Raspbian 2 player chess game

[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);

[Quantum1982]

Thank you very much. It is working now.

[Quantum1982]

Although the next stage is decide what mechanism to use to draw a checkered board.

[Quantum1982]

Ok I am making progress. This is the output so far :!

Do you have any idea why the last column and row is being stretched ?

[Quantum1982]

Sorry here is the code :
#include "mainwindow.h"
#include "ui_mainwindow.h"

#include <QImage>
#include <QLabel>

MainWindow::MainWindow(QWidget *parent)
: QMainWindow(parent)
, ui(new Ui::MainWindow)
{
ui->setupUi(this);
scene = new QGraphicsScene(this);
ui->graphicsView->setScene(scene);

QBrush greenBrush(Qt::green);
QBrush blueBrush(Qt::blue);
QPen outlinePen(Qt::black);
outlinePen.setWidth(2);

for (int i=0;i<8;i++)
    for (int j=0;j<8;j++)
        if ((i+j)%2==0)
        rectangle = scene->addRect(BOARD_X1+(i*SQUARE_WIDTH),BOARD_Y1+(j*SQUARE_HEIGHT)
                                   ,BOARD_X1+(i*SQUARE_WIDTH)+SQUARE_WIDTH ,
                                   BOARD_Y1+(j*SQUARE_HEIGHT)+SQUARE_HEIGHT, outlinePen, blueBrush);
        else rectangle = scene->addRect(BOARD_X1+(i*SQUARE_WIDTH),BOARD_Y1+(j*SQUARE_HEIGHT)
                                        ,BOARD_X1+(i*SQUARE_WIDTH)+SQUARE_WIDTH ,
                                        BOARD_Y1+(j*SQUARE_HEIGHT)+SQUARE_HEIGHT, outlinePen, greenBrush);


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 = new QLabel(this);

WhiteQueen->setGeometry(50,50,100,100);
WhiteQueen->setPixmap(Pixmap);

}

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

#ifndef MAINWINDOW_H
#define MAINWINDOW_H

#define BOARD_X1 20
#define BOARD_Y1 20
#define SQUARE_WIDTH 50
#define SQUARE_HEIGHT 50

#include <QMainWindow>
#include <QGraphicsView>
#include <QGraphicsItem>
#include <QLabel>

class CChessBoard : public QGraphicsView
{
public:

};

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;
QGraphicsScene *scene;
QGraphicsRectItem *rectangle;
};
#endif // MAINWINDOW_H

[SGaist]

Are you doing anything else with rectangle ?

Since you are using the graphics view framework, why are you using QLabel for your chess pieces ?

[Quantum1982]

Well can I use an array of QImages instead ?

[SGaist]

QGraphicsPixmapItem

You really should take the time to explore the documentation.

[Quantum1982]

Yeah QGraphicsPixmapItem solves the problem

[Quantum1982]

I am having a problem loading multiple pixmaps ?

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

#include <QImage>
#include <QLabel>

MainWindow::MainWindow(QWidget *parent)
: QMainWindow(parent)
, ui(new Ui::MainWindow)
{
ui->setupUi(this);
scene = new QGraphicsScene(this);
ui->graphicsView->setScene(scene);

QBrush greenBrush(Qt::green);
QBrush blueBrush(Qt::blue);
QPen outlinePen(Qt::black);
outlinePen.setWidth(2);

for (int i=0;i<8;i++)
    for (int j=0;j<8;j++)
        if ((i+j)%2==0)
        rectangle = scene->addRect(BOARD_X1+(i*SQUARE_WIDTH),BOARD_Y1+(j*SQUARE_HEIGHT)
                                   ,BOARD_X1+(i*SQUARE_WIDTH)+SQUARE_WIDTH ,
                                   BOARD_Y1+(j*SQUARE_HEIGHT)+SQUARE_HEIGHT, outlinePen, blueBrush);
        else rectangle = scene->addRect(BOARD_X1+(i*SQUARE_WIDTH),BOARD_Y1+(j*SQUARE_HEIGHT)
                                        ,BOARD_X1+(i*SQUARE_WIDTH)+SQUARE_WIDTH ,
                                        BOARD_Y1+(j*SQUARE_HEIGHT)+SQUARE_HEIGHT, outlinePen, greenBrush);


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";

for (int i=0;i<8;i++)
    ChessPieceIndexes[i][1] = 0; // White Pawns
ChessPieceIndexes[0][0] = 1; // White Rook
ChessPieceIndexes[7][0] = 1; // White Rook

ChessPieceIndexes[1][0] = 2; // White Knight
ChessPieceIndexes[7][0] = 2; // White Knight

ChessPieceIndexes[2][0] = 3; // White Bishop
ChessPieceIndexes[6][0] = 3; // White Bishop

ChessPieceIndexes[3][0] = 4; // White Queen
ChessPieceIndexes[4][0] = 5; // White King


/*
WhiteQueen = new QLabel(this);

WhiteQueen->setGeometry(BOARD_X1+4*SQUARE_WIDTH,BOARD_Y1+4*SQUARE_HEIGHT,
                        BOARD_X1+4*SQUARE_WIDTH+SQUARE_WIDTH,BOARD_Y1+4*SQUARE_HEIGHT+SQUARE_HEIGHT);
WhiteQueen->setPixmap(Pixmap);
*/

QPixmap Pixmap(ChessPieces[0]); // White Pawn

for (int i=0;i<8;i++)
{
    QGraphicsPixmapItem* item = new QGraphicsPixmapItem(Pixmap);
    item->setPos(BOARD_X1+(i*SQUARE_WIDTH),BOARD_Y1+(7*SQUARE_HEIGHT));
    scene->addItem(item);
}
// White Rooks
Pixmap.load(ChessPieces[1]);
QGraphicsPixmapItem* item = new QGraphicsPixmapItem(Pixmap);
item->setPos(BOARD_X1+(0*SQUARE_WIDTH),BOARD_Y1+(8*SQUARE_HEIGHT));
scene->addItem(item);

//QGraphicsPixmapItem* item = new QGraphicsPixmapItem(Pixmap);
item->setPos(BOARD_X1+(7*SQUARE_WIDTH),BOARD_Y1+(8*SQUARE_HEIGHT));
scene->addItem(item);

// White Knights
Pixmap.load(ChessPieces[2]);
//QGraphicsPixmapItem* item = new QGraphicsPixmapItem(Pixmap);
item->setPos(BOARD_X1+(1*SQUARE_WIDTH),BOARD_Y1+(8*SQUARE_HEIGHT));
scene->addItem(item);

}

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