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diff --git a/doc/src/porting4-canvas.qdoc b/doc/src/porting4-canvas.qdoc deleted file mode 100644 index 54861bc..0000000 --- a/doc/src/porting4-canvas.qdoc +++ /dev/null @@ -1,703 +0,0 @@ -/**************************************************************************** -** -** Copyright (C) 2009 Nokia Corporation and/or its subsidiary(-ies). -** Contact: Nokia Corporation (qt-info@nokia.com) -** -** This file is part of the documentation of the Qt Toolkit. -** -** $QT_BEGIN_LICENSE:LGPL$ -** No Commercial Usage -** This file contains pre-release code and may not be distributed. -** You may use this file in accordance with the terms and conditions -** contained in the Technology Preview License Agreement accompanying -** this package. -** -** GNU Lesser General Public License Usage -** Alternatively, this file may be used under the terms of the GNU Lesser -** General Public License version 2.1 as published by the Free Software -** Foundation and appearing in the file LICENSE.LGPL included in the -** packaging of this file. Please review the following information to -** ensure the GNU Lesser General Public License version 2.1 requirements -** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html. -** -** In addition, as a special exception, Nokia gives you certain -** additional rights. These rights are described in the Nokia Qt LGPL -** Exception version 1.1, included in the file LGPL_EXCEPTION.txt in this -** package. -** -** If you have questions regarding the use of this file, please contact -** Nokia at qt-info@nokia.com. -** -** -** -** -** -** -** -** -** $QT_END_LICENSE$ -** -****************************************************************************/ - -/*! - \page graphicsview-porting.html - \title Porting to Graphics View - \contentspage {Porting Guides}{Contents} - \previouspage Porting .ui Files to Qt 4 - \nextpage qt3to4 - The Qt 3 to 4 Porting Tool - \ingroup porting - \ingroup multimedia - \brief Hints and tips to assist with porting canvas applications to the - Graphics View framework. - - \keyword QGraphicsView GraphicsView Porting Graphics Canvas - \since 4.2 - - 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, QCanvas. For - more on Graphics View, see \l{The Graphics View Framework}. - - This document walks through the steps needed, class by class and function - by function, to port a QCanvas application to Graphics View. - - \tableofcontents - - Qt 4.2 provides two complete examples of Q3Canvas applications ported to - Graphics View: - - \list - \o \l{Ported Canvas Example}, the canvas example from Qt 3. - \o \l{Ported Asteroids Example}, the Asteroids game from the Qt 3 demo. - \endlist - - \section1 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 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 Q3Canvas. If you have not done - so already, as a first step, run the \l 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 - \l{Porting to Qt 4}. - - \section1 Porting from Q3Canvas - - QGraphicsScene is the closest equivalent to Q3Canvas. There - are some noticable differences in this new API: Whereas the - Q3Canvas classes use integer precision, QGraphicsScene is - entirely based on double coordinates, with graphical - primitives such as QPointF instead of QPoint, QRectF instead - of QRect, and QPolygonF and QPainterPath. The canvas area is - defined by a scene rectangle, allowing negative coordinates, - as opposed to Q3Canvas, which only defines a size (QSize), and - whose top-left corner is always (0, 0). - - In addition, there is no explicit support for canvas tiles - anymore; see \l{Porting scenes with tiles} for more - information. The chunks-based indexing system has been - replaced with an implicitly maintained internal BSP tree. - - \section2 Porting table - - \table - \header \o Q3Canvas \o QGraphicsScene - - \row \o Q3Canvas::Q3Canvas() \o There is no QPixmap based - constructor, and the concept of tiles is gone. You can use - QGraphicsScene::backgroundBrush to set a brush pattern for - the background, or