEventHandler TouchUp

Event Type

MyraEventHandler

VisibleChanged

Occurs when the widget's visibility has changed.

public event MyraEventHandler VisibleChanged

Event Type

MyraEventHandler
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