previewdialog.cpp Example File
^{painting/fontsampler/previewdialog.cpp}

 /****************************************************************************
 **
 ** Copyright (C) 2006-2008 Trolltech ASA. All rights reserved.
 **
 ** This file is part of the documentation of the Qt Toolkit.
 **
 ** This file may be used under the terms of the GNU General Public
** License versions 2.0 or 3.0 as published by the Free Software
** Foundation and appearing in the files LICENSE.GPL2 and LICENSE.GPL3
** included in the packaging of this file.  Alternatively you may (at
** your option) use any later version of the GNU General Public
** License if such license has been publicly approved by Trolltech ASA
** (or its successors, if any) and the KDE Free Qt Foundation. In
** addition, as a special exception, Trolltech gives you certain
** additional rights. These rights are described in the Trolltech GPL
** Exception version 1.2, which can be found at
** http://www.trolltech.com/products/qt/gplexception/ and in the file
** GPL_EXCEPTION.txt in this package.
**
** Please review the following information to ensure GNU General
** Public Licensing requirements will be met:
** http://trolltech.com/products/qt/licenses/licensing/opensource/. If
** you are unsure which license is appropriate for your use, please
** review the following information:
** http://trolltech.com/products/qt/licenses/licensing/licensingoverview
** or contact the sales department at sales@trolltech.com.
**
** In addition, as a special exception, Trolltech, as the sole
** copyright holder for Qt Designer, grants users of the Qt/Eclipse
** Integration plug-in the right for the Qt/Eclipse Integration to
** link to functionality provided by Qt Designer and its related
** libraries.
**
** This file is provided "AS IS" with NO WARRANTY OF ANY KIND,
** INCLUDING THE WARRANTIES OF DESIGN, MERCHANTABILITY AND FITNESS FOR
** A PARTICULAR PURPOSE. Trolltech reserves all rights not expressly
** granted herein.
 **
 ** This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE
 ** WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
 **
 ****************************************************************************/

 #include <QtGui>
 #include "previewdialog.h"

 PreviewDialog::PreviewDialog(QPrinter &printer, QWidget *parent)
     : QDialog(parent), printer(printer)
 {
     setupUi(this);

     currentPage = 0;
     pageCount = 0;
     pageList->setIconSize(QSize(SmallPreviewLength, SmallPreviewLength));
     pageList->header()->hide();
     previewLabel = new PreviewLabel;
     previewArea->setWidget(previewLabel);
     setupComboBoxes();

