Редактирование: Qt:Документация 4.3.2/graphicsview-porting

{{Qt4.3.2_header}}

=Porting to Graphics View<br />=
<div id="qgraphicsview-graphicsview-porting-graphics-canvas"></div>Graphics View provides a surface for managing and interacting with a large number of custom-made 2D graphical items, and a view widget for visualizing the items, with support for zooming and rotation. Graphics View was introduced in Qt 4.2, replacing its predecessor, [[Qt:Документация 4.3.2/porting4#qcanvas | QCanvas]]. For more on Graphics View, see [[Qt:Документация 4.3.2/graphicsview | The Graphics View Framework]].

This document walks through the steps needed, class by class and function by function, to port a [[Qt:Документация 4.3.2/porting4#qcanvas | QCanvas]] application to Graphics View.

*[[#introduction | Introduction]]
*[[#porting-from-q3canvas | Porting from Q3Canvas]]
**[[#porting-table | Porting table]]
**[[#porting-scenes-with-tiles | Porting scenes with tiles]]
*[[#porting-from-q3canvasview | Porting from Q3CanvasView]]
**[[#porting-table | Porting table]]
**[[#other-differences | Other differences]]
*[[#porting-from-q3canvasitem | Porting from Q3CanvasItem]]
**[[#q3canvaspolygonalitem | Q3CanvasPolygonalItem]]
**[[#q3canvasellipse | Q3CanvasEllipse]]
**[[#q3canvasline | Q3CanvasLine]]
**[[#q3canvaspolygon | Q3CanvasPolygon]]
**[[#q3canvasspline | Q3CanvasSpline]]
**[[#q3canvasrectangle | Q3CanvasRectangle]]
**[[#q3canvassprite | Q3CanvasSprite]]
***[[#q3canvaspixmap-q3canvaspixmaparray | Q3CanvasPixmap, Q3CanvasPixmapArray]]
**[[#q3canvastext | Q3CanvasText]]
**[[#q3canvasitemlist | Q3CanvasItemList]]

Qt 4.2 provides two complete examples of [[Qt:Документация 4.3.2/q3canvas | Q3Canvas]] applications ported to Graphics View:
*[[Qt:Документация 4.3.2/graphicsview-portedcanvas | Ported Canvas Example]], the canvas example from Qt 3.
*[[Qt:Документация 4.3.2/graphicsview-portedasteroids | Ported Asteroids Example]], the Asteroids game from the Qt 3 demo.


<div id="introduction"></div>
===Introduction===
Conceptually, the Graphics View classes from Qt 4 and the Canvas classes from Qt 3 provide similar functionality using a similar design. Instead of "canvas", we use the term "scene". Otherwise, the class names and functions are almost the same as in Qt 3. The easiest classes to port will be [[Qt:Документация 4.3.2/porting4#qcanvas | QCanvas]] and QCanvasView. Experience shows that most time is spent porting the item classes, depending on the complexity of the QCanvasItem classes you have been using before.

This porting guide will assume you have already ported your application to Qt 4, by making use of [[Qt:Документация 4.3.2/q3canvas | Q3Canvas]]. If you have not done so already, as a first step, run the [[Qt:Документация 4.3.2/qt3to4#qt3to4 | qt3to4]] tool on your project. This tool will automate the most tedious part of the porting effort.

Some additional steps are usually required before your application will compile and run. You can read more about the porting process in [[Qt:Документация 4.3.2/porting4 | Porting to Qt 4]].

<div id="porting-from-q3canvas"></div>

===Porting from Q3Canvas===

[[Qt:Документация 4.3.2/qgraphicsscene | QGraphicsScene]] is the closest equivalent to [[Qt:Документация 4.3.2/q3canvas | Q3Canvas]]. There are some noticable differences in this new API: Whereas the [[Qt:Документация 4.3.2/q3canvas | Q3Canvas]] classes use integer precision, [[Qt:Документация 4.3.2/qgraphicsscene | QGraphicsScene]] is entirely based on double coordinates, with graphical primitives such as [[Qt:Документация 4.3.2/qpointf | QPointF]] instead of [[Qt:Документация 4.3.2/qpoint | QPoint]], [[Qt:Документация 4.3.2/qrectf | QRectF]] instead of [[Qt:Документация 4.3.2/qrect | QRect]], and [[Qt:Документация 4.3.2/qpolygonf | QPolygonF]] and [[Qt:Документация 4.3.2/qpainterpath | QPainterPath]]. The canvas area is defined by a scene rectangle, allowing negative coordinates, as opposed to [[Qt:Документация 4.3.2/q3canvas | Q3Canvas]], which only defines a size ([[Qt:Документация 4.3.2/qsize | QSize]]), and whose top-left corner is always (0, 0).

In addition, there is no explicit support for canvas tiles anymore; see [[#porting-scenes-with-tiles | Porting scenes with tiles]] for more information. The chunks-based indexing system has been replaced with an implicitly maintained internal BSP tree.

<div id="porting-table"></div>

====Porting table====


{| align="center" cellpadding="2" cellspacing="1" border="0"


|- valign="top" class="qt-style" | 
![[Qt:Документация 4.3.2/q3canvas | Q3Canvas]]
![[Qt:Документация 4.3.2/qgraphicsscene | QGraphicsScene]]

|- valign="top" class="odd" | 
|[[Qt:Документация 4.3.2/q3canvas#Q3Canvas | Q3Canvas::Q3Canvas]]()
|There is no [[Qt:Документация 4.3.2/qpixmap | QPixmap]] based constructor, and the concept of tiles is gone. You can use [[Qt:Документация 4.3.2/qgraphicsscene#backgroundBrush-prop | QGraphicsScene::backgroundBrush]] to set a brush pattern for the background, or reimplement [[Qt:Документация 4.3.2/qgraphicsscene#drawBackground | QGraphicsScene::drawBackground]]() in a [[Qt:Документация 4.3.2/qgraphicsscene | QGraphicsScene]] subclass (see [[#porting-scenes-with-tiles | Porting scenes with tiles]]). In addition, the [[Qt:Документация 4.3.2/qgraphicsscene | QGraphicsScene]] geometry is provided as a full [[Qt:Документация 4.3.2/qrectf | QRectF]]. Instead of [[Qt:Документация 4.3.2/q3canvas | Q3Canvas]](int width, int height), you can use [[Qt:Документация 4.3.2/qgraphicsscene | QGraphicsScene]](int top, int left, int width, int height).

|- valign="top" class="even" | 
|[[Qt:Документация 4.3.2/q3canvas#allItems | Q3Canvas::allItems]]()
|[[Qt:Документация 4.3.2/qgraphicsscene#items | QGraphicsScene::items]]() returns a list of all items on the scene.

|- valign="top" class="odd" | 
|[[Qt:Документация 4.3.2/q3canvas#backgroundColor | Q3Canvas::backgroundColor]]()
|You can assign a color for the background through the [[Qt:Документация 4.3.2/qgraphicsscene#backgroundBrush-prop | QGraphicsScene::backgroundBrush]] or [[Qt:Документация 4.3.2/qgraphicsview#backgroundBrush-prop | QGraphicsView::backgroundBrush]] properties.

