scribblewidget.cpp Example File

qws/mousecalibration/scribblewidget.cpp
 /****************************************************************************
 **
 ** Copyright (C) 2015 The Qt Company Ltd.
 ** Contact: http://www.qt.io/licensing/
 **
 ** 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 The Qt Company Ltd 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 "scribblewidget.h"

 ScribbleWidget::ScribbleWidget(QWidget *parent)
     : QWidget(parent)
 {
     scribbling = false;
 }

 void ScribbleWidget::resizeEvent(QResizeEvent *e)
 {
     image = QImage(e->size(), QImage::Format_RGB32);
     image.fill(QColor(Qt::white).rgb());
 }

 void ScribbleWidget::mousePressEvent(QMouseEvent *event)
 {
     if (event->button() != Qt::LeftButton)
         return;

     lastPoint = event->pos();
     scribbling = true;
 }

 void ScribbleWidget::mouseMoveEvent(QMouseEvent *event)
 {
     if ((event->buttons() & Qt::LeftButton) && scribbling)
         drawLineTo(event->pos());
 }

 void ScribbleWidget::mouseReleaseEvent(QMouseEvent *event)
 {
     if (event->button() == Qt::LeftButton && scribbling) {
         drawLineTo(event->pos());
         scribbling = false;
     }
 }

 void ScribbleWidget::paintEvent(QPaintEvent *)
 {
     QPainter painter(this);
     painter.drawImage(QPoint(0, 0), image);
 }

 void ScribbleWidget::drawLineTo(const QPoint &endPoint)
 {
     QPainter painter(&image);
     painter.setPen(QPen(Qt::blue, 1, Qt::SolidLine,
                         Qt::RoundCap, Qt::RoundJoin));
     painter.drawLine(lastPoint, endPoint);
     update();
     lastPoint = endPoint;
 }