scribblearea.cpp Example File
widgets/scribble/scribblearea.cpp
/****************************************************************************
**
** Copyright (C) 2005-2005 Trolltech AS. All rights reserved.
**
** This file is part of the documentation of the Qt Toolkit.
**
** Licensees holding valid Qt Preview licenses may use this file in
** accordance with the Qt Preview License Agreement provided with the
** Software.
**
** See http://www.trolltech.com/pricing.html or email sales@trolltech.com for
** information about Qt Commercial License Agreements.
**
** Contact info@trolltech.com if any conditions of this licensing are
** not clear to you.
**
** 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 "scribblearea.h"
ScribbleArea::ScribbleArea(QWidget *parent)
: QWidget(parent)
{
setAttribute(Qt::WA_StaticContents);
modified = false;
scribbling = false;
myPenWidth = 1;
myPenColor = Qt::blue;
}
bool ScribbleArea::openImage(const QString &fileName)
{
QImage loadedImage;
if (!loadedImage.load(fileName))
return false;
QSize newSize = loadedImage.size().expandedTo(size());
resizeImage(&loadedImage, newSize);
image = loadedImage;
modified = false;
update();
return true;
}
bool ScribbleArea::saveImage(const QString &fileName, const char *fileFormat)
{
QImage visibleImage = image;
resizeImage(&visibleImage, size());
if (visibleImage.save(fileName, fileFormat)) {
modified = false;
return true;
} else {
return false;
}
}
void ScribbleArea::setPenColor(const QColor &newColor)
{
myPenColor = newColor;
}
void ScribbleArea::setPenWidth(int newWidth)
{
myPenWidth = newWidth;
}
void ScribbleArea::clearImage()
{
image.fill(qRgb(255, 255, 255));
modified = true;
update();
}
void ScribbleArea::mousePressEvent(QMouseEvent *event)
{
if (event->button() == Qt::LeftButton) {
lastPoint = event->pos();
scribbling = true;
}
}
void ScribbleArea::mouseMoveEvent(QMouseEvent *event)
{
if ((event->buttons() & Qt::LeftButton) && scribbling)
drawLineTo(event->pos());
}
void ScribbleArea::mouseReleaseEvent(QMouseEvent *event)
{
if (event->button() == Qt::LeftButton && scribbling) {
drawLineTo(event->pos());
scribbling = false;
}
}
void ScribbleArea::paintEvent(QPaintEvent * /* event */)
{
QPainter painter(this);
painter.drawImage(QPoint(0, 0), image);
}
void ScribbleArea::resizeEvent(QResizeEvent *event)
{
if (width() > image.width() || height() > image.height()) {
int newWidth = qMax(width() + 128, image.width());
int newHeight = qMax(height() + 128, image.height());
resizeImage(&image, QSize(newWidth, newHeight));
update();
}
QWidget::resizeEvent(event);
}
void ScribbleArea::drawLineTo(const QPoint &endPoint)
{
QPainter painter(&image);
painter.setPen(QPen(myPenColor, myPenWidth, Qt::SolidLine, Qt::RoundCap,
Qt::RoundJoin));
painter.drawLine(lastPoint, endPoint);
modified = true;
int rad = myPenWidth / 2;
update(QRect(lastPoint, endPoint).normalized()
.adjusted(-rad, -rad, +rad, +rad));
lastPoint = endPoint;
}
void ScribbleArea::resizeImage(QImage *image, const QSize &newSize)
{
if (image->size() == newSize)
return;
QImage newImage(newSize, QImage::Format_RGB32);
newImage.fill(qRgb(255, 255, 255));
QPainter painter(&newImage);
painter.drawImage(QPoint(0, 0), *image);
*image = newImage;
}