reimplement - QGraphicsScene::drawBackground() in a QGraphicsScene - subclass (see \l{Porting scenes with tiles}). In addition, - the QGraphicsScene geometry is provided as a full - QRectF. Instead of Q3Canvas(int width, int height), you can - use QGraphicsScene(int top, int left, int width, int - height). - - \row \o Q3Canvas::allItems() \o QGraphicsScene::items() - returns a list of all items on the scene. - - \row \o Q3Canvas::backgroundColor() \o You can assign a color for the - background through the QGraphicsScene::backgroundBrush - or QGraphicsView::backgroundBrush properties. - - \row \o Q3Canvas::backgroundPixmap() \o You can set a tiled - pixmap for the background through - QGraphicsScene::backgroundBrush or - QGraphicsView::backgroundBrush. For more control on the pixmap - positioning, you can reimplement - QGraphicsScene::drawBackground() or - QGraphicsView::drawBackground(). - - \row \o Q3Canvas::chunkSize() \o The closest equivalent to the - chunks size in Q3Canvas is the depth of QGraphicsScene's BSP - tree. QGraphicsScene assigns a depth automatically, and the - size of each scene segment depends on this depth, and - QGraphicsScene::sceneRect(). See - QGraphicsScene::itemIndexMethod. - - \row \o Q3Canvas::collisions() \o QGraphicsScene provides - several means to detect item collisions. The - QGraphicsScene::items() overloads return items that collide - with a point, a rectangle, a polygon, or an arbitrary vector - path (QPainterPath). You can also call - QGraphicsScene::collidingItems() to determine collision with - an item. - - \row \o Q3Canvas::drawArea() \o The QGraphicsScene::render() - function provides the original behavior - 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. QGraphicsScene::render() can - optionally transform the source rectangle to fit into the - destination rectangle. See \l{Printing} - - \row \o Q3Canvas::onCanvas() \o The is no equivalent to this - function in Graphics View. However, you can combine - QGraphicsScene::sceneRect() and QRectF::intersects(): - \snippet doc/src/snippets/code/doc_src_porting4-canvas.qdoc 0 - - \row \o Q3Canvas::rect() \o The equivalent, - QGraphicsScene::sceneRect(), returns a QRectF (double - precision coordinates). Its top-left corner can be an - arbitrary coordinate (Q3Canvas::rect().topLeft() is always (0, - 0)). - - \row \o Q3Canvas::resize() \o You can call - QGraphicsScene::setSceneRect(0, 0, width, height) instead. - - \row \o Q3Canvas::retune() \o See - QGraphicsScene::itemIndexMethod. You can tune the indexing by - setting a suitable sceneRect(). The optimal depth of - QGraphicsScene's BSP tree is determined automatically. - - \row \o Q3Canvas::setAdvancePeriod() \o There is no concept of - an advance period in the new API; instead, you can connect - QTimer::timeout() to the QGraphicsScene::advance() slot to - obtain similar functionality. This will cause all items' - QGraphicsItem::advance() function to be called. See also - QGraphicsItemAnimation. - - \row \o Q3Canvas::setAllChanged() \o You can call - QGraphicsScene::update() with no arguments. - - \row \o Q3Canvas::setChanged() \o QGraphicsScene::update() - will trigger a repaint of the whole scene, or parts of the - scene. - - \row \o Q3Canvas::setDoubleBuffering() \o 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 QGraphicsScene's background - through - QGraphicsView::setCacheMode(). QGraphicsView::resetCachedContent() - will reset the areas of the cache that has changed. - - \row \o Q3Canvas::tile() \o See \l{Porting scenes with tiles}. - - \row \o Q3Canvas::setTiles() \o See \l{Porting scenes with tiles}. - - \row \o Q3Canvas::setUnchanged() \o There is no equivalent in - Graphics View. This call can usually be removed with no side - effects. - - \row \o Q3Canvas::setUpdatePeriod() \o There is no concept of an - update period in the new API; instead, you can connect - QTimer::timeout() to the QGraphicsScene::update() slot to obtain - similar functionality. See also QGraphicsItemAnimation. - - \row \o Q3Canvas::size() \o - \tt{QGraphicsScene::sceneRect().size()} returns