/**************************************************************************** ** ** Copyright (C) 2011 Nokia Corporation and/or its subsidiary(-ies). ** All rights reserved. ** Contact: Nokia Corporation (qt-info@nokia.com) ** ** This file is part of the documentation of the Qt Toolkit. ** ** $QT_BEGIN_LICENSE:FDL$ ** GNU Free Documentation License ** Alternatively, this file may be used under the terms of the GNU Free ** Documentation License version 1.3 as published by the Free Software ** Foundation and appearing in the file included in the packaging of ** this file. ** ** Other Usage ** Alternatively, this file may be used in accordance with the terms ** and conditions contained in a signed written agreement between you ** and Nokia. ** ** ** ** ** $QT_END_LICENSE$ ** ****************************************************************************/ /*! \example painting/imagecomposition \title Image Composition Example \brief The Image Composition example lets the user combine images together using any composition mode supported by QPainter, described in detail in \l{QPainter#Composition Modes}{Composition Modes}. \image imagecomposition-example.png \section1 Setting Up The Resource File The Image Composition example requires two source images, \e butterfly.png and \e checker.png that are embedded within \e imagecomposition.qrc. The file contains the following code: \quotefile examples/painting/imagecomposition/imagecomposition.qrc For more information on resource files, see \l{The Qt Resource System}. \section1 ImageComposer Class Definition The \c ImageComposer class is a subclass of QWidget that implements three private slots, \c chooseSource(), \c chooseDestination(), and \c recalculateResult(). \snippet examples/painting/imagecomposition/imagecomposer.h 0 In addition, \c ImageComposer consists of five private functions, \c addOp(), \c chooseImage(), \c loadImage(), \c currentMode(), and \c imagePos(), as well as private instances of QToolButton, QComboBox, QLabel, and QImage. \snippet examples/painting/imagecomposition/imagecomposer.h 1 \section1 ImageComposer Class Implementation We declare a QSize object, \c resultSize, as a static constant with width and height equal to 200. \snippet examples/painting/imagecomposition/imagecomposer.cpp 0 Within the constructor, we instantiate a QToolButton object, \c sourceButton and set its \l{QAbstractButton::setIconSize()}{iconSize} property to \c resultSize. The \c operatorComboBox is instantiated and then populated using the \c addOp() function. This function accepts a QPainter::CompositionMode, \a mode, and a QString, \a name, representing the name of the composition mode. \snippet examples/painting/imagecomposition/imagecomposer.cpp 1 The \c destinationButton is instantiated and its \l{QAbstractButton::setIconSize()}{iconSize} property is set to \c resultSize as well. The \l{QLabel}s \c equalLabel and \c resultLabel are created and \c{resultLabel}'s \l{QWidget::setMinimumWidth()} {minimumWidth} is set. \snippet examples/painting/imagecomposition/imagecomposer.cpp 2 We connect the following signals to their corresponding slots: \list \o \c{sourceButton}'s \l{QPushButton::clicked()}{clicked()} signal is connected to \c chooseSource(), \o \c{operatorComboBox}'s \l{QComboBox::activated()}{activated()} signal is connected to \c recalculateResult(), and \o \c{destinationButton}'s \l{QToolButton::clicked()}{clicked()} signal is connected to \c chooseDestination(). \endlist \snippet examples/painting/imagecomposition/imagecomposer.cpp 3 A QGridLayout, \c mainLayout, is used to place all the widgets. Note that \c{mainLayout}'s \l{QLayout::setSizeConstraint()}{sizeConstraint} property is set to QLayout::SetFixedSize, which means that \c{ImageComposer}'s size cannot be resized at all. \snippet examples/painting/imagecomposition/imagecomposer.cpp 4 We create a QImage, \c resultImage, and we invoke \c loadImage() twice to load both the image files in our \e imagecomposition.qrc file. Then, we set the \l{QWidget::setWindowTitle()}{windowTitle} property to "Image Composition". \snippet examples/painting/imagecomposition/imagecomposer.cpp 5 The \c chooseSource() and \c chooseDestination() functions are convenience functions that invoke \c chooseImage() with specific parameters. \snippet examples/painting/imagecomposition/imagecomposer.cpp 6 \codeline \snippet examples/painting/imagecomposition/imagecomposer.cpp 7 The \c chooseImage() function loads an image of the user's choice, depending on the \a title, \a image, and \a button. \snippet examples/painting/imagecomposition/imagecomposer.cpp 10 The \c recalculateResult() function is used to calculate amd display the result of combining the two images together with the user's choice of composition mode. \snippet examples/painting/imagecomposition/imagecomposer.cpp 8 The \c addOp() function adds an item to the \c operatorComboBox using \l{QComboBox}'s \l{QComboBox::addItem()}{addItem} function. This function accepts a QPainter::CompositionMode, \a mode, and a QString, \a name. The rectangle is filled with Qt::Transparent and both the \c sourceImage and \c destinationImage are painted, before displaying it on \c resultLabel. \snippet examples/painting/imagecomposition/imagecomposer.cpp 9 The \c loadImage() function paints a transparent background using \l{QPainter::fillRect()}{fillRect()} and draws \c image in a centralized position using \l{QPainter::drawImage()}{drawImage()}. This \c image is then set as the \c{button}'s icon. \snippet examples/painting/imagecomposition/imagecomposer.cpp 11 The \c currentMode() function returns the composition mode currently selected in \c operatorComboBox. \snippet examples/painting/imagecomposition/imagecomposer.cpp 12 We use the \c imagePos() function to ensure that images loaded onto the QToolButton objects, \c sourceButton and \c destinationButton, are centralized. \snippet examples/painting/imagecomposition/imagecomposer.cpp 13 \section1 The \c main() Function The \c main() function instantiates QApplication and \c ImageComposer and invokes its \l{QWidget::show()}{show()} function. \snippet examples/painting/imagecomposition/main.cpp 0 */