PyQt5 在 QLabel 使用 QPainter 绘制矩形
一.基础使用
在QLabel 上绘制矩形,需要使用 paintEvent 并且重写 paintEvent 函数,因为Qpainter 在 QWidget 上不会报错,在其他地方直接使用就会报错.
from PyQt5.QtGui import QImage,QPixmap
import cv2
from PyQt5.QtCore import *
from PyQt5.QtGui import *
from PyQt5.QtWidgets import *
import sys
class MyLabel(QLabel):
def __init__(self,text):
super(MyLabel,self).__init__()
self.x0 = 150
self.y0 = 120
self.x1 = 400
self.y1 = 220
self.x2 = 150
self.y2 = 320
self.x3 = 400
self.y3 = 420
self.lab1 = QLabel(self)
self.lab2 = QLabel(self)
self.lab1.setText(text)
self.lab2.setText("操作区")
self.lab1.setStyleSheet("QLabel{color:rgb(0,0,255);font-size:18px;font-family:Arial;background:transparent;}")
self.lab2.setStyleSheet("QLabel{color:rgb(0,0,255);font-size:18px;font-family:Arial;background:transparent;}")
self.lab1.setMaximumSize(100,200)
self.lab2.setMaximumSize(100,200)
self.lab1.move(150,120)
self.lab2.move(150,320)
#绘制事件
def paintEvent(self, event):
super().paintEvent(event)
rect =QRect(self.x0, self.y0, abs(self.x1-self.x0), abs(self.y1-self.y0))
painter = QPainter(self)
painter.setPen(QPen(Qt.red,2,Qt.SolidLine))
painter.drawRect(rect)
rect1 = QRect(self.x2, self.y2, abs(self.x3 - self.x2), abs(self.y3 - self.y2))
painter2 = QPainter(self)
painter2.setPen(QPen(Qt.red, 2, Qt.SolidLine))
painter2.drawRect(rect1)
class Example(QWidget):
def __init__(self):
super().__init__()
self.initUI()
def initUI(self):
self.resize(675, 500)
self.move(100,50)
self.setWindowTitle('在label中绘制矩形')
self.lb = MyLabel("输入区") #重定义的label
img = cv2.imread('a5.jpg')
showImage = QImage(img.data, img.shape[1], img.shape[0],
QImage.Format_RGB888) # 把读取到的图片数据变成QImage形式
# 往显示视频的Label里 显示QImage
self.lb.setPixmap(QPixmap.fromImage(showImage))
#self.lb.setCursor(Qt.CrossCursor)
self.horizontalLayout = QHBoxLayout(self)
self.horizontalLayout.addWidget(self.lb)
self.show()
if __name__ == '__main__':
app = QApplication(sys.argv)
x = Example()
sys.exit(app.exec_())上面的代码运行后就会在嵌套图片的QLabel中画了两个红色矩形.也可根据自己的需求是否要文字提示.
二.升级版一
from PyQt5.QtWidgets import QWidget, QApplication, QLabel
from PyQt5.QtCore import QRect, Qt
from PyQt5.QtGui import QImage, QPixmap, QPainter, QPen
import cv2
import sys
class MyLabel(QLabel):
x0 = 0
y0 = 0
x1 = 0
y1 = 0
flag = False
#鼠标点击事件
def mousePressEvent(self,event):
self.flag = True
self.x0 = event.x()
self.y0 = event.y()
#鼠标释放事件
def mouseReleaseEvent(self,event):
self.flag = False
#鼠标移动事件
def mouseMoveEvent(self,event):
if self.flag:
self.x1 = event.x()
self.y1 = event.y()
self.update()
#绘制事件
def paintEvent(self, event):
super().paintEvent(event)
rect =QRect(self.x0, self.y0, abs(self.x1-self.x0), abs(self.y1-self.y0))
painter = QPainter(self)
painter.setPen(QPen(Qt.red,2,Qt.SolidLine))
painter.drawRect(rect)
class Example(QWidget):
def __init__(self):
super().__init__()
self.initUI()
def initUI(self):
self.resize(675, 500)
self.move(100,50)
self.setWindowTitle('在label中绘制矩形')
self.lb = MyLabel(self) #重定义的label
img = cv2.imread('a5.jpg')
showImage = QImage(img.data, img.shape[1], img.shape[0],
QImage.Format_RGB888) # 把读取到的图片数据变成QImage形式
# 往显示视频的Label里 显示QImage
self.lb.setPixmap(QPixmap.fromImage(showImage))
self.lb.setCursor(Qt.CrossCursor)#图片可以绘制
self.show()
if __name__ == '__main__':
app = QApplication(sys.argv)
x = Example()
sys.exit(app.exec_())代码运行后如下图所示,可以用鼠标绘制一个红色的方框.
三.升级版二
直接上代码:
代码运行后如截图所示,这个升级版的亮点在于在制作界面Qlabel绘制方框时,可以根据具体界面的需求来绘制多个矩形方框.而不需要一直在MyLabel 类中设置方框(x,y)的位置,可以直接在调用函数中设置矩形的坐标直接绘制出矩形.这样方便制作界面,减少代码的重复率.
from PyQt5.QtGui import QImage,QPixmap
import cv2
from PyQt5.QtCore import *
from PyQt5.QtGui import *
from PyQt5.QtWidgets import *
import sys
class MyLabel(QLabel):
def __init__(self):
super().__init__()
self.data = []
def setxy(self,x1,y1,x2,y2,text):
self.lab1 = QLabel(self)
self.lab1.setText(text)
self.lab1.setStyleSheet("QLabel{color:rgb(0,0,255);\
font-size:18px;font-family:Arial;background:transparent;}")
self.lab1.move(x1,y1)
self.setGeometry(QRect(x1,y1,x2,y2))
data = [x1,y1,x2,y2]
self.data.append(data)
#绘制表格
def paintEvent(self,event):
super().paintEvent(event)
painter = QPainter()
painter.begin(self)
for data in self.data:
rect = QRect(data[0], data[1], abs(data[2] - data[0]), abs(data[3] - data[1]))
painter.setPen(QPen(Qt.red, 2, Qt.SolidLine))
painter.drawRect(rect)
painter.end()
class Example(QWidget):
def __init__(self):
super().__init__()
self.initUI()
def initUI(self):
self.resize(675, 500)
self.move(100,50)
self.setWindowTitle('在label中绘制矩形')
self.lb = MyLabel() #重定义的label
self.lb.setxy(150, 120, 250, 220, "输入区")
#self.lb.setGeometry(QRect(150, 120, 250, 220))
self.lb.setxy(300, 150, 400, 350, "绘图")
#self.lb.setGeometry(QRect(300, 150, 400, 350))
img = cv2.imread('a5.jpg')
showImage = QImage(img.data, img.shape[1], img.shape[0],
QImage.Format_RGB888) # 把读取到的图片数据变成QImage形式
# 往显示视频的Label里 显示QImage
self.lb.setPixmap(QPixmap.fromImage(showImage))
#self.lb.setCursor(Qt.CrossCursor)
self.horizontalLayout = QHBoxLayout(self)
self.horizontalLayout.addWidget(self.lb)
self.show()
if __name__ == '__main__':
app = QApplication(sys.argv)
x = Example()
sys.exit(app.exec_())
参考链接:https://blog.csdn.net/zzzzjh/article/details/82985209
https://blog.csdn.net/pansaky/article/details/98958012