Random number of QGraphicsItem

[salmanmanekia]

Hi All,
I have to draw a custom QGraphicsItem or QGraphicsRectItem ..depending on the user input..for eg if the input is 3...then i should be drawing 9 items in a 3 X 3 matrix...if the input is 4 ..then 16 items in 4 X 4 matrix...the problem is that there can be any value as a input so the cordinates and the size of the item changes...the smaller the item is when the bigger the number is...any solution ??...i was thinking of putting each condition in a if block but obviously that isnt a good idea ..

[high_flyer]

What exactly if the question?
Do you need help with the logic of the application, or working with QGraphcis View?

[salmanmanekia]

i jus need to know if its possible and if it is how it is possible logicaly...

[tbscope]

Try this:

#include "matrixscene.h"
 
#include <QGraphicsRectItem>
 
MatrixScene::MatrixScene(QObject *parent) :
    QGraphicsScene(parent)
{
    setSceneRect(0,0,200,200);
}
 
void MatrixScene::setNumberOfItems(int number)
{
    items().clear();
 
    qreal rectWidth = (width() / number) - 5;
    qreal rectHeight = (height() / number) - 5;
 
    qreal startX = 1;
    qreal startY = 1;
 
    int counterX = 0;
    int counterY = 0;
 
    QGraphicsRectItem *newItem;
 
    for(counterY = 0; counterY < number; ++counterY) {
        startY = counterY * (rectHeight + 5);
        for(counterX = 0; counterX < number; ++counterX) {
            startX = counterX * (rectWidth + 5);
            newItem = new QGraphicsRectItem;
            newItem->setRect(0, 0, rectWidth, rectHeight);
            newItem->setPos(startX, startY);
            addItem(newItem);
        }
    }
}

#include "matrixscene.h"

#include <QGraphicsRectItem>

MatrixScene::MatrixScene(QObject *parent) :
    QGraphicsScene(parent)
{
    setSceneRect(0,0,200,200);
}

void MatrixScene::setNumberOfItems(int number)
{
    items().clear();

    qreal rectWidth = (width() / number) - 5;
    qreal rectHeight = (height() / number) - 5;

    qreal startX = 1;
    qreal startY = 1;

    int counterX = 0;
    int counterY = 0;

    QGraphicsRectItem *newItem;

    for(counterY = 0; counterY < number; ++counterY) {
        startY = counterY * (rectHeight + 5);
        for(counterX = 0; counterX < number; ++counterX) {
            startX = counterX * (rectWidth + 5);
            newItem = new QGraphicsRectItem;
            newItem->setRect(0, 0, rectWidth, rectHeight);
            newItem->setPos(startX, startY);
            addItem(newItem);
        }
    }
}

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[salmanmanekia]

it compiles succesfuly but there is no output....when i remove the for blocks i can see my view and widgets but as i include the for blocks No Output !

[tbscope]

You must call setNumberOfItems somewhere, in your constructor for example.
If you define it as a slot, you can create a combobox or lineedit with button and use it to change the matrix.