a QSizeF, with - double precision coordinates. - - \row \o Q3Canvas::validChunk() \o To determine if an area is - inside the scene area or not, you can combine - QRectF::intersects() with QGraphicsScene::sceneRect(). - - \row \o Q3Canvas::resized() \o QGraphicsScene emits - \l{QGraphicsScene::sceneRectChanged()}{sceneRectChanged()} - whenever the scene rect changes. - - \row \o Q3Canvas::drawBackground() \o You can reimplement - QGraphicsScene::drawBackground() to render the scene - background. You can also reimplement - QGraphicsView::drawBackground() to override this background if - you need different backgrounds for different views. - - \row \o Q3Canvas::drawForeground() \o You can reimplement - QGraphicsScene::drawForeground() to render the scene - foreground. You can also reimplement - QGraphicsView::drawForeground() to override this foreground if - you need different foregrounds for different views. - - \endtable - - \section2 Porting scenes with tiles - - QGraphicsScene does not provide an API for tiles. However, you - can achieve similar behavior by drawing pixmaps in a reimplementation of - QGraphicsScene::drawBackground(). - - 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. - - \table - \row \i 0 \i 1 \i 2 \i 3 - \row \i 4 \i 5 \i 6 \i 7 - \endtable - - With Graphics View, this pixmap can be stored as a member of a - subclass of 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: - - \snippet doc/src/snippets/code/doc_src_porting4-canvas.qdoc 1 - - 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 Q3Canvas functions. - - We start by creating a subclass of QGraphicsScene ("TileScene"). - In this class, we declare two of the tile - functions from 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. - - \snippet doc/src/snippets/code/doc_src_porting4-canvas.qdoc 2 - - 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. - - \snippet doc/src/snippets/code/doc_src_porting4-canvas.qdoc 3 - - The setTile() function updates the tiles index, and then - updates the corresponding rect in the scene by calling - tileRect(). - - \snippet doc/src/snippets/code/doc_src_porting4-canvas.qdoc 4 - - The first tileRect() function returns a QRect for the tile at - position (x, y). - - \snippet doc/src/snippets/code/doc_src_porting4-canvas.qdoc 5 - - The second tileRect() function returns a QRect for a tile number. - With these functions in place, we can implement the drawBackground() - function. - - \snippet doc/src/snippets/code/doc_src_porting4-canvas.qdoc 6 - - In drawBackground(), we redraw all tiles that have been - exposed by intersecting each tile rect with the exposed background - area. - - \section1 Porting from Q3CanvasView - - The closest equivalent to Q3CanvasView in Graphics View is - called QGraphicsView. In most cases, this is the easiest - class to port. In addition to providing all of Q3CanvasView's - functionality, QGraphicsView includes some useful new features. You - can read more about this in QGraphicsView's documentation. - - \section2 Porting table - - \table - \header \o Q3CanvasView \o QGraphicsView - - \row \o Q3CanvasView::Q3CanvasView() \o QGraphicsView provides - the same constructors as Q3CanvasView, but without the name - and flags arguments. You can set the name by calling - \l{QWidget::setObjectName()}{setObjectName()}, and the flags by - calling \l{QWidget::setWindowFlags()}{setWindowFlags()}. - - \row \o Q3CanvasView::canvas() \o QGraphicsView::scene() - returns the scene that is currently associated with the - view. QGraphicsScene also provides the opposite function, - QGraphicsScene::views(), which returns a list of views - observing the scene. - - \row \o Q3CanvasView::inverseWorldMatrix() \o You can call - QGraphicsView::matrix() and QMatrix::inverted(). - QGraphicsView::mapToScene() and QGraphicsView::mapFromScene() - allow transforming of viewport shapes to scene shapes, and - vice versa. - - \row \o Q3CanvasView::setCanvas() \o QGraphicsView::setScene(). - - \row \o Q3CanvasView::setWorldMatrix() \o - QGraphicsView::setMatrix(), QGraphicsView::rotate(), - QGraphicsView::scale(), QGraphicsView::shear() and - QGraphicsView::translate(). - - \row \o Q3CanvasView::worldMatrix() \o QGraphicsView::matrix() - - \row \o Q3CanvasView::drawContents() \o The - QGraphicsView::drawBackground() function draws the background, - QGraphicsView::drawItems() draws the items, and - QGraphicsView::drawForeground() draws the foreground of the - scene in scene coordinates. You can also reimplement these - functions in QGraphicsScene. - - \endtable - - \section2 Other differences - - QGraphicsView can cache the visible contents of the scene, - similar to how Q3Canvas::setDoubleBuffering() could cache the - entire scene contents. You can call - QGraphicsView::setCacheMode() to configure cacheing, and - QGraphicsView::resetCachedContent() invalidates the cache. - - For improved navigation support, you can set a resize or - transformation anchor through QGraphicsView::resizeAnchor and - 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 QGraphicsView::dragMode of the view, - QGraphicsView will provide rubber band selection or - click-and-pull navigation using the - \l{Qt::OpenHandCursor}{OpenHandCursor} and - \l{Qt::ClosedHandCursor}{ClosedHandCursor} cursors. - - \section1 Porting from Q3CanvasItem - - The closest equivalent to Q3CanvasItem in Graphics View is - called QGraphicsItem. Deriving from this class is very common, - and because of that, porting from Q3CanvasItem often involves - more work than Q3Canvas and Q3CanvasView. - - Q3CanvasItem has become easier to use, easier to subclass, and more - powerful with QGraphicsItem. The key difference from 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 QGraphicsItem - in its own class documentation. - - This section starts with a table that shows how to port each function - from Q3CanvasItem to QGraphicsItem. Immediately after that, each of - Q3CanvasItem's standard subclasses have a section of their own. - - \table - \header \o Q3CanvasItem \o QGraphicsItem - - \row \o Q3CanvasItem::advance() \o QGraphicsItem::advance() is - provided for compatibility. QGraphicsScene::advance() calls - QGraphicsItem::advance() for all items. See also QTimeLine and - QGraphicsItemAnimation. - - \row \o Q3CanvasItem::animated() \o No equivalent; all items - are advanced by QGraphicsScene::advance(). - - \row \o Q3CanvasItem::boundingRectAdvanced() \o No - equivalent. You can translate QGraphicsItem::boundingRect() - instead (see QRectF::translate()). - - \row \o Q3CanvasItem::canvas() \o QGraphicsItem::scene() - - \row \o Q3CanvasItem::collidesWith() \o - QGraphicsItem::collidesWithItem() and - QGraphicsItem::collidesWithPath(). - - \row \o Q3CanvasItem::collisions() \o - 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. - - \row \o Q3CanvasItem::draw() \o QGraphicsItem::paint(). See - also QStyleOptionGraphicsItem, QGraphicsScene::drawItems() and - QGraphicsView::drawItems(). - - \row \o Q3CanvasItem::hide() \o QGraphicsItem::hide() or - QGraphicsItem::setVisible(). \l{QGraphicsItem}s are \e visible by - default; \l{Q3CanvasItem}s, however, are not. - - \row \o Q3CanvasItem::isActive() \o No equivalent. To achieve - similar behavior, you can add this property in a custom - subclass of QGraphicsItem. - - \row \o Q3CanvasItem::isVisible() \o - QGraphicsItem::isVisible(). \l{QGraphicsItem}s are \e visible by - default; \l{Q3CanvasItem}s, however, are not. - - \row \o Q3CanvasItem::move() \o You can call - QGraphicsItem::setPos() to change the position of the item. - - \row \o Q3CanvasItem::rtti() \o QGraphicsItem::type() and qgraphicsitem_cast(). - - \row \o Q3CanvasItem::setActive() \o No equivalent. - - \row \o Q3CanvasItem::setAnimated() \o No equivalent; all - items are by default "animated" (i.e., - QGraphicsScene::advance() advances all items on the scene). - - \row \o Q3CanvasItem::setCanvas() \o You can call - QGraphicsScene::addItem(), or pass a pointer to the canvas to - QGraphicsItem's constructor. - - \row \o Q3CanvasItem::setVelocity() \o No equivalent. You can - add x and y velocity as member