Pyqtgraph是Python平台上一种功能强大的2D/3D绘图库

1 说明：

=====

1.1 pyqtgraph是Python平台上一种功能强大的2D/3D绘图库，相当于matplotlib库，比它更强大。

1.2 由于内部实现方式上，使用了高速计算的numpy信号处理库以及Qt的GraphicsView框架。

1.3 环境：

华为笔记本电脑、深度deepin-linux操作系统、python3.8和微软vscode编辑器。

1.4 对开源的源代码进行删减、修改、注释和整理，突出重点，易于操作。

不在迷茫

2 安装：

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2.1 pyqtgraph库安装：

pip install --user pyqtgraph
#本机安装
#pip3.8 install -i https://mirrors.aliyun.com/pypi/simple pyqtgraph #超快

2.2 PyQt5安装：需要配合

pip install PyQt5 #文件太大，速度太慢
#本机安装，推荐国内源安装
pip3.8 install -i https://mirrors.aliyun.com/pypi/simple PyQt5

2.3 小插曲：本机，每个电脑可能不一样。

#在微软vscode编辑器中python中可以导出模块，报错
https://stackoverflow.com/questions/26191513/opengl-error-in-python-pyqtgraph-opengl-items-glscatterplotitem-glscatterplot-it
#发现这个包放错了
Requirement already satisfied: pyqtgraph in ./.local/lib/python3.8/site-packages (0.10.0)
#复制到
Requirement already satisfied: numpy in /usr/local/python3.8/lib/python3.8/site-packages (from pyqtgraph) (1.18.2)
#root形式进入

2.4 官网：源码来源。

https://github.com/pyqtgraph/pyqtgraph
http://pyqtgraph.org/

官网的源码的一个动画，暂时不是本章重点讲解，本次讲解基础。

3 sin、cos：

========

3.1 sin和cos，代码放在一起，注释里有：

import pyqtgraph as pg
import numpy as np
import array

App = pg.mkQApp()#建立app
win = pg.GraphicsWindow()#建立窗口
win.setWindowTitle('pyqtgraph逐点画波形图') #窗口名称
win.resize(800, 500)#窗口大小

data = array.array('d') #可动态改变数组的大小,double型数组
historyLength = 100#横坐标长度
p = win.addPlot()#把图p加入到窗口中
p.showGrid(x=True, y=True)#把X和Y的表格打开
p.setRange(xRange=[0,historyLength], yRange=[-1.2, 1.2], padding=0)
p.setLabel(axis='left', text='y / V')#靠左，y轴
p.setLabel(axis='bottom', text='x / point') #靠下，x轴
p.setTitle('y = sin(x)')#表格的名字
curve = p.plot()#绘制一个图形
idx = 0
#定义函数
def plotData():
    global idx#内部作用域想改变外部域变量
    tmp = np.sin(np.pi / 50 * idx)  #sin动态函数曲线
    #tmp = np.cos(np.pi / 50 * idx)  #cos动态函数曲线
    if len(data)<historyLength:
        data.append(tmp)
    else:
        data[:-1] = data[1:]#前移
        data[-1] = tmp
    curve.setData(data)
    idx += 1
#启动定时器
timer = pg.QtCore.QTimer()
timer.timeout.connect(plotData)#定时调用plotData函数
timer.start(50)#多少ms调用一次
#注意exec后面的下划线
app.exec_()

3.2 效果图：

3.3 高级一些：

# -*- coding: utf-8 -*-
import pyqtgraph as pg
from pyqtgraph.Qt import QtCore, QtGui
import numpy as np

#数据，可自定义
x = np.linspace(-20, 20, 1000)
y = np.sin(x) / x #sin
#y = np.cos(x) / x  #cos，省略

plot = pg.plot()
plot.setYRange(-1, 2) #y轴取值范围
plot.setWindowTitle('pyqtgraph example: text') #表格名称
curve = plot.plot(x,y) 

#导入html格式的text静态标签，本次重点
text = pg.TextItem(
    html='<div style="text-align: center">
          <span style="color: #FFF;">This is the</span>
          <br><span style="color: #FF0; font-size: 16pt;">PEAK</span>
          </div>', anchor=(-0.3,0.5), angle=20, border='w', fill=(0, 0, 255, 100))
plot.addItem(text)
text.setPos(0, y.max())

#画箭头
arrow = pg.ArrowItem(pos=(0, y.max()), angle=-45)
plot.addItem(arrow)

