Transformation demo
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#ifndef RENDERAREA_H
#define RENDERAREA_H
#include <QFont>
#include <QList>
#include <QPainterPath>
#include <QRect>
#include <QWidget>
QT_BEGIN_NAMESPACE
class QPaintEvent;
QT_END_NAMESPACE
enum Operation { NoTransformation, Translate, Rotate, Scale };
class RenderArea : public QWidget
{
Q_OBJECT
public:
RenderArea(QWidget *parent = 0);
void setOperations(const QList<Operation> &operations);
void setShape(const QPainterPath &shape);
QSize minimumSizeHint() const;
QSize sizeHint() const;
protected:
void paintEvent(QPaintEvent *event);
private:
void drawCoordinates(QPainter &painter);
void drawOutline(QPainter &painter);
void drawShape(QPainter &painter);
void transformPainter(QPainter &painter);
QList<Operation> operations;
QPainterPath shape;
QRect xBoundingRect;
QRect yBoundingRect;
};
#endif
#include <QtGui>
#include "renderarea.h"
RenderArea::RenderArea(QWidget *parent)
: QWidget(parent)
{
QFont newFont = font();
newFont.setPixelSize(12);
setFont(newFont);
QFontMetrics fontMetrics(newFont);
xBoundingRect = fontMetrics.boundingRect(tr("x"));
yBoundingRect = fontMetrics.boundingRect(tr("y"));
}
void RenderArea::setOperations(const QList<Operation> &operations)
{
this->operations = operations;
update();
}
void RenderArea::setShape(const QPainterPath &shape)
{
this->shape = shape;
update();
}
QSize RenderArea::minimumSizeHint() const
{
return QSize(182, 182);
}
QSize RenderArea::sizeHint() const
{
return QSize(232, 232);
}
void RenderArea::paintEvent(QPaintEvent *event)
{
QPainter painter(this);
painter.setRenderHint(QPainter::Antialiasing);
painter.fillRect(event->rect(), QBrush(Qt::white));
painter.translate(66, 66);
painter.save();
transformPainter(painter);
drawShape(painter);
painter.restore();
drawOutline(painter);
transformPainter(painter);
drawCoordinates(painter);
}
void RenderArea::drawCoordinates(QPainter &painter)
{
painter.setPen(Qt::red);
painter.drawLine(0, 0, 50, 0);
painter.drawLine(48, -2, 50, 0);
painter.drawLine(48, 2, 50, 0);
painter.drawText(60 - xBoundingRect.width() / 2,
0 + xBoundingRect.height() / 2, tr("x"));
painter.drawLine(0, 0, 0, 50);
painter.drawLine(-2, 48, 0, 50);
painter.drawLine(2, 48, 0, 50);
painter.drawText(0 - yBoundingRect.width() / 2,
60 + yBoundingRect.height() / 2, tr("y"));
}
void RenderArea::drawOutline(QPainter &painter)
{
painter.setPen(Qt::darkGreen);
painter.setPen(Qt::DashLine);
painter.setBrush(Qt::NoBrush);
painter.drawRect(0, 0, 100, 100);
}
void RenderArea::drawShape(QPainter &painter)
{
painter.fillPath(shape, Qt::blue);
}
void RenderArea::transformPainter(QPainter &painter)
{
for (int i = 0; i < operations.size(); ++i) {
switch (operations[i]) {
case Translate:
painter.translate(50, 50);
break;
case Scale:
painter.scale(0.75, 0.75);
break;
case Rotate:
painter.rotate(60);
break;
case NoTransformation:
default:
;
}
}
}
#ifndef WINDOW_H
#define WINDOW_H
#include <QList>
#include <QPainterPath>
#include <QWidget>
#include "renderarea.h"
QT_BEGIN_NAMESPACE
class QComboBox;
QT_END_NAMESPACE
class Window : public QWidget
{
Q_OBJECT
public:
Window();
public slots:
void operationChanged();
void shapeSelected(int index);
private:
void setupShapes();
enum { NumTransformedAreas = 3 };
RenderArea *originalRenderArea;
RenderArea *transformedRenderAreas[NumTransformedAreas];
QComboBox *shapeComboBox;
