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Need a Little Help Drawing On Screen [Qt]
stuck_student13 last edited by
I have already read all the of examples etc on this topic and I am still confused.
I'm working on a project, the general idea is I need to give the user a space within a layout when they can click and the program will use the x & y coordinates of those clicks in several calculations. The program must then draw in that same area the shapes generated by those calculations. I am doing this through visual studios as required by my professor.
Right now I have constructed my layout and have placed a QWidget in the area I wish to use. I have attempted to use QPainter with the following section in an attempt to just draw a line and figure out how to use it. I am having a lot of trouble here and could use some help. Any incite into how to use QPainter or accomplish this with a better widget would be greatly appreciated.
@ middle_box = new QGroupBox(tr("Middle Box"));
QHBoxLayout *middle_layout = new QHBoxLayout();
QGL_1 = new QWidget();
button_2 = new QPushButton(tr("M2 Button"));
button_3 = new QPushButton(tr("M3 Button"));
button_4 = new QPushButton(tr("M4 Button"));
Thank you in advance for the help.
lgeyer last edited by
QPainter allows you to draw to any QPaintDevice subclass (typically QPixmap and QWidget). The most common usecase is to subclass QWidget, to reimplement the paintEvent() method and to use a QPainter to do custom painting.
Be aware that you cannot use QPainter to draw on a widget outside of its paintEvent() method!
Reimplementing various *Event() methods is "quite common":http://qt-project.org/doc/qt-4.8/QWidget.html#events in Qt, and is amongst others used for handling mouse events.
The "programming tutorial":http://qt-project.org/doc/qt-4.8/gettingstartedqt.html, the "QWidget":http://qt-project.org/doc/qt-4.8/QWidget.html#events and "QPainter":http://qt-project.org/doc/qt-4.8/QPainter.html#details documentation as well as the "examples":http://qt-project.org/doc/qt-4.8/painting-basicdrawing.html and freely available books like "C++ GUI Programming with Qt 4":http://www.qtrac.eu/C++-GUI-Programming-with-Qt-4-1st-ed.zip are a good place to start reading.