|- valign="top" class="even" | 
|[[Qt:Документация 4.3.2/q3canvas#backgroundPixmap | Q3Canvas::backgroundPixmap]]()
|You can set a tiled pixmap for the background through [[Qt:Документация 4.3.2/qgraphicsscene#backgroundBrush-prop | QGraphicsScene::backgroundBrush]] or [[Qt:Документация 4.3.2/qgraphicsview#backgroundBrush-prop | QGraphicsView::backgroundBrush]]. For more control on the pixmap positioning, you can reimplement [[Qt:Документация 4.3.2/qgraphicsscene#drawBackground | QGraphicsScene::drawBackground]]() or [[Qt:Документация 4.3.2/qgraphicsview#drawBackground | QGraphicsView::drawBackground]]().

|- valign="top" class="odd" | 
|[[Qt:Документация 4.3.2/q3canvas#chunkSize | Q3Canvas::chunkSize]]()
|The closest equivalent to the chunks size in [[Qt:Документация 4.3.2/q3canvas | Q3Canvas]] is the depth of [[Qt:Документация 4.3.2/qgraphicsscene | QGraphicsScene]]'s BSP tree. [[Qt:Документация 4.3.2/qgraphicsscene | QGraphicsScene]] assigns a depth automatically, and the size of each scene segment depends on this depth, and [[Qt:Документация 4.3.2/qgraphicsscene#sceneRect-prop | QGraphicsScene::sceneRect]](). See [[Qt:Документация 4.3.2/qgraphicsscene#itemIndexMethod-prop | QGraphicsScene::itemIndexMethod]].

|- valign="top" class="even" | 
|[[Qt:Документация 4.3.2/q3canvas#collisions | Q3Canvas::collisions]]()
|[[Qt:Документация 4.3.2/qgraphicsscene | QGraphicsScene]] provides several means to detect item collisions. The [[Qt:Документация 4.3.2/qgraphicsscene#items | QGraphicsScene::items]]() overloads return items that collide with a point, a rectangle, a polygon, or an arbitrary vector path ([[Qt:Документация 4.3.2/qpainterpath | QPainterPath]]). You can also call [[Qt:Документация 4.3.2/qgraphicsscene#collidingItems | QGraphicsScene::collidingItems]]() to determine collision with an item.

|- valign="top" class="odd" | 
|[[Qt:Документация 4.3.2/q3canvas#drawArea | Q3Canvas::drawArea]]()
|The [[Qt:Документация 4.3.2/qgraphicsscene#render | QGraphicsScene::render]]() function provides the original behavior [[Qt:Документация 4.3.2/q3canvas#drawArea | Q3Canvas::drawArea]](). In addition, you can pass a source rectangle for rendering only parts of the scene, and a destination rectangle for rendering onto designated area of the destination device. [[Qt:Документация 4.3.2/qgraphicsscene#render | QGraphicsScene::render]]() can optionally transform the source rectangle to fit into the destination rectangle. See [[Qt:Документация 4.3.2/graphicsview#printing | Printing]]

|- valign="top" class="even" | 
|[[Qt:Документация 4.3.2/q3canvas#onCanvas | Q3Canvas::onCanvas]]()
|The is no equivalent to this function in Graphics View. However, you can combine [[Qt:Документация 4.3.2/qgraphicsscene#sceneRect-prop | QGraphicsScene::sceneRect]]() and [[Qt:Документация 4.3.2/qrectf#intersects | QRectF::intersects]]():<source lang="cpp-qt"> item->scene().sceneRect().intersects(item->sceneBoundingRect());
 item->mapToScene(item->shape()).intersects(item->scene().sceneRect());</source> 


|- valign="top" class="odd" | 
|[[Qt:Документация 4.3.2/q3canvas#rect | Q3Canvas::rect]]()
|The equivalent, [[Qt:Документация 4.3.2/qgraphicsscene#sceneRect-prop | QGraphicsScene::sceneRect]](), returns a [[Qt:Документация 4.3.2/qrectf | QRectF]] (double precision coordinates). Its top-left corner can be an arbitrary coordinate ([[Qt:Документация 4.3.2/q3canvas#rect | Q3Canvas::rect]]().topLeft() is always (0, 0)).

|- valign="top" class="even" | 
|[[Qt:Документация 4.3.2/q3canvas#resize | Q3Canvas::resize]]()
|You can call QGraphicsScene::setSceneRect(0, 0, width, height) instead.

|- valign="top" class="odd" | 
|[[Qt:Документация 4.3.2/q3canvas#retune | Q3Canvas::retune]]()
|See [[Qt:Документация 4.3.2/qgraphicsscene#itemIndexMethod-prop | QGraphicsScene::itemIndexMethod]]. You can tune the indexing by setting a suitable sceneRect(). The optimal depth of [[Qt:Документация 4.3.2/qgraphicsscene | QGraphicsScene]]'s BSP tree is determined automatically.

|- valign="top" class="even" | 
|[[Qt:Документация 4.3.2/q3canvas#setAdvancePeriod | Q3Canvas::setAdvancePeriod]]()
|There is no concept of an advance period in the new API; instead, you can connect [[Qt:Документация 4.3.2/qtimer#timeout | QTimer::timeout]]() to the [[Qt:Документация 4.3.2/qgraphicsscene#advance | QGraphicsScene::advance]]() slot to obtain similar functionality. This will cause all items' [[Qt:Документация 4.3.2/qgraphicsitem#advance | QGraphicsItem::advance]]() function to be called. See also [[Qt:Документация 4.3.2/qgraphicsitemanimation | QGraphicsItemAnimation]].

|- valign="top" class="odd" | 
|[[Qt:Документация 4.3.2/q3canvas#setAllChanged | Q3Canvas::setAllChanged]]()
|You can call [[Qt:Документация 4.3.2/qgraphicsscene#update | QGraphicsScene::update]]() with no arguments.

|- valign="top" class="even" | 
|[[Qt:Документация 4.3.2/q3canvas#setChanged | Q3Canvas::setChanged]]()
|[[Qt:Документация 4.3.2/qgraphicsscene#update | QGraphicsScene::update]]() will trigger a repaint of the whole scene, or parts of the scene.

|- valign="top" class="odd" | 
|[[Qt:Документация 4.3.2/q3canvas#setDoubleBuffering | Q3Canvas::setDoubleBuffering]]()
|[[Qt:Документация 4.3.2/q3canvas | Q3Canvas]]' double buffering enabled cacheing of the scene contents in device (i.e., viewport) coordinates. This cache layer has been moved to the view instead; you can cache [[Qt:Документация 4.3.2/qgraphicsscene | QGraphicsScene]]'s background through [[Qt:Документация 4.3.2/qgraphicsview#cacheMode-prop | QGraphicsView::setCacheMode]](). [[Qt:Документация 4.3.2/qgraphicsview#resetCachedContent | QGraphicsView::resetCachedContent]]() will reset the areas of the cache that has changed.

|- valign="top" class="even" | 
|[[Qt:Документация 4.3.2/q3canvas#tile | Q3Canvas::tile]]()
|See [[#porting-scenes-with-tiles | Porting scenes with tiles]].

|- valign="top" class="odd" | 
|[[Qt:Документация 4.3.2/q3canvas#setTiles | Q3Canvas::setTiles]]()
|See [[#porting-scenes-with-tiles | Porting scenes with tiles]].

|- valign="top" class="even" | 
|[[Qt:Документация 4.3.2/q3canvas#setUnchanged | Q3Canvas::setUnchanged]]()
|There is no equivalent in Graphics View. This call can usually be removed with no side effects.

