Pyqt5:Qpainter绘制基础图形（二）：鼠标拖画
接着上文：绘制基础图形函数已经全部清楚，然后进阶鼠标拖画。
鼠标拖画，需要用到鼠标事件
鼠标事件：
与C++Qt一样，鼠标事件，需要重载鼠标事件函数如下：
def mousePressEvent(self, e):
print("鼠标按下事件") def mouseReleaseEvent(self, e):
print("鼠标释放事件")
if e.button() == Qt.LeftButton:
print("左键")
elif e.button() == Qt.RightButton:
print("右键")
elif e.button() == Qt.MidButton:
print("点击滚轮") def mouseMoveEvent(self, e):
print("鼠标移动事件")鼠标绘制图形：
点击相应按钮，鼠标拖动画出对应图形：
思路：
创建对应List用来存储鼠标坐标点。
鼠标左键点击绘制，右键清空
画点：
创建List
self.Point_list = [] 绘制点
if self.Draw == "Point":
len_point_list = len(self.Point_list)/2
for i in range(int(len_point_list)): #for循环绘制所有坐标点
painter.drawPoint(self.Point_list[i*2],self.Point_list[i*2+1])
print("DrawPoint")鼠标按下事件：存储坐标点
if self.Draw =="Point":
self.Point_list.append(e.x())
self.Point_list.append(e.y())
self.update()#更新界面所有绘制：
List创建：
其中点、多边行的绘制，皆为不确定List，所以定义为不定长空List。
其他绘制均为定长List
self.Line_list = [0,0,0,0]
self.Point_list = []
self.Elipse_list = [0,0,0,0]
self.Rectangle_list = [0,0,0,0]
self.Polygon_list = []
self.Pie_list = [0,0,0,0]
self.Arc_list = [0,0,0,0]绘制函数：
绘制多边形部分，只有鼠标左键按下三次，记录三个坐标点及以上才能绘制多边形
def paintEvent(self, QPaintEvent):
painter = QPainter(self)
painter.setPen(QColor(166,66,250))
painter.begin(self)
if self.Draw == "Line":
painter.drawLine(self.Line_list[0],self.Line_list[1],self.Line_list[2],self.Line_list[3])
print("DrawLine")
elif self.Draw == "Point":
len_point_list = len(self.Point_list)/2
for i in range(int(len_point_list)):
painter.drawPoint(self.Point_list[i*2],self.Point_list[i*2+1])
print("DrawPoint")
elif self.Draw == "Elipse":
painter.drawEllipse(self.Elipse_list[0],self.Elipse_list[1],self.Elipse_list[2],self.Elipse_list[3])
print("DrawElipse")
elif self.Draw == "Rectangle":
painter.drawRect(self.Rectangle_list[0],self.Rectangle_list[1],self.Rectangle_list[2],self.Rectangle_list[3])
print("DrawRectangle")
elif self.Draw == "Text":
painter.drawText(120,120,"文字")
print("DrawText")
elif self.Draw == "Polygon":
polygon = QPolygon()
if len(self.Polygon_list) >= 6:
polygon.setPoints(self.Polygon_list)
print(len(self.Polygon_list))
painter.drawPolygon(polygon)
print("DrawPolygon")
elif self.Draw == "Pie":
painter.drawPie(self.Pie_list[0],self.Pie_list[1],self.Pie_list[2],self.Pie_list[3],0*16,120*16)
print("DrawPie")
elif self.Draw =="Arc":
painter.drawArc(self.Arc_list[0],self.Arc_list[1],self.Arc_list[2],self.Arc_list[3],30*16,120*16)
print("DrawArc")
elif self.Draw == "Path":
path = QPainterPath()
path.addRect(100,100,100,100)
path.addEllipse(150,150,60,80)
painter.setBrush(Qt.blue)
#path.setFillRule(Qt.WindingFill)
path.setFillRule(Qt.OddEvenFill)
painter.drawPath(path)
print("DrawPath")
painter.end()鼠标按下事件：
def mousePressEvent(self, e):
if self.Draw == "Line" :
self.Line_list[0] = e.x()
self.Line_list[1] = e.y()
print("start",self.Line_list[0],self.Line_list[1])
elif self.Draw =="Point":
self.Point_list.append(e.x())
self.Point_list.append(e.y())
self.update()
elif self.Draw == "Elipse":
self.Elipse_list[0]=e.x()
self.Elipse_list[1]=e.y()
elif self.Draw == "Rectangle":
self.Rectangle_list[0] = e.x()
self.Rectangle_list[1] = e.y()
elif self.Draw == "Polygon":
self.Polygon_list.append(e.x())
self.Polygon_list.append(e.y())
print(self.Polygon_list)
self.update()
elif self.Draw == "Pie":
self.Pie_list[0] = e.x()
self.Pie_list[1] = e.y()
elif self.Draw == "Arc":
self.Arc_list[0] = e.x()
self.Arc_list[1] = e.y()
if e.button() == Qt.RightButton:
self.Point_list.clear()
self.Elipse_list = [0,0,0,0]
self.Rectangle_list = [0,0,0,0]
self.Polygon_list.clear()
self.Pie_list = [0,0,0,0]
self.Arc_list = [0,0,0,0]
self.update()鼠标移动事件：
除画线以为，其他第二个坐标点均为相对坐标点，长，宽或者半径
def mouseMoveEvent(self, e):
if self.Draw == "Line" :
self.Line_list[2] = e.x()
self.Line_list[3] = e.y()
print("end",self.Line_list[2],self.Line_list[3])
self.update()
elif self.Draw == "Elipse":
self.Elipse_list[2] = e.x()-self.Elipse_list[0]
self.Elipse_list[3] = e.y()-self.Elipse_list[1]
self.update()
print("Radius",self.Elipse_list[2],self.Elipse_list[3])
elif self.Draw == "Rectangle":
self.Rectangle_list[2] = e.x()-self.Rectangle_list[0]
self.Rectangle_list[3] = e.y()-self.Rectangle_list[1]
self.update()
elif self.Draw == "Pie":
self.Pie_list[2] = e.x() - self.Pie_list[0]
self.Pie_list[3] = e.y() - self.Pie_list[1]
self.update()
elif self.Draw == "Arc":
self.Arc_list[2] = e.x() - self.Arc_list[0]
self.Arc_list[3] = e.y() - self.Arc_list[1]
self.update()源代码如下：
源代码