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Diffstat (limited to 'doc/src/snippets/separations/viewer.cpp')
| -rw-r--r-- | doc/src/snippets/separations/viewer.cpp | 329 |
1 files changed, 329 insertions, 0 deletions
diff --git a/doc/src/snippets/separations/viewer.cpp b/doc/src/snippets/separations/viewer.cpp new file mode 100644 index 0000000..f33be69 --- /dev/null +++ b/doc/src/snippets/separations/viewer.cpp @@ -0,0 +1,329 @@ +/**************************************************************************** +** +** Copyright (C) 2009 Nokia Corporation and/or its subsidiary(-ies). +** Contact: Qt Software Information (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 either Technology Preview License Agreement or the +** Beta Release License Agreement. +** +** 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 1.0, included in the file LGPL_EXCEPTION.txt in this +** package. +** +** GNU General Public License Usage +** Alternatively, this file may be used under the terms of the GNU +** General Public License version 3.0 as published by the Free Software +** Foundation and appearing in the file LICENSE.GPL included in the +** packaging of this file. Please review the following information to +** ensure the GNU General Public License version 3.0 requirements will be +** met: http://www.gnu.org/copyleft/gpl.html. +** +** If you are unsure which license is appropriate for your use, please +** contact the sales department at qt-sales@nokia.com. +** $QT_END_LICENSE$ +** +****************************************************************************/ + +/* +viewer.cpp + +Provides a main window for displaying a user-specified original image +with three color separations in a grid layout. + +A main menu provides entries for selecting files, and adjusting the +brightness of the separations. +*/ + +#include <QtGui> + +#include "finalwidget.h" +#include "screenwidget.h" +#include "viewer.h" + +/* + Constructor: initializes a default value for the brightness, creates + the main menu entries, and constructs a central widget that contains + enough space for images to be displayed. +*/ + +Viewer::Viewer() +{ + setWindowTitle(tr("QImage Color Separations")); + + brightness = 255; + + createMenus(); + setCentralWidget(createCentralWidget()); +} + +/* + Creates a main menu with two entries: a File menu, to allow the image + to be selected, and a Brightness menu to allow the brightness of the + separations to be changed. + + Initially, the Brightness menu items are disabled, but the first entry in + the menu is checked to reflect the default brightness. +*/ + +void Viewer::createMenus() +{ + fileMenu = new QMenu(tr("&File"), this); + brightnessMenu = new QMenu(tr("&Brightness"), this); + + QAction *openAction = fileMenu->addAction(tr("&Open...")); + openAction->setShortcut(QKeySequence("Ctrl+O")); + saveAction = fileMenu->addAction(tr("&Save...")); + saveAction->setShortcut(QKeySequence("Ctrl+S")); + saveAction->setEnabled(false); + QAction *quitAction = fileMenu->addAction(tr("E&xit")); + quitAction->setShortcut(QKeySequence("Ctrl+Q")); + + QAction *noBrightness = brightnessMenu->addAction(tr("&0%")); + noBrightness->setCheckable(true); + QAction *quarterBrightness = brightnessMenu->addAction(tr("&25%")); + quarterBrightness->setCheckable(true); + QAction *halfBrightness = brightnessMenu->addAction(tr("&50%")); + halfBrightness->setCheckable(true); + QAction *threeQuartersBrightness = brightnessMenu->addAction(tr("&75%")); + threeQuartersBrightness->setCheckable(true); + QAction *fullBrightness = brightnessMenu->addAction(tr("&100%")); + fullBrightness->setCheckable(true); + + menuMap[noBrightness] = None; + menuMap[quarterBrightness] = Quarter; + menuMap[halfBrightness] = Half; + menuMap[threeQuartersBrightness] = ThreeQuarters; + menuMap[fullBrightness] = Full; + + currentBrightness = fullBrightness; + currentBrightness->setChecked(true); + brightnessMenu->setEnabled(false); + + menuBar()->addMenu(fileMenu); + menuBar()->addMenu(brightnessMenu); + + connect(openAction, SIGNAL(triggered()), this, SLOT(chooseFile())); + connect(saveAction, SIGNAL(triggered()), this, SLOT(saveImage())); + connect(quitAction, SIGNAL(triggered()), qApp, SLOT(quit())); + connect(brightnessMenu, SIGNAL(triggered(QAction *)), this, + SLOT(setBrightness(QAction *))); +} + +/* + Constructs a central widget for the window consisting of a two-by-two + grid of labels, each of which will contain an image. We restrict the + size of the labels to 256 pixels, and ensure that the window cannot + be resized. +*/ + +QFrame* Viewer::createCentralWidget() +{ + QFrame* frame = new QFrame(this); + grid = new QGridLayout(frame); + grid->setSpacing(8); + grid->setMargin(4); + + layout()->setSizeConstraint(QLayout::SetFixedSize); + + QSize labelSize(256, 256); + + finalWidget = new FinalWidget(frame, tr("Final image"), labelSize); + + cyanWidget = new ScreenWidget(frame, Qt::cyan, tr("Cyan"), + ScreenWidget::Cyan, labelSize); + magentaWidget = new ScreenWidget(frame, Qt::magenta, tr("Magenta"), + ScreenWidget::Magenta, labelSize); + yellowWidget = new