博客

实时图像

写了一个关于实时图像滚动显示的例子，做个记录。

 

滚动算法：

 

难点：

将内存数据绘制到界面，需要用到QImage和QPixmap，使用QImage转换一下，具体参见代码。这个费了好大劲才弄出来（网上的资料大都很简单，处理个QImage打开保存啊等等操作，项目实用性不强。）

 

from PIL import Image

import numpy as np

import threading

import time

 

class GraphicWidget(QWidget):

    def __init__(self):

        super(GraphicWidget,self).__init__()

        self.threadStop = False

        self.drawWidth = 1080

        self.drawHeight = 800

        self.imgWholeData = None

        self.imgScreenData = np.zeros([self.drawHeight,self.drawWidth],np.uint8)

        self.imgTotalLines = 0

        self.imgWidth = 0

        self.threadStop = True

        pass

   

    def doscroll(self):

 

        if self.threadStop:

            img = Image.open(“d:/test2.png”)

            self.imgWholeData = np.array(img)

            self.imgTotalLines, self.imgWidth = self.imgWholeData.shape

           

            scrollThread = threading.Thread(target = self.scroll)

            scrollThread.start()

 

    def stop(self):

        self.threadStop = True

 

    def scroll(self):

        step = 5

        srcStartLine = 0

        srcEndLine = step

        destEndLine = step

        self.threadStop = False

        while not self.threadStop:

            if destEndLine > self.drawHeight:

                destEndLine = self.drawHeight

 

            if srcEndLine > self.drawHeight:

                srcStartLine = srcEndLine – self.drawHeight

 

            if srcEndLine > self.imgTotalLines:

                print(“scroll end”)

                self.threadStop = True

                break

            if srcStartLine < self.drawHeight:

                self.imgScreenData = np.zeros([self.drawHeight,self.drawWidth],np.uint8)

           

            self.imgScreenData[0:destEndLine] = self.imgWholeData[srcStartLine:srcEndLine]

 

            self.update()

           

            destEndLine = destEndLine + step

            srcEndLine = srcEndLine + step

 

            time.sleep(0.005)

        pass

 

    def paintEvent(self,event):

        try:

            painter = QPainter()

            destRect = QRect(0,0,self.drawWidth,self.drawHeight)

            srcRect = QRect(0,0,self.drawWidth,self.drawHeight)

            img = QImage(self.imgScreenData.data, self.drawWidth, self.drawHeight, QImage.Format_Indexed8)

            pix = QPixmap.fromImage(img)

            painter.begin(self)

            painter.drawPixmap(destRect, pix, srcRect)

            painter.end()

        except Exception as e:

            print(e)

            raise

       

        Pass

 

经验证，图像“拖尾”比较严重，图像滚动平滑效果比不上用DirectX做的效果，但是刷新效率很高，QT这块做的比C#好很多。

 

下次，实用Opengl做一个，看看效果咋样。