PyQt4 tutorial读书笔记（9）-- Drawing
==应用程序中需要绘画，特别当我们想要改变或者加强现有部件，或者我们从头创建一个自定义部件。
==绘画在paintEvent()方法中执行。绘画代码被放在QtGui.QPainter对象的begin（）和end（）方法之间。.它在组件上和其他绘图设备上执行低级别的绘图。
1、Drawing text
import sys
from PyQt4 import QtGui, QtCore
class Example(QtGui.QWidget):
def __init__(self):
super(Example, self).__init__()
self.initUI()
def initUI(self):
self.text = u'\u041b\u0435\u0432 \u041d\u0438\u043a\u043e\u043b\u0430\ \u0435\u0432\u0438\u0447 \u0422\u043e\u043b\u0441\u0442\u043e\u0439: \n\ \u0410\u043d\u043d\u0430 \u041a\u0430\u0440\u0435\u043d\u0438\u043d\u0430'
self.setGeometry(300, 300, 280, 170)
self.setWindowTitle('Draw text')
self.show()
def paintEvent(self, event):
qp = QtGui.QPainter()
qp.begin(self)
self.drawText(event, qp)
qp.end()
def drawText(self, event, qp):
qp.setPen(QtGui.QColor(168, 34, 3))
qp.setFont(QtGui.QFont('Decorative', 10))
qp.drawText(event.rect(), QtCore.Qt.AlignCenter, self.text)
def main():
app = QtGui.QApplication(sys.argv)
ex = Example()
sys.exit(app.exec_())
if __name__ == '__main__':
main()（1）设置 处于水平和垂直方向上的中心点
qp.drawText(event.rect(), QtCore.Qt.AlignCenter, self.text) （2） QtGui.QPainter负责所有的低级绘画。所有的绘画方法都在begin()和end()函数之间。
qp = QtGui.QPainter()
qp.begin(self)
self.drawText(event, qp)
qp.end()2、Drawing points
import sys, random
from PyQt4 import QtGui, QtCore
class Example(QtGui.QWidget):
def __init__(self):
super(Example, self).__init__()
self.initUI()
def initUI(self):
self.setGeometry(300, 300, 280, 170)
self.setWindowTitle('Points')
self.show()
def paintEvent(self, e):
qp = QtGui.QPainter()
qp.begin(self)
self.drawPoints(qp)
qp.end()
def drawPoints(self, qp):
qp.setPen(QtCore.Qt.red)
size = self.size()
for i in range(1000):
x = random.randint(1, size.width()-1)
y = random.randint(1, size.height()-1)
qp.drawPoint(x, y)
def main():
app = QtGui.QApplication(sys.argv)
ex = Example()
sys.exit(app.exec_())
if __name__ == '__main__':
main()3、Colours
import sys
from PyQt4 import QtGui, QtCore
class Example(QtGui.QWidget):
def __init__(self):
super(Example, self).__init__()
self.initUI()
def initUI(self):
self.setGeometry(300, 300, 350, 100)
self.setWindowTitle('Colours')
self.show()
def paintEvent(self, e):
qp = QtGui.QPainter()
qp.begin(self)
self.drawRectangles(qp)
qp.end()
def drawRectangles(self, qp):
color = QtGui.QColor(0, 0, 0)
color.setNamedColor('#d4d4d4')
qp.setPen(color)
qp.setBrush(QtGui.QColor(200, 0, 0))
qp.drawRect(10, 15, 90, 60)
qp.setBrush(QtGui.QColor(255, 80, 0, 160))
qp.drawRect(130, 15, 90, 60)
qp.setBrush(QtGui.QColor(25, 0, 90, 200))
qp.drawRect(250, 15, 90, 60)
def main():
app = QtGui.QApplication(sys.argv)
ex = Example()
sys.exit(app.exec_())
if __name__ == '__main__':
main()
4、QtGui.QPen
QtGui.QPen基本图形绘画对象，用于画线，曲线，矩形轮廓，椭圆形，多边形和其他形状。
import sys
from PyQt4 import QtGui, QtCore
class Example(QtGui.QWidget): def __init__(self): super(Example, self).__init__() self.initUI() def initUI(self): self.setGeometry(300, 300, 280, 270) self.setWindowTitle('Pen styles') self.show() def paintEvent(self, e): qp = QtGui.QPainter() qp.begin(self) self.drawLines(qp) qp.end() def drawLines(self, qp): pen = QtGui.QPen(QtCore.Qt.black, 2, QtCore.Qt.SolidLine) qp.setPen(pen) qp.drawLine(20, 40, 250, 40) pen.setStyle(QtCore.Qt.DashLine) qp.setPen(pen) qp.drawLine(20, 80, 250, 80) pen.setStyle(QtCore.Qt.DashDotLine) qp.setPen(pen) qp.drawLine(20, 120, 250, 120) pen.setStyle(QtCore.Qt.DotLine) qp.setPen(pen) qp.drawLine(20, 160, 250, 160) pen.setStyle(QtCore.Qt.DashDotDotLine) qp.setPen(pen) qp.drawLine(20, 200, 250, 200) pen.setStyle(QtCore.Qt.CustomDashLine) pen.setDashPattern([1, 4, 5, 4]) qp.setPen(pen) qp.drawLine(20, 240, 250, 240)
5、QtGui.QBrush
是一个基本的图形对象。它用于绘画背景图形形状。比如矩形，椭圆形或者多边形。一个brush可以有三种不同类别，预定义brush,
such as rectangles, ellipses(椭圆形), or polygons(多边形). A brush can be of three different types: a predefined brush, a gradient(梯度), or a texture(质地) pattern.
import sys
from PyQt4 import QtGui, QtCore
class Example(QtGui.QWidget): def __init__(self): super(Example, self).__init__() self.initUI() def initUI(self): self.setGeometry(300, 300, 355, 280) self.setWindowTitle('Brushes') self.show() def paintEvent(self, e): qp = QtGui.QPainter() qp.begin(self) self.drawBrushes(qp) qp.end() def drawBrushes(self, qp): brush = QtGui.QBrush(QtCore.Qt.SolidPattern) qp.setBrush(brush) qp.drawRect(10, 15, 90, 60) brush.setStyle(QtCore.Qt.Dense1Pattern) qp.setBrush(brush) qp.drawRect(130, 15, 90, 60) brush.setStyle(QtCore.Qt.Dense2Pattern) qp.setBrush(brush) qp.drawRect(250, 15, 90, 60) brush.setStyle(QtCore.Qt.Dense3Pattern) qp.setBrush(brush) qp.drawRect(10, 105, 90, 60) brush.setStyle(QtCore.Qt.DiagCrossPattern) qp.setBrush(brush) qp.drawRect(10, 105, 90, 60) brush.setStyle(QtCore.Qt.Dense5Pattern) qp.setBrush(brush) qp.drawRect(130, 105, 90, 60) brush.setStyle(QtCore.Qt.Dense6Pattern) qp.setBrush(brush) qp.drawRect(250, 105, 90, 60) brush.setStyle(QtCore.Qt.HorPattern) qp.setBrush(brush) qp.drawRect(10, 195, 90, 60) brush.setStyle(QtCore.Qt.VerPattern) qp.setBrush(brush) qp.drawRect(130, 195, 90, 60) brush.setStyle(QtCore.Qt.BDiagPattern) qp.setBrush(brush) qp.drawRect(250, 195, 90, 60) def main(): app = QtGui.QApplication(sys.argv) ex = Example() sys.exit(app.exec_()) if __name__ == '__main__': main()