Class TCastleUserInterface

Unit

Declaration

type TCastleUserInterface = class(TCastleComponent)

Description

Basic user-interface class. All UI controls derive from this class, overriding chosen methods to react to some events.

Every control can have children controls, see Controls and ControlsCount. Parent control is recorded inside the Parent. A control may only be a child of one other control — that is, you cannot insert to the UI hierarchy the same control multiple times.

Control may handle mouse/keyboard input, see Press and Release methods.

Various methods return boolean saying if input event is handled. The idea is that not handled events are passed to the next control suitable. Handled events are generally not processed more — otherwise the same event could be handled by more than one listener, which is bad. Generally, return ExclusiveEvents if anything (possibly) was done (you changed any field value etc.) as a result of this, and only return False when you're absolutely sure that nothing was done by this control.

Every control also has a position and size and takes some rectangular space on the container.

The position is controlled using a Translation that works relative to the currently set anchors. You can change the position, adjusting also anchor, using an utility method Anchor: one overloaded version of Anchor changes the horizontal position and anchors (HorizontalAnchorSelf, HorizontalAnchorParent, Translation.X), the other overloaded version changes vertical position and anchors (VerticalAnchorSelf, VerticalAnchorParent, Translation.Y). You can also change each individual property mentioned above.

The size is controlled using the Width, WidthFraction, Height, HeightFraction, FullSize, or AutoSizeToChildren properties.

The size (before UI scaling is applied) can be queried using EffectiveWidth and EffectiveHeight methods. The rectangle where the control is visible (during rendering, after applying UI scaling) can be queried using RenderRect and RenderRectWithBorder methods.

Note that some descendants perform auto-sizing, that is: their effective size follows some natural property of the control. For example, TCastleLabel size by default follows the TCastleLabel.Caption value, and ignores the explicit size set in Width and Height. You can turn off auto-sizing by TCastleLabel.AutoSize, to manually control the size using Width and Height.

All the coordinates passed here should follow the Castle Game Engine convention that (0, 0) is left-bottom window corner.

Hierarchy

Overview

Fields

Public nested const DefaultWidth = 100.0;
Public nested const DefaultHeight = 100.0;

Methods

Protected procedure Loaded; override;
Protected function ContainerWidth: Cardinal; virtual;
Protected function ContainerHeight: Cardinal; virtual;
Protected function ContainerRect: TRectangle; virtual;
Protected function ContainerSizeKnown: boolean; virtual;
Protected procedure DoCursorChange; virtual; deprecated 'better override VisibleChange and watch for chCursor in Changes';
Protected procedure DefineProperties(Filer: TFiler); override;
Protected procedure UIScaleChanged; virtual;
Protected procedure PreferredSize(var PreferredWidth, PreferredHeight: Single); virtual;
Protected procedure BeforeSizing; virtual;
Protected procedure DoInternalMouseEnter; virtual;
Protected procedure DoInternalMouseLeave; virtual;
Protected function Theme: TCastleTheme;
Public constructor Create(AOwner: TComponent); override;
Public destructor Destroy; override;
Public procedure CustomSerialization(const SerializationProcess: TSerializationProcess); override;
Public function PropertySections(const PropertyName: String): TPropertySections; override;
Public function GetEnumerator: TEnumerator;
Public procedure InternalSetContainer(const Value: TCastleContainer); virtual;
Public function Press(const Event: TInputPressRelease): boolean; virtual;
Public function Release(const Event: TInputPressRelease): boolean; virtual;
Public function PreviewPress(const Event: TInputPressRelease): boolean; virtual;
Public function PreviewRelease(const Event: TInputPressRelease): boolean; virtual;
Public function Motion(const Event: TInputMotion): boolean; virtual;
Public function SensorRotation(const X, Y, Z, Angle: Double; const SecondsPassed: Single): boolean; virtual;
Public function SensorTranslation(const X, Y, Z, Length: Double; const SecondsPassed: Single): boolean; virtual;
Public function JoyAxisMove(const JoyID, Axis: Byte): boolean; virtual; deprecated 'use event Joysticks.OnAxisMove, or just observe Joysticks[0].Axis';
Public function JoyButtonPress(const JoyID, Button: Byte): boolean; virtual; deprecated 'use Joysticks.OnButtonDown or Joysticks.OnButtonPress';
Public procedure Update(const SecondsPassed: Single; var HandleInput: boolean); virtual;
Public procedure VisibleChange(const Changes: TCastleUserInterfaceChanges; const ChangeInitiatedByChildren: boolean = false); overload; virtual;
Public function AllowSuspendForInput: boolean; virtual;
Public procedure Resize; virtual;
Public procedure ContainerResize(const AContainerWidth, AContainerHeight: Cardinal); virtual; deprecated 'use Resize';
Public function ControlsCount: Integer;
Public procedure InsertFront(const NewItem: TCastleUserInterface); overload;
Public procedure InsertFrontIfNotExists(const NewItem: TCastleUserInterface);
Public procedure InsertFront(const NewItems: TCastleUserInterfaceList); overload;
Public procedure InsertBack(const NewItem: TCastleUserInterface); overload;
Public procedure InsertBackIfNotExists(const NewItem: TCastleUserInterface);
Public procedure InsertBack(const NewItems: TCastleUserInterfaceList); overload;
Public procedure InsertControl(const Index: Integer; const NewItem: TCastleUserInterface);
Public procedure RemoveControl(const Item: TCastleUserInterface);
Public function IndexOfControl(const Item: TCastleUserInterface): Integer;
Public procedure ClearControls;
Public function CapturesEventsAtPosition(const Position: TVector2): boolean; virtual;
Public procedure BeforeRender; virtual;
Public procedure Render; virtual;
Public procedure RenderOverChildren; virtual;
Public function TooltipExists: Boolean; virtual; deprecated 'use TooltipControl to customize tooltip look';
Public procedure TooltipRender(const TooltipPosition: TVector2); virtual; deprecated 'use TooltipControl to customize tooltip look';
Public procedure GLContextOpen; virtual;
Public procedure GLContextClose; virtual;
Public procedure SetFocused(const Value: boolean); virtual;
Public function EffectiveRect: TFloatRectangle;
Public function EffectiveWidth: Single;
Public function EffectiveHeight: Single;
Public function EffectiveWidthForChildren: Single;
Public function EffectiveHeightForChildren: Single;
Public function CalculatedWidth: Cardinal; deprecated 'use EffectiveWidth';
Public function CalculatedHeight: Cardinal; deprecated 'use EffectiveHeight';
Public function CalculatedRect: TRectangle; deprecated 'use EffectiveRect';
Public function RenderRect: TFloatRectangle;
Public function RenderRectWithBorder: TFloatRectangle;
Public function ScreenRect: TRectangle; deprecated 'use RenderRect';
Public function ContainerToLocalPosition(ContainerPosition: TVector2; const ContainerPositionScaled: Boolean = true): TVector2;
Public function LocalToContainerPosition(const LocalPosition: TVector2; const ContainerPositionScaled: Boolean = true): TVector2;
Public function ParentRect: TFloatRectangle;
Public procedure Anchor(const AHorizontalAnchor: THorizontalPosition; const TranslationX: Single = 0); overload;
Public procedure Anchor( const AHorizontalAnchorSelf, AHorizontalAnchorParent: THorizontalPosition; const TranslationX: Single = 0); overload;
Public procedure Anchor(const AVerticalAnchor: TVerticalPosition; const TranslationY: Single = 0); overload;
Public procedure Anchor( const AVerticalAnchorSelf, AVerticalAnchorParent: TVerticalPosition; const TranslationY: Single = 0); overload;
Public procedure AlignHorizontal( const ControlPosition: TPositionRelative = prMiddle; const ContainerPosition: TPositionRelative = prMiddle; const X: Single = 0); deprecated 'use Anchor';
Public procedure Align( const ControlPosition: THorizontalPosition; const ContainerPosition: THorizontalPosition; const X: Single = 0); overload; deprecated 'use Anchor';
Public procedure AlignVertical( const ControlPosition: TPositionRelative = prMiddle; const ContainerPosition: TPositionRelative = prMiddle; const Y: Single = 0); deprecated 'use Anchor';
Public procedure Align( const ControlPosition: TVerticalPosition; const ContainerPosition: TVerticalPosition; const Y: Single = 0); overload; deprecated 'use Anchor';
Public procedure Center; deprecated 'use Anchor(hpMiddle); Anchor(vpMiddle); to reliably center the control';
Public function UIScale: Single; virtual;
Public procedure EditorAllowResize(out ResizeWidth, ResizeHeight: Boolean; out Reason: String); virtual;