ScreenWidget(frame, Qt::yellow, tr("Yellow"), + ScreenWidget::Yellow, labelSize); + + connect(cyanWidget, SIGNAL(imageChanged()), this, SLOT(createImage())); + connect(magentaWidget, SIGNAL(imageChanged()), this, SLOT(createImage())); + connect(yellowWidget, SIGNAL(imageChanged()), this, SLOT(createImage())); + + grid->addWidget(finalWidget, 0, 0, Qt::AlignTop | Qt::AlignHCenter); + grid->addWidget(cyanWidget, 0, 1, Qt::AlignTop | Qt::AlignHCenter); + grid->addWidget(magentaWidget, 1, 0, Qt::AlignTop | Qt::AlignHCenter); + grid->addWidget(yellowWidget, 1, 1, Qt::AlignTop | Qt::AlignHCenter); + + return frame; +} + +/* + Provides a dialog window to allow the user to specify an image file. + If a file is selected, the appropriate function is called to process + and display it. +*/ + +void Viewer::chooseFile() +{ + QString imageFile = QFileDialog::getOpenFileName(this, + tr("Choose an image file to open"), path, tr("Images (*.*)")); + + if (!imageFile.isEmpty()) { + openImageFile(imageFile); + path = imageFile; + } +} + +/* + Changes the value of the brightness according to the entry selected in the + Brightness menu. The selected entry is checked, and the previously selected + entry is unchecked. + + The color separations are updated to use the new value for the brightness. +*/ + +void Viewer::setBrightness(QAction *action) +{ + if (!menuMap.contains(action) || scaledImage.isNull()) + return; + + Brightness amount = menuMap[action]; + + switch (amount) { + case None: + brightness = 0; break; + case Quarter: + brightness = 64; break; + case Half: + brightness = 128; break; + case ThreeQuarters: + brightness = 191; break; + case Full: + brightness = 255; break; + default: return; + } + + currentBrightness->setChecked(false); + currentBrightness = action; + currentBrightness->setChecked(true); + + createImage(); +} + +/* + Load the image from the file given, and create four pixmaps based + on the original image. + + The window caption is set, and the Brightness menu enabled if the image file + can be loaded. +*/ + +void Viewer::openImageFile(QString &imageFile) +{ + QImage originalImage; + + if (originalImage.load(imageFile)) { + setWindowTitle(imageFile); + //menuBar()->setItemEnabled(brightnessMenuId, true); + saveAction->setEnabled(true); + brightnessMenu->setEnabled(true); + + /* Note: the ScaleMin value may be different for Qt 4. */ + scaledImage = originalImage.scaled(256, 256, Qt::KeepAspectRatio); + + cyanWidget->setImage(scaledImage); + magentaWidget->setImage(scaledImage); + yellowWidget->setImage(scaledImage); + createImage(); + } + else + (void) QMessageBox::warning(this, tr("Cannot open file"), + tr("The selected file could not be opened."), + QMessageBox::Cancel, QMessageBox::NoButton, QMessageBox::NoButton); +} + +/* + Creates an image by combining the contents of the three screens + to present a page preview. + + The image associated with each screen is separated into cyan, + magenta, and yellow components. We add up the values for each + component from the three screen images, and subtract the totals + from the maximum value for each corresponding primary color. +*/ + +void Viewer::createImage() +{ + QImage newImage = scaledImage.copy(); + + QImage *image1 = cyanWidget->image(); + QImage *image2 = magentaWidget->image(); + QImage *image3 = yellowWidget->image(); + int darkness = 255 - brightness; + + for (int y = 0; y < newImage.height(); ++y) { + for (int x = 0; x < newImage.width(); ++x) { + + // Create three screens, using the quantities of the source + // CMY components to determine how much of each of the + // inks are to be put on each screen. + QRgb p1(image1->pixel(x, y)); + float cyan1 = 255 - qRed(p1); + float magenta1 = 255 - qGreen(p1); + float yellow1 = 255 - qBlue(p1); + + QRgb p2(image2->pixel(x, y)); + float cyan2 = 255 - qRed(p2); + float magenta2 = 255 - qGreen(p2); + float yellow2 = 255 - qBlue(p2); + + QRgb p3(image3->pixel(x, y)); + float cyan3 = 255 - qRed(p3); + float magenta3 = 255 - qGreen(p3); + float yellow3 = 255 - qBlue(p3); + + QColor newColor( + qMax(255 - int(cyan1+cyan2+cyan3) - darkness, 0), + qMax(255 - int(magenta1+magenta2+magenta3) - darkness, 0), + qMax(255 - int(yellow1+yellow2+yellow3) - darkness, 0)); + + newImage.setPixel(x, y, newColor.rgb()); + } + } + + finalWidget->setPixmap(QPixmap::fromImage(newImage)); +} + +/* + Provides a dialog window to allow the user to save the image file. +*/ + +void Viewer::saveImage() +{ + QString imageFile = QFileDialog::getSaveFileName(this, + tr("Choose a filename to save the image"), "", tr("Images (*.png)")); + + QFileInfo info(imageFile); + + if (!info.baseName().isEmpty()) { + QString newImageFile = QFileInfo(info.absoluteDir(), + info.baseName() + ".png").absoluteFilePath(); + + if (!finalWidget->pixmap()->save(newImageFile, "PNG")) + (void) QMessageBox::warning(this, tr("Cannot save file"), + tr("The file could not be saved."), + QMessageBox::Cancel, QMessageBox::NoButton, + QMessageBox::NoButton); + } + else + (void) QMessageBox::warning(this, tr("Cannot save file"), + tr("Please enter a valid filename."), + QMessageBox::Cancel, QMessageBox::NoButton, + QMessageBox::NoButton); +} |