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Line drawing using qpainter



  • After trying many things and failed, i finally came here to do what i was trying.
    I want to display lines which are stored in a file named "line.txt" in comma seperated values.
    i have successfully read the values, but unable to draw them on the screen.
    please help.



  • Hi!

    You need to re-implement

    @void paintEvent(QPaintEvent *);@

    Inside it, create a QPainter. With it, call drawLine (look "here":https://qt-project.org/doc/qt-4.8/qpainter.html#drawLine). Hope this helps.

    Regards



  • the method you likely want is the drawText().

    Notice that you may just want to use a QTextDocument, which has a paint method too.

    Or even higher level, use the QTextEdit widget.



  • [quote author="QMartin" date="1360425719"]Hi!

    You need to re-implement

    @void paintEvent(QPaintEvent *);@

    Inside it, create a QPainter. With it, call drawLine (look "here":https://qt-project.org/doc/qt-4.8/qpainter.html#drawLine). Hope this helps.

    Regards[/quote]

    i have tried it but somehow it is not working. It is working for a single line. but for drawing multiple lines it doesn't show them all.



  • [quote author="Thomas Zander" date="1360429277"]the method you likely want is the drawText().

    Notice that you may just want to use a QTextDocument, which has a paint method too.

    Or even higher level, use the QTextEdit widget.[/quote]

    I need to draw only lines and not text.
    anyway thanks for the help.



  • Ok , i tried again and succeeded this time.
    method used:
    read all the lines from the file into a qvector<qline> and used qpainter::drawlines() to draw the lines all at a time.


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