## 设置动画和曲线
curvePoint = pg.CurvePoint(curve)
plot.addItem(curvePoint)
#text2是动态显示text
text2 = pg.TextItem("test", anchor=(0.5, -1.0))
text2.setParentItem(curvePoint)
arrow2 = pg.ArrowItem(angle=90)
arrow2.setParentItem(curvePoint)

index = 0
def update():
    global curvePoint, index
    index = (index + 1) % len(x)
    curvePoint.setPos(float(index)/(len(x)-1))
    text2.setText('[%0.1f, %0.1f]' % (x[index], y[index]))
    
timer = QtCore.QTimer()
timer.timeout.connect(update)
timer.start(10) #every 10ms

if __name__ == '__main__':
    QtGui.QApplication.instance().exec_()

3.4 效果图：

4 3D-GL模块调用的效果图：

4.1 代码：

# -*- coding: utf-8 -*-
#导出模块
from pyqtgraph.Qt import QtCore, QtGui
import pyqtgraph as pg
import pyqtgraph.opengl as gl
import numpy as np

## Create a GL View widget to display data，GL模块
app = QtGui.QApplication([])
w = gl.GLViewWidget()
w.show()
w.setWindowTitle('pyqtgraph example: GLSurfacePlot')
w.setCameraPosition(distance=50)

## Add a grid to the view
g = gl.GLGridItem()
g.scale(2,2,1)
g.setDepthValue(10) 
w.addItem(g)

#P1图
z = pg.gaussianFilter(np.random.normal(size=(50,50)), (1,1))
p1 = gl.GLSurfacePlotItem(z=z, shader='shaded', color=(0.5, 0.5, 1, 1))
p1.scale(16./49., 16./49., 1.0)
p1.translate(-18, 2, 0)
w.addItem(p1)

#P2图
x = np.linspace(-8, 8, 50)
y = np.linspace(-8, 8, 50)
z = 0.1 * ((x.reshape(50,1) ** 2) - (y.reshape(1,50) ** 2))
p2 = gl.GLSurfacePlotItem(x=x, y=y, z=z, shader='normalColor')
p2.translate(-10,-10,0)
w.addItem(p2)

#P3图
z = pg.gaussianFilter(np.random.normal(size=(50,50)), (1,1))
x = np.linspace(-12, 12, 50)
y = np.linspace(-12, 12, 50)
colors = np.ones((50,50,4), dtype=float)
colors[...,0] = np.clip(np.cos(((x.reshape(50,1) ** 2) + (y.reshape(1,50) ** 2)) ** 0.5), 0, 1)
colors[...,1] = colors[...,0]

p3 = gl.GLSurfacePlotItem(z=z, colors=colors.reshape(50*50,4), shader='shaded', smooth=False)
p3.scale(16./49., 16./49., 1.0)
p3.translate(2, -18, 0)
w.addItem(p3)

#P4图：动画
cols = 90
rows = 100
x = np.linspace(-8, 8, cols+1).reshape(cols+1,1)
y = np.linspace(-8, 8, rows+1).reshape(1,rows+1)
d = (x**2 + y**2) * 0.1
d2 = d ** 0.5 + 0.1

phi = np.arange(0, np.pi*2, np.pi/20.)
z = np.sin(d[np.newaxis,...] + phi.reshape(phi.shape[0], 1, 1)) / d2[np.newaxis,...]

p4 = gl.GLSurfacePlotItem(x=x[:,0], y = y[0,:], shader='heightColor', computeNormals=False, smooth=False)
p4.shader()['colorMap'] = np.array([0.2, 2, 0.5, 0.2, 1, 1, 0.2, 0, 2])
p4.translate(10, 10, 0)
w.addItem(p4)

index = 0
def update():
    global p4, z, index
    index -= 1
    p4.setData(z=z[index%z.shape[0]])
    
timer = QtCore.QTimer()
timer.timeout.connect(update)
timer.start(30)

if __name__ == '__main__':
    QtGui.QApplication.instance().exec_()

4.2 效果图：

4.3 代码：

from pyqtgraph.Qt import QtCore, QtGui
import pyqtgraph.opengl as gl

app = QtGui.QApplication([])
w = gl.GLViewWidget()
w.opts['distance'] = 20
w.show()
w.setWindowTitle('pyqtgraph example: GLViewWidget')

ax = gl.GLAxisItem()
ax.setSize(5,5,5)
w.addItem(ax)

b = gl.GLBoxItem()
w.addItem(b)

ax2 = gl.GLAxisItem()
ax2.setParentItem(b)

b.translate(1,1,1)

if __name__ == '__main__':
    #import sys
    #if (sys.flags.interactive != 1) or not hasattr(QtCore, 'PYQT_VERSION'):
        #QtGui.QApplication.instance().exec_()
    QtGui.QApplication.instance().exec_() #采用简化的，注意

