Photorealism

[MScottM]

I'm interested in creating photorealistic gauges for a dashboard. I've searched around and haven't (yet) seen this being done with QT. I'm guessing it isn't as simple as animating a needle over an image of a gauge to create a 'realistic' looking one? Not sure how I would even start!

I would appreciate hearing thoughts on how this might be possible, or pointers to where it has already been done.

Thanks!

[mrjj]

@MScottM said in Photorealism:

photorealistic gauges

But what would be considered one ?

[aha_1980]

@MScottM e.g. here you have a real world Qt example.

[MScottM]

Thanks for the replies.

By photo-realistic what I mean is, the gauge looks like it could be, say, the tachometer out of a Ferrari Dino, because it is an actual photo of a Dino tachometer (*.png, or *.jpg for example), only the pointer responds to input from software. I think I've seen this done in a flight simulator a while back, but I can't remember which.

@aha_1980 I appreciate the link to the QT dashboard, its very interesting, but it isn't quite what I mean. those gauges are drawn programmatically, like from the gauge library. I hope I'm describing the distinction I'm trying for clearly enough!

-Scott

[mrjj]

Hi
It really depend on the photos how you
would paint the pointer as to look good.
If you are skilled with 3D software, its possible to render a really
authentic look version.

[MScottM]

Okay - I managed to put a needle onto a photo of a gauge that I downloaded and photo-edited the original needle out of:

Original:

Mine:

Here is the code I kluged together:

#include "mainwindow.h"
#include "ui_mainwindow.h"
#include "QBitmap"
#include "QPainter"
#include "QTime"
#include <QtGui>
//#include "rasterwindow.h"

/*class gaugeWindow
//{
//public:
//    gaugeWindow();

//protected:
//    void timerEvent(QTimerEvent *);
//    void render(QPainter *painter);

//private:
//    int m_timerId;
//};

//gaugeWindow::gaugeWindow() {
//    m_timerId = startTimer(1000);
//}

//void gaugeWindow::timerEvent() {
//    if (event->timerId() == m_timerId)
//        renderLater();
//}
*/

MainWindow::MainWindow(QWidget *parent) :
    QMainWindow(parent),
    ui(new Ui::MainWindow)
{
    ui->setupUi(this);

    static const QPoint needle[3] = {
            QPoint(7, 8),
            QPoint(-7, 8),
            QPoint(0, -70)
        };
    QColor needleColor(0, 0, 0);

    //QLabel lblRpm;
    QPixmap pixmap("C:\\Users\\scott\\Documents\\Qt\\Gauge_Test\\RPM_Gauge_no_needle.png");
    QPainter painter(&pixmap);
    //painter.setPen(needleColor);

    painter.setRenderHint(QPainter::Antialiasing);
    painter.translate(151, 146); //center
    painter.setPen(Qt::NoPen);
    painter.setBrush(needleColor);

    painter.save();
    painter.rotate(angle); //degrees
    painter.drawConvexPolygon(needle, 3);
    painter.restore();

    ui->lblRpm->setPixmap(pixmap);
    ui->lblRpm->setMask(pixmap.mask());
    ui->lblRpm->show();
}

//int MainWindow::updateAngle(int angle)
//{
//        int newAngle = -90;
//        for (int i=0; i<180; i++) {
//            newAngle += 1;
//        }
//        return angle;
//}

MainWindow::~MainWindow()
{
    delete ui;
}

Now I'm trying to figure out how to attach the needle to something that will let me update it on the fly for demonstration, like a timer, or a slider. I would appreciate if someone could give me a pointer (HA!) towards some way to make that work...

Thanks!!

[mrjj]

Hi
Looking good.
Convert it to a custom widget, give it a setSpeed slot and
hook slot up to a timer to make it do something.