     buttonBox->button(QDialogButtonBox::Ok)->setText(tr("&Print"));
 }

 void PreviewDialog::setupComboBoxes()
 {
     paperSizeCombo->addItem(tr("A0 (841 x 1189 mm)"), QPrinter::A0);
     paperSizeCombo->addItem(tr("A1 (594 x 841 mm)"), QPrinter::A1);
     paperSizeCombo->addItem(tr("A2 (420 x 594 mm)"), QPrinter::A2);
     paperSizeCombo->addItem(tr("A3 (297 x 420 mm)"), QPrinter::A3);
     paperSizeCombo->addItem(tr("A4 (210 x 297 mm, 8.26 x 11.7 inches)"), QPrinter::A4);
     paperSizeCombo->addItem(tr("A5 (148 x 210 mm)"), QPrinter::A5);
     paperSizeCombo->addItem(tr("A6 (105 x 148 mm)"), QPrinter::A6);
     paperSizeCombo->addItem(tr("A7 (74 x 105 mm)"), QPrinter::A7);
     paperSizeCombo->addItem(tr("A8 (52 x 74 mm)"), QPrinter::A8);
     paperSizeCombo->addItem(tr("A9 (37 x 52 mm)"), QPrinter::A9);
     paperSizeCombo->addItem(tr("B0 (1000 x 1414 mm)"), QPrinter::B0);
     paperSizeCombo->addItem(tr("B1 (707 x 1000 mm)"), QPrinter::B1);
     paperSizeCombo->addItem(tr("B2 (500 x 707 mm)"), QPrinter::B2);
     paperSizeCombo->addItem(tr("B3 (353 x 500 mm)"), QPrinter::B3);
     paperSizeCombo->addItem(tr("B4 (250 x 353 mm)"), QPrinter::B4);
     paperSizeCombo->addItem(tr("B5 (176 x 250 mm, 6.93 x 9.84 inches)"), QPrinter::B5);
     paperSizeCombo->addItem(tr("B6 (125 x 176 mm)"), QPrinter::B6);
     paperSizeCombo->addItem(tr("B7 (88 x 125 mm)"), QPrinter::B7);
     paperSizeCombo->addItem(tr("B8 (62 x 88 mm)"), QPrinter::B8);
     paperSizeCombo->addItem(tr("B9 (44 x 62 mm)"), QPrinter::B9);
     paperSizeCombo->addItem(tr("B10 (31 x 44 mm)"), QPrinter::B10);
     paperSizeCombo->addItem(tr("C5E (163 x 229 mm)"), QPrinter::C5E);
     paperSizeCombo->addItem(tr("DLE (110 x 220 mm)"), QPrinter::DLE);
     paperSizeCombo->addItem(tr("Executive (7.5 x 10 inches, 191 x 254 mm)"), QPrinter::Executive);
     paperSizeCombo->addItem(tr("Folio (210 x 330 mm)"), QPrinter::Folio);
     paperSizeCombo->addItem(tr("Ledger (432 x 279 mm)"), QPrinter::Ledger);
     paperSizeCombo->addItem(tr("Legal (8.5 x 14 inches, 216 x 356 mm)"), QPrinter::Legal);
     paperSizeCombo->addItem(tr("Letter (8.5 x 11 inches, 216 x 279 mm)"), QPrinter::Letter);
     paperSizeCombo->addItem(tr("Tabloid (279 x 432 mm)"), QPrinter::Tabloid);
     paperSizeCombo->addItem(tr("US Common #10 Envelope (105 x 241 mm)"), QPrinter::Comm10E);
     paperSizeCombo->setCurrentIndex(paperSizeCombo->findData(QPrinter::A4));

     paperOrientationCombo->addItem(tr("Portrait"), QPrinter::Portrait);
     paperOrientationCombo->addItem(tr("Landscape"), QPrinter::Landscape);
 }

 void PreviewDialog::addPage()
 {
     if (currentPage >= pageCount)
         return;

     QTreeWidgetItem *item = new QTreeWidgetItem(pageList);
     item->setCheckState(0, Qt::Checked);

     paintItem(item, currentPage);
     if (pageList->indexOfTopLevelItem(pageList->currentItem()) < 0)
         pageList->setCurrentItem(pageList->topLevelItem(0));

     qApp->processEvents();
     ++currentPage;

     QTimer::singleShot(0, this, SLOT(addPage()));
 }

 void PreviewDialog::setNumberOfPages(int count)
 {
     pageCount = count;
     QTimer::singleShot(0, this, SLOT(addPage()));
 }

 void PreviewDialog::paintItem(QTreeWidgetItem *item, int index)
 {
     QPixmap pixmap(SmallPreviewLength, SmallPreviewLength);
     paintPreview(pixmap, index);
     item->setIcon(0, QIcon(pixmap));
 }

 void PreviewDialog::paintPreview(QPixmap &pixmap, int index)
 {
     qreal longestSide = qreal(qMax(printer.paperRect().width(),
                               printer.paperRect().height()));
     qreal width = pixmap.width() * printer.paperRect().width()/longestSide;
     qreal height = pixmap.height() * printer.paperRect().height()/longestSide;