|- valign="top" class="odd" | 
|[[Qt:Документация 4.3.2/q3canvas#setUpdatePeriod | Q3Canvas::setUpdatePeriod]]()
|There is no concept of an update period in the new API; instead, you can connect [[Qt:Документация 4.3.2/qtimer#timeout | QTimer::timeout]]() to the [[Qt:Документация 4.3.2/qgraphicsscene#update | QGraphicsScene::update]]() slot to obtain similar functionality. See also [[Qt:Документация 4.3.2/qgraphicsitemanimation | QGraphicsItemAnimation]].

|- valign="top" class="even" | 
|[[Qt:Документация 4.3.2/q3canvas#size | Q3Canvas::size]]()
|<tt>[[Qt:Документация 4.3.2/qgraphicsscene#sceneRect-prop | QGraphicsScene::sceneRect]]().size()</tt> returns a [[Qt:Документация 4.3.2/qsizef | QSizeF]], with double precision coordinates.

|- valign="top" class="odd" | 
|[[Qt:Документация 4.3.2/q3canvas#validChunk | Q3Canvas::validChunk]]()
|To determine if an area is inside the scene area or not, you can combine [[Qt:Документация 4.3.2/qrectf#intersects | QRectF::intersects]]() with [[Qt:Документация 4.3.2/qgraphicsscene#sceneRect-prop | QGraphicsScene::sceneRect]]().

|- valign="top" class="even" | 
|[[Qt:Документация 4.3.2/q3canvas#resized | Q3Canvas::resized]]()
|[[Qt:Документация 4.3.2/qgraphicsscene | QGraphicsScene]] emits [[Qt:Документация 4.3.2/qgraphicsscene#sceneRectChanged | sceneRectChanged()]] whenever the scene rect changes.

|- valign="top" class="odd" | 
|[[Qt:Документация 4.3.2/q3canvas#drawBackground | Q3Canvas::drawBackground]]()
|You can reimplement [[Qt:Документация 4.3.2/qgraphicsscene#drawBackground | QGraphicsScene::drawBackground]]() to render the scene background. You can also reimplement [[Qt:Документация 4.3.2/qgraphicsview#drawBackground | QGraphicsView::drawBackground]]() to override this background if you need different backgrounds for different views.

|- valign="top" class="even" | 
|[[Qt:Документация 4.3.2/q3canvas#drawForeground | Q3Canvas::drawForeground]]()
|You can reimplement [[Qt:Документация 4.3.2/qgraphicsscene#drawForeground | QGraphicsScene::drawForeground]]() to render the scene foreground. You can also reimplement [[Qt:Документация 4.3.2/qgraphicsview#drawForeground | QGraphicsView::drawForeground]]() to override this foreground if you need different foregrounds for different views.

|}

<div id="porting-scenes-with-tiles"></div>

====Porting scenes with tiles====

[[Qt:Документация 4.3.2/qgraphicsscene | QGraphicsScene]] does not provide an API for tiles. However, you can achieve similar behavior by drawing pixmaps in a reimplementation of [[Qt:Документация 4.3.2/qgraphicsscene#drawBackground | QGraphicsScene::drawBackground]]().

[[Qt:Документация 4.3.2/q3canvas | Q3Canvas]]' tile support is based on providing one pixmap containing tiles of a fixed width and height, and then accessing them (reading and replacing tiles) by index. The tiles in the pixmap are arranged from the left to right, top to bottom.


{| align="center" cellpadding="2" cellspacing="1" border="0"


|- valign="top" class="odd" | 
|0
|1
|2
|3

|- valign="top" class="even" | 
|4
|5
|6
|7

|}

With Graphics View, this pixmap can be stored as a member of a subclass of [[Qt:Документация 4.3.2/qgraphicsscene | QGraphicsScene]]. The three main functions that make out the public tile API can then be declared as new members of this class. Here is one example of how to implement tile support:

<source lang="cpp-qt">     class TileScene : public QGraphicsScene
     {
     public:
         ...

         void setTiles(const QPixmap &pixmap, int h, int v,
                       int tileHeight, int tileWidth);
         void setTile(int x, int y, int tilenum);

     private:
         QRect tileRect(int x, int y) const;
         QRect tileRect(int tileNum) const;

         QVector<QVector<int> > tiles;
         QPixmap tilePixmap;
         int tileW, tileH;
         int hTiles, vTiles;
     };</source> 
Depending on how your scene uses tiles, you may be able to simplify this approach. In this example, we will try to mimic the behavior of the [[Qt:Документация 4.3.2/q3canvas | Q3Canvas]] functions.

We start by creating a subclass of [[Qt:Документация 4.3.2/qgraphicsscene | QGraphicsScene]] ("TileScene"). In this class, we declare two of the tile functions from [[Qt:Документация 4.3.2/q3canvas | Q3Canvas]], and we then add two helper function that returns the rectangle for a certain tile in our tile pixmap. We will use a two-dimensional vector of ints to keep track of what tiles should be used at what parts of the scene.

<source lang="cpp-qt">     void TileScene::setTiles(const QPixmap &pixmap, int h, int v,
                              int tileHeight, int tileWidth)
     {
         tilePixmap = pixmap;
         tileW = tileWidth;
         tileH = tileHeight;
         hTiles = h;
         vTiles = v;

         tiles.resize(v);
         for (int y = 0; y < v; ++y)
             tiles[y].resize(h);
     }</source> 
In setTiles(), we store the pixmap and tile properties as members of the class. Then we resize the tiles vector to match the width and height of our tile grid.

<source lang="cpp-qt">     void TileScene::setTile(int x, int y, int tilenum)
     {
         tiles[y][x] = tilenum;
         update(tileRect(x, y));
     }</source> 
The setTile() function updates the tiles index, and then updates the corresponding rect in the scene by calling tileRect().

<source lang="cpp-qt">     QRect TileScene::tileRect(int x, int y) const
     {
         return QRect(x * tileW, y * tileH, tileW, tileH);
     }</source> 
The first tileRect() function returns a [[Qt:Документация 4.3.2/qrect | QRect]] for the tile at position (x, y).

<source lang="cpp-qt">     QRect TileScene::tileRect(int tileNum) const
     {
         int numHTiles = tilePixmap.width() / tileW;
         int numVTiles = tilePixmap.height() / tileH;
         return tileRect(tileNum % numHTiles, tileNum / numHTiles);
     }</source> 
The second tileRect() function returns a [[Qt:Документация 4.3.2/qrect | QRect]] for a tile number. With these functions in place, we can implement the drawBackground() function.

<source lang="cpp-qt">     void drawBackground(QPainter *painter, const QRectF &exposed)
     {
         for (int y = 0; y < vTiles; ++y) {
             for (int x = 0; x < hTiles; ++x) {
                 QRect destRect = tileRect(x, y);
                 if (exposed.intersects(destRect)) {
                     painter->drawPixmap(destRect, tilePixmap,
                                         tileRect(tiles[y][x]));
                 }
             }
         }
     }</source> 
In drawBackground(), we redraw all tiles that have been exposed by intersecting each tile rect with the exposed background area.