data of your class, and call - QGraphicsItem::moveBy(x, y) from inside - QGraphicsItem::advance(). See also QTimeLine and - QGraphicsItemAnimation. - - \row \o Q3CanvasItem::setVisible() \o - QGraphicsItem::setVisible(). \l{QGraphicsItem}s are \e visible by - default; \l{Q3CanvasItem}s, however, are not. - - \row \o Q3CanvasItem::setX() \o QGraphicsItem::setPos() - \row \o Q3CanvasItem::setY() \o QGraphicsItem::setPos() - - \row \o Q3CanvasItem::setXVelocity() \o No equivalent. - \row \o Q3CanvasItem::setYVelocity() \o No equivalent. - - \row \o Q3CanvasItem::setZ() \o QGraphicsItem::setZValue() - - \row \o Q3CanvasItem::show() \o QGraphicsItem::show() or - QGraphicsItem::setVisible(). \l{QGraphicsItem}s are \e visible by - default; \l{Q3CanvasItem}s, however, are not. - - \row \o Q3CanvasItem::xVelocity() \o No equivalent. - \row \o Q3CanvasItem::yVelocity() \o No equivalent. - - \endtable - - Note that some virtual functions that have passed on to - QGraphicsItem have lost their virtuality. An example is - Q3CanvasItem::moveBy(), which was often used to track movement of - items. In this case, the virtual QGraphicsItem::itemChange() has - taken over as a substitute. - - \section2 Q3CanvasPolygonalItem - - The closest equivalent to Q3CanvasPolygonalItem in - Graphics View is called QAbstractGraphicsShapeItem. Unlike - Q3CanvasPolygonalItem, it does not define area points - (Q3CanvasPolygonalItem::areaPoints()); instead, each - item's geometry is stored as a member of the subclasses. - - The Q3CanvasPolygonalItem::drawShape() function is no longer - available; instead, you can set the brush and pen from inside - QGraphicsItem::paint(). - - \table - \header \o Q3CanvasPolygonalItem \o QAbstractGraphicsShapeItem - - \row \o Q3CanvasPolygonalItem::areaPoints() \o No equivalent; each - item's geometry is stored in the respective subclass. - - \row \o Q3CanvasPolygonalItem::areaPointsAdvanced() \o No - equivalent; you can use QPolygonF::translate() or - QPainterPath::translate() instead. - - \row \o Q3CanvasPolygonalItem::drawShape() \o - QGraphicsItem::paint(). You can set the pen and brush from inside - this function. - - \row \o Q3CanvasPolygonalItem::invalidate() \o Call - QGraphicsItem::prepareGeometryChange() before changing the - item's geometry. - - \row \o Q3CanvasPolygonalItem::isValid() \o No equivalent; - items' geometry is always in a valid state. - - \row \o Q3CanvasPolygonalItem::winding() \o This function is only - useful for polygon items and path items; see - QGraphicsPolygonItem::fillRule(), and QPainterPath::fillRule() for - QGraphicsPathItem. - - \endtable - - \section2 Q3CanvasEllipse - - The closest equivalent to Q3CanvasEllipse in Graphics View - is called QGraphicsEllipseItem. The most noticable - difference to QGraphicsEllipseItem is that the ellipse is - not longer drawn centered around its position; rather, it - is drawn using a bounding QRectF, just like - QPainter::drawEllipse(). - - For compatibility, you may want to shift the ellipse up and to the - left to keep the ellipse centered. Example: - - \snippet doc/src/snippets/code/doc_src_porting4-canvas.qdoc 7 - - Note: QGraphicsEllipseItem uses QAbstractGraphicsShapeItem::pen() - for outlines, whereas Q3CanvasEllipse did not use - Q3CanvasPolygonalItem::pen(). - - \table - \header \o Q3CanvasEllipse \o QGraphicsEllipseItem - - \row \o Q3CanvasEllipse::angleLength() \o QGraphicsEllipseItem::spanAngle() - - \row \o Q3CanvasEllipse::angleStart() \o QGraphicsEllipseItem::startAngle() - - \row \o Q3CanvasEllipse::setAngles() \o - QGraphicsEllipseItem::setStartAngle() and - QGraphicsEllipseItem::setSpanAngle() - - \row \o Q3CanvasEllipse::setSize() \o QGraphicsEllipseItem::setRect() - - \endtable - - \section2 Q3CanvasLine - - The closest equivalent to Q3CanvasLine in Graphics View is - called QGraphicsLineItem. - - \table - \header \o Q3CanvasLine \o QGraphicsLineItem - - \row \o Q3CanvasLine::endPoint() \o QGraphicsLineItem::line() and QLineF::p2() - - \row \o Q3CanvasLine::setPoints() \o QGraphicsLineItem::setLine() - - \row \o