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UnrealEngine/Engine/Source/Editor/UMGEditor/Private/Designer/SRuler.h
2025-05-18 13:04:45 +08:00

108 lines
3.6 KiB
C++

// Copyright Epic Games, Inc. All Rights Reserved.
#pragma once
#include "HAL/Platform.h"
#include "Input/Reply.h"
#include "Layout/Clipping.h"
#include "Math/Vector2D.h"
#include "Misc/Optional.h"
#include "Types/SlateEnums.h"
#include "Types/WidgetMouseEventsDelegate.h"
#include "Widgets/DeclarativeSyntaxSupport.h"
#include "Widgets/SCompoundWidget.h"
class FPaintArgs;
class FSlateRect;
class FSlateWindowElementList;
class FWidgetStyle;
struct FGeometry;
struct FPointerEvent;
class SRuler : public SCompoundWidget
{
public:
SLATE_BEGIN_ARGS(SRuler)
: _Orientation(Orient_Horizontal)
, _OnMouseButtonDown()
{
_Clipping = EWidgetClipping::ClipToBounds;
}
SLATE_ARGUMENT(EOrientation, Orientation)
SLATE_EVENT(FPointerEventHandler, OnMouseButtonDown)
SLATE_END_ARGS()
/**
* Construct the widget
*
* @param InArgs A declaration from which to construct the widget
*/
void Construct( const FArguments& InArgs );
/**
* Determines the optimal spacing between tick marks in the slider for a given pixel density
* Increments until a minimum amount of slate units specified by MinTick is reached
*
* @param InPixelsPerInput The density of pixels between each input
* @param MinTick The minimum slate units per tick allowed
* @param MinTickSpacing The minimum tick spacing in time units allowed
* @return the optimal spacing in time units
*/
float DetermineOptimalSpacing(float InPixelsPerInput, uint32 MinTick, float MinTickSpacing) const;
/**
* Sets the rules to use when rendering the ruler.
*
* @param AbsoluteOrigin The origin of the ruler in absolute window space.
* @param SlateToUnitScale The scaler applied to slate units to get the same number
* of units currently being displayed by the rule marks.
*/
void SetRuling(FVector2D AbsoluteOrigin, float SlateToUnitScale);
/**
* Sets the cursor position in window absolute space.
*
* @param AbsoluteCursor The position of the cursor in absolute window space.
*/
void SetCursor(TOptional<FVector2D> AbsoluteCursor);
protected:
// SWidget interface
virtual FVector2D ComputeDesiredSize(float) const override;
virtual int32 OnPaint( const FPaintArgs& Args, const FGeometry& AllottedGeometry, const FSlateRect& MyCullingRect, FSlateWindowElementList& OutDrawElements, int32 LayerId, const FWidgetStyle& InWidgetStyle, bool bParentEnabled ) const override;
virtual FReply OnMouseButtonDown( const FGeometry& MyGeometry, const FPointerEvent& MouseEvent ) override;
virtual FReply OnMouseButtonUp( const FGeometry& MyGeometry, const FPointerEvent& MouseEvent ) override;
virtual FReply OnMouseMove( const FGeometry& MyGeometry, const FPointerEvent& MouseEvent ) override;
virtual FReply OnMouseWheel( const FGeometry& MyGeometry, const FPointerEvent& MouseEvent ) override;
private:
// forward declared as class members to prevent name collision with similar types defined in other units
struct FDrawTickArgs;
struct FScrubRangeToScreen;
/** Draws the ticks on the track */
int32 DrawTicks(FSlateWindowElementList& OutDrawElements, const FScrubRangeToScreen& RangeToScreen, FDrawTickArgs& InArgs) const;
private:
/** The orientation of the ruler */
EOrientation Orientation;
/** The absolute origin of the document being measured. The 0 on the ruler will start here. */
FVector2D AbsoluteOrigin;
/** The absolute position of the cursor so that little lines can be drawn showing the cursors position on the ruler. */
TOptional<FVector2D> AbsoluteCursor;
/** The current conversion from Slate Pixel To Unit Size. */
float SlateToUnitScale;
/** The public event we expose when the mouse button is pressed onto the ruler. */
FPointerEventHandler MouseButtonDownHandler;
};