PtGenTree

A generic superclass for tree widgets

Class hierarchy:

PtWidget → PtBasic → PtContainer → PtCompound → PtGenList → PtGenTree

Immediate subclasses:

• PtFileSel
• PtRawTree
• PtTree

For more information, see the diagram of the widget hierarchy.

PhAB icon:

None — not normally instantiated.

Public header:

<photon/PtGenTree.h>

Description:

The PtGenTree widget displays a tree of items. When you expand an item, another list of items drops down from it. Additional items can be added to an expandable item when it's about to be expanded. Expanded items can be collapsed, which results in the exclusion of items from the displayed list.

The tree can actually be a “forest” — the widget can contain multiple items at the root level. The root items are always visible (included on the displayed list) because they don't have a parent that could be collapsed.

You can build a tree (or a forest) that isn't linked to any widget and then add the whole tree to a widget as a root or subtree. Alternatively, you can add each item to the widget tree separately, but once the widget is realized, you'll have to use PtHold() and PtUpdate() to avoid multiple redraws.

PtGenTreeItem_t is the data structure used for the items.

For more information about this class, see Building Custom Widgets.

New resources:

Pt_ARG_TREE_FLAGS

Possible values are:

Pt_TREE_HAS_BUTTONS

Display the buttons for expanding and collapsing items.

Pt_TREE_INDENT_BUTTONS

Indent the buttons.

Pt_TREE_INDENT_LINES

If Pt_TREE_SHOW_LINES is set, indent the lines to match the tree item indentation.

Pt_TREE_SHOW_CONNECTORS

Display the connectors.

Pt_TREE_SHOW_LINES

Display horizontal lines between each item in the tree.

Pt_TREE_SHOW_MARGIN

Display the margins.

Pt_TREE_TO_RIGHT

Extend the items to the right edge of the widget.

Pt_TREE_TO_LEFT

Extend the item background to the left edge.

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The PtTree subclass defines some additional flags.

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Pt_ARG_TREE_LINE_COLOR

The color of the lines. See PgColor_t in the Photon Library Reference.

Pt_ARG_TREE_LINE_SPACING

The spacing between lines, in pixels.

Pt_ARG_TREE_MARGIN_COLOR

The color of the margins. See PgColor_t in the Photon Library Reference.

Pt_CB_GEN_TREE_INPUT

A list of PtCallback_t structures that define the callbacks invoked on mouse and key events. Each callback is passed a PtCallbackInfo_t structure that contains at least the following members:

reason

Pt_CB_GEN_TREE_INPUT

reason_subtype

The event type (same as event->type). For more info, see the types described for PhEvent_t in the Photon Library Reference.

event

A pointer to a PhEvent_t structure that describes the event that caused the callback to be invoked.

cbdata

A pointer to a PtGenTreeInput_t structure that contains at least the following members:

PtGenTreeItem_t *item;

For mouse events, the item pointed to by the mouse or NULL if the mouse doesn't point to an item. For key events, the item that is going to be the current item (see “Current item” in the description of PtGenList) after the event is normally processed by the widget.

unsigned index;

The index of the item.

PhPoint_t pos;

The pointer position relative to the item. See PhPoint_t in the Photon Library Reference.

int consumed;

Initially set to Pt_CONTINUE. Your callback function can suppress normal handling of the event by setting this field to another value. In the case of key events, set it to Pt_END to consume the event, or to Pt_HALT to pass the event to the parent widget. Mouse events are always consumed.

These callbacks should return Pt_CONTINUE.

Inherited resources:

If the widget modifies an inherited resource, the “Default override” column indicates the new value. This modification affects any subclasses of the widget.

Pt_CB_DND

For Pt_CB_DND callbacks for a PtGenTree, the cbinfo->cbdata is a pointer to a PtTreeDndCallback_t structure, containing at least the following members:

PtDndCallbackInfo_t dnd_info

See the description of Pt_CB_DND for PtWidget.

PtGenTreeItem_t *item

A pointer to the target item involved in the drag-and-drop operation.

int item_pos

The index of that item.

unsigned long flags

Possible values:

• Pt_LIST_ITEM_DNDSELECTED_UP — the drop occurred above the item.
• Pt_LIST_ITEM_DNDSELECTED_DOWN — the drop occurred below the item.

If neither of these is set, the drop occurred inside the item.

int action

This member is initially set to Pt_LIST_ITEM_DNDSELECTED_UP | Pt_LIST_ITEM_DNDSELECTED_DOWN | Pt_LIST_ITEM_DNDSELECTED_IN. You can unset some of these values to indicate that the drag-and-drop isn't accepted in that case. For example, if you unset Pt_LIST_ITEM_DNDSELECTED_IN, the drag-and-drop can't occur inside the item, only above or below.

Convenience functions:

PtGenTree defines the following convenience functions and data structure:

PtGenTreeAddAfter()

Add items after a given item.

PtGenTreeAddFirst()

Add items in front of any existing items.

PtGenTreeAllItems()

Get pointers to all the items in the tree.

PtGenTreeClearSelection()

Clear the selection.

PtGenTreeCollapse()

Collapse a subtree.

PtGenTreeDamageItem()

Redraw an item when its data has changed.

PtGenTreeExpand()

Expand a given subtree.

PtGenTreeExpandParents()

Expand any collapsed ancestors of a given item.

PtGenTreeFreeAllItems()

Free all the items in a tree.

PtGenTreeFreeItems()

Free the items in a subtree.

PtGenTreeGetCurrent()

Get a pointer to the current item.

PtGenTreeGetSelIndexes()

Get the indexes of the selected items.

PtGenTreeGoto()

Set the current item and position so that a given item is visible.

PtGenTreeItem_t

PtGenTree item structure

PtGenTreeItemIndex()

Calculate the index of a given item.

PtGenTreeItemRealloc()

Reallocate an item.

PtGenTreeItemResize()

Resize an item.

PtGenTreeRemoveChildren()

Unlink all the children of a given item.

PtGenTreeRemoveItem()

Remove a given item and its children from its parents and siblings.

PtGenTreeRemoveList()

Remove a given items and its siblings from their parent.

PtGenTreeResize()

Resize many items.

PtGenTreeRootItem()

Get a pointer to the first root item.

PtGenTreeSelect()

Select a given item.

PtGenTreeSelectedItems()

Get pointers to the selected items.

PtGenTreeSetSelIndexes()

Set the selection indexes.

PtGenTreeShow()

Set the current position so that a given item is visible.

PtGenTreeUnselect()

Unselect a given item.

PtGenTreeUnselectNonBrothers()

Unselect all items that aren't siblings of a given item.

The following convenience functions are useful only if you're creating a custom tree widget; they're described in the Creating a Tree Widget chapter of Building Custom Widget:

PtSuperClassGenTreeDrawItem()

Invoke the Tree Draw Item method of a given superclass.

PtSuperClassGenTreeItemState()

Invoke the Tree Item State method of a superclass.