QGraphicsItem

#include

• QGraphicsEllipseItem provides an ellipse item
• QGraphicsLineItem provides a line item
• QGraphicsPathItem provides an arbitrary path item
• QGraphicsPixmapItem provides a pixmap item
• QGraphicsPolygonItem provides a polygon item
• QGraphicsRectItem provides a rectangular item
• QGraphicsSimpleTextItem provides a simple text label item
• QGraphicsTextItem provides an advanced text browser item

•  

  1,The item's position, pos(), is the only function that does not operate in local coordinates, as it returns a position in parent coordinates.

  2,setVisible().setEnabled().

  3,ItemIsSelectable,setSelected().

  4,two pure virtual public functions: boundingRect(),and paint()

  5,prepareGeometryChange(),shape(),collidesWithItem()

  6,contains()

  7,pos().setRotation() or setScale(),setTransform().setTransformations().sceneTransform(),scenePos(),resetTransform().

• The item's base transform is applied (transform())
• The item's transformations list is applied in order (transformations())
• The item is rotated relative to its transform origin point (rotation(), transformOriginPoint())
• The item is scaled relative to its transform origin point (scale(), transformOriginPoint())

• 8,setZValue(),sibling items are stacked by insertion order

• You can call setZValue() on an item to explicitly stack it on top of, or under, other sibling items. The default Z value for an item is 0. Items with the same Z value are stacked by insertion order.
• You can call stackBefore() to reorder the list of children. This will directly modify the insertion order.
• You can set the ItemStacksBehindParent flag to stack a child item behind its parent.

• 9,installSceneEventFilter(),removeSceneEventFilter().

  10,enum QGraphicsItem::CacheMode

  QGraphicsItem::DeviceCoordinateCache  ------>always renders at maximum quality.

  11,enum QGraphicsItem::GraphicsItemChange

  ItemEnabledChange,ItemEnabledHasChanged

  ItemMatrixChange

  ItemPositionChange,ItemPositionHasChanged…This notification is sent if the ItemSendsGeometryChanges flag is enabled,itemChange().

  ItemTransformChange,ItemTransformHasChanged…This notification is send if the ItemSendsGeometryChanges flag is enabled,itemChange().

  ItemSelectedChange,ItemSelectedHasChanged

  ItemVisibleChange,ItemVisibleHasChanged

  ItemParentChange,ItemParentHasChanged

  ItemChildAddedChange,ItemChildRemovedChange

  ItemSceneChange,ItemSceneHasChanged

  ItemCursorChange,ItemCursorHasChanged

  ItemToolTipChange,ItemToolTipHasChanged

  ItemFlagsChange,ItemFlagsHaveChanged

  ItemZValueChange,ItemZValueHasChanged

  ItemOpacityChange,ItemOpacityHasChanged

  ItemScenePositionHasChanged…This notification is sent if the ItemSendsScenePositionChanges flag is enabled

   

  12,

  enum QGraphicsItem::GraphicsItemFlag
  flags QGraphicsItem::GraphicsItemFlags

  ItemIsMovable,ItemIsSelectable,ItemIsFocusable,ItemClipsToShape,ItemClipsChildrenToShape,ItemIgnoresTransformations,ItemIgnoresParentOpacity,ItemDoesntPropagateOpacityToChildren,ItemStacksBehindParent,ItemUsesExtendedStyleOption,ItemHasNoContents,ItemSendsGeometryChanges,ItemAcceptsInputMethod,ItemNegativeZStacksBehindParent,ItemIsPanel,ItemSendsScenePositionChanges

   

  13,enum QGraphicsItem::PanelModality

  NonModal,PanelModal,SceneModal

  14,