Create a matrix from a .csv file

mrjj

Yes its possible. we can paint it any way we like. teasers included.

Well im getting very tired as 4.20 in the morning is late for me even i do love programming at night.

Tomorrow we add the last part. It's not that much. Promise.
You did good. First custom widget is always a bit tuff.

alt text

AliM93

thank you so much! you help me a lot also in understand the ideas. thanks. night!

mrjj

Hi
The last remaining steps are to
+Add box width/height as members to use when clicking and a variable to keep track of the number of selected

class MatrixWidget : public QWidget
{....    
    int bw =0;
    int bh =0;
    int selCount=0; // to make sure we can only select 3
,...

+call loadData from construtor.

+Set some colors in void MatrixWidget::LoadData()
for 0 cells and 1 cells (see code)

+Add selection logic to mousePress

void MatrixWidget::mousePressEvent(QMouseEvent *event)
{
    QPoint p = event->pos(); // where we clicked

    int xindex =  p.x() / bw;
    int yindex =  p.y() / bh;

    qDebug() << xindex << " " << yindex;
    // get the data point ( we should check index is not outside array...)
    DataPoint &dp = Data[xindex + 1 ][yindex + 1]; 

    // value zero cannot be selected
    if ( dp.value == 0 ) return;

    // selection logic. If not already selected, select it and set color. Else deselect and reset color
    if ( dp.isSelected == false) {

        // no more than 3 selected ( 0,1,2 )
        if ( selCount > 2 ) return;

        dp.DrawColor = Qt::blue;
        dp.isSelected = true;
        selCount++; // extra selected
    } else {
        dp.DrawColor =  Qt::green;
        dp.isSelected = false;
        selCount--; // less selected
    }
    update(); // tell it to redraw grid

}

+Adjust draw to skip 0,0 as we don't use it but the array must start at zero.

void MatrixWidget::paintEvent(QPaintEvent *event)
{

    QPainter p(this);
    // draw frame.
    p.drawRect(0, 0, width() - 1, height() - 1);

    // size of area we have. w = width , h = height , we take 2 pixles for border
    int w = width() - 2;
    int h = height() - 2;

    // now we find out how big each box should be which area we have  divided with how many on x and y
    bw = w / max_x;
    bh = h / max_y;

    // now we loop and draw the boxes. we dont use the boxes from 0,0 as data starts with 1,1
    for (int xi = 0; xi < max_x - 1; ++xi) {
        for (int yi = 0; yi < max_x - 1; ++yi) {
            p.setBrush(QBrush( Data[xi + 1][yi + 1].DrawColor )); // +1 as we dont want to use from 0,0
            QRect cellRect( xi * bw, yi * bh, bw, bh  );
            p.drawRect( cellRect );
            // show x,y . just for debug
            p.drawText( cellRect ,
                       QString::number(xi + 1) + "," +
                       QString::number(yi +1) );

        }
    }
}

Then we have a working version.

alt text

project
https://www.dropbox.com/s/z4nllgag1tjy4j3/GridWidgetApp.zip?dl=0

Things to improve/add
The limit of how many points user can select,
should be a parameter to the class so it can be set to anything and not a fixed value.

The colors could also be parameters ( for not selectable, selectable and selected)

Add a function to return the selected data pointsby looping the Data list and check isSelected.

AliM93

thanks! i'll do it step by step, i quite understand it, but when i run i got a black grid, and the error floating point exeption (core dumped) No more error, (i also see the coordinates in the debug), but black grid.

mrjj

@AliM93 said in Create a matrix from a .csv file:

it, but when i run i got a black grid, and the error floating point exeption (core dumped)

In my project or yours ?

AliM93

@mrjj in mine

mrjj

@AliM93

Ok, i would guess that you forgot something from the maxtric class to put in yours.
But if the grid is drawn ( you see it) and then when you click error comes ?

AliM93

This post is deleted!

mrjj

@AliM93
If it compiles then all includes are fine.

Do you load data ?

Did you change LoadData function to set colors ?
(or use mine, just change the path to the data file)

I think all is just black :)
(default zero)

AliM93

@mrjj Done!! now i wii implement the function to save points! i'll let you know. thanks so much

mrjj

Hi
Ok super.
Good work. Your first custom Widget :)

Saving the points should be ok easy.
you can loop the Data array and take all where isSelected is true.

Ps please flag this as solved:)