<div id="porting-from-q3canvasview"></div>

===Porting from Q3CanvasView===

The closest equivalent to [[Qt:Документация 4.3.2/q3canvasview | Q3CanvasView]] in Graphics View is called [[Qt:Документация 4.3.2/qgraphicsview | QGraphicsView]]. In most cases, this is the easiest class to port. In addition to providing all of [[Qt:Документация 4.3.2/q3canvasview | Q3CanvasView]]'s functionality, [[Qt:Документация 4.3.2/qgraphicsview | QGraphicsView]] includes some useful new features. You can read more about this in [[Qt:Документация 4.3.2/qgraphicsview | QGraphicsView]]'s documentation.

<div id="porting-table"></div>

====Porting table====


{| align="center" cellpadding="2" cellspacing="1" border="0"


|- valign="top" class="qt-style" | 
![[Qt:Документация 4.3.2/q3canvasview | Q3CanvasView]]
![[Qt:Документация 4.3.2/qgraphicsview | QGraphicsView]]

|- valign="top" class="odd" | 
|[[Qt:Документация 4.3.2/q3canvasview#Q3CanvasView | Q3CanvasView::Q3CanvasView]]()
|[[Qt:Документация 4.3.2/qgraphicsview | QGraphicsView]] provides the same constructors as [[Qt:Документация 4.3.2/q3canvasview | Q3CanvasView]], but without the name and flags arguments. You can set the name by calling [[Qt:Документация 4.3.2/qobject#objectName-prop | setObjectName()]], and the flags by calling [[Qt:Документация 4.3.2/qwidget#windowFlags-prop | setWindowFlags()]].

|- valign="top" class="even" | 
|[[Qt:Документация 4.3.2/q3canvasview#canvas | Q3CanvasView::canvas]]()
|[[Qt:Документация 4.3.2/qgraphicsview#scene | QGraphicsView::scene]]() returns the scene that is currently associated with the view. [[Qt:Документация 4.3.2/qgraphicsscene | QGraphicsScene]] also provides the opposite function, [[Qt:Документация 4.3.2/qgraphicsscene#views | QGraphicsScene::views]](), which returns a list of views observing the scene.

|- valign="top" class="odd" | 
|[[Qt:Документация 4.3.2/q3canvasview#inverseWorldMatrix | Q3CanvasView::inverseWorldMatrix]]()
|You can call [[Qt:Документация 4.3.2/qgraphicsview#matrix | QGraphicsView::matrix]]() and [[Qt:Документация 4.3.2/qmatrix#inverted | QMatrix::inverted]](). [[Qt:Документация 4.3.2/qgraphicsview#mapToScene | QGraphicsView::mapToScene]]() and [[Qt:Документация 4.3.2/qgraphicsview#mapFromScene | QGraphicsView::mapFromScene]]() allow transforming of viewport shapes to scene shapes, and vice versa.

|- valign="top" class="even" | 
|[[Qt:Документация 4.3.2/q3canvasview#setCanvas | Q3CanvasView::setCanvas]]()
|[[Qt:Документация 4.3.2/qgraphicsview#setScene | QGraphicsView::setScene]]().

|- valign="top" class="odd" | 
|[[Qt:Документация 4.3.2/q3canvasview#setWorldMatrix | Q3CanvasView::setWorldMatrix]]()
|[[Qt:Документация 4.3.2/qgraphicsview#setMatrix | QGraphicsView::setMatrix]](), [[Qt:Документация 4.3.2/qgraphicsview#rotate | QGraphicsView::rotate]](), [[Qt:Документация 4.3.2/qgraphicsview#scale | QGraphicsView::scale]](), [[Qt:Документация 4.3.2/qgraphicsview#shear | QGraphicsView::shear]]() and [[Qt:Документация 4.3.2/qgraphicsview#translate | QGraphicsView::translate]]().

|- valign="top" class="even" | 
|[[Qt:Документация 4.3.2/q3canvasview#worldMatrix | Q3CanvasView::worldMatrix]]()
|[[Qt:Документация 4.3.2/qgraphicsview#matrix | QGraphicsView::matrix]]()

|- valign="top" class="odd" | 
|[[Qt:Документация 4.3.2/q3canvasview#drawContents | Q3CanvasView::drawContents]]()
|The [[Qt:Документация 4.3.2/qgraphicsview#drawBackground | QGraphicsView::drawBackground]]() function draws the background, [[Qt:Документация 4.3.2/qgraphicsview#drawItems | QGraphicsView::drawItems]]() draws the items, and [[Qt:Документация 4.3.2/qgraphicsview#drawForeground | QGraphicsView::drawForeground]]() draws the foreground of the scene in scene coordinates. You can also reimplement these functions in [[Qt:Документация 4.3.2/qgraphicsscene | QGraphicsScene]].

|}

<div id="other-differences"></div>

====Other differences====

[[Qt:Документация 4.3.2/qgraphicsview | QGraphicsView]] can cache the visible contents of the scene, similar to how [[Qt:Документация 4.3.2/q3canvas#setDoubleBuffering | Q3Canvas::setDoubleBuffering]]() could cache the entire scene contents. You can call [[Qt:Документация 4.3.2/qgraphicsview#cacheMode-prop | QGraphicsView::setCacheMode]]() to configure cacheing, and [[Qt:Документация 4.3.2/qgraphicsview#resetCachedContent | QGraphicsView::resetCachedContent]]() invalidates the cache.

For improved navigation support, you can set a resize or transformation anchor through [[Qt:Документация 4.3.2/qgraphicsview#resizeAnchor-prop | QGraphicsView::resizeAnchor]] and [[Qt:Документация 4.3.2/qgraphicsview#transformationAnchor-prop | QGraphicsView::transformationAnchor]]. This allows you to easily rotate and zoom the view while keeping the center fixed, or zooming towards the position under the mouse cursor. In addition, if you set the [[Qt:Документация 4.3.2/qgraphicsview#dragMode-prop | QGraphicsView::dragMode]] of the view, [[Qt:Документация 4.3.2/qgraphicsview | QGraphicsView]] will provide rubber band selection or click-and-pull navigation using the [[Qt:Документация 4.3.2/qt#CursorShape-enum | OpenHandCursor]] and [[Qt:Документация 4.3.2/qt#CursorShape-enum | ClosedHandCursor]] cursors.

<div id="porting-from-q3canvasitem"></div>

===Porting from Q3CanvasItem===

The closest equivalent to [[Qt:Документация 4.3.2/q3canvasitem | Q3CanvasItem]] in Graphics View is called [[Qt:Документация 4.3.2/qgraphicsitem | QGraphicsItem]]. Deriving from this class is very common, and because of that, porting from [[Qt:Документация 4.3.2/q3canvasitem | Q3CanvasItem]] often involves more work than [[Qt:Документация 4.3.2/q3canvas | Q3Canvas]] and [[Qt:Документация 4.3.2/q3canvasview | Q3CanvasView]].

[[Qt:Документация 4.3.2/q3canvasitem | Q3CanvasItem]] has become easier to use, easier to subclass, and more powerful with [[Qt:Документация 4.3.2/qgraphicsitem | QGraphicsItem]]. The key difference from [[Qt:Документация 4.3.2/q3canvasitem | Q3CanvasItem]] lies in event propagation and item groups, but you will also find several convenient new features, such as support for tooltips, cursors, item transformation and drag and drop. You can read all about [[Qt:Документация 4.3.2/qgraphicsitem | QGraphicsItem]] in its own class documentation.

