This is my participation 11 The fourth of the yuegengwen challenge 18 God , Check out the activity details ：2021 One last more challenge

Preface

We are facing matplotlib Module underlying structure learning , For its pyplot class （ Script layer ） Class to draw a line chart 、 Histogram 、 The pie chart 、 Histogram and other statistical charts , List previous articles as follows .

• matplotlib The underlying structure ：matplotlib The module is divided into script layer 、 Art layer and back end , Collaborative workflow learning

• matplotlib Draw line chart ： Yes pyplot.plot() Draw a line chart and summarize the related attributes

• matplotlib Draw a histogram ： Yes pyplot.bar() Draw the relevant attributes of the Shao histogram to summarize and explain

• matplotlib Draw histogram ：pyolot.hist() Draw histogram related attributes for summary description

matplotlib The module not only provides the function of drawing statistical charts , It also supports drawing circles 、 Square 、 Rectangle and other graphics

In this issue , Let's learn to use matplotlib Module draw common graphics ,Let's go~

1. matplotlib.patches summary

matplotlib.patches A class dedicated to drawing graphics , In this class, we use Artist Base class

• pathes It's specially drawn 2D Graphic class
• patch The drawing defaults to rc params Set up
• patch The module provides up to 10 A graphic method to meet daily needs

2. Drawing method

Corresponding matplotlib The module says ,patches Class to draw a circle 、 ellipse 、 Rectangle and other graphic methods

Method	effect
patches.Rectangle(xy,width,height,angle=0)	Draw a rectangle
patches.Polygon(xy)	Draw polygon
patches.Arc(xy,width,height,angle=0)	Draw an ellipse
patches.Circle(xy,radius)	Draw a circle
patches.Ellipse(xy,width,height,angle=0.0)	Draw an ellipse
patches.Arrow(x,y,dx,dy)	Draw the shear head
patches.wedge(center,r,theta1,theta2,width)	Draw a wedge
patches.PathPatch()	Draw a multi curve graph
patches.FancyBboxPatch()	Draw a fancy graphic box
patches.Line2D()	Draw lines

3. Drawing graphics steps

stay matplotlib Module , The charts are made of figure、Axes and Axis Three basic elements , So when drawing graphics , The general steps are mainly composed of the following .

• Import matplotlib pyplot and patches class

import matplotlib.pyplot as plt
import matplotlib.patches as mpatch
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• Use subplots() Create subgraphs Axes object

fig,ax =plt.subplots()
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• call pathes Class to draw graphics, such as drawing a rectangle Rectangle()

Rect = mpatch.Rectangle((0.2,0.75),0.4,0.4,color="r")
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• Subgraphs Axes Object call set_xlim() and set_ylim Axis range

patches By default ,x The coordinate range of the axis is （0,1）,y The coordinate range of the axis is （0,1）

ax.set_xlim(-2,5)
ax.set_ylim(-2,5)
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• Subgraphs Axes Object call add_patch() Method to add graphics

ax.add_patch(Rect)
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• call pyplot.show() Show graphics

4. Draw graphic properties

• Set transparency

  • keyword ：alpha
  • The value type is ： floating-point

• Set the color

  • Set graphic keywords ：color
  • Set border keyword ：edgecolor
  • The value is optional ：
    • English words for color ： Like red "red"
    • Abbreviations of words indicating color, such as ： Red "r", yellow "y"
    • RGB Format ： Hexadecimal format, such as "#88c999";(r,g,b) Tuple form

5. A profound

After learning the above sections , We draw circles in the chart 、 Rectangles and straight lines

def drawpicture():

    fig,ax =plt.subplots()

    Rect = mpatch.Rectangle((1,0.75),0.4,0.4,color="yellow",alpha=0.5)

    Cri = mpatch.Circle((0,0),1,angle=30,color="pink",alpha=0.2,capstyle="round")

    Py = mpatch.Arrow(1,2,2,2)

    ax.set_xlim(-1,5)
    ax.set_ylim(-1,5)

    ax.add_patch(Rect)
    ax.add_patch(Cri)
    ax.add_patch(Py)
    plt.show()

drawpicture()
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summary

In this issue , We are right. matplotlib Draw graphics related methods and steps to learn , In practice , It takes a lot of practice to use... More skillfully

The above is the content of this issue , Welcome big guys to praise and comment , See you next time ~