QComboBox *operationComboBoxes[NumTransformedAreas];
QList<QPainterPath> shapes;
};
#endif
#include <QtGui>
#include "window.h"
Window::Window()
{
originalRenderArea = new RenderArea;
shapeComboBox = new QComboBox;
shapeComboBox->addItem(tr("Clock"));
shapeComboBox->addItem(tr("House"));
shapeComboBox->addItem(tr("Text"));
shapeComboBox->addItem(tr("Truck"));
QGridLayout *layout = new QGridLayout;
layout->addWidget(originalRenderArea, 0, 0);
layout->addWidget(shapeComboBox, 1, 0);
for (int i = 0; i < NumTransformedAreas; ++i) {
transformedRenderAreas[i] = new RenderArea;
operationComboBoxes[i] = new QComboBox;
operationComboBoxes[i]->addItem(tr("No transformation"));
operationComboBoxes[i]->addItem(tr("Rotate by 60\xB0"));
operationComboBoxes[i]->addItem(tr("Scale to 75%"));
operationComboBoxes[i]->addItem(tr("Translate by (50, 50)"));
connect(operationComboBoxes[i], SIGNAL(activated(int)),
this, SLOT(operationChanged()));
layout->addWidget(transformedRenderAreas[i], 0, i + 1);
layout->addWidget(operationComboBoxes[i], 1, i + 1);
}
setLayout(layout);
setupShapes();
shapeSelected(0);
setWindowTitle(tr("Transformations"));
}
void Window::setupShapes()
{
QPainterPath truck;
truck.setFillRule(Qt::WindingFill);
truck.moveTo(0.0, 87.0);
truck.lineTo(0.0, 60.0);
truck.lineTo(10.0, 60.0);
truck.lineTo(35.0, 35.0);
truck.lineTo(100.0, 35.0);
truck.lineTo(100.0, 87.0);
truck.lineTo(0.0, 87.0);
truck.moveTo(17.0, 60.0);
truck.lineTo(55.0, 60.0);
truck.lineTo(55.0, 40.0);
truck.lineTo(37.0, 40.0);
truck.lineTo(17.0, 60.0);
truck.addEllipse(17.0, 75.0, 25.0, 25.0);
truck.addEllipse(63.0, 75.0, 25.0, 25.0);
QPainterPath clock;
clock.addEllipse(-50.0, -50.0, 100.0, 100.0);
clock.addEllipse(-48.0, -48.0, 96.0, 96.0);
clock.moveTo(0.0, 0.0);
clock.lineTo(-2.0, -2.0);
clock.lineTo(0.0, -42.0);
clock.lineTo(2.0, -2.0);
clock.lineTo(0.0, 0.0);
clock.moveTo(0.0, 0.0);
clock.lineTo(2.732, -0.732);
clock.lineTo(24.495, 14.142);
clock.lineTo(0.732, 2.732);
clock.lineTo(0.0, 0.0);
QPainterPath house;
house.moveTo(-45.0, -20.0);
house.lineTo(0.0, -45.0);
house.lineTo(45.0, -20.0);
house.lineTo(45.0, 45.0);
house.lineTo(-45.0, 45.0);
house.lineTo(-45.0, -20.0);
house.addRect(15.0, 5.0, 20.0, 35.0);
house.addRect(-35.0, -15.0, 25.0, 25.0);
QPainterPath text;
QFont font;
font.setPixelSize(50);
QRect fontBoundingRect = QFontMetrics(font).boundingRect(tr("Qt"));
text.addText(-QPointF(fontBoundingRect.center()), font, tr("Qt"));
shapes.append(clock);
shapes.append(house);
shapes.append(text);
shapes.append(truck);
connect(shapeComboBox, SIGNAL(activated(int)),
this, SLOT(shapeSelected(int)));
}
void Window::operationChanged()
{
static const Operation operationTable[] = {
NoTransformation, Rotate, Scale, Translate
};
QList<Operation> operations;
for (int i = 0; i < NumTransformedAreas; ++i) {
int index = operationComboBoxes[i]->currentIndex();
operations.append(operationTable[index]);
transformedRenderAreas[i]->setOperations(operations);
}
}
void Window::shapeSelected(int index)
{
QPainterPath shape = shapes[index];
originalRenderArea->setShape(shape);
for (int i = 0; i < NumTransformedAreas; ++i)
transformedRenderAreas[i]->setShape(shape);
}
#include <QApplication>
#include "window.h"
int main(int argc, char *argv[])
{
QApplication app(argc, argv);
Window window;
window.show();
return app.exec();
}
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