scribblearea.cpp Example File

touch/fingerpaint/scribblearea.cpp
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#include <QtWidgets> #if defined(QT_PRINTSUPPORT_LIB) #include <QtPrintSupport/qtprintsupportglobal.h> #if QT_CONFIG(printdialog) #include <QPrinter> #include <QPrintDialog> #endif #endif #include "scribblearea.h" static const qreal MinimumDiameter = 3.0; static const qreal MaximumDiameter = 50.0; ScribbleArea::ScribbleArea(QWidget *parent) : QWidget(parent) { setAttribute(Qt::WA_AcceptTouchEvents); setAttribute(Qt::WA_StaticContents); modified = false; myPenColors << QColor("green") << QColor("purple") << QColor("red") << QColor("blue") << QColor("yellow") << QColor("pink") << QColor("orange") << QColor("brown") << QColor("grey") << QColor("black"); } 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::clearImage() { image.fill(qRgb(255, 255, 255)); modified = true; update(); } void ScribbleArea::paintEvent(QPaintEvent *event) { QPainter painter(this); const QRect rect = event->rect(); painter.drawImage(rect.topLeft(), image, rect); } 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::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; } void ScribbleArea::print() { #if QT_CONFIG(printdialog) QPrinter printer(QPrinter::HighResolution); QPrintDialog printDialog(&printer, this); if (printDialog.exec() == QDialog::Accepted) { QPainter painter(&printer); QRect rect = painter.viewport(); QSize size = image.size(); size.scale(rect.size(), Qt::KeepAspectRatio); painter.setViewport(rect.x(), rect.y(), size.width(), size.height()); painter.setWindow(image.rect()); painter.drawImage(0, 0, image); } #endif // QT_CONFIG(printdialog) } bool ScribbleArea::event(QEvent *event) { switch (event->type()) { case QEvent::TouchBegin: case QEvent::TouchUpdate: case QEvent::TouchEnd: { QTouchEvent *touch = static_cast<QTouchEvent *>(event); QList<QTouchEvent::TouchPoint> touchPoints = static_cast<QTouchEvent *>(event)->touchPoints(); foreach (const QTouchEvent::TouchPoint &touchPoint, touchPoints) { switch (touchPoint.state()) { case Qt::TouchPointStationary: case Qt::TouchPointReleased: // don't do anything if this touch point hasn't moved or has been released continue; default: { QRectF rect = touchPoint.rect(); if (rect.isEmpty()) { qreal diameter = MaximumDiameter; if (touch->device()->capabilities() & QTouchDevice::Pressure) diameter = MinimumDiameter + (MaximumDiameter - MinimumDiameter) * touchPoint.pressure(); rect.setSize(QSizeF(diameter, diameter)); } QPainter painter(&image); painter.setPen(Qt::NoPen); painter.setBrush(myPenColors.at(touchPoint.id() % myPenColors.count())); painter.drawEllipse(rect); painter.end(); modified = true; int rad = 2; update(rect.toRect().adjusted(-rad,-rad, +rad, +rad)); } break; } } break; } default: return QWidget::event(event); } return true; }