This section starts with a table that shows how to port each function from [[Qt:Документация 4.3.2/q3canvasitem | Q3CanvasItem]] to [[Qt:Документация 4.3.2/qgraphicsitem | QGraphicsItem]]. Immediately after that, each of [[Qt:Документация 4.3.2/q3canvasitem | Q3CanvasItem]]'s standard subclasses have a section of their own.


{| align="center" cellpadding="2" cellspacing="1" border="0"


|- valign="top" class="qt-style" | 
![[Qt:Документация 4.3.2/q3canvasitem | Q3CanvasItem]]
![[Qt:Документация 4.3.2/qgraphicsitem | QGraphicsItem]]

|- valign="top" class="odd" | 
|[[Qt:Документация 4.3.2/q3canvasitem#advance | Q3CanvasItem::advance]]()
|[[Qt:Документация 4.3.2/qgraphicsitem#advance | QGraphicsItem::advance]]() is provided for compatibility. [[Qt:Документация 4.3.2/qgraphicsscene#advance | QGraphicsScene::advance]]() calls [[Qt:Документация 4.3.2/qgraphicsitem#advance | QGraphicsItem::advance]]() for all items. See also [[Qt:Документация 4.3.2/qtimeline | QTimeLine]] and [[Qt:Документация 4.3.2/qgraphicsitemanimation | QGraphicsItemAnimation]].

|- valign="top" class="even" | 
|[[Qt:Документация 4.3.2/q3canvasitem#animated | Q3CanvasItem::animated]]()
|No equivalent; all items are advanced by [[Qt:Документация 4.3.2/qgraphicsscene#advance | QGraphicsScene::advance]]().

|- valign="top" class="odd" | 
|[[Qt:Документация 4.3.2/q3canvasitem#boundingRectAdvanced | Q3CanvasItem::boundingRectAdvanced]]()
|No equivalent. You can translate [[Qt:Документация 4.3.2/qgraphicsitem#boundingRect | QGraphicsItem::boundingRect]]() instead (see [[Qt:Документация 4.3.2/qrectf#translate | QRectF::translate]]()).

|- valign="top" class="even" | 
|[[Qt:Документация 4.3.2/q3canvasitem#canvas | Q3CanvasItem::canvas]]()
|[[Qt:Документация 4.3.2/qgraphicsitem#scene | QGraphicsItem::scene]]()

|- valign="top" class="odd" | 
|[[Qt:Документация 4.3.2/q3canvasitem#collidesWith | Q3CanvasItem::collidesWith]]()
|[[Qt:Документация 4.3.2/qgraphicsitem#collidesWithItem | QGraphicsItem::collidesWithItem]]() and [[Qt:Документация 4.3.2/qgraphicsitem#collidesWithPath | QGraphicsItem::collidesWithPath]]().

|- valign="top" class="even" | 
|[[Qt:Документация 4.3.2/q3canvasitem#collisions | Q3CanvasItem::collisions]]()
|[[Qt:Документация 4.3.2/qgraphicsitem#collidingItems | QGraphicsItem::collidingItems]]() returns a list of all items that collide with an item. You can specify whether you want fast, rough estimate collision between bounding rectangles, or the slower, more accurate shapes.

|- valign="top" class="odd" | 
|[[Qt:Документация 4.3.2/q3canvasitem#draw | Q3CanvasItem::draw]]()
|[[Qt:Документация 4.3.2/qgraphicsitem#paint | QGraphicsItem::paint]](). See also [[Qt:Документация 4.3.2/qstyleoptiongraphicsitem | QStyleOptionGraphicsItem]], [[Qt:Документация 4.3.2/qgraphicsscene#drawItems | QGraphicsScene::drawItems]]() and [[Qt:Документация 4.3.2/qgraphicsview#drawItems | QGraphicsView::drawItems]]().

|- valign="top" class="even" | 
|[[Qt:Документация 4.3.2/q3canvasitem#hide | Q3CanvasItem::hide]]()
|[[Qt:Документация 4.3.2/qgraphicsitem#hide | QGraphicsItem::hide]]() or [[Qt:Документация 4.3.2/qgraphicsitem#setVisible | QGraphicsItem::setVisible]](). [[Qt:Документация 4.3.2/qgraphicsitem | QGraphicsItem]]s are ''visible'' by default; [[Qt:Документация 4.3.2/q3canvasitem | Q3CanvasItem]]s, however, are not.

|- valign="top" class="odd" | 
|[[Qt:Документация 4.3.2/q3canvasitem#isActive | Q3CanvasItem::isActive]]()
|No equivalent. To achieve similar behavior, you can add this property in a custom subclass of [[Qt:Документация 4.3.2/qgraphicsitem | QGraphicsItem]].

|- valign="top" class="even" | 
|[[Qt:Документация 4.3.2/q3canvasitem#isVisible | Q3CanvasItem::isVisible]]()
|[[Qt:Документация 4.3.2/qgraphicsitem#isVisible | QGraphicsItem::isVisible]](). [[Qt:Документация 4.3.2/qgraphicsitem | QGraphicsItem]]s are ''visible'' by default; [[Qt:Документация 4.3.2/q3canvasitem | Q3CanvasItem]]s, however, are not.

|- valign="top" class="odd" | 
|[[Qt:Документация 4.3.2/q3canvasitem#move | Q3CanvasItem::move]]()
|You can call [[Qt:Документация 4.3.2/qgraphicsitem#setPos | QGraphicsItem::setPos]]() to change the position of the item.

|- valign="top" class="even" | 
|[[Qt:Документация 4.3.2/q3canvasitem#rtti | Q3CanvasItem::rtti]]()
|[[Qt:Документация 4.3.2/qgraphicsitem#type | QGraphicsItem::type]]() and [[Qt:Документация 4.3.2/qgraphicsitem#qgraphicsitem_cast | qgraphicsitem_cast]]().

|- valign="top" class="odd" | 
|[[Qt:Документация 4.3.2/q3canvasitem#setActive | Q3CanvasItem::setActive]]()
|No equivalent.

|- valign="top" class="even" | 
|[[Qt:Документация 4.3.2/q3canvasitem#setAnimated | Q3CanvasItem::setAnimated]]()
|No equivalent; all items are by default "animated" (i.e., [[Qt:Документация 4.3.2/qgraphicsscene#advance | QGraphicsScene::advance]]() advances all items on the scene).

|- valign="top" class="odd" | 
|[[Qt:Документация 4.3.2/q3canvasitem#setCanvas | Q3CanvasItem::setCanvas]]()
|You can call [[Qt:Документация 4.3.2/qgraphicsscene#addItem | QGraphicsScene::addItem]](), or pass a pointer to the canvas to [[Qt:Документация 4.3.2/qgraphicsitem | QGraphicsItem]]'s constructor.

|- valign="top" class="even" | 
|[[Qt:Документация 4.3.2/q3canvasitem#setVelocity | Q3CanvasItem::setVelocity]]()
|No equivalent. You can add x and y velocity as member data of your class, and call QGraphicsItem::moveBy(x, y) from inside [[Qt:Документация 4.3.2/qgraphicsitem#advance | QGraphicsItem::advance]](). See also [[Qt:Документация 4.3.2/qtimeline | QTimeLine]] and [[Qt:Документация 4.3.2/qgraphicsitemanimation | QGraphicsItemAnimation]].

