DiagramEventAddPath Class Reference

The DiagramEventAddPath class Pen tool: interactively draw a new Path (Bezier) shape, following the same vocabulary every vector editor's pen tool uses: More...

#include <diagrameventaddpath.h>

Inheritance diagram for DiagramEventAddPath:

Collaboration diagram for DiagramEventAddPath:

Public Member Functions
	DiagramEventAddPath (Diagram *diagram)
	DiagramEventAddPath::DiagramEventAddPath.
	~DiagramEventAddPath () override
void	mousePressEvent (QGraphicsSceneMouseEvent *event) override
	DiagramEventAddPath::mousePressEvent Left click: on the very first click, creates the shape with a real node and an immediate preview node at the same spot, so a segment exists (even if zero-length) from the start rather than requiring a second click before anything is visible. On later clicks: either confirms the live preview into a real point and appends a fresh one for the next segment, or – if close enough to the first node – closes the path.
void	mouseMoveEvent (QGraphicsSceneMouseEvent *event) override
	DiagramEventAddPath::mouseMoveEvent Two mutually exclusive behaviours, matching whether a button is held: with the left button down on a just-placed node, dragging shapes that node's handles (same convention as editing an existing node – see QetShapeItem::dragPathControlHandle()). With no button held, the trailing preview node instead tracks the mouse, giving the live rubber-band segment.
void	mouseReleaseEvent (QGraphicsSceneMouseEvent *event) override
	DiagramEventAddPath::mouseReleaseEvent Left release just ends the current node's drag phase (the trailing preview resumes tracking the mouse on the next move). Right release steps back one confirmed point (the preview is left alone), or cancels outright once only one remains, or exits the tool entirely if nothing is in progress at all.
void	mouseDoubleClickEvent (QGraphicsSceneMouseEvent *event) override
	DiagramEventAddPath::mouseDoubleClickEvent A double-click is a press, release, press, release, doubleclick sequence – the second press already confirmed the preview into a duplicate point (mousePressEvent can't distinguish a double-click from two single clicks in the same place) and appended a fresh preview after it. Dropping the last node here removes that fresh preview; finishPath()'s own trailing-preview removal then removes the duplicate underneath it, leaving only the genuinely-placed points.
void	keyPressEvent (QKeyEvent *event) override
	DiagramEventAddPath::keyPressEvent Escape or Enter finish the path open once at least two real points exist; Escape with fewer (or none placed at all) cancels/exits instead, since there's nothing meaningful to keep.
void	init () override
Public Member Functions inherited from DiagramEventInterface
	DiagramEventInterface (Diagram *diagram)
	~DiagramEventInterface () override=0
virtual void	wheelEvent (QGraphicsSceneWheelEvent *event)
virtual void	keyReleaseEvent (QKeyEvent *event)
virtual bool	isRunning () const

Private Member Functions
void	updateHelpCross (const QPointF &p)
	DiagramEventAddPath::updateHelpCross Same crosshair guide as every other shape tool (see DiagramEventAddShape::updateHelpCross) – duplicated rather than shared, since the two classes don't otherwise share a common base beyond DiagramEventInterface.
void	showHint () const
	DiagramEventAddPath::showHint Re-asserted on every move within the canvas (see mouseMoveEvent), not just once at activation: Qt's own built-in "show an action's statusTip on hover" has its own internal "restore whatever was there before" logic for when the hover ends. Since this message is first shown during that same hover session (the user is still over the toolbar icon when the deferred constructor-time call above fires), Qt's hover-tracking has no idea this code changed the status bar in the meantime – the moment the mouse leaves the icon for the canvas, it silently restores whatever it remembers being there before its own tip started, overwriting this one. Re-showing it on every move within the canvas simply outlasts that one-time restore.
void	finishPath (bool closed)
	DiagramEventAddPath::finishPath Strips the trailing live-preview node, commits the in-progress path onto the undo stack, and resets so the tool is ready to draw another one immediately – matching every other shape tool's own behaviour after finishing a shape.
void	cancelPath ()
	DiagramEventAddPath::cancelPath Discards the in-progress path entirely – nothing worth keeping (an empty or single-point path isn't a usable shape).
bool	nearFirstNode (const QPointF &scenePos) const
	DiagramEventAddPath::nearFirstNode m_shape_item's pos()/transform() stay at their identity defaults for its entire construction here – nothing during drawing ever touches them – so the first node's anchor, stored in local coordinates, is directly comparable to a scene position without any mapping.
int	confirmedNodeCount () const
QPointF	snapped (const QPointF &scenePos, Qt::KeyboardModifiers mods) const

