Raspbian 2 player chess game

SGaist

The code you posted does not include anything that would bring the QImage on screen.

Quantum1982

@Quantum1982 said in Raspbian 2 player chess game:

Painter->drawImage(Dest,*Image,Source);

But what about the line :

Painter->drawImage(Dest,*Image,Source); ?

SGaist

That painter does in fact not paint on anything.

Please re-read the class documentation.

Quantum1982

Ok

I changed it to this :

#include "mainwindow.h"
#include "ui_mainwindow.h"
#include <QPainter>
#include <QImage>
#include <QRectF>

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

QRectF target(10.0,10.0,50.0,50.0);
QRectF source(0.0,0.0,50.0,50.0);

// QImage Image("C:/Users/User/Desktop/WhiteQueen.jpg");

QPixmap Pixmap("C:/Users/User/Desktop/WhiteQueen.jpg");
QPainter Painter;

Painter.drawPixmap(target,Pixmap,source);

}

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

Still no chess piece on the screen ?

SGaist

Because you are still using QPainter incorrectly. A bit less than before but still incorrectly.

You should paint what you want on a QPixmap that you will set on a QLabel if you want to show it.

Quantum1982

Ok, but now I am getting this error

C:\Users\User\Documents\Chess\main.cpp:-1: error: C1041: cannot open program database 'C:\Users\User\Documents\build-Chess-Desktop_Qt_5_12_12_MSVC2015_64bit-Debug\debug\Chess.vc.pdb'; if multiple CL.EXE write to the same .PDB file, please use /FS

Quantum1982

Ok I fixed it.

Now I am trying this :

#include "mainwindow.h"
#include "ui_mainwindow.h"

#include <QImage>
#include <QLabel>

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

QPixmap Pixmap("C:/Users/User/Desktop/WhiteQueen.jpg");
QLabel WhiteQueen;
WhiteQueen.setGeometry(50,50,100,100);
WhiteQueen.setPixmap(Pixmap);

}

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

Still nothing appears ?

JonB

@Quantum1982
QLabel WhiteQueen; is a local variable. It goes out of scope at the end of the constructor. And you never added the QLabel to the MainWindow anyway.

I would take some time to look at some basic Qt widgets examples.

Quantum1982

Ok, so where should I declare the label then for it to be drawn ?

JonB

@Quantum1982
This is not a longterm design plan. But from where you are now:

Move the variable out to be a member of the MainWindow class.
Change it to be a pointer.
Set it to a newed instance back in the constructor, with the MainWindow as its parent: WhiteQueen = new QLabel(this).

At least you should then be able to see it.

I'm not sure I would do this whole chess UI with widgets, probably a graphics scene with QGraphicsPixmapItems instead, but that's a whole different matter.

Quantum1982

I am not sure how to do that.
This is what I have so far :
#include "mainwindow.h"
#include "ui_mainwindow.h"

#include <QImage>
#include <QLabel>

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

QString ChessPieces[12];

ChessPieces[0] = "C:/Users/User/Desktop/WhitePawn.jpg";
ChessPieces[1] = "C:/Users/User/Desktop/WhiteRook.jpg";
ChessPieces[2] = "C:/Users/User/Desktop/WhiteKnight.jpg";
ChessPieces[3] = "C:/Users/User/Desktop/WhiteBishop.jpg";
ChessPieces[4] = "C:/Users/User/Desktop/WhiteQueen.jpg";
ChessPieces[5] = "C:/Users/User/Desktop/WhiteKing.jpg";
ChessPieces[6] = "C:/Users/User/Desktop/BlackPawn.jpg";
ChessPieces[7] = "C:/Users/User/Desktop/BlackRook.jpg";
ChessPieces[8] = "C:/Users/User/Desktop/BlackKnight.jpg";
ChessPieces[9] = "C:/Users/User/Desktop/BlackBishop.jpg";
ChessPieces[10] = "C:/Users/User/Desktop/BlackQueen.jpg";
ChessPieces[11] = "C:/Users/User/Desktop/BlackKing.jpg";

QPixmap Pixmap("C:/Users/User/Desktop/WhiteQueen.jpg");
WhiteQueen.setGeometry(50,50,100,100);
WhiteQueen.setPixmap(Pixmap);

}

MainWindow::~MainWindow()
{
delete ui;
}
#ifndef MAINWINDOW_H
#define MAINWINDOW_H

#include <QMainWindow>
#include <QLabel>

QT_BEGIN_NAMESPACE
namespace Ui { class MainWindow; }
QT_END_NAMESPACE

class MainWindow : public QMainWindow
{
Q_OBJECT

public:
QLabel WhiteQueen;
MainWindow(QWidget *parent = nullptr);
~MainWindow();

private:
Ui::MainWindow *ui;
};
#endif // MAINWINDOW_H

Then there is still no chess piece displayed ?

JonB

@Quantum1982
You still have not added your WhiteQueen onto your main window. I suggested code which will do this.

Quantum1982

I want to add the pieces programmatically. I don't want to drag and drop labels onto the form. These pieces are going to be stored inside an array which will be loaded dynamically.

JonB

@Quantum1982
I know this.

I don't know how to explain any better. Drag & drop has never been discussed. I have told you what you need to do, but you have not done it. You really should read enough to understand how widgets work and how you place widgets onto other widgets/forms/windows; at present you do not know just how to put a label on. I suggested earlier that you should "take some time to look at some basic Qt widgets examples", up to you.

Quantum1982

Ok but the issue is getting the right code sample, not an abstract overview.

JonB

@Quantum1982
The code I gave you told you exactly what you need to do:

with the MainWindow as its parent: WhiteQueen = new QLabel(this).

You have chosen not to do anything about this, so there's not much point keep telling you. I'll leave you to it.

Quantum1982

Ok but why do you have to use a pointer ?

JonB

@Quantum1982 said in Raspbian 2 player chess game:

These pieces are going to be stored inside an array which will be loaded dynamically.

That's one reason. Another reason is there may be more than 1 white queen. Another reason is that you'll want to create pieces as you go.

If you don't want to use a pointer, set its parent in the header file, or via setParent(). Or when you add it properly onto the form, such as onto MainWindow's centralWidget(), which you are not doing at the moment anyway, so it will appear in an odd place.

Quantum1982

Can you show me exactly where in the code these changes need to be made ?

JonB

@Quantum1982
.h file:

public:
    QLabel *WhiteQueen;

.cpp file, in MainWindow::MainWindow()

// QLabel WhiteQueen; --- instead of that line the following one:
WhiteQueen = new QLabel(this);