characterwidget.cpp Example File

 /****************************************************************************
 **
 ** Copyright (C) 2012 Nokia Corporation and/or its subsidiary(-ies).
 ** Contact: http://www.qt-project.org/
 **
 ** This file is part of the examples of the Qt Toolkit.
 **
 ** $QT_BEGIN_LICENSE:BSD$
 ** You may use this file under the terms of the BSD license as follows:
 **
 ** "Redistribution and use in source and binary forms, with or without
 ** modification, are permitted provided that the following conditions are
 ** met:
 **   * Redistributions of source code must retain the above copyright
 **     notice, this list of conditions and the following disclaimer.
 **   * Redistributions in binary form must reproduce the above copyright
 **     notice, this list of conditions and the following disclaimer in
 **     the documentation and/or other materials provided with the
 **     distribution.
 **   * Neither the name of Nokia Corporation and its Subsidiary(-ies) nor
 **     the names of its contributors may be used to endorse or promote
 **     products derived from this software without specific prior written
 **     permission.
 **
 ** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 ** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 ** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 ** A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 ** OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 ** SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 ** LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 ** DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 ** THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 ** (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 ** OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE."
 **
 ** $QT_END_LICENSE$
 **
 ****************************************************************************/

 #include <QtWidgets>

 #include "characterwidget.h"

 CharacterWidget::CharacterWidget(QWidget *parent)
     : QWidget(parent)
 {
     squareSize = 24;
     columns = 16;
     lastKey = -1;
     setMouseTracking(true);
 }

 void CharacterWidget::updateFont(const QFont &font)
 {
     displayFont.setFamily(font.family());
     squareSize = qMax(24, QFontMetrics(displayFont).xHeight() * 3);
     adjustSize();
     update();
 }

 void CharacterWidget::updateSize(const QString &fontSize)
 {
     displayFont.setPointSize(fontSize.toInt());
     squareSize = qMax(24, QFontMetrics(displayFont).xHeight() * 3);
     adjustSize();
     update();
 }

 void CharacterWidget::updateStyle(const QString &fontStyle)
 {
     QFontDatabase fontDatabase;
     const QFont::StyleStrategy oldStrategy = displayFont.styleStrategy();
     displayFont = fontDatabase.font(displayFont.family(), fontStyle, displayFont.pointSize());
     displayFont.setStyleStrategy(oldStrategy);
     squareSize = qMax(24, QFontMetrics(displayFont).xHeight() * 3);
     adjustSize();
     update();
 }

 void CharacterWidget::updateFontMerging(bool enable)
 {
     if (enable)
         displayFont.setStyleStrategy(QFont::PreferDefault);
     else
         displayFont.setStyleStrategy(QFont::NoFontMerging);
     adjustSize();
     update();
 }

 QSize CharacterWidget::sizeHint() const
 {
     return QSize(columns*squareSize, (65536/columns)*squareSize);
 }

 void CharacterWidget::mouseMoveEvent(QMouseEvent *event)
 {
     QPoint widgetPosition = mapFromGlobal(event->globalPos());
     uint key = (widgetPosition.y()/squareSize)*columns + widgetPosition.x()/squareSize;

     QString text = QString::fromLatin1("<p>Character: <span style=\"font-size: 24pt; font-family: %1\">").arg(displayFont.family())
                   + QChar(key)
                   + QString::fromLatin1("</span><p>Value: 0x")
                   + QString::number(key, 16);
     QToolTip::showText(event->globalPos(), text, this);
 }

 void CharacterWidget::mousePressEvent(QMouseEvent *event)
 {
     if (event->button() == Qt::LeftButton) {
         lastKey = (event->y()/squareSize)*columns + event->x()/squareSize;
         if (QChar(lastKey).category() != QChar::Other_NotAssigned)
             emit characterSelected(QString(QChar(lastKey)));
         update();
     }
     else
         QWidget::mousePressEvent(event);
 }

 void CharacterWidget::paintEvent(QPaintEvent *event)
 {
     QPainter painter(this);
     painter.fillRect(event->rect(), QBrush(Qt::white));
     painter.setFont(displayFont);

     QRect redrawRect = event->rect();
     int beginRow = redrawRect.top()/squareSize;
     int endRow = redrawRect.bottom()/squareSize;
     int beginColumn = redrawRect.left()/squareSize;
     int endColumn = redrawRect.right()/squareSize;

     painter.setPen(QPen(Qt::gray));
     for (int row = beginRow; row <= endRow; ++row) {
         for (int column = beginColumn; column <= endColumn; ++column) {
             painter.drawRect(column*squareSize, row*squareSize, squareSize, squareSize);
         }
     }

     QFontMetrics fontMetrics(displayFont);
     painter.setPen(QPen(Qt::black));
     for (int row = beginRow; row <= endRow; ++row) {

         for (int column = beginColumn; column <= endColumn; ++column) {

             int key = row*columns + column;
             painter.setClipRect(column*squareSize, row*squareSize, squareSize, squareSize);

             if (key == lastKey)
                 painter.fillRect(column*squareSize + 1, row*squareSize + 1, squareSize, squareSize, QBrush(Qt::red));

             painter.drawText(column*squareSize + (squareSize / 2) - fontMetrics.width(QChar(key))/2,
                              row*squareSize + 4 + fontMetrics.ascent(),
                              QString(QChar(key)));
         }
     }
 }