tabletcanvas.cpp Example File
widgets/tablet/tabletcanvas.cpp
#include <QtGui>
#include <math.h>
#include "tabletcanvas.h"
TabletCanvas::TabletCanvas()
{
myBrush = QBrush();
myPen = QPen();
image = QImage(500, 500, QImage::Format_ARGB32);
QPainter painter(&image);
painter.fillRect(0, 0, 499, 499, Qt::white);
setAutoFillBackground(true);
deviceDown = false;
myColor = Qt::red;
myTabletDevice = QTabletEvent::Stylus;
alphaChannelType = NoAlpha;
colorSaturationType = NoSaturation;
lineWidthType = LineWidthPressure;
}
bool TabletCanvas::saveImage(const QString &file)
{
return image.save(file);
}
bool TabletCanvas::loadImage(const QString &file)
{
bool success = image.load(file);
if (success) {
update();
return true;
}
return false;
}
void TabletCanvas::tabletEvent(QTabletEvent *event)
{
switch (event->type()) {
case QEvent::TabletPress:
if (!deviceDown)
deviceDown = true;
break;
case QEvent::TabletRelease:
if (deviceDown)
deviceDown = false;
break;
case QEvent::TabletMove:
polyLine[2] = polyLine[1];
polyLine[1] = polyLine[0];
polyLine[0] = event->pos();
if (deviceDown) {
updateBrush(event);
QPainter painter(&image);
paintImage(painter, event);
}
break;
default:
break;
}
update();
}
void TabletCanvas::paintEvent(QPaintEvent *)
{
QPainter painter(this);
painter.drawImage(QPoint(0, 0), image);
}
void TabletCanvas::paintImage(QPainter &painter, QTabletEvent *event)
{
QPoint brushAdjust(10, 10);
switch (myTabletDevice) {
case QTabletEvent::Stylus:
painter.setBrush(myBrush);
painter.setPen(myPen);
painter.drawLine(polyLine[1], event->pos());
break;
case QTabletEvent::Airbrush:
myBrush.setColor(myColor);
myBrush.setStyle(brushPattern(event->pressure()));
painter.setPen(Qt::NoPen);
painter.setBrush(myBrush);
for (int i = 0; i < 3; ++i) {
painter.drawEllipse(QRect(polyLine[i] - brushAdjust,
polyLine[i] + brushAdjust));
}
break;
default:
qWarning("Unsupported tablet device.");
}
}
Qt::BrushStyle TabletCanvas::brushPattern(qreal value)
{
int pattern = int((value) * 100.0) % 7;
switch (pattern) {
case 0:
return Qt::SolidPattern;
case 1:
return Qt::Dense1Pattern;
case 2:
return Qt::Dense2Pattern;
case 3:
return Qt::Dense3Pattern;
case 4:
return Qt::Dense4Pattern;
case 5:
return Qt::Dense5Pattern;
case 6:
return Qt::Dense6Pattern;
default:
return Qt::Dense7Pattern;
}
}
void TabletCanvas::updateBrush(QTabletEvent *event)
{
int hue, saturation, value, alpha;
myColor.getHsv(&hue, &saturation, &value, &alpha);
int vValue = int(((event->yTilt() + 60.0) / 120.0) * 255);
int hValue = int(((event->xTilt() + 60.0) / 120.0) * 255);
switch (alphaChannelType) {
case AlphaPressure:
myColor.setAlpha(int(event->pressure() * 255.0));
break;
case AlphaTilt:
myColor.setAlpha(max(abs(vValue - 127), abs(hValue - 127)));
break;
default:
myColor.setAlpha(255);
}
switch (colorSaturationType) {
case SaturationVTilt:
myColor.setHsv(hue, vValue, value, alpha);
break;
case SaturationHTilt:
myColor.setHsv(hue, hValue, value, alpha);
break;
case SaturationPressure:
myColor.setHsv(hue, int(event->pressure() * 255.0), value, alpha);
break;
default:
;
}
switch (lineWidthType) {
case LineWidthPressure:
myPen.setWidthF(event->pressure() * 10 + 1);
break;
case LineWidthTilt:
myPen.setWidthF(max(abs(vValue - 127), abs(hValue - 127)) / 12);
break;
default:
myPen.setWidthF(1);
}
if (event->pointerType() == QTabletEvent::Eraser) {
myBrush.setColor(Qt::white);
myPen.setColor(Qt::white);
myPen.setWidthF(event->pressure() * 10 + 1);
} else {
myBrush.setColor(myColor);
myPen.setColor(myColor);
}
}