Why my QTextTable aren't insert with sized correctly?

[JackMyson]

I wrote a rich text program with some margin- and pagination-handling functions with QTextEdit. Now I'm dealing with some table problems. I know that I can insert a table by calling richTextEditor->textCursor().insertTable(int rows, int cols), and that's the problem.
I have the following code, for inserting the table with a dialog:

void DialogInsertTable::insertTable(/*int rows, int columns*/) {
    int row = rowsEdit->value();
    int column = columnsEdit->value();

    // ed is the subclassed QTextEdit
    QTextCursor cursor = ed->textCursor();
    QTextTable* table = cursor.insertTable(row, column);
    QTextTableFormat tableForm;
    tableForm.setWidth(QTextLength(QTextLength::Type::PercentageLength, 100));
    qreal v = (((ed->viewport()->width()) / column - (ed->marginLeft()) - (ed->marginRight())));
    qreal rawValue = tableForm.width().value(v);
    QList<QTextLength> list;
    for (int i=1; i<=column; i++) {
        list << QTextLength(QTextLength::Type::FixedLength, rawValue);
    }
    tableForm.setColumnWidthConstraints(list);
    tableForm.setBorderCollapse(true);
    table->setFormat(tableForm);
    
    close();
}

3 columns is the only perfect columns number for inserting this table. If I insert the table with 1 column or 2 columns or 4 or more, things go crazy.

Can somebody tells me why my table become smaller and smaller? I want something like this:

Environment

• Operating System: macOS Big Sur 11.7.1;
• Model: MacBook Air (11-inch, Mid 2013) running 64-bit Intel processor x86_64;
• Qt version: 6.3.2 (Clang 13.0);
• Qt Creator version: 8.0.2;

Any help will be appreciate! Thanks!!

[Chris Kawa]

You've got your column width calculation wrong. You're multiplying margins for each column.
It should rather be

qreal v = (ed->viewport()->width() - ed->marginLeft() - ed->marginRight()) / columns;

and make sure to center your table via tableFormat.setAlignment(Qt::AlignCenter);.

Btw. QList has a constructor that can fill it with multiple copies of the same value, so you can avoid the for loop like this:

QList<QTextLength> list {columns, QTextLength{QTextLength::FixedLength, rawValue}};

[JackMyson]

Hello,

With your code,

void DialogInsertTable::insertTable(/*int rows, int columns*/) {
    int row = rowsEdit->value();
    int column = columnsEdit->value();

    QTextCursor cursor = ed->textCursor();
    QTextTable* table = cursor.insertTable(row, column);
    QTextTableFormat tableForm;
    tableForm.setWidth(QTextLength(QTextLength::Type::PercentageLength, 100));
    qreal v = (ed->viewport()->width() - ed->marginLeft() - ed->marginRight()) / column;
    qreal rawValue = tableForm.width().value(v);
    QList<QTextLength> list {column, QTextLength{QTextLength::FixedLength, rawValue}};
    tableForm.setAlignment(Qt::AlignCenter);
    tableForm.setColumnWidthConstraints(list);
    tableForm.setBorderCollapse(true);
    table->setFormat(tableForm);

    close();
}

It's still unsolved. The table is still exceed the margin.

How can I implement a QTextTable fitting the margin?

[JackMyson]

Oh.. I figured it out.
That's just a simple unit conversion error.

I used millimeter instead of pixel...

>>> # Python
>>> __editor.mmMarginLeft()
20
>>> __editor.pxMarginLeft()
110
>>> __editor.mmMarginLeft() == __editor.pxMarginLeft()
False

Now it's solved! THANKS a lot!