|- valign="top" class="odd" | 
|[[Qt:Документация 4.3.2/q3canvasitem#setVisible | Q3CanvasItem::setVisible]]()
|[[Qt:Документация 4.3.2/qgraphicsitem#setVisible | QGraphicsItem::setVisible]](). [[Qt:Документация 4.3.2/qgraphicsitem | QGraphicsItem]]s are ''visible'' by default; [[Qt:Документация 4.3.2/q3canvasitem | Q3CanvasItem]]s, however, are not.

|- valign="top" class="even" | 
|[[Qt:Документация 4.3.2/q3canvasitem#setX | Q3CanvasItem::setX]]()
|[[Qt:Документация 4.3.2/qgraphicsitem#setPos | QGraphicsItem::setPos]]()

|- valign="top" class="odd" | 
|[[Qt:Документация 4.3.2/q3canvasitem#setY | Q3CanvasItem::setY]]()
|[[Qt:Документация 4.3.2/qgraphicsitem#setPos | QGraphicsItem::setPos]]()

|- valign="top" class="even" | 
|[[Qt:Документация 4.3.2/q3canvasitem#setXVelocity | Q3CanvasItem::setXVelocity]]()
|No equivalent.

|- valign="top" class="odd" | 
|[[Qt:Документация 4.3.2/q3canvasitem#setYVelocity | Q3CanvasItem::setYVelocity]]()
|No equivalent.

|- valign="top" class="even" | 
|[[Qt:Документация 4.3.2/q3canvasitem#setZ | Q3CanvasItem::setZ]]()
|[[Qt:Документация 4.3.2/qgraphicsitem#setZValue | QGraphicsItem::setZValue]]()

|- valign="top" class="odd" | 
|[[Qt:Документация 4.3.2/q3canvasitem#show | Q3CanvasItem::show]]()
|[[Qt:Документация 4.3.2/qgraphicsitem#show | QGraphicsItem::show]]() or [[Qt:Документация 4.3.2/qgraphicsitem#setVisible | QGraphicsItem::setVisible]](). [[Qt:Документация 4.3.2/qgraphicsitem | QGraphicsItem]]s are ''visible'' by default; [[Qt:Документация 4.3.2/q3canvasitem | Q3CanvasItem]]s, however, are not.

|- valign="top" class="even" | 
|[[Qt:Документация 4.3.2/q3canvasitem#xVelocity | Q3CanvasItem::xVelocity]]()
|No equivalent.

|- valign="top" class="odd" | 
|[[Qt:Документация 4.3.2/q3canvasitem#yVelocity | Q3CanvasItem::yVelocity]]()
|No equivalent.

|}

<div id="q3canvaspolygonalitem"></div>

====Q3CanvasPolygonalItem====

The closest equivalent to [[Qt:Документация 4.3.2/q3canvaspolygonalitem | Q3CanvasPolygonalItem]] in Graphics View is called [[Qt:Документация 4.3.2/qabstractgraphicsshapeitem | QAbstractGraphicsShapeItem]]. Unlike [[Qt:Документация 4.3.2/q3canvaspolygonalitem | Q3CanvasPolygonalItem]], it does not define area points ([[Qt:Документация 4.3.2/q3canvaspolygonalitem#areaPoints | Q3CanvasPolygonalItem::areaPoints]]()); instead, each item's geometry is stored as a member of the subclasses.

The [[Qt:Документация 4.3.2/q3canvaspolygonalitem#drawShape | Q3CanvasPolygonalItem::drawShape]]() function is no longer available; instead, you can set the brush and pen from inside [[Qt:Документация 4.3.2/qgraphicsitem#paint | QGraphicsItem::paint]]().


{| align="center" cellpadding="2" cellspacing="1" border="0"


|- valign="top" class="qt-style" | 
![[Qt:Документация 4.3.2/q3canvaspolygonalitem | Q3CanvasPolygonalItem]]
![[Qt:Документация 4.3.2/qabstractgraphicsshapeitem | QAbstractGraphicsShapeItem]]

|- valign="top" class="odd" | 
|[[Qt:Документация 4.3.2/q3canvaspolygonalitem#areaPoints | Q3CanvasPolygonalItem::areaPoints]]()
|No equivalent; each item's geometry is stored in the respective subclass.

|- valign="top" class="even" | 
|[[Qt:Документация 4.3.2/q3canvaspolygonalitem#areaPointsAdvanced | Q3CanvasPolygonalItem::areaPointsAdvanced]]()
|No equivalent; you can use [[Qt:Документация 4.3.2/qpolygonf#translate | QPolygonF::translate]]() or QPainterPath::translate() instead.

|- valign="top" class="odd" | 
|[[Qt:Документация 4.3.2/q3canvaspolygonalitem#drawShape | Q3CanvasPolygonalItem::drawShape]]()
|[[Qt:Документация 4.3.2/qgraphicsitem#paint | QGraphicsItem::paint]](). You can set the pen and brush from inside this function.

|- valign="top" class="even" | 
|[[Qt:Документация 4.3.2/q3canvaspolygonalitem#invalidate | Q3CanvasPolygonalItem::invalidate]]()
|Call [[Qt:Документация 4.3.2/qgraphicsitem#prepareGeometryChange | QGraphicsItem::prepareGeometryChange]]() before changing the item's geometry.

|- valign="top" class="odd" | 
|[[Qt:Документация 4.3.2/q3canvaspolygonalitem#isValid | Q3CanvasPolygonalItem::isValid]]()
|No equivalent; items' geometry is always in a valid state.

|- valign="top" class="even" | 
|[[Qt:Документация 4.3.2/q3canvaspolygonalitem#winding | Q3CanvasPolygonalItem::winding]]()
|This function is only useful for polygon items and path items; see [[Qt:Документация 4.3.2/qgraphicspolygonitem#fillRule | QGraphicsPolygonItem::fillRule]](), and [[Qt:Документация 4.3.2/qpainterpath#fillRule | QPainterPath::fillRule]]() for [[Qt:Документация 4.3.2/qgraphicspathitem | QGraphicsPathItem]].

|}

<div id="q3canvasellipse"></div>

====Q3CanvasEllipse====

The closest equivalent to [[Qt:Документация 4.3.2/q3canvasellipse | Q3CanvasEllipse]] in Graphics View is called [[Qt:Документация 4.3.2/qgraphicsellipseitem | QGraphicsEllipseItem]]. The most noticable difference to [[Qt:Документация 4.3.2/qgraphicsellipseitem | QGraphicsEllipseItem]] is that the ellipse is not longer drawn centered around its position; rather, it is drawn using a bounding [[Qt:Документация 4.3.2/qrectf | QRectF]], just like [[Qt:Документация 4.3.2/qpainter#drawEllipse | QPainter::drawEllipse]]().

For compatibility, you may want to shift the ellipse up and to the left to keep the ellipse centered. Example:

<source lang="cpp-qt">         // Before
         Q3CanvasEllipse ellipse(10, 10);

         // After
         QGraphicsEllipseItem ellipse(-5, -5, 10, 10);</source> 
Note: [[Qt:Документация 4.3.2/qgraphicsellipseitem | QGraphicsEllipseItem]] uses [[Qt:Документация 4.3.2/qabstractgraphicsshapeitem#pen | QAbstractGraphicsShapeItem::pen]]() for outlines, whereas [[Qt:Документация 4.3.2/q3canvasellipse | Q3CanvasEllipse]] did not use [[Qt:Документация 4.3.2/q3canvaspolygonalitem#pen | Q3CanvasPolygonalItem::pen]]().