     pixmap.fill(qRgb(224,224,224));
     QPainter painter;
     painter.begin(&pixmap);
     painter.setRenderHint(QPainter::Antialiasing);
     painter.translate((pixmap.width() - width)/2,
                       (pixmap.height() - height)/2);
     painter.fillRect(QRectF(0, 0, width, height), QBrush(Qt::white));
     painter.scale(pixmap.width() / longestSide, pixmap.height() / longestSide);
     painter.translate(printer.pageRect().topLeft());
     emit pageRequested(index, painter, printer);
     painter.end();
 }

 void PreviewDialog::accept()
 {
     int markedPages = 0;
     int pageIndex;
     for (pageIndex = 0; pageIndex < pageList->topLevelItemCount(); ++pageIndex) {
         if (pageList->topLevelItem(pageIndex)->checkState(0) == Qt::Checked)
             ++markedPages;
     }

     // Print all pages that have yet to be previewed.
     markedPages += pageCount - pageIndex;

     printer.setPageSize(QPrinter::PageSize(
         paperSizeCombo->itemData(paperSizeCombo->currentIndex()).toInt()));
     printer.setOrientation(QPrinter::Orientation(
         paperOrientationCombo->itemData(
         paperOrientationCombo->currentIndex()).toInt()));

     QPrintDialog dialog(&printer, this);
     if (dialog.exec() != QDialog::Accepted)
         return;

     progressBar->setMaximum(markedPages);
     progressBar->setEnabled(true);
     progressBar->setTextVisible(true);

     QPainter painter;
     painter.begin(&printer);

     canceled = false;
     int printed = 0;
     bool firstPage = true;
     for (pageIndex = 0; pageIndex < pageCount; ++pageIndex) {

         qApp->processEvents();

         if (canceled)
             break;

         if (pageIndex >= currentPage || isSelected(pageIndex)) {
             // Print all pages that are either marked or have yet to be
             // previewed.
             if (!firstPage)
                 printer.newPage();

             emit pageRequested(pageIndex, painter, printer);
             progressBar->setValue(++printed);
             firstPage = false;
         }
     }
     painter.end();

     progressBar->setTextVisible(false);
     progressBar->setEnabled(false);

     QDialog::accept();
 }

 bool PreviewDialog::isSelected(int index)
 {
     if (index >= 0 && index < pageList->topLevelItemCount())
         return (pageList->topLevelItem(index)->checkState(0) == Qt::Checked);
     else
         return false;
 }

 void PreviewDialog::reject()
 {
     canceled = true;
     QDialog::reject();
 }

 void PreviewDialog::resizeEvent(QResizeEvent *)
 {
     int size = qMax(qMin(previewArea->width() - previewArea->verticalScrollBar()->width(),
                          previewArea->height() - previewArea->horizontalScrollBar()->height()),
                     int(LargePreviewLength));
     previewLabel->resize(size, size);
     on_pageList_currentItemChanged();
 }

 void PreviewDialog::on_pageList_currentItemChanged()
 {
     if (pageList->indexOfTopLevelItem(pageList->currentItem()) < 0)
         return;

     QPixmap pixmap(previewLabel->size());
     paintPreview(pixmap, pageList->indexOfTopLevelItem(pageList->currentItem()));
     previewLabel->setPixmap(pixmap);
     previewLabel->update();
 }

 void PreviewDialog::on_paperSizeCombo_activated(int index)
 {
     printer.setPageSize(QPrinter::PageSize(paperSizeCombo->itemData(index).toInt()));

     for (index = 0; index < pageList->topLevelItemCount(); ++index)
         paintItem(pageList->topLevelItem(index), index);

     on_pageList_currentItemChanged();
 }

 void PreviewDialog::on_paperOrientationCombo_activated(int index)
 {
     printer.setOrientation(QPrinter::Orientation(paperOrientationCombo->itemData(index).toInt()));

     for (index = 0; index < pageList->topLevelItemCount(); ++index)
         paintItem(pageList->topLevelItem(index), index);

     on_pageList_currentItemChanged();
 }