diff -r dee5afe5301f -r 3f74d0d4af4c doc/src/snippets/separations/screenwidget.cpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/doc/src/snippets/separations/screenwidget.cpp	Thu Apr 08 14:19:33 2010 +0300
@@ -0,0 +1,218 @@
+/****************************************************************************
+**
+** 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.
+**
+**
+**
+**
+**
+**
+**
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+/*
+screenwidget.cpp
+
+A widget to display colour components from an image using independently
+selected colors. Controls are provided to allow the image to be inverted, and
+the color to be selection via a standard dialog. The image is displayed in a
+label widget.
+*/
+
+#include <QApplication>
+#include <QColorDialog>
+#include <QGridLayout>
+#include <QImage>
+#include <QLabel>
+#include <QMenu>
+#include <QMimeData>
+#include <QMouseEvent>
+#include <QPixmap>
+#include <QPushButton>
+#include <QWidget>
+
+#include "screenwidget.h"
+
+/*!
+Initializes the paint color, the mask color (cyan, magenta,
+or yellow), connects the color selector and invert checkbox to functions,
+and creates a two-by-two grid layout.
+*/
+
+ScreenWidget::ScreenWidget(QWidget *parent, QColor initialColor,
+                           const QString &name, Separation mask,
+                           const QSize &labelSize)
+    : QFrame(parent)
+{
+    paintColor = initialColor;
+    maskColor = mask;
+    inverted = false;
+
+    imageLabel = new QLabel;
+    imageLabel->setFrameShadow(QFrame::Sunken);
+    imageLabel->setFrameShape(QFrame::StyledPanel);
+    imageLabel->setMinimumSize(labelSize);
+
+    nameLabel = new QLabel(name);
+    colorButton = new QPushButton(tr("Modify..."));
+    colorButton->setBackgroundRole(QPalette::Button);
+    colorButton->setMinimumSize(32, 32);
+
+    QPalette palette(colorButton->palette());
+    palette.setColor(QPalette::Button, initialColor);
+    colorButton->setPalette(palette);
+
+    invertButton = new QPushButton(tr("Invert"));
+    //invertButton->setToggleButton(true);
+    //invertButton->setOn(inverted);
+    invertButton->setEnabled(false);
+
+    connect(colorButton, SIGNAL(clicked()), this, SLOT(setColor()));
+    connect(invertButton, SIGNAL(clicked()), this, SLOT(invertImage()));
+
+    QGridLayout *gridLayout = new QGridLayout;
+    gridLayout->addWidget(imageLabel, 0, 0, 1, 2);
+    gridLayout->addWidget(nameLabel, 1, 0);
+    gridLayout->addWidget(colorButton, 1, 1);
+    gridLayout->addWidget(invertButton, 2, 1, 1, 1);
+    setLayout(gridLayout);
+}
+
+/*!
+    Creates a new image by separating out the cyan, magenta, or yellow
+    component, depending on the mask color specified in the constructor.
+
+    The amount of the component found in each pixel of the image is used
+    to determine how much of a user-selected ink is used for each pixel
+    in the new image for the label widget.
+*/
+
+void ScreenWidget::createImage()
+{
+    newImage = originalImage.copy();
+
+    // Create CMY components for the ink being used.
+    float cyanInk = (255 - paintColor.red())/255.0;
+    float magentaInk = (255 - paintColor.green())/255.0;
+    float yellowInk = (255 - paintColor.blue())/255.0;
+
+    int (*convert)(QRgb);
+
+    switch (maskColor) {
+        case Cyan:
+            convert = qRed;
+            break;
+        case Magenta:
+            convert = qGreen;
+            break;
+        case Yellow:
+            convert = qBlue;
+            break;
+    }
+
+    for (int y = 0; y < newImage.height(); ++y) {
+        for (int x = 0; x < newImage.width(); ++x) {
+            QRgb p(originalImage.pixel(x, y));
+
+            // Separate the source pixel into its cyan component.
+            int amount;
+
+            if (inverted)
+                amount = convert(p);
+            else
+                amount = 255 - convert(p);
+
+            QColor newColor(
+                255 - qMin(int(amount * cyanInk), 255),
+                255 - qMin(int(amount * magentaInk), 255),
+                255 - qMin(int(amount * yellowInk), 255));
+
+            newImage.setPixel(x, y, newColor.rgb());
+        }
+    }
+
+    imageLabel->setPixmap(QPixmap::fromImage(newImage));
+}
+
+/*!
+    Returns a pointer to the modified image.
+*/
+
+QImage* ScreenWidget::image()
+{
+    return &newImage;
+}
+
+/*!
+    Sets whether the amount of ink applied to the canvas is to be inverted
+    (subtracted from the maximum value) before the ink is applied.
+*/
+
+void ScreenWidget::invertImage()
+{
+    //inverted = invertButton->isOn();
+    inverted = !inverted;
+    createImage();
+    emit imageChanged();
+}
+
+/*!
+    Separate the current image into cyan, magenta, and yellow components.
+    Create a representation of how each component might appear when applied
+    to a blank white piece of paper.
+*/
+
+void ScreenWidget::setColor()
+{
+    QColor newColor = QColorDialog::getColor(paintColor);
+
+    if (newColor.isValid()) {
+        paintColor = newColor;
+        QPalette palette(colorButton->palette());
+        palette.setColor(QPalette::Button, paintColor);
+        colorButton->setPalette(palette);
+        createImage();
+        emit imageChanged();
+    }
+}
+
+/*!
+    Records the original image selected by the user, creates a color
+    separation, and enables the invert image checkbox.
+*/
+
+void ScreenWidget::setImage(QImage &image)
+{
+    originalImage = image;
+    createImage();
+    invertButton->setEnabled(true);
+}