Properties

Public property OnVisibleChange: TCastleUserInterfaceChangeEvent read FOnVisibleChange write FOnVisibleChange;
Public property Container: TCastleContainer read FContainer;
Public property OnCursorChange: TNotifyEvent read FOnCursorChange write FOnCursorChange; deprecated 'use OnVisibleChange (or override VisibleChange) and watch for Changes that include chCursor';
Public property ExclusiveEvents: boolean read FExclusiveEvents write FExclusiveEvents default true;
Public property Controls [const Index: Integer]: TCastleUserInterface read GetControls write SetControls;
Public property GetExists: Boolean read FExists; deprecated 'use Exists';
Public property GLInitialized: boolean read FGLInitialized default false;
Public property Focused: boolean read FFocused write SetFocused;
Public property Parent: TCastleUserInterface read FParent;
Public property FloatWidth: Single read FWidth write SetWidth stored false; deprecated 'use Width';
Public property FloatHeight: Single read FHeight write SetHeight stored false; deprecated 'use Height';
Public property AnchorDelta: TVector2 read FTranslation write SetTranslation; deprecated 'use Translation';
Public property Translation: TVector2 read FTranslation write SetTranslation;
Public property KeepInFront: boolean read FKeepInFront write FKeepInFront default false;
Public property BorderColor: TCastleColor read FBorderColor write SetBorderColor;
Public property HasHorizontalAnchor: boolean read FHasHorizontalAnchor write FHasHorizontalAnchor stored false; deprecated 'this property does not do anything anymore, anchors are always active';
Public property HasVerticalAnchor: boolean read FHasVerticalAnchor write FHasVerticalAnchor stored false; deprecated 'this property does not do anything anymore, anchors are always active';
Public property HorizontalAnchorDelta: Single read GetHorizontalAnchorDelta write SetHorizontalAnchorDelta default 0; deprecated 'use Translation.X';
Public property VerticalAnchorDelta: Single read GetVerticalAnchorDelta write SetVerticalAnchorDelta default 0; deprecated 'use Translation.Y';
Public property Visible: Boolean read FVisible;
Public property EnableUIScaling: boolean read FEnableUIScaling write SetEnableUIScaling default true;
Public property CapturesEvents: boolean read FCapturesEvents write FCapturesEvents default true;
Public property OnInternalMouseEnter: TUiNotifyEvent read FOnInternalMouseEnter write FOnInternalMouseEnter;
Public property OnInternalMouseLeave: TUiNotifyEvent read FOnInternalMouseLeave write FOnInternalMouseLeave;
Published property Cursor: TMouseCursor read FCursor write SetCursor default mcDefault;
Published property OnUpdate: TUiUpdateEvent read FOnUpdate write FOnUpdate;
Published property OnPress: TUiPressReleaseEvent read FOnPress write FOnPress;
Published property OnRelease: TUiPressReleaseEvent read FOnRelease write FOnRelease;
Published property OnMotion: TUiMotionEvent read FOnMotion write FOnMotion;
Published property OnRender: TUiNotifyEvent read FOnRender write FOnRender;
Published property Exists: boolean read FExists write SetExists default true;
Published property Left: Single read FLeft write SetLeft stored false default 0; deprecated 'use Translation.X';
Published property Bottom: Single read FBottom write SetBottom default 0; deprecated 'use Translation.Y';
Published property FullSize: boolean read FFullSize write SetFullSize default false;
Published property Width: Single read FWidth write SetWidth default DefaultWidth;
Published property Height: Single read FHeight write SetHeight default DefaultHeight;
Published property WidthFraction: Single read FWidthFraction write SetWidthFraction default 0.0;
Published property HeightFraction: Single read FHeightFraction write SetHeightFraction default 0.0;
Published property AutoSizeToChildren: Boolean read FAutoSizeToChildren write SetAutoSizeToChildren default false;
Published property AutoSizeToChildrenPaddingRight: Single read FAutoSizeToChildrenPaddingRight write SetAutoSizeToChildrenPaddingRight default 0;
Published property AutoSizeToChildrenPaddingTop: Single read FAutoSizeToChildrenPaddingTop write SetAutoSizeToChildrenPaddingTop default 0;
Published property HorizontalAnchorSelf: THorizontalPosition read FHorizontalAnchorSelf write SetHorizontalAnchorSelf default hpLeft;
Published property HorizontalAnchorParent: THorizontalPosition read FHorizontalAnchorParent write SetHorizontalAnchorParent default hpLeft;
Published property VerticalAnchorSelf: TVerticalPosition read FVerticalAnchorSelf write SetVerticalAnchorSelf default vpBottom;
Published property VerticalAnchorParent: TVerticalPosition read FVerticalAnchorParent write SetVerticalAnchorParent default vpBottom;
Published property Culling: Boolean read FCulling write SetCulling default false;
Published property ClipChildren: Boolean read FClipChildren write SetClipChildren default false;
Published property Border: TBorder read FBorder;
Published property CustomTheme: TCastleTheme read FCustomTheme write SetCustomTheme;
Published property TooltipControl: TCastleUserInterface read FTooltipControl write SetTooltipControl;
Published property BorderColorPersistent: TCastleColorPersistent read FBorderColorPersistent ;
Published property TranslationPersistent: TCastleVector2Persistent read FTranslationPersistent ;

Description

Fields

Public nested const DefaultWidth = 100.0;

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Public nested const DefaultHeight = 100.0;

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Methods

Protected procedure Loaded; override;

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Protected function ContainerWidth: Cardinal; virtual;

Container sizes.

