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Python Matplotlib drawing graphics

2022-02-01 00:07:48 Little cute in the circle of friends

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

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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

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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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image.png

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 ~

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