Shulou(Shulou.com)06/01 Report--

This article mainly introduces "how to achieve Qt mouse positioning crosshairs". In daily operation, I believe many people have doubts about how to achieve Qt mouse positioning crosshairs. The editor consulted all kinds of materials and sorted out simple and easy-to-use methods of operation. I hope it will be helpful to answer the doubts of "how to achieve Qt mouse positioning crosshairs". Next, please follow the editor to study!

I. Preface

How to use Qt to draw a mouse positioning crosshairs, took two minutes to complete a, the least gold content of a demo, is to use drawline to draw two lines, this effect in the classic CAD software is very commonly used, there are some stock software, there are also this kind of crosshair positioning lines, sometimes need in the cross to obtain the corresponding point data to display and so on. Qt to draw a variety of effects is still very convenient, the same sentence: there are coordinates in the heart, everything is painter.

2. Code idea void Widget::mouseMoveEvent (QMouseEvent * event) {lastPos = event- > pos (); update ();} void Widget::mouseReleaseEvent (QMouseEvent * event) {/ / here are the coordinates pressed by the mouse, and you save them in the database lastPos = event- > pos (); update (); qDebug ()

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