Protected function ContainerHeight: Cardinal; virtual;

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Protected function ContainerRect: TRectangle; virtual;

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Protected function ContainerSizeKnown: boolean; virtual;

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Protected procedure DoCursorChange; virtual; deprecated 'better override VisibleChange and watch for chCursor in Changes';

Warning: this symbol is deprecated: better override VisibleChange and watch for chCursor in Changes

Called when Cursor changed. In TCastleUserInterface class, just calls OnCursorChange.

Protected procedure DefineProperties(Filer: TFiler); override;

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Protected procedure UIScaleChanged; virtual;

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Protected procedure PreferredSize(var PreferredWidth, PreferredHeight: Single); virtual;

Controls that have a preferred size should override this. By default this contains values derived from Width, WidthFraction, Height, HeightFraction, with Border subtracted.

Note that the arguments should be already scaled, i.e. multiplied by UIScale, i.e. expressed in final device pixels.

Note that the returned PreferredWidth and PreferredHeight must not include the space for Border. Border size will be added later.

Protected procedure BeforeSizing; virtual;

Called right before calculating size. This is your only chance to adjust e.g. children size, if you need them to be synchronized with something, and you may use AutoSizeToChildren.

In most use-cases, you rather adjust preferred size by overriding PreferredSize.

Protected procedure DoInternalMouseEnter; virtual;

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Protected procedure DoInternalMouseLeave; virtual;

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Protected function Theme: TCastleTheme;

Theme that should be used by this control. Either CustomTheme or global Theme.

Public constructor Create(AOwner: TComponent); override;

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Public destructor Destroy; override;

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Public procedure CustomSerialization(const SerializationProcess: TSerializationProcess); override;

This item has no description. Showing description inherited from TCastleComponent.CustomSerialization.

Override this method to call various methods of SerializationProcess, which in turn allows to serialize/deserialize things that are not published. This allows to serialize/deserialize with more freedom, e.g. to serialize/deserialize some private field.

Public function PropertySections(const PropertyName: String): TPropertySections; override;

This item has no description. Showing description inherited from TCastleComponent.PropertySections.

Section where to show property in the editor.

Public function GetEnumerator: TEnumerator;

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Public procedure InternalSetContainer(const Value: TCastleContainer); virtual;

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Public function Press(const Event: TInputPressRelease): boolean; virtual;

Handle press or release of a key, mouse button or mouse wheel. Return True if the event was somehow handled, which prevents from passing this event to other UI controls.

When implementing in descendants it is best to override it like this:

function TMyControl.Press(const Event: TInputPressRelease): boolean;
begin
  Result := inherited;
  if Result then Exit; // exit if ancestor already handled event

  if Event.IsKey(keyEnter) then
  begin
    // do something in reaction on Enter
    Exit(ExclusiveEvents); // ExclusiveEvents is true by default
  end;

  if Event.IsMouseButton(buttonLeft) then
  begin
    // do something in reaction on Enter
    Exit(ExclusiveEvents); // ExclusiveEvents is true by default
  end;
end;

Note that releasing of the mouse wheel is not reported now by any backend. Only releasing of keys and mouse buttons is reported.

The events PreviewPress and PreviewRelease are passed first to the parent control, before children have a chance to process this event. Overriding them makes sense if you draw something in TCastleUserInterface.RenderOverChildren.

The events Press and Release are passed to the parent only after the children had a chance to process this event. Overriding them makes sense if you draw something in TCastleUserInterface.Render. This is usually more natural, and adviced.

Public function Release(const Event: TInputPressRelease): boolean; virtual;

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Public function PreviewPress(const Event: TInputPressRelease): boolean; virtual;

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Public function PreviewRelease(const Event: TInputPressRelease): boolean; virtual;

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Public function Motion(const Event: TInputMotion): boolean; virtual;

Motion of mouse or touch.

Public function SensorRotation(const X, Y, Z, Angle: Double; const SecondsPassed: Single): boolean; virtual;

Rotation detected by 3D sensor. Used for example by 3Dconnexion devices.

Parameters
X
X axis (tilt forward/backwards)
Y
Y axis (rotate)
Z
Z axis (tilt sidewards)
Angle
Angle of rotation (in radians)
SecondsPassed
The time passed since last SensorRotation call. This is necessary because some sensors, e.g. 3Dconnexion, may *not* reported as often as normal Update calls.
Public function SensorTranslation(const X, Y, Z, Length: Double; const SecondsPassed: Single): boolean; virtual;

Translation detected by 3D sensor. Used for example by 3Dconnexion devices.

Parameters
X
X axis (move left/right)
Y
Y axis (move up/down)
Z
Z axis (move forward/backwards)
Length
Length of the vector consisting of the above
SecondsPassed
The time passed since last SensorRotation call. This is necessary because some sensors, e.g. 3Dconnexion, may *not* reported as often as normal Update calls.
Public function JoyAxisMove(const JoyID, Axis: Byte): boolean; virtual; deprecated 'use event Joysticks.OnAxisMove, or just observe Joysticks[0].Axis';

Warning: this symbol is deprecated: use event Joysticks.OnAxisMove, or just observe Joysticks[0].Axis

Axis movement detected by joystick.

Parameters
JoyID
ID of joystick with pressed button
Axis
Number of moved axis
Public function JoyButtonPress(const JoyID, Button: Byte): boolean; virtual; deprecated 'use Joysticks.OnButtonDown or Joysticks.OnButtonPress';

Warning: this symbol is deprecated: use Joysticks.OnButtonDown or Joysticks.OnButtonPress

Joystick button pressed.

Parameters
JoyID
ID of joystick with pressed button
Button
Number of pressed button
Public procedure Update(const SecondsPassed: Single; var HandleInput: boolean); virtual;

Control may do here anything that must be continuously repeated. E.g. camera handles here falling down due to gravity, rotating model in Examine mode, and many more.

This method may be used, among many other things, to continuously react to the fact that user pressed some key (or mouse button). For example, if holding some key should move some 3D object, you should do something like:

if HandleInput then
begin
  if Container.Pressed[keyArrowRight] then
    Transform.Position := Transform.Position + Vector3(SecondsPassed * 10, 0, 0);
  HandleInput := not ExclusiveEvents;
end;

Instead of directly using a key code, consider also using TInputShortcut that makes the input key nicely configurable. See engine tutorial about handling inputs.

Multiplying movement by SecondsPassed makes your operation frame-rate independent. Object will move by 10 units in a second, regardless of how many FPS your game has.