Q3CanvasLine::startPoint() \o QGraphicsLineItem::line() - and QLineF::p1() - - \endtable - - \section2 Q3CanvasPolygon - - The closest equivalent to Q3CanvasPolygon in Graphics View - is called QGraphicsPolygonItem. - - \table - \header \o Q3CanvasPolygon \o QGraphicsPolygonItem - - \row \o Q3CanvasPolygon::areaPoints() \o - QGraphicsPolygonItem::polygon() and QGraphicsItem::mapToParent() - - \row \o Q3CanvasPolygon::points() \o QGraphicsPolygonItem::polygon() - - \row \o Q3CanvasPolygon::setPoints() \o QGraphicsPolygonItem::setPolygon() - - \endtable - - \section2 Q3CanvasSpline - - The closest equivalent to Q3CanvasSpline in Graphics View - is called QGraphicsPathItem. This item can be used to - describe any type of path supported by QPainter. - - Q3CanvasSpline takes its control points as a Q3PointArray, but - QPainterPath operates on a sequence of calls to - QPainterPath::moveTo() and QPainterPath::cubicTo(). Here is how - you can convert a bezier curve Q3PointArray to a QPainterPath: - - \snippet doc/src/snippets/code/doc_src_porting4-canvas.qdoc 8 - - Note: QGraphicsPathItem uses QAbstractGraphicsShapeItem::pen() for - outlines, whereas Q3CanvasSpline did not use - Q3CanvasPolygonalItem::pen(). - - \table - \header \o Q3CanvasSpline \o QGraphicsPathItem - - \row \o Q3CanvasSpline::closed() \o No equivalent. You can call - QPainterPath::closeSubPath() to close a subpath explicitly. - - \endtable - - \section2 Q3CanvasRectangle - - The closest equivalent to Q3CanvasRectangle in Graphics - View is called QGraphicsRectItem. - - \table - \header \o Q3CanvasRectangle \o QGraphicsRectItem - - \row \o Q3CanvasRectangle::height() \o QGraphicsRectItem::rect() - and QRectF::height() - - \row \o Q3CanvasRectangle::setSize() \o QGraphicsRectItem::setRect() - - \row \o Q3CanvasRectangle::size() \o QGraphicsRectItem::rect() and QRectF::size() - - \row \o Q3CanvasRectangle::width() \o QGraphicsRectItem::rect() and QRectF::width() - - \row \o Q3CanvasRectangle::chunks() \o No equivalent. - - \endtable - - \section2 Q3CanvasSprite - - Q3CanvasSprite is the item class that differs the most from its - Q3Canvas predecessor. The closest resemblance of Q3CanvasSprite in - Graphics View is QGraphicsPixmapItem. - - Q3CanvasSprite supports animated pixmaps; 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 \l{Ported Asteroids Example}, a subclass of - QGraphicsPixmapItem is used to replace Q3CanvasSprite, storing a - list of pixmaps and a frame counter. The animation is advanced in - QGraphicsItem::advance(). - - \section3 Q3CanvasPixmap, Q3CanvasPixmapArray - - These classes have been removed from the API. You can use - QPixmap instead of Q3CanvasPixmap, and QList instead of - Q3CanvasPixmapArray. - - Q3CanvasPixmapArray included convenience for loading a - sequence of pixmaps or masks using a path with a wildcard (see - Q3CanvasPixmapArray::readPixmaps() and - Q3CanvasPixmapArray::readCollisionMasks()). To achieve similar - functionality using Graphics View, you can load the images by - using QDir: - - \snippet doc/src/snippets/code/doc_src_porting4-canvas.qdoc 9 - - \section2 Q3CanvasText - - Q3CanvasText has been split into two classes in Graphics View: - QGraphicsSimpleTextItem and QGraphicsTextItem. For porting, - QGraphicsSimpleTextItem should be adequate. QGraphicsTextItem - provides advanced document structuring features similar to that of - QTextEdit, and it also allows interaction (e.g., editing and - selection). - - \table - \header \o Q3CanvasText \o QGraphicsSimpleTextItem - - \row \o Q3CanvasText::color() \o QGraphicsSimpleTextItem::pen(). - - \row \o Q3CanvasText::setColor() \o QGraphicsSimpleTextItem::setPen(). - - \row \o Q3CanvasText::textFlags() \o Use QGraphicsTextItem instead. - - \endtable - - - \section2 Q3CanvasItemList - - Use QList instead. - - \section1 Other Resources - - The \l{Porting to Qt 4.2's Graphics View} article in Qt Quarterly 21 covered the - process of porting the Qt 3 canvas example to Qt 4. - The result of this is the \l{Ported Canvas Example}{Ported Canvas} example. -*/ |