Private Attributes
QetShapeItem *	m_shape_item
QVector< QetShapeItem::PathNode >	m_nodes
int	m_dragging_node = -1
QGraphicsLineItem *	m_help_horiz
QGraphicsLineItem *	m_help_verti

Static Private Attributes
static constexpr qreal	CLOSE_THRESHOLD = 12.0

Additional Inherited Members
Signals inherited from DiagramEventInterface
void	finish ()
Protected Attributes inherited from DiagramEventInterface
QPointer< Diagram >	m_diagram
bool	m_running {false}
bool	m_abort {false}

Detailed Description

The DiagramEventAddPath class Pen tool: interactively draw a new Path (Bezier) shape, following the same vocabulary every vector editor's pen tool uses:

• click places a Corner node;
• press-drag-release places a Smooth node, with the drag defining a pair of mirrored handles (same convention as QetShapeItem::dragPathControlHandle's "Smooth" mirroring);
• clicking back on the first node closes the path;
• double-click, Enter, or Escape (once 2+ nodes exist) finishes it open;
• right-click steps back one node;
• right-click or Escape with nothing placed yet cancels the tool. While running, m_nodes always carries one extra "preview" node at the end, tracking the mouse so a live rubber-band segment is always visible – confirmedNodeCount() excludes it; every public gesture handler is responsible for stripping it before treating the list as "the path so far" (see finishPath(), which does this once for every finishing gesture).

Constructor & Destructor Documentation

DiagramEventAddPath()

DiagramEventAddPath::DiagramEventAddPath

(

Diagram *

diagram

)

DiagramEventAddPath::DiagramEventAddPath.

Parameters

diagram

: the diagram where this event must operate

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~DiagramEventAddPath()

DiagramEventAddPath::~DiagramEventAddPath ( )

override

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Member Function Documentation

cancelPath()

void DiagramEventAddPath::cancelPath ( )

private

DiagramEventAddPath::cancelPath Discards the in-progress path entirely – nothing worth keeping (an empty or single-point path isn't a usable shape).

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confirmedNodeCount()

int DiagramEventAddPath::confirmedNodeCount ( ) const

private

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finishPath()

void DiagramEventAddPath::finishPath ( bool closed )

private

DiagramEventAddPath::finishPath Strips the trailing live-preview node, commits the in-progress path onto the undo stack, and resets so the tool is ready to draw another one immediately – matching every other shape tool's own behaviour after finishing a shape.

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init()

void DiagramEventAddPath::init ( )

overridevirtual

Reimplemented from DiagramEventInterface.

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keyPressEvent()

void DiagramEventAddPath::keyPressEvent ( QKeyEvent * event )

overridevirtual

DiagramEventAddPath::keyPressEvent Escape or Enter finish the path open once at least two real points exist; Escape with fewer (or none placed at all) cancels/exits instead, since there's nothing meaningful to keep.

Reimplemented from DiagramEventInterface.

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mouseDoubleClickEvent()

void DiagramEventAddPath::mouseDoubleClickEvent ( QGraphicsSceneMouseEvent * event )

overridevirtual

DiagramEventAddPath::mouseDoubleClickEvent A double-click is a press, release, press, release, doubleclick sequence – the second press already confirmed the preview into a duplicate point (mousePressEvent can't distinguish a double-click from two single clicks in the same place) and appended a fresh preview after it. Dropping the last node here removes that fresh preview; finishPath()'s own trailing-preview removal then removes the duplicate underneath it, leaving only the genuinely-placed points.