The code related to HandleInput is important if you write a generally-useful control that should nicely cooperate with all other controls, even when placed on top of them or under them. The correct approach is to only look at pressed keys/mouse buttons if HandleInput is True. Moreover, if you did check that HandleInput is True, and you did actually handle some keys, then you have to set HandleInput := not ExclusiveEvents. As ExclusiveEvents is True in normal circumstances, this will prevent the other controls (behind the current control) from handling the keys (they will get HandleInput = False). And this is important to avoid doubly-processing the same key press, e.g. if two controls react to the same key, only the one on top should process it.

Note that to handle a single press / release (like "switch light on when pressing a key") you should rather use Press and Release methods. Use this method only for continuous handling (like "holding this key makes the light brighter and brighter").

To understand why such HandleInput approach is needed, realize that the "Update" events are called differently than simple mouse and key events like "Press" and "Release". "Press" and "Release" events return whether the event was somehow "handled", and the container passes them only to the controls under the mouse (decided by TCastleUserInterface.CapturesEventsAtPosition). And as soon as some control says it "handled" the event, other controls (even if under the mouse) will not receive the event.

This approach is not suitable for Update events. Some controls need to do the Update job all the time, regardless of whether the control is under the mouse and regardless of what other controls already did. So all controls (well, all controls that exist, in case of TCastleUserInterface, see TCastleUserInterface.Exists) receive Update calls.

So the "handled" status is passed through HandleInput. If a control is not under the mouse, it will receive HandleInput = False. If a control is under the mouse, it will receive HandleInput = True as long as no other control on top of it didn't already change it to False.

Parameters
SecondsPassed
Should be calculated like TFramesPerSecond.SecondsPassed, and usually it's in fact just taken from TCastleWindow.Fps.SecondsPassed.
Public procedure VisibleChange(const Changes: TCastleUserInterfaceChanges; const ChangeInitiatedByChildren: boolean = false); overload; virtual;

Called always when something important inside this control (or it's children) changed. To be more precise, this is called when something mentioned among the TCastleUserInterfaceChange enumerated items changed.

This is always called with Changes <> [] (non-empty set).

Public function AllowSuspendForInput: boolean; virtual;

Allow window containing this control to suspend waiting for user input. Typically you want to override this to return False when you do something in the overridden Update method.

In this class, this simply returns always True.

See also
TCastleWindow.AllowSuspendForInput
Is it allowed to suspend (for an indefinite amount of time) waiting for user input.
Public procedure Resize; virtual;

Event called when the container (component or window with OpenGL context) size changes.

You can resize/reposition your component here, for example set TCastleUserInterface.Left or TCastleUserInterface.Bottom, to react to parent size changes. This is called only when the OpenGL context of the container is initialized, so you can be sure that this is called only between GLContextOpen and GLContextClose.

We also call this once when inserting into the controls list (like TCastleWindow.Controls or TCastleControl.Controls or inside parent TCastleUserInterface), if inserting into the container/parent with already initialized OpenGL context. If inserting into the container/parent without OpenGL context initialized, it will be called later, when OpenGL context will get initialized, right after GLContextOpen.

In other words, this is always called to let the control know the size of the container, if and only if the OpenGL context is initialized.

Public procedure ContainerResize(const AContainerWidth, AContainerHeight: Cardinal); virtual; deprecated 'use Resize';

Warning: this symbol is deprecated: use Resize

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Public function ControlsCount: Integer;

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Public procedure InsertFront(const NewItem: TCastleUserInterface); overload;

Add child control, at the front of other children.

Public procedure InsertFrontIfNotExists(const NewItem: TCastleUserInterface);

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Public procedure InsertFront(const NewItems: TCastleUserInterfaceList); overload;

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Public procedure InsertBack(const NewItem: TCastleUserInterface); overload;

Add child control, at the back of other children.

Public procedure InsertBackIfNotExists(const NewItem: TCastleUserInterface);

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Public procedure InsertBack(const NewItems: TCastleUserInterfaceList); overload;

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Public procedure InsertControl(const Index: Integer; const NewItem: TCastleUserInterface);

Add child control at specified position. It is usually easier to use InsertFront or InsertBack, if possible.

Public procedure RemoveControl(const Item: TCastleUserInterface);

Remove control added by InsertFront or InsertBack.

Note that this method does not free the Item instance. This method merely removes Item from our controls, so that Item is no longer rendered as part of this parent. It is still the caller's responsibility to make sure the Item is freed at some point.

See https://castle-engine.io/modern_pascal_introduction.html#_freeing_classes for description how to free instances in Pascal. As TCastleUserInterface descends from TComponent, a simple and proper solution is often just to create it with some "owner" (like TUIState.FreeAtStop or Application) that will take care of freeing it.

Public function IndexOfControl(const Item: TCastleUserInterface): Integer;

Index of child control, or -1 if not present.

Public procedure ClearControls;

Remove all child controls added by InsertFront or InsertBack.

Note that, just like RemoveControl, this method does not free the children controls. This method merely removes children controls, so they are no longer rendered as part of the parent. It is still the caller's responsibility to make sure the children controls are freed at some point.

See https://castle-engine.io/modern_pascal_introduction.html#_freeing_classes for description how to free instances in Pascal. As TCastleUserInterface descends from TComponent, a simple and proper solution is often just to create it with some "owner" (like TUIState.FreeAtStop or Application) that will take care of freeing it.

Public function CapturesEventsAtPosition(const Position: TVector2): boolean; virtual;

Does this control capture events under this container position. The default implementation simply checks whether Position is inside RenderRect. It also checks whether CapturesEvents is True.

Always treated like False when Exists returns False, so the implementation of this method only needs to make checks assuming that Exists = True.

Public procedure BeforeRender; virtual;

Prepare your resources, right before drawing. Called only when Exists and GLInitialized.

Do not explicitly call this method. Instead, render controls by adding them to the TCastleContainer.Controls list, or render them explicitly (for off-screen rendering) by TCastleContainer.RenderControl.

Public procedure Render; virtual;

Render a control. Called only when Exists and GLInitialized, you can depend on it in the implementation of this method.

Do not explicitly call this method. Instead, render controls by adding them to the TCastleContainer.Controls list, or render them explicitly (for off-screen rendering) by TCastleContainer.RenderControl. This is method should only be overridden in your own code.

Before calling this method we always set some OpenGL state, and you can depend on it (and you can carelessly change it, as it will be reset again before rendering other control).

OpenGL state always set:

  • Viewport is set to include whole container.

  • Depth test is off.

  • (For fixed-function pipeline:) The 2D orthographic projection is always set at the beginning. Useful for 2D controls, 3D controls can just override projection matrix, e.g. use CastleRenderContext.PerspectiveProjection.

  • (For fixed-function pipeline:) The modelview matrix is set to identity. The matrix mode is always modelview.