4.4 效果图：

4.5 立方体代码：

# -*- coding: utf-8 -*-
#导出模块
from pyqtgraph.Qt import QtCore, QtGui
import pyqtgraph as pg
import pyqtgraph.opengl as gl
import numpy as np
#基本初始化定义
app = QtGui.QApplication([])
w = gl.GLViewWidget()
w.show()
w.setWindowTitle('pyqtgraph example: GLMeshItem') #标题名
w.setCameraPosition(distance=40) #设置摄像机位置

g = gl.GLGridItem()
g.scale(2,2,1)
w.addItem(g)
## Example 1:
verts = np.array([
    [0, 0, 0],
    [2, 0, 0],
    [1, 2, 0],
    [1, 1, 1],
])
faces = np.array([
    [0, 1, 2],
    [0, 1, 3],
    [0, 2, 3],
    [1, 2, 3]
])
colors = np.array([
    [1, 0, 0, 0.3],
    [0, 1, 0, 0.3],
    [0, 0, 1, 0.3],
    [1, 1, 0, 0.3]
])

## Mesh item will automatically compute face normals.
m1 = gl.GLMeshItem(vertexes=verts, faces=faces, faceColors=colors, smooth=False)
m1.translate(5, 5, 0)
m1.setGLOptions('additive')
w.addItem(m1)

## Example 2:
## Array of vertex positions, three per face，3角体
verts = np.empty((36, 3, 3), dtype=np.float32)
theta = np.linspace(0, 2*np.pi, 37)[:-1]
verts[:,0] = np.vstack([2*np.cos(theta), 2*np.sin(theta), [0]*36]).T
verts[:,1] = np.vstack([4*np.cos(theta+0.2), 4*np.sin(theta+0.2), [-1]*36]).T
verts[:,2] = np.vstack([4*np.cos(theta-0.2), 4*np.sin(theta-0.2), [1]*36]).T
    
## Colors are specified per-vertex
colors = np.random.random(size=(verts.shape[0], 3, 4))
m2 = gl.GLMeshItem(vertexes=verts, vertexColors=colors, smooth=False, shader='balloon', 
                   drawEdges=True, edgeColor=(1, 1, 0, 1))
m2.translate(-5, 5, 0)
w.addItem(m2)

## Example 3:
## sphere，球
md = gl.MeshData.sphere(rows=10, cols=20)
colors = np.ones((md.faceCount(), 4), dtype=float)
colors[::2,0] = 0
colors[:,1] = np.linspace(0, 1, colors.shape[0])
md.setFaceColors(colors)
m3 = gl.GLMeshItem(meshdata=md, smooth=False)#, shader='balloon')
m3.translate(5, -5, 0)
w.addItem(m3)

# Example 4:
# wireframe，火焰
md = gl.MeshData.sphere(rows=4, cols=8)
m4 = gl.GLMeshItem(meshdata=md, smooth=False, drawFaces=False, drawEdges=True, edgeColor=(1,1,1,1))
m4.translate(0,10,0)
w.addItem(m4)

# Example 5:
# cylinder，圆柱体
md = gl.MeshData.cylinder(rows=10, cols=20, radius=[1., 2.0], length=5.)
md2 = gl.MeshData.cylinder(rows=10, cols=20, radius=[2., 0.5], length=10.)
colors = np.ones((md.faceCount(), 4), dtype=float)
colors[::2,0] = 0
colors[:,1] = np.linspace(0, 1, colors.shape[0])
md.setFaceColors(colors)
m5 = gl.GLMeshItem(meshdata=md, smooth=True, drawEdges=True, edgeColor=(1,0,0,1), shader='balloon')
colors = np.ones((md.faceCount(), 4), dtype=float)
colors[::2,0] = 0
colors[:,1] = np.linspace(0, 1, colors.shape[0])
md2.setFaceColors(colors)
m6 = gl.GLMeshItem(meshdata=md2, smooth=True, drawEdges=False, shader='balloon')
m6.translate(0,0,7.5)

m6.rotate(0., 0, 1, 1)
w.addItem(m5)
w.addItem(m6)

QtGui.QApplication.instance().exec_()  #这种方法：注意有三种方法结尾

4.6 效果图：

以上是总体介绍，以后有空做逐个详细介绍。也可以自己学习。

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