{| align="center" cellpadding="2" cellspacing="1" border="0"


|- valign="top" class="qt-style" | 
![[Qt:Документация 4.3.2/q3canvasellipse | Q3CanvasEllipse]]
![[Qt:Документация 4.3.2/qgraphicsellipseitem | QGraphicsEllipseItem]]

|- valign="top" class="odd" | 
|[[Qt:Документация 4.3.2/q3canvasellipse#angleLength | Q3CanvasEllipse::angleLength]]()
|[[Qt:Документация 4.3.2/qgraphicsellipseitem#spanAngle | QGraphicsEllipseItem::spanAngle]]()

|- valign="top" class="even" | 
|[[Qt:Документация 4.3.2/q3canvasellipse#angleStart | Q3CanvasEllipse::angleStart]]()
|[[Qt:Документация 4.3.2/qgraphicsellipseitem#startAngle | QGraphicsEllipseItem::startAngle]]()

|- valign="top" class="odd" | 
|[[Qt:Документация 4.3.2/q3canvasellipse#setAngles | Q3CanvasEllipse::setAngles]]()
|[[Qt:Документация 4.3.2/qgraphicsellipseitem#setStartAngle | QGraphicsEllipseItem::setStartAngle]]() and [[Qt:Документация 4.3.2/qgraphicsellipseitem#setSpanAngle | QGraphicsEllipseItem::setSpanAngle]]()

|- valign="top" class="even" | 
|[[Qt:Документация 4.3.2/q3canvasellipse#setSize | Q3CanvasEllipse::setSize]]()
|[[Qt:Документация 4.3.2/qgraphicsellipseitem#setRect | QGraphicsEllipseItem::setRect]]()

|}

<div id="q3canvasline"></div>

====Q3CanvasLine====

The closest equivalent to [[Qt:Документация 4.3.2/q3canvasline | Q3CanvasLine]] in Graphics View is called [[Qt:Документация 4.3.2/qgraphicslineitem | QGraphicsLineItem]].


{| align="center" cellpadding="2" cellspacing="1" border="0"


|- valign="top" class="qt-style" | 
![[Qt:Документация 4.3.2/q3canvasline | Q3CanvasLine]]
![[Qt:Документация 4.3.2/qgraphicslineitem | QGraphicsLineItem]]

|- valign="top" class="odd" | 
|[[Qt:Документация 4.3.2/q3canvasline#endPoint | Q3CanvasLine::endPoint]]()
|[[Qt:Документация 4.3.2/qgraphicslineitem#line | QGraphicsLineItem::line]]() and [[Qt:Документация 4.3.2/qlinef#p2 | QLineF::p2]]()

|- valign="top" class="even" | 
|[[Qt:Документация 4.3.2/q3canvasline#setPoints | Q3CanvasLine::setPoints]]()
|[[Qt:Документация 4.3.2/qgraphicslineitem#setLine | QGraphicsLineItem::setLine]]()

|- valign="top" class="odd" | 
|[[Qt:Документация 4.3.2/q3canvasline#startPoint | Q3CanvasLine::startPoint]]()
|[[Qt:Документация 4.3.2/qgraphicslineitem#line | QGraphicsLineItem::line]]() and [[Qt:Документация 4.3.2/qlinef#p1 | QLineF::p1]]()

|}

<div id="q3canvaspolygon"></div>

====Q3CanvasPolygon====

The closest equivalent to [[Qt:Документация 4.3.2/q3canvaspolygon | Q3CanvasPolygon]] in Graphics View is called [[Qt:Документация 4.3.2/qgraphicspolygonitem | QGraphicsPolygonItem]].


{| align="center" cellpadding="2" cellspacing="1" border="0"


|- valign="top" class="qt-style" | 
![[Qt:Документация 4.3.2/q3canvaspolygon | Q3CanvasPolygon]]
![[Qt:Документация 4.3.2/qgraphicspolygonitem | QGraphicsPolygonItem]]

|- valign="top" class="odd" | 
|[[Qt:Документация 4.3.2/q3canvaspolygon#areaPoints | Q3CanvasPolygon::areaPoints]]()
|[[Qt:Документация 4.3.2/qgraphicspolygonitem#polygon | QGraphicsPolygonItem::polygon]]() and [[Qt:Документация 4.3.2/qgraphicsitem#mapToParent | QGraphicsItem::mapToParent]]()

|- valign="top" class="even" | 
|[[Qt:Документация 4.3.2/q3canvaspolygon#points | Q3CanvasPolygon::points]]()
|[[Qt:Документация 4.3.2/qgraphicspolygonitem#polygon | QGraphicsPolygonItem::polygon]]()

|- valign="top" class="odd" | 
|[[Qt:Документация 4.3.2/q3canvaspolygon#setPoints | Q3CanvasPolygon::setPoints]]()
|[[Qt:Документация 4.3.2/qgraphicspolygonitem#setPolygon | QGraphicsPolygonItem::setPolygon]]()

|}

<div id="q3canvasspline"></div>

====Q3CanvasSpline====

The closest equivalent to [[Qt:Документация 4.3.2/q3canvasspline | Q3CanvasSpline]] in Graphics View is called [[Qt:Документация 4.3.2/qgraphicspathitem | QGraphicsPathItem]]. This item can be used to describe any type of path supported by [[Qt:Документация 4.3.2/qpainter | QPainter]].

[[Qt:Документация 4.3.2/q3canvasspline | Q3CanvasSpline]] takes its control points as a [[Qt:Документация 4.3.2/q3pointarray | Q3PointArray]], but [[Qt:Документация 4.3.2/qpainterpath | QPainterPath]] operates on a sequence of calls to [[Qt:Документация 4.3.2/qpainterpath#moveTo | QPainterPath::moveTo]]() and [[Qt:Документация 4.3.2/qpainterpath#cubicTo | QPainterPath::cubicTo]](). Here is how you can convert a bezier curve [[Qt:Документация 4.3.2/q3pointarray | Q3PointArray]] to a [[Qt:Документация 4.3.2/qpainterpath | QPainterPath]]:

<source lang="cpp-qt">     static QPainterPath fromControlPoints(const Q3PointArray &pa)
     {
         QPainterPath path;
         path.moveTo(pa[0]);
         for (int i = 1; i < pa.size(); i += 3)
             path.cubicTo(pa[i], pa[(i + 1) % pa.size()], pa[(i + 2) % pa.size()]);
         return path;
     }</source> 
Note: [[Qt:Документация 4.3.2/qgraphicspathitem | QGraphicsPathItem]] uses [[Qt:Документация 4.3.2/qabstractgraphicsshapeitem#pen | QAbstractGraphicsShapeItem::pen]]() for outlines, whereas [[Qt:Документация 4.3.2/q3canvasspline | Q3CanvasSpline]] did not use [[Qt:Документация 4.3.2/q3canvaspolygonalitem#pen | Q3CanvasPolygonalItem::pen]]().