  • (For fixed-function pipeline:) The raster position is set to (0,0). The (deprecated) WindowPos is also set to (0,0).

  • (For fixed-function pipeline:) Texturing, lighting, fog is off.

Beware that GLSL RenderContext.CurrentProgram has undefined value when this is called. You should always set it, before making direct OpenGL drawing calls (all the engine drawing routines of course do it already, this is only a concern if you make direct OpenGL / OpenGLES calls).

Public procedure RenderOverChildren; virtual;

Render a control contents over the children controls. This is analogous to Render, but it executes after children are drawn. You should usually prefer to override Render instead of this method, as the convention is that the parent is underneath children.

Public function TooltipExists: Boolean; virtual; deprecated 'use TooltipControl to customize tooltip look';

Warning: this symbol is deprecated: use TooltipControl to customize tooltip look

Render a tooltip of this control. If you want to have tooltip for this control detected, you have to override TooltipExists. Then the TooltipRender will be called.

TooltipRender is called in the same way as Render. TooltipRender is always called as a last (front-most) control. Argument TooltipPosition is the left-bottom (in screen space, regardless of UIScaling) suggested position of the tooltip.

It is simplest to descend from TCastleUserInterfaceFont, that implements simple TCastleUserInterfaceFont.Tooltip property and overrides these two methods as necessary.

Public procedure TooltipRender(const TooltipPosition: TVector2); virtual; deprecated 'use TooltipControl to customize tooltip look';

Warning: this symbol is deprecated: use TooltipControl to customize tooltip look

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Public procedure GLContextOpen; virtual;

Initialize your OpenGL resources.

This is called when OpenGL context of the container is created, or when the control is added to the already existing context. In other words, this is the moment when you can initialize OpenGL resources, like display lists, VBOs, OpenGL texture names, etc.

As an exception, this is called regardless of the Exists value. This way a control can prepare it's resources, regardless if it exists now.

Public procedure GLContextClose; virtual;

Destroy your OpenGL resources.

Called when OpenGL context of the container is destroyed. Also called when controls is removed from the container Controls list. Also called from the destructor.

You should release here any resources that are tied to the OpenGL context. In particular, the ones created in GLContextOpen.

As an exception, this is called regardless of the Exists value. This way a control can release it's resources, regardless if it exists now.

Public procedure SetFocused(const Value: boolean); virtual;

Called when this control becomes or stops being focused, that is: under the mouse cursor and will receive events.

This updates Focused property. This also calls OnInternalMouseEnter / OnInternalMouseLeave.

Public function EffectiveRect: TFloatRectangle;

Control position and size. Use this to base other controls size/position on this control's calculated size/position.

The algorithm that determines control position and size is like this:

The above describes the size of the content and border, summed. The content itself may be a little smaller, when the Border is used. The size of the "content itself" is returned only by RenderRect (in already-scaled coordinates, i.e. using final device pixels).

The anchors (see Anchor) also affect the final position of the control.

Note that some descendants do auto-sizing by default. This means that some of these properties may be ignored, and instead the calculated size (EffectiveWidth, EffectiveHeight) depends on some core values of the control.

For example:

Consult the documentation of each descendant for the exact specification of the size behavior.

This method returns the rectangle in local coordinates (relative to the parent 2D control). The returned rectangle size includes the border size. The returned rectangle size uses "unscaled" coordinates, which means that they correspond to the sizes you set e.g. in TCastleUserInterface.Width, TCastleUserInterface.Height, and translation units you use with e.g. TCastleUserInterface.Anchor.

If you're looking for a way to query the size of the control in final scaled coordinates (in real device pixels), and not relative to the parent position, use RenderRect or RenderRectWithBorder instead.

This method ignores the current value of the Exists method and Exists property, that is: the result of this function assumes that control does exist.

See also
TCastleUserInterface.EffectiveWidth
Calculated width of the control, without UI scaling.
TCastleUserInterface.EffectiveHeight
Calculated height of the control, without UI scaling.
Public function EffectiveWidth: Single;

Calculated width of the control, without UI scaling. Useful if you want to base other controls size/position on this control calculated size.

Unlike the Width property, this is the effective size, not the desired size. So this is already processed by any auto-sizing mechanism (e.g. TCastleImageControl may adjust it's own size to the underlying image, depending on settings), it is changed by FullSize and so on.

It is always equal to just EffectiveRect.Width. It is 0 when EffectiveRect is empty.

See also
EffectiveRect
Control position and size.
Public function EffectiveHeight: Single;

Calculated height of the control, without UI scaling. Useful if you want to base other controls size/position on this control calculated size.

Unlike the Height property, this is the effective size, not the desired size. So this is already processed by any auto-sizing mechanism (e.g. TCastleImageControl may adjust it's own size to the underlying image, depending on settings), it is changed by FullSize and so on.

It is always equal to just EffectiveRect.Height. It is 0 when EffectiveRect is empty.

See also
EffectiveRect
Control position and size.
Public function EffectiveWidthForChildren: Single;

EffectiveWidth without Border size.

Public function EffectiveHeightForChildren: Single;

EffectiveHeight without Border size.

Public function CalculatedWidth: Cardinal; deprecated 'use EffectiveWidth';

Warning: this symbol is deprecated: use EffectiveWidth

This item has no description.

Public function CalculatedHeight: Cardinal; deprecated 'use EffectiveHeight';

Warning: this symbol is deprecated: use EffectiveHeight

This item has no description.

Public function CalculatedRect: TRectangle; deprecated 'use EffectiveRect';

Warning: this symbol is deprecated: use EffectiveRect

This item has no description.

Public function RenderRect: TFloatRectangle;

Position and size of this control, assuming it exists, in container coordinates (in final device pixels). The primary use of this is inside Render. A proper UI control should adjust to draw precisely in this rectangle.

Public function RenderRectWithBorder: TFloatRectangle;

This item has no description.

Public function ScreenRect: TRectangle; deprecated 'use RenderRect';

Warning: this symbol is deprecated: use RenderRect

This item has no description.

Public function ContainerToLocalPosition(ContainerPosition: TVector2; const ContainerPositionScaled: Boolean = true): TVector2;

Convert position relative to container (in final device coordinates, without UI scaling, by default) into position relative to this UI control (in coordinates with UI scaling). Useful e.g. to convert mouse/touch position from TInputPressRelease.Position into position useful for children of this UI control.

The exact definition is that using the result of this to set our child AnchorDelta, assuming the child is anchored to the left-bottom (the default state) and child has Left = Bottom = 0, sets child position exactly to the indicated point on the container.

Parameters
ContainerPositionScaled
If True (default) then the container position (the ContainerPosition parameter) is assumed to be in final device pixels, i.e. the window area in X is from 0 to TCastleContainer.Width, in Y from 0 and TCastleContainer.Height. This is useful when the parameter comes e.g. from TInputPressRelease.Position.

