AlignmentGuide Class Reference

Manages alignment guides and snapping for widget movement. More...

#include <alignmentguide.h>

Classes
struct	AlignmentPoints
struct	GuideLine

Public Types
enum class	GuideType {   None , LeftEdge , RightEdge , HorizontalCenter ,   TopEdge , BottomEdge , VerticalCenter }

Public Member Functions
	AlignmentGuide (UMLScene *scene)
	~AlignmentGuide ()
QPointF	snapPosition (UMLWidget *widget, const QPointF &proposedPos)
void	snapResize (UMLWidget *widget, qreal proposedWidth, qreal proposedHeight, qreal &newWidth, qreal &newHeight)
QList< GuideLine >	activeGuides () const
void	clear ()
void	setSnapThreshold (qreal threshold)
qreal	snapThreshold () const
void	setEnabled (bool enabled)
bool	isEnabled () const

Private Member Functions
AlignmentPoints	getAlignmentPoints (UMLWidget *widget, const QPointF &pos) const
void	findBestSnap (qreal position, const QList< qreal > &candidates, qreal &minDistance, qreal &bestSnap, qreal &offset, GuideType &bestGuideType, GuideType guideType) const

Private Attributes
UMLScene *	m_scene
QList< GuideLine >	m_activeGuides
qreal	m_snapThreshold
bool	m_enabled

Detailed Description

Manages alignment guides and snapping for widget movement.

This class provides visual alignment guides and automatic snapping when dragging widgets near alignment points of other widgets.

Alignment points include:

• Horizontal guides: top edge, bottom edge, vertical center
• Vertical guides: left edge, right edge, horizontal center

Member Enumeration Documentation

GuideType

enum class AlignmentGuide::GuideType

strong

Types of alignment guides.

Enumerator
None
LeftEdge
RightEdge
HorizontalCenter
TopEdge
BottomEdge
VerticalCenter

Constructor & Destructor Documentation

AlignmentGuide()

AlignmentGuide::AlignmentGuide ( UMLScene *  scene )

explicit

~AlignmentGuide()

AlignmentGuide::~AlignmentGuide

(

)

Member Function Documentation

activeGuides()

QList< AlignmentGuide::GuideLine > AlignmentGuide::activeGuides

(

)

const

Get the list of active guide lines to render.

Returns

List of guide lines

Get the list of active guide lines.

clear()

void AlignmentGuide::clear

(

)

Clear all active guides.

findBestSnap()

void AlignmentGuide::findBestSnap ( qreal  position, const QList< qreal > &  candidates, qreal &  minDistance, qreal &  bestSnap, qreal &  offset, GuideType &  bestGuideType, GuideType  guideType  ) const

private

Find the best snap among candidates for a given position.

Parameters

position	The position to check
candidates	List of candidate alignment values
minDistance	In/out parameter for minimum distance found
bestSnap	Out parameter for the best snap position
offset	Out parameter for the offset to apply
bestGuideType	In/out parameter for tracking the best guide type
guideType	The guide type to set if this is the best match

Find the best snap among candidates for a given position.

getAlignmentPoints()

AlignmentGuide::AlignmentPoints AlignmentGuide::getAlignmentPoints ( UMLWidget *  widget, const QPointF &  pos  ) const

private

Calculate alignment points for a widget at a given position.

isEnabled()

bool AlignmentGuide::isEnabled

(

)

const

Check if alignment guides are enabled.

Returns

True if enabled

Check if alignment guides are enabled.

setEnabled()

void AlignmentGuide::setEnabled

(

bool

enabled

)

Enable or disable alignment guides.

Parameters

enabled

True to enable, false to disable

Enable or disable alignment guides.

setSnapThreshold()

void AlignmentGuide::setSnapThreshold

(

qreal

threshold

)

Set the snap threshold distance in pixels (screen coordinates).

Parameters

threshold

Distance within which snapping occurs

Set the snap threshold.

snapPosition()

QPointF AlignmentGuide::snapPosition	(	UMLWidget *	widget,
		const QPointF &	proposedPos
	)

Check for alignment opportunities and snap the position if near an alignment.

Parameters

widget	The widget being moved
proposedPos	The proposed new position

Returns

The snapped position (may be same as proposedPos if no snap)

Snap the proposed position to nearby alignment guides.

snapResize()

void AlignmentGuide::snapResize	(	UMLWidget *	widget,
		qreal	proposedWidth,
		qreal	proposedHeight,
		qreal &	newWidth,
		qreal &	newHeight
	)

Check for alignment opportunities and snap the size during resize.

Parameters

widget	The widget being resized
proposedWidth	The proposed new width
proposedHeight	The proposed new height
newWidth	Output parameter for snapped width
newHeight	Output parameter for snapped height

Snap the size during resize operations.

snapThreshold()

qreal AlignmentGuide::snapThreshold

(

)

const

Get the current snap threshold in scene coordinates. This is adjusted based on the current zoom level to maintain a consistent screen-space distance.

Returns

Snap threshold in scene coordinates

Get the snap threshold in scene coordinates. Adjusts for zoom level to maintain consistent screen-space distance.

Member Data Documentation

m_activeGuides

QList<GuideLine> AlignmentGuide::m_activeGuides

private

m_enabled

bool AlignmentGuide::m_enabled

private

m_scene

UMLScene* AlignmentGuide::m_scene

private

m_snapThreshold

qreal AlignmentGuide::m_snapThreshold

private

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The documentation for this class was generated from the following files:

• umbrello/umlwidgets/alignmentguide.h
• umbrello/umlwidgets/alignmentguide.cpp