--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/doc/src/snippets/separations/viewer.cpp Wed Mar 31 11:06:36 2010 +0300
@@ -0,0 +1,329 @@
+/****************************************************************************
+**
+** Copyright (C) 2010 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.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** 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.
+**
+**
+**
+**
+**
+**
+**
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+/*
+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);
+}