If False then the container position (the ContainerPosition parameter) is assumed to be in unscaled device pixels, i.e. the window area in X is from 0 to TCastleContainer.UnscaledWidth, in Y from 0 and TCastleContainer.UnscaledHeight.

Public function LocalToContainerPosition(const LocalPosition: TVector2; const ContainerPositionScaled: Boolean = true): TVector2;

Convert position relative to this UI control (in coordinates with UI scaling) into relative to container (in final device coordinates, without UI scaling, by default). Reverses ContainerToLocalPosition.

Parameters
ContainerPositionScaled
If True (default) then the container position (the result of this method) is assumed to be in final device pixels, i.e. the window area in X is from 0 to TCastleContainer.Width, in Y from 0 and TCastleContainer.Height.

If False then the container position (the result of this method) is assumed to be in unscaled device pixels, i.e. the window area in X is from 0 to TCastleContainer.UnscaledWidth, in Y from 0 and TCastleContainer.UnscaledHeight.

Public function ParentRect: TFloatRectangle;

Rectangle filling the parent control (or container), in local coordinates. Since this is in local coordinates, the returned rectangle Left and Bottom are always zero, unless parent has Border (the returned rectangle is shrunk by Parent.Border). This is already scaled by UI scaling.

Public procedure Anchor(const AHorizontalAnchor: THorizontalPosition; const TranslationX: Single = 0); overload;

Adjust position to align us with the parent horizontally. The resulting EffectiveRect and RenderRect and RenderRectWithBorder will immediately reflect the new position.

Note that position set here (anchors, Translation) are ignored when FullSize is set to true. In case of FullSize, the control fills the parent perfectly.

This utility method sets HorizontalAnchorSelf, HorizontalAnchorParent, Translation.X.

Public procedure Anchor( const AHorizontalAnchorSelf, AHorizontalAnchorParent: THorizontalPosition; const TranslationX: Single = 0); overload;

Adjust position to align us with the parent horizontally. The resulting EffectiveRect and RenderRect and RenderRectWithBorder will immediately reflect the new position.

Note that position set here (anchors, Translation) are ignored when FullSize is set to true. In case of FullSize, the control fills the parent perfectly.

This utility method sets HorizontalAnchorSelf, HorizontalAnchorParent, Translation.X.

Public procedure Anchor(const AVerticalAnchor: TVerticalPosition; const TranslationY: Single = 0); overload;

Adjust position to align us to the parent vertically. The resulting EffectiveRect and RenderRect and RenderRectWithBorder will immediately reflect the new position.

Note that position set here (anchors, Translation) are ignored when FullSize is set to true. In case of FullSize, the control fills the parent perfectly.

This utility method sets VerticalAnchorSelf, VerticalAnchorParent, Translation.Y.

Public procedure Anchor( const AVerticalAnchorSelf, AVerticalAnchorParent: TVerticalPosition; const TranslationY: Single = 0); overload;

Adjust position to align us to the parent vertically. The resulting EffectiveRect and RenderRect and RenderRectWithBorder will immediately reflect the new position.

Note that position set here (anchors, Translation) are ignored when FullSize is set to true. In case of FullSize, the control fills the parent perfectly.

This utility method sets VerticalAnchorSelf, VerticalAnchorParent, Translation.Y.

Public procedure AlignHorizontal( const ControlPosition: TPositionRelative = prMiddle; const ContainerPosition: TPositionRelative = prMiddle; const X: Single = 0); deprecated 'use Anchor';

Warning: this symbol is deprecated: use Anchor

Immediately position the control with respect to the parent by adjusting Left. Deprecated, use Align with THorizontalPosition.

Public procedure Align( const ControlPosition: THorizontalPosition; const ContainerPosition: THorizontalPosition; const X: Single = 0); overload; deprecated 'use Anchor';

Warning: this symbol is deprecated: use Anchor

Immediately position the control with respect to the parent by adjusting Left.

Note that using Anchor is often more comfortable than this method, since you only need to set anchor once (for example, right after creating the control). In contract, adjusting position using this method will typically need to be repeated at each window on resize, like in TCastleWindow.OnResize.

Public procedure AlignVertical( const ControlPosition: TPositionRelative = prMiddle; const ContainerPosition: TPositionRelative = prMiddle; const Y: Single = 0); deprecated 'use Anchor';

Warning: this symbol is deprecated: use Anchor

Immediately position the control with respect to the parent by adjusting Bottom. Deprecated, use Align with TVerticalPosition.

Public procedure Align( const ControlPosition: TVerticalPosition; const ContainerPosition: TVerticalPosition; const Y: Single = 0); overload; deprecated 'use Anchor';

Warning: this symbol is deprecated: use Anchor

Immediately position the control with respect to the parent by adjusting Bottom.

Note that using Anchor is often more comfortable than this method, since you only need to set anchor once (for example, right after creating the control). In contract, adjusting position using this method will typically need to be repeated at each window on resize, like in TCastleWindow.OnResize.

Public procedure Center; deprecated 'use Anchor(hpMiddle); Anchor(vpMiddle); to reliably center the control';

Warning: this symbol is deprecated: use Anchor(hpMiddle); Anchor(vpMiddle); to reliably center the control

Immediately center the control within the parent, both horizontally and vertically.

Note that using Anchor is often more comfortable than this method, since you only need to set anchor once. For example, right after creating the control call Anchor(hpMiddle); Anchor(vpMiddle);. In contrast, adjusting position using this method will typically need to be repeated at each window on resize, like in TCastleWindow.OnResize.

Public function UIScale: Single; virtual;

UI scale of this control, derived from container (see TCastleContainer.UIScaling and EnableUIScaling).

Public procedure EditorAllowResize(out ResizeWidth, ResizeHeight: Boolean; out Reason: String); virtual;

Override this to prevent resizing some dimension in CGE editor.

Properties

Public property OnVisibleChange: TCastleUserInterfaceChangeEvent read FOnVisibleChange write FOnVisibleChange;

Called always when something important inside this control (or it's children) changed. See VisibleChange for details about when and how this is called.

Be careful when handling this event. Various changes may cause this, so be prepared to handle it at any moment, even in the middle when UI control is changing. It may also occur very often. It's usually safest to only set a boolean flag like "something should be recalculated" when this event happens, and do the actual recalculation later.

Public property Container: TCastleContainer read FContainer;

Container of this control. When adding control to container's Controls list (like TCastleWindow.Controls) container will automatically set itself here, and when removing from container this will be changed back to Nil.

May be Nil if this control is not yet inserted into any container.

Public property OnCursorChange: TNotifyEvent read FOnCursorChange write FOnCursorChange; deprecated 'use OnVisibleChange (or override VisibleChange) and watch for Changes that include chCursor';

Warning: this symbol is deprecated: use OnVisibleChange (or override VisibleChange) and watch for Changes that include chCursor

Event called when the Cursor property changes. This event is, in normal circumstances, used by the Container, so you should not use it in your own programs.

