QTableView/QTableWidget Cell Span Range

Adam Crowe

Hello,

Is there a way to get the range of a spanned cell from any position within the spanned cell?

For example, I can use QTableView::rowSpan(1, 1) and QTableView::columnSpan(1, 1) to find that the cell with "B" in it has a span of 2x2; but how can I find the beginning of the spanned range if I query cell at row 2 and column 2 (the bottom right corner of cell "B")? I need a way to get back (row 1, column 1) from it.

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Thank you!

Christian Ehrlicher

I think it should be possible through QTableView::rowSpan() and QTableView::columnSpan()

Adam Crowe

Thank you @Christian-Ehrlicher. Unfortunately, all QTableView::rowSpan() and QTableView::columnSpan() tells me is what the total span is, but it doesn't tell me which cell it starts at, so if I had a span of 3x3 and I checked the rowSpan and colSpan of the middle cell, it would tell me 3 and 3.

Christian Ehrlicher

From looking a little bit at the sources you have to remember it by youself. No chance to get it out of the QTableView

JonB

@Adam-Crowe
I don't see there is a quicker way than: you must iterate through the columns/rows (left-to-right/top-to-bottom) looking at the current value of row/columnSpan() in each cell. From that you can obviously calculate where a given cell coordinate really lies in your terms.

@Christian-Ehrlicher : You say "No chance to get it out of the QTableView". I agree there is not a simple call to return this, but I say you can calculate it in loops. Have I said anything incorrect here?

Adam Crowe

Thank you everybody,

I wrote this little thing just now and it seems to work:

struct Coordinates { int row; int col; };

Coordinates getFirstCellInSpan(const int &row, const int &col)
{
    Coordinates xy;

    int firstRow = 0;
    int firstCol = 0;

    while (firstRow + rowSpan(firstRow, col) <= row)
    {
        firstRow++;
    }

    while (firstCol + columnSpan(firstRow, firstCol) <= col)
    {
        firstCol++;
    }

    xy.row = firstRow;
    xy.col = firstCol;

    return xy;
}

JonB

@Adam-Crowe
Exactly, as I said you have to iterate to find out, just as you have done :) Qt could have provided such a function, but it does not, and I don't know that internally it saves the data in any way which would be quicker than this; and even if it does, there is no public API for you to access that, other than what you have done.