Reimplemented from DiagramEventInterface.

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mouseMoveEvent()

void DiagramEventAddPath::mouseMoveEvent ( QGraphicsSceneMouseEvent * event )

overridevirtual

DiagramEventAddPath::mouseMoveEvent Two mutually exclusive behaviours, matching whether a button is held: with the left button down on a just-placed node, dragging shapes that node's handles (same convention as editing an existing node – see QetShapeItem::dragPathControlHandle()). With no button held, the trailing preview node instead tracks the mouse, giving the live rubber-band segment.

Reimplemented from DiagramEventInterface.

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mousePressEvent()

void DiagramEventAddPath::mousePressEvent ( QGraphicsSceneMouseEvent * event )

overridevirtual

DiagramEventAddPath::mousePressEvent Left click: on the very first click, creates the shape with a real node and an immediate preview node at the same spot, so a segment exists (even if zero-length) from the start rather than requiring a second click before anything is visible. On later clicks: either confirms the live preview into a real point and appends a fresh one for the next segment, or – if close enough to the first node – closes the path.

Reimplemented from DiagramEventInterface.

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mouseReleaseEvent()

void DiagramEventAddPath::mouseReleaseEvent ( QGraphicsSceneMouseEvent * event )

overridevirtual

DiagramEventAddPath::mouseReleaseEvent Left release just ends the current node's drag phase (the trailing preview resumes tracking the mouse on the next move). Right release steps back one confirmed point (the preview is left alone), or cancels outright once only one remains, or exits the tool entirely if nothing is in progress at all.

Reimplemented from DiagramEventInterface.

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nearFirstNode()

bool DiagramEventAddPath::nearFirstNode ( const QPointF & scenePos ) const

private

DiagramEventAddPath::nearFirstNode m_shape_item's pos()/transform() stay at their identity defaults for its entire construction here – nothing during drawing ever touches them – so the first node's anchor, stored in local coordinates, is directly comparable to a scene position without any mapping.

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showHint()

void DiagramEventAddPath::showHint ( ) const

private

DiagramEventAddPath::showHint Re-asserted on every move within the canvas (see mouseMoveEvent), not just once at activation: Qt's own built-in "show an action's statusTip on hover" has its own internal "restore whatever was there before" logic for when the hover ends. Since this message is first shown during that same hover session (the user is still over the toolbar icon when the deferred constructor-time call above fires), Qt's hover-tracking has no idea this code changed the status bar in the meantime – the moment the mouse leaves the icon for the canvas, it silently restores whatever it remembers being there before its own tip started, overwriting this one. Re-showing it on every move within the canvas simply outlasts that one-time restore.

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snapped()

QPointF DiagramEventAddPath::snapped ( const QPointF & scenePos, Qt::KeyboardModifiers mods ) const

private

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updateHelpCross()

void DiagramEventAddPath::updateHelpCross ( const QPointF & p )

private

DiagramEventAddPath::updateHelpCross Same crosshair guide as every other shape tool (see DiagramEventAddShape::updateHelpCross) – duplicated rather than shared, since the two classes don't otherwise share a common base beyond DiagramEventInterface.

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Member Data Documentation

CLOSE_THRESHOLD

qreal DiagramEventAddPath::CLOSE_THRESHOLD = 12.0

staticconstexprprivate

m_dragging_node

int DiagramEventAddPath::m_dragging_node = -1

private

m_help_horiz

QGraphicsLineItem* DiagramEventAddPath::m_help_horiz

private

m_help_verti

QGraphicsLineItem * DiagramEventAddPath::m_help_verti

private

m_nodes

QVector<QetShapeItem::PathNode> DiagramEventAddPath::m_nodes

private

m_shape_item

QetShapeItem* DiagramEventAddPath::m_shape_item

private

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

• sources/diagramevent/diagrameventaddpath.h
• sources/diagramevent/diagrameventaddpath.cpp