Public property ExclusiveEvents: boolean read FExclusiveEvents write FExclusiveEvents default true;

Should we disable further mouse / keys handling for events that we already handled in this control. If True, then our events will return True for mouse and key events handled.

This means that events will not be simultaneously handled by both this control and some other (or camera or normal window callbacks), which is usually more sensible, but sometimes somewhat limiting.

Public property Controls [const Index: Integer]: TCastleUserInterface read GetControls write SetControls;

This item has no description.

Public property GetExists: Boolean read FExists; deprecated 'use Exists';

Warning: this symbol is deprecated: use Exists

This item has no description.

Public property GLInitialized: boolean read FGLInitialized default false;

This item has no description.

Public property Focused: boolean read FFocused write SetFocused;

See SetFocused.

Public property Parent: TCastleUserInterface read FParent;

Visual parent control. This control is rendered within the parent, and it's anchors and coordinates are relative to the parent. Parent may be Nil, which means that the Container (if set) is our direct parent.

Public property FloatWidth: Single read FWidth write SetWidth stored false; deprecated 'use Width';

Warning: this symbol is deprecated: use Width

This item has no description.

Public property FloatHeight: Single read FHeight write SetHeight stored false; deprecated 'use Height';

Warning: this symbol is deprecated: use Height

This item has no description.

Public property AnchorDelta: TVector2 read FTranslation write SetTranslation; deprecated 'use Translation';

Warning: this symbol is deprecated: use Translation

Position of the control, relative to the anchor at parent (by default, relative to left-bottom corner of the parent).

Public property Translation: TVector2 read FTranslation write SetTranslation;

Position of the control, relative to the anchor at parent (by default, relative to left-bottom corner of the parent).

Public property KeepInFront: boolean read FKeepInFront write FKeepInFront default false;

Keep the control in front of other controls (with KeepInFront=False) when inserting.

TODO: Do not change this property while the control is already a child of something.

Public property BorderColor: TCastleColor read FBorderColor write SetBorderColor;

Color of the Border, by default completely transparent black.

Public property HasHorizontalAnchor: boolean read FHasHorizontalAnchor write FHasHorizontalAnchor stored false; deprecated 'this property does not do anything anymore, anchors are always active';

Warning: this symbol is deprecated: this property does not do anything anymore, anchors are always active

This item has no description.

Public property HasVerticalAnchor: boolean read FHasVerticalAnchor write FHasVerticalAnchor stored false; deprecated 'this property does not do anything anymore, anchors are always active';

Warning: this symbol is deprecated: this property does not do anything anymore, anchors are always active

This item has no description.

Public property HorizontalAnchorDelta: Single read GetHorizontalAnchorDelta write SetHorizontalAnchorDelta default 0; deprecated 'use Translation.X';

Warning: this symbol is deprecated: use Translation.X

Delta between our border and parent.

See also
Anchor
Adjust position to align us to the parent vertically.
Public property VerticalAnchorDelta: Single read GetVerticalAnchorDelta write SetVerticalAnchorDelta default 0; deprecated 'use Translation.Y';

Warning: this symbol is deprecated: use Translation.Y

Delta between our border and parent.

See also
Anchor
Adjust position to align us to the parent vertically.
Public property Visible: Boolean read FVisible;

Is the control possibly visible. This is always True when Culling is False (the default).

Public property EnableUIScaling: boolean read FEnableUIScaling write SetEnableUIScaling default true;

Enable or disable UI scaling for this particular control. See more about UI scaling on TCastleContainer.UIScaling and TCastleUserInterface.UIScale. Setting this to False forces TCastleUserInterface.UIScale to always return 1.0.

Note that this does not work recursively, i.e. it does not affect the children of this control. Setting this to False does not prevent UI scaling on children (you have to turn it off explicitly for children too, if you need to disable UI scaling recursively).

The use-cases for changing this property to "false" are very rare. Usually you should use UI scaling for 100% of your UI.

Public property CapturesEvents: boolean read FCapturesEvents write FCapturesEvents default true;

Capture input events (keyboard, mouse, joystick). If False, then the methods like Press and Release will never be called, and Update will always be called with HandleInput = False. The control will never behave like focused.

The only exception is when this control is set as TCastleContainer.ForceCaptureInput. In this case, the control will receive inputs. In other words, TCastleContainer.ForceCaptureInput overrides the intent of this property.

This property may be replaced by something like "CaptureInput" or just universal "Enabled" in the future.

Public property OnInternalMouseEnter: TUiNotifyEvent read FOnInternalMouseEnter write FOnInternalMouseEnter;

Called when control starts being under the mouse cursor and will receive events. See SetFocused, this is called when Focused changes from False to True.

This is called "Internal" now, because we do not guarantee it's 100% always paired with OnInternalMouseLeave. A different approach to this may be done in the future releases.

Public property OnInternalMouseLeave: TUiNotifyEvent read FOnInternalMouseLeave write FOnInternalMouseLeave;

Called when control stops being under the mouse cursor and will receive events. See SetFocused, this is called when Focused changes from True to False.

This is called "Internal" now, because we do not guarantee it's 100% always paired with OnInternalMouseEnter. A different approach to this may be done in the future releases.

Published property Cursor: TMouseCursor read FCursor write SetCursor default mcDefault;

Mouse cursor over this control. When user moves mouse over the Container, the currently focused (topmost under the cursor) control determines the mouse cursor look.

Published property OnUpdate: TUiUpdateEvent read FOnUpdate write FOnUpdate;

Event that occurs continuously on each control. See Update for details.

Published property OnPress: TUiPressReleaseEvent read FOnPress write FOnPress;

An input (key, mouse button, mouse wheel) was pressed. See Press for details.

Published property OnRelease: TUiPressReleaseEvent read FOnRelease write FOnRelease;

An input (key, mouse button, mouse wheel) was released. See Release for details.

Published property OnMotion: TUiMotionEvent read FOnMotion write FOnMotion;

Pointer (mouse or finger) moved. See Motion for details.

Published property OnRender: TUiNotifyEvent read FOnRender write FOnRender;

Control is being displayed. See Render for details. This event it called after the Render method of this control finished.

Published property Exists: boolean read FExists write SetExists default true;

Not existing control is not visible, it doesn't receive input and generally doesn't exist from the point of view of user. This is mostly equivalent to just removing this control from parent list.

Non-existing controls still receive GLContextOpen, GLContextClose, Resize events.

Published property Left: Single read FLeft write SetLeft stored false default 0; deprecated 'use Translation.X';

Warning: this symbol is deprecated: use Translation.X

Position from the left side of the parent control.

It's usually better to use anchors instead of this property. For example, instead of setting Control.Left := 10, you can call Control.Anchor(hpLeft, 10), or just change Translation.X.

Note that the effects of this property and Translation.X are summed, if you set both. We advise to leave Left as zero and just use anchors in new code.

