如何为绘制的对象(例如 drawLine)制作透明背景? [英] how to make transparent background for drawn objects (ex. drawLine)?

问题描述

我想制作一个应用程序，其中只有绘制的对象(例如 drawLine)可见，而不是背景.

I want to make to make an application where just the drawn objects (ex. drawLine) is visible, not the background.

因此，如果用户打开应用程序，他/她可以绘制形状，并且只能看到绘制的形状.

So, if a user opens up the application, he/she can draw shapes, and only see the shapes drawn.

我是 pyside 的新手，但我发现了只有小部件可见的示例，但我认为这不适用于此问题.

I'm new to pyside, but I've found examples where only the widget is visible, but I don't think that applies to this problem.

a = QPoint(22, 22)
b = QPoint(444, 444)

def __init__(self, parent=None):
    QWidget.__init__(self, parent)
    self.setGeometry(300, 300, 350, 350)
    self.setWindowTitle('Draw circles')

def paintEvent(self, event):
    paint = QPainter()
    paint.begin(self)
    paint.drawLine(self.a, self.b)
    paint.end()

上面的程序只是在不透明背景上画一条线的例子.不知道如何从这个变成透明背景.

The above program is just an example of a line drawn on an opaque background. Not sure how to go from this to a transparent background.

推荐答案

您必须启用标志 Qt::WA_TranslucentBackground:

from PySide import QtCore, QtGui


class Widget(QtGui.QWidget):
    def __init__(self, parent=None):
        super(Widget, self).__init__(parent)
        self.setAttribute(QtCore.Qt.WA_TranslucentBackground, True)

    def paintEvent(self, event):
        a = QtCore.QPoint(22, 22)
        b = QtCore.QPoint(444, 444)

        painter = QtGui.QPainter(self)
        pen = QtGui.QPen(QtGui.QColor("red"))
        pen.setWidth(5)
        painter.setPen(pen)
        painter.drawLine(a, b)


if __name__ == "__main__":
    import sys

    app = QtGui.QApplication(sys.argv)
    w = Widget()
    w.resize(640, 480)
    w.show()
    sys.exit(app.exec_())

正如它所说的 @Heike 似乎在 windows 中需要添加:

As it says @Heike it seems that in windows it is necessary to add:

self.setWindowFlags(QtCore.Qt.FramelessWindowHint) 

这篇关于如何为绘制的对象(例如 drawLine)制作透明背景?的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！