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96 lines
3.9 KiB
96 lines
3.9 KiB
/****************************************************************************
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**
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** Documentation for the canvas module
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**
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** Copyright (C) 2000-2008 Trolltech ASA. All rights reserved.
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**
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** This file is part of the Qt GUI Toolkit.
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**
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** This file may be used under the terms of the GNU General
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** Public License versions 2.0 or 3.0 as published by the Free
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** Software Foundation and appearing in the files LICENSE.GPL2
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** and LICENSE.GPL3 included in the packaging of this file.
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** Alternatively you may (at your option) use any later version
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** of the GNU General Public License if such license has been
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** publicly approved by Trolltech ASA (or its successors, if any)
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** and the KDE Free Qt Foundation.
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**
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** Please review the following information to ensure GNU General
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** Public Licensing requirements will be met:
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** http://trolltech.com/products/qt/licenses/licensing/opensource/.
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** If you are unsure which license is appropriate for your use, please
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** review the following information:
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** http://trolltech.com/products/qt/licenses/licensing/licensingoverview
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** or contact the sales department at sales@trolltech.com.
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**
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** This file may be used under the terms of the Q Public License as
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** defined by Trolltech ASA and appearing in the file LICENSE.QPL
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** included in the packaging of this file. Licensees holding valid Qt
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** Commercial licenses may use this file in accordance with the Qt
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** Commercial License Agreement provided with the Software.
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**
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** This file is provided "AS IS" with NO WARRANTY OF ANY KIND,
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** INCLUDING THE WARRANTIES OF DESIGN, MERCHANTABILITY AND FITNESS FOR
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** A PARTICULAR PURPOSE. Trolltech reserves all rights not granted
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** herein.
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**
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**********************************************************************/
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/*!
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\page canvas.html
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\title Canvas Module
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\if defined(commercial)
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This module is part of the \link commercialeditions.html Qt Enterprise Edition
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\endlink.
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\endif
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The canvas module provides a highly optimized 2D graphic area called
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\l QCanvas. The canvas can contain an arbitrary number of \link
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QCanvasItem QCanvasItems \endlink. Canvas items can have an arbitrary
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shape, size and content, can be freely moved around in the canvas,
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and can be checked for collisions. Canvas items can be set to move
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across the canvas automatically and animated canvas items are
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supported with QCanvasSprite. (If you require 3D graphics see Qt's
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\link opengl.html OpenGL module \endlink.)
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The canvas module uses a document/view model. The \l QCanvasView class
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is used to show a particular view of a canvas. Multiple views can operate
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on the same canvas at the same time. Every view can use an arbitrary
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transformation matrix on the canvas which makes it easy to implement
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features such as zooming.
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<center><a href="qcanvas.html">
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<img src="qcanvas.png" alt="Screenshot of a canvas"></a></center>
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Qt provides a number of predefined \l QCanvas items as listed below.
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\list
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\i QCanvasItem -- An abstract base class for all canvas items.
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\i QCanvasEllipse -- An ellipse or "pie segment".
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\i QCanvasLine -- A line segment.
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\i QCanvasPolygon -- A polygon.
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\i QCanvasPolygonalItem -- A base class for items that have a
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non-rectangular shape. Most canvas items derive from this class.
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\i QCanvasRectangle -- A rectangle. The rectangle cannot be tilted or
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rotated. Rotated rectangles can be drawn using QCanvasPolygon.
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\i QCanvasSpline -- A multi-bezier spline.
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\i QCanvasSprite -- An animated pixmap.
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\i QCanvasText -- A text string.
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\endlist
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The two classes \l QCanvasPixmap and \l QCanvasPixmapArray are used
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by \l QCanvasSprite to show animated and moving pixmaps on the
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canvas.
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More specialized items can be created by inheriting from one of the
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canvas item classes. It is easiest to inherit from one of
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QCanvasItem's derived classes (usually \l QCanvasPolygonalItem) rather
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than inherit QCanvasItem directly.
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See \c examples/canvas for an example that shows off some of QCanvas's
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capabilities.
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*/
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