LayerTreeModel Class Reference

QAbstractItemModel that mirrors the layer stack of a MapCanvas, grouped by category. More...

#include <layertreepanel.h>

Inheritance diagram for LayerTreeModel:

Collaboration diagram for LayerTreeModel:

Public Member Functions
	LayerTreeModel (MapCanvas *canvas=nullptr, QObject *parent=nullptr)
	~LayerTreeModel () override
void	setCanvas (MapCanvas *canvas)
	Rebind to a different MapCanvas (called on MDI tab switch). Pass nullptr to detach (empty tree).
MapCanvas *	canvas () const
QModelIndex	index (int row, int column, const QModelIndex &parent={}) const override
QModelIndex	parent (const QModelIndex &child) const override
int	rowCount (const QModelIndex &parent={}) const override
int	columnCount (const QModelIndex &parent={}) const override
QVariant	data (const QModelIndex &index, int role=Qt::DisplayRole) const override
bool	setData (const QModelIndex &index, const QVariant &value, int role) override
Qt::ItemFlags	flags (const QModelIndex &index) const override
QVariant	headerData (int section, Qt::Orientation orientation, int role) const override
Qt::DropActions	supportedDropActions () const override
bool	canDropMimeData (const QMimeData *data, Qt::DropAction action, int row, int column, const QModelIndex &parent) const override
bool	dropMimeData (const QMimeData *data, Qt::DropAction action, int row, int column, const QModelIndex &parent) override
QMimeData *	mimeData (const QModelIndexList &indexes) const override
QStringList	mimeTypes () const override
OpenSWMMVisLayer *	layerForIndex (const QModelIndex &index) const
	Returns the OpenSWMMVisLayer for a layer-row index, or nullptr for category rows / invalid indices.
bool	isCategoryIndex (const QModelIndex &index) const
	True if index is a category header row (no associated layer).
bool	isKindIndex (const QModelIndex &index) const
OpenSWMMVisLayer *	kindParentLayer (const QModelIndex &index) const
int	kindOrdinal (const QModelIndex &index) const
bool	isSublayerIndex (const QModelIndex &index) const
OpenSWMMVisLayer *	sublayerParentLayer (const QModelIndex &index) const
OpenSWMM::Render::ISublayer *	sublayerForIndex (const QModelIndex &index) const
bool	reorderCategory (int categoryId, int dstTreeRow)
	Slice LTR-2026-09-19 — moves the category group categoryId (an openswmmvis::ui::CategoryId currently shown in the tree) to tree row dstTreeRow, then batch-reorders the canvas layer stack so paint order follows (an undoable ReorderLayersCommand) and records the new group order on the canvas (MapCanvas::setLayerGroupOrder, persisted per project).
int	categoryIdForIndex (const QModelIndex &index) const
QModelIndex	indexForCategory (int categoryId) const
QModelIndex	indexForLayer (OpenSWMMVisLayer *layer) const
QModelIndex	indexForSublayer (OpenSWMMVisLayer *layer, OpenSWMM::Render::ISublayer *sublayer) const
void	notifyHostSubOrderChanged ()
	Slice GUI-2026-05-30 §2 / §3 — notify the model that the sublayer or kind paint-order on a host layer has changed externally (context-menu Move Up / Down or drop). Rebuilds the cached sub-row storage and emits a model reset so the view re-renders in the new order.

Detailed Description

QAbstractItemModel that mirrors the layer stack of a MapCanvas, grouped by category.

Two-level tree:

     Root
     ├── Category (e.g. "SWMM Model")
     │   └── Layer
     ├── Category (e.g. "Vectors")
     │   ├── Layer
     │   └── Layer
     └── …

     Categories are derived from each layer's `OpenSWMMVisLayerType`. A
     category is shown only if it contains at least one layer. Within a
     category, layers appear in canvas-stack order (top-of-stack first).

     Columns: [0] visibility checkbox + layer/category name + icon ·
              [1] opacity (layer rows only).

     The model reacts to layerAdded / layerRemoved / layerOrderChanged
     signals from the canvas so it stays in sync automatically.

     Reordering (Slice LTR-2026-09-19): category rows, layer rows and
     sublayer rows are all draggable. A layer can only be dropped
     inside its own category (its type decides the category, so a
     cross-category drop is refused with the forbidden cursor); a
     sublayer only inside its host layer. Every drop changes the
     canvas paint order (or the host's sublayer paint order) and is
     undoable; the canvas keeps the stack grouped by category so the
     tree is always an exact picture of the drawing order.

Constructor & Destructor Documentation

LayerTreeModel()

LayerTreeModel::LayerTreeModel ( MapCanvas *  canvas = nullptr, QObject *  parent = nullptr  )

explicit

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~LayerTreeModel()

LayerTreeModel::~LayerTreeModel ( )

overridedefault

Member Function Documentation

canDropMimeData()

bool LayerTreeModel::canDropMimeData ( const QMimeData *  data, Qt::DropAction  action, int  row, int  column, const QModelIndex &  parent  ) const

override

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canvas()

MapCanvas * LayerTreeModel::canvas

(

)

const

Bound canvas, or nullptr once it is unbound or destroyed. Out-of-line so QPointer<MapCanvas>::data() is not instantiated against the forward declaration.