{| align="center" cellpadding="2" cellspacing="1" border="0"


|- valign="top" class="qt-style" | 
![[Qt:Документация 4.3.2/q3canvasspline | Q3CanvasSpline]]
![[Qt:Документация 4.3.2/qgraphicspathitem | QGraphicsPathItem]]

|- valign="top" class="odd" | 
|[[Qt:Документация 4.3.2/q3canvasspline#closed | Q3CanvasSpline::closed]]()
|No equivalent. You can call QPainterPath::closeSubPath() to close a subpath explicitly.

|}

<div id="q3canvasrectangle"></div>

====Q3CanvasRectangle====

The closest equivalent to [[Qt:Документация 4.3.2/q3canvasrectangle | Q3CanvasRectangle]] in Graphics View is called [[Qt:Документация 4.3.2/qgraphicsrectitem | QGraphicsRectItem]].


{| align="center" cellpadding="2" cellspacing="1" border="0"


|- valign="top" class="qt-style" | 
![[Qt:Документация 4.3.2/q3canvasrectangle | Q3CanvasRectangle]]
![[Qt:Документация 4.3.2/qgraphicsrectitem | QGraphicsRectItem]]

|- valign="top" class="odd" | 
|[[Qt:Документация 4.3.2/q3canvasrectangle#height | Q3CanvasRectangle::height]]()
|[[Qt:Документация 4.3.2/qgraphicsrectitem#rect | QGraphicsRectItem::rect]]() and [[Qt:Документация 4.3.2/qrectf#height | QRectF::height]]()

|- valign="top" class="even" | 
|[[Qt:Документация 4.3.2/q3canvasrectangle#setSize | Q3CanvasRectangle::setSize]]()
|[[Qt:Документация 4.3.2/qgraphicsrectitem#setRect | QGraphicsRectItem::setRect]]()

|- valign="top" class="odd" | 
|[[Qt:Документация 4.3.2/q3canvasrectangle#size | Q3CanvasRectangle::size]]()
|[[Qt:Документация 4.3.2/qgraphicsrectitem#rect | QGraphicsRectItem::rect]]() and [[Qt:Документация 4.3.2/qrectf#size | QRectF::size]]()

|- valign="top" class="even" | 
|[[Qt:Документация 4.3.2/q3canvasrectangle#width | Q3CanvasRectangle::width]]()
|[[Qt:Документация 4.3.2/qgraphicsrectitem#rect | QGraphicsRectItem::rect]]() and [[Qt:Документация 4.3.2/qrectf#width | QRectF::width]]()

|- valign="top" class="odd" | 
|[[Qt:Документация 4.3.2/q3canvasrectangle#chunks | Q3CanvasRectangle::chunks]]()
|No equivalent.

|}

<div id="q3canvassprite"></div>

====Q3CanvasSprite====

[[Qt:Документация 4.3.2/q3canvassprite | Q3CanvasSprite]] is the item class that differs the most from its [[Qt:Документация 4.3.2/q3canvas | Q3Canvas]] predecessor. The closest resemblance of [[Qt:Документация 4.3.2/q3canvassprite | Q3CanvasSprite]] in Graphics View is [[Qt:Документация 4.3.2/qgraphicspixmapitem | QGraphicsPixmapItem]].

[[Qt:Документация 4.3.2/q3canvassprite | Q3CanvasSprite]] supports animated pixmaps; [[Qt:Документация 4.3.2/qgraphicspixmapitem | QGraphicsPixmapItem]], however, is a simple single-frame pixmap item. If all you need is a pixmap item, porting is straight-forward. If you do need the animation support, extra work is required; there is no direct porting approach.

For the [[Qt:Документация 4.3.2/graphicsview-portedasteroids | Ported Asteroids Example]], a subclass of [[Qt:Документация 4.3.2/qgraphicspixmapitem | QGraphicsPixmapItem]] is used to replace [[Qt:Документация 4.3.2/q3canvassprite | Q3CanvasSprite]], storing a list of pixmaps and a frame counter. The animation is advanced in [[Qt:Документация 4.3.2/qgraphicsitem#advance | QGraphicsItem::advance]]().

<div id="q3canvaspixmap-q3canvaspixmaparray"></div>

=====Q3CanvasPixmap, Q3CanvasPixmapArray=====

These classes have been removed from the API. You can use [[Qt:Документация 4.3.2/qpixmap | QPixmap]] instead of [[Qt:Документация 4.3.2/q3canvaspixmap | Q3CanvasPixmap]], and [[Qt:Документация 4.3.2/qlist | QList]] instead of [[Qt:Документация 4.3.2/q3canvaspixmaparray | Q3CanvasPixmapArray]].

[[Qt:Документация 4.3.2/q3canvaspixmaparray | Q3CanvasPixmapArray]] included convenience for loading a sequence of pixmaps or masks using a path with a wildcard (see [[Qt:Документация 4.3.2/q3canvaspixmaparray#readPixmaps | Q3CanvasPixmapArray::readPixmaps]]() and [[Qt:Документация 4.3.2/q3canvaspixmaparray#readCollisionMasks | Q3CanvasPixmapArray::readCollisionMasks]]()). To achieve similar functionality using Graphics View, you can load the images by using [[Qt:Документация 4.3.2/qdir | QDir]]:

<source lang="cpp-qt">             wildcardPath.replace("%1", "*");
             QFileInfo fi(wildcardPath);

             QList<QPixmap> frames;
             foreach (QString entry, QDir(fi.path(), fi.fileName()).entryList())
                 frames << QPixmap(fi.path() + "/" + entry);</source> 
<div id="q3canvastext"></div>

====Q3CanvasText====

[[Qt:Документация 4.3.2/q3canvastext | Q3CanvasText]] has been split into two classes in Graphics View: [[Qt:Документация 4.3.2/qgraphicssimpletextitem | QGraphicsSimpleTextItem]] and [[Qt:Документация 4.3.2/qgraphicstextitem | QGraphicsTextItem]]. For porting, [[Qt:Документация 4.3.2/qgraphicssimpletextitem | QGraphicsSimpleTextItem]] should be adequate. [[Qt:Документация 4.3.2/qgraphicstextitem | QGraphicsTextItem]] provides advanced document structuring features similar to that of [[Qt:Документация 4.3.2/qtextedit | QTextEdit]], and it also allows interaction (e.g., editing and selection).


{| align="center" cellpadding="2" cellspacing="1" border="0"


|- valign="top" class="qt-style" | 
![[Qt:Документация 4.3.2/q3canvastext | Q3CanvasText]]
![[Qt:Документация 4.3.2/qgraphicssimpletextitem | QGraphicsSimpleTextItem]]

|- valign="top" class="odd" | 
|[[Qt:Документация 4.3.2/q3canvastext#color | Q3CanvasText::color]]()
|[[Qt:Документация 4.3.2/qabstractgraphicsshapeitem#pen | QGraphicsSimpleTextItem::pen]]().

|- valign="top" class="even" | 
|[[Qt:Документация 4.3.2/q3canvastext#setColor | Q3CanvasText::setColor]]()
|[[Qt:Документация 4.3.2/qabstractgraphicsshapeitem#setPen | QGraphicsSimpleTextItem::setPen]]().

|- valign="top" class="odd" | 
|[[Qt:Документация 4.3.2/q3canvastext#textFlags | Q3CanvasText::textFlags]]()
|Use [[Qt:Документация 4.3.2/qgraphicstextitem | QGraphicsTextItem]] instead.

|}

<div id="q3canvasitemlist"></div>

====Q3CanvasItemList====

Use [[Qt:Документация 4.3.2/qlist | QList]] instead.

{{Qt4.3.2_footer}}