Published property Bottom: Single read FBottom write SetBottom default 0; deprecated 'use Translation.Y';

Warning: this symbol is deprecated: use Translation.Y

Position from the bottom side of the parent control.

It's usually better to use anchors instead of this property. For example, instead of setting Control.Bottom := 10, you can call Control.Anchor(vpBottom, 10), or just change Translation.Y.

Note that the effects of this property and Translation.Y are summed, if you set both. We advise to leave Bottom as zero and just use anchors in new code.

Published property FullSize: boolean read FFullSize write SetFullSize default false;

When FullSize, the control will always fill the whole parent area.

See also
TCastleUserInterface.EffectiveRect
Control position and size.
TCastleUserInterface.EffectiveWidth
Calculated width of the control, without UI scaling.
TCastleUserInterface.EffectiveHeight
Calculated height of the control, without UI scaling.
Published property Width: Single read FWidth write SetWidth default DefaultWidth;

These properties determine the control size. See the EffectiveRect documentation for details how the size is calculated.

See also
TCastleUserInterface.EffectiveRect
Control position and size.
TCastleUserInterface.EffectiveWidth
Calculated width of the control, without UI scaling.
TCastleUserInterface.EffectiveHeight
Calculated height of the control, without UI scaling.
Published property Height: Single read FHeight write SetHeight default DefaultHeight;

This item has no description.

Published property WidthFraction: Single read FWidthFraction write SetWidthFraction default 0.0;

This item has no description.

Published property HeightFraction: Single read FHeightFraction write SetHeightFraction default 0.0;

This item has no description.

Published property AutoSizeToChildren: Boolean read FAutoSizeToChildren write SetAutoSizeToChildren default false;

Adjust size to encompass all the children. The properties FullSize, Width, Height are ignored in this case. Our Left and Bottom still matter.

Our size is adjusted to all existing children sizes and positions.

We add AutoSizeToChildrenPaddingTop to the resulting height, and AutoSizeToChildrenPaddingRight to the resulting width.

Published property AutoSizeToChildrenPaddingRight: Single read FAutoSizeToChildrenPaddingRight write SetAutoSizeToChildrenPaddingRight default 0;

Padding added when AutoSizeToChildren is used. TODO: Should be AutoSizeToChildrenPaddingHorizontal, there's nothing that makes it specific to "right" or "left" side now.

Published property AutoSizeToChildrenPaddingTop: Single read FAutoSizeToChildrenPaddingTop write SetAutoSizeToChildrenPaddingTop default 0;

Padding added when AutoSizeToChildren is used. TODO: Should be AutoSizeToChildrenPaddingVertical, there's nothing that makes it specific to "top" or "bottom" side now.

Published property HorizontalAnchorSelf: THorizontalPosition read FHorizontalAnchorSelf write SetHorizontalAnchorSelf default hpLeft;

Which our border to align with parent.

See also
Anchor
Adjust position to align us to the parent vertically.
Published property HorizontalAnchorParent: THorizontalPosition read FHorizontalAnchorParent write SetHorizontalAnchorParent default hpLeft;

Which parent border is aligned to our HorizontalAnchorSelf border.

See also
Anchor
Adjust position to align us to the parent vertically.
Published property VerticalAnchorSelf: TVerticalPosition read FVerticalAnchorSelf write SetVerticalAnchorSelf default vpBottom;

Which our border to align with parent.

See also
Anchor
Adjust position to align us to the parent vertically.
Published property VerticalAnchorParent: TVerticalPosition read FVerticalAnchorParent write SetVerticalAnchorParent default vpBottom;

Which parent border is aligned to our VerticalAnchorSelf border.

See also
Anchor
Adjust position to align us to the parent vertically.
Published property Culling: Boolean read FCulling write SetCulling default false;

Optimize rendering and event processing by checking whether the control can be visible. The visibility is checked by looking at container rectangle, and all possible clipping parents (set by TCastleScrollView, or any other control with ClipChildren).

This is useful for UI controls that have expensive rendering or other events (e.g. they do something non-trivial in Render or RenderOverChildren, or they include a lot of children controls). And they may be placed off-screen, or they may be outside of a parent with clipping, which is often the case when the parent is TCastleScrollView.

Published property ClipChildren: Boolean read FClipChildren write SetClipChildren default false;

Clip the rendering of children.

By default this is False and so the control can draw outside of it's designated rectangle (RenderRect). Although all the standard UI controls are carefully implemented such that their Render and RenderOverChildren draw only within their RenderRect. But it is easy to place children controls outside of this rectangle.

When this property is True, the rendering is clipped, so the "overflowing" parts are never visible. This affects both Render and RenderOverChildren of this control, as well as all children rendering.

Published property Border: TBorder read FBorder;

Border (by default transparent) of the control. Border adds a space from the control content (drawn within RenderRect) to the control rectangle (returned by RenderRectWithBorder) (scaled), or EffectiveRect (unscaled) and friends).

It is transparent by default, but you can change it by BorderColor.

Border works always, regardless of FullSize or AutoSizeToChildren.

One obvious use-case is to use this for visual space (empty space or a colorful frame, separating this control from the rest).

Another use-case is to reserve a predictable space for as additional (sibling) control within the same parent. E.g. you can set FullSize=true and Border.Top=100, and this way there is always a strip with Height=100 at the top of the parent, where you can insert another control (with Height=100, anchored to the top).

Published property CustomTheme: TCastleTheme read FCustomTheme write SetCustomTheme;

Use a custom instance of TCastleTheme to determine the look of this control.

Published property TooltipControl: TCastleUserInterface read FTooltipControl write SetTooltipControl;

If set, the indicated control will act as a tooltip: we will make it existing when we should show the tooltip for this control, we will make it no longer existing when the tooltip for this should be hidden. Initially the TooltipControl should usually have Exists=false, because you usually do not want to show it until we start showing it as a tooltip.

If TooltipControl is assigned then TCastleUserInterfaceFont no longer does tooltip rendering. The Tooltip text is ignored.

The visual parent of TooltipControl can be whatever is comfortable. That is, it is OK to make TooltipControl parent of this control, and it is OK not to: you can as well place TooltipControl as e.g. parent of container or design root.

Published property BorderColorPersistent: TCastleColorPersistent read FBorderColorPersistent ;

BorderColor that can be visually edited in Castle Game Engine Editor, Lazarus and Delphi. Normal user code does not need to deal with this, instead read or write BorderColor directly.

See also
BorderColor
Color of the Border, by default completely transparent black.
Published property TranslationPersistent: TCastleVector2Persistent read FTranslationPersistent ;

Translation that can be visually edited in Castle Game Engine Editor, Lazarus and Delphi. Normal user code does not need to deal with this, instead read or write Translation directly.

See also
Translation
Position of the control, relative to the anchor at parent (by default, relative to left-bottom corner of the parent).

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