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categoryIdForIndex()

int LayerTreeModel::categoryIdForIndex

(

const QModelIndex &

index

)

const

CategoryId of a category row; -1 for any other row / invalid index.

columnCount()

int LayerTreeModel::columnCount ( const QModelIndex &  parent = {} ) const

override

data()

QVariant LayerTreeModel::data ( const QModelIndex &  index, int  role = Qt::DisplayRole  ) const

override

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dropMimeData()

bool LayerTreeModel::dropMimeData ( const QMimeData *  data, Qt::DropAction  action, int  row, int  column, const QModelIndex &  parent  )

override

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flags()

Qt::ItemFlags LayerTreeModel::flags ( const QModelIndex &  index ) const

override

headerData()

QVariant LayerTreeModel::headerData ( int  section, Qt::Orientation  orientation, int  role  ) const

override

index()

QModelIndex LayerTreeModel::index ( int  row, int  column, const QModelIndex &  parent = {}  ) const

override

indexForCategory()

QModelIndex LayerTreeModel::indexForCategory

(

int

categoryId

)

const

indexForLayer()

QModelIndex LayerTreeModel::indexForLayer

(

OpenSWMMVisLayer *

layer

)

const

indexForSublayer()

QModelIndex LayerTreeModel::indexForSublayer	(	OpenSWMMVisLayer *	layer,
		OpenSWMM::Render::ISublayer *	sublayer
	)		const

isCategoryIndex()

bool LayerTreeModel::isCategoryIndex

(

const QModelIndex &

index

)

const

True if index is a category header row (no associated layer).

isKindIndex()

bool LayerTreeModel::isKindIndex

(

const QModelIndex &

index

)

const

True if index is a kind-row (3rd-level sub-row under a SWMMModelLayer).

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isSublayerIndex()

bool LayerTreeModel::isSublayerIndex

(

const QModelIndex &

index

)

const

True if index is a sublayer-row (3rd-level sub-row under an ISublayerHost).

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kindOrdinal()

int LayerTreeModel::kindOrdinal

(

const QModelIndex &

index

)

const

Kind ordinal (0..10, matches SWMMModelLayer::Category) for a kind-row index; -1 for any other row type.

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kindParentLayer()

OpenSWMMVisLayer * LayerTreeModel::kindParentLayer

(

const QModelIndex &

index

)

const

Parent layer for a kind-row index; nullptr for any other row type.

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layerForIndex()

OpenSWMMVisLayer * LayerTreeModel::layerForIndex

(

const QModelIndex &

index

)

const

Returns the OpenSWMMVisLayer for a layer-row index, or nullptr for category rows / invalid indices.

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mimeData()

QMimeData * LayerTreeModel::mimeData ( const QModelIndexList &  indexes ) const

override

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mimeTypes()

QStringList LayerTreeModel::mimeTypes ( ) const

override

notifyHostSubOrderChanged()

void LayerTreeModel::notifyHostSubOrderChanged

(

)

Slice GUI-2026-05-30 §2 / §3 — notify the model that the sublayer or kind paint-order on a host layer has changed externally (context-menu Move Up / Down or drop). Rebuilds the cached sub-row storage and emits a model reset so the view re-renders in the new order.

parent()

QModelIndex LayerTreeModel::parent ( const QModelIndex &  child ) const

override

reorderCategory()

bool LayerTreeModel::reorderCategory	(	int	categoryId,
		int	dstTreeRow
	)

Slice LTR-2026-09-19 — moves the category group categoryId (an openswmmvis::ui::CategoryId currently shown in the tree) to tree row dstTreeRow, then batch-reorders the canvas layer stack so paint order follows (an undoable ReorderLayersCommand) and records the new group order on the canvas (MapCanvas::setLayerGroupOrder, persisted per project).

Tree row 0 = top of tree = highest canvas z-order. Rows are positions among the NON-EMPTY categories the tree displays; dstTreeRow is the row the group occupies after the move. Returns false (no-op) when the id is not shown, the row is out of range, or the move is a no-op.

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rowCount()

int LayerTreeModel::rowCount ( const QModelIndex &  parent = {} ) const

override

setCanvas()

void LayerTreeModel::setCanvas

(

MapCanvas *

canvas

)

Rebind to a different MapCanvas (called on MDI tab switch). Pass nullptr to detach (empty tree).

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setData()

bool LayerTreeModel::setData ( const QModelIndex &  index, const QVariant &  value, int  role  )

override

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sublayerForIndex()

OpenSWMM::Render::ISublayer * LayerTreeModel::sublayerForIndex

(

const QModelIndex &

index

)

const

The ISublayer pointer for a sublayer-row index; nullptr otherwise.

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sublayerParentLayer()

OpenSWMMVisLayer * LayerTreeModel::sublayerParentLayer

(

const QModelIndex &

index

)

const

Parent layer for a sublayer-row index; nullptr for any other row type.

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supportedDropActions()

Qt::DropActions LayerTreeModel::supportedDropActions ( ) const

override

---

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

• /home/runner/work/openswmm.gui/openswmm.gui/include/ui/panels/layertreepanel.h
• /home/runner/work/openswmm.gui/openswmm.gui/src/ui/panels/layertreepanel.cpp