Python使用Matplotlib通过鼠标交互实现缩放、移动以及线上点坐标显示功能

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import numpy as np
import matplotlib.pyplot as plt
import matplotlib as mpl
 
from matplotlib.text import Text, Annotation
from matplotlib.patches import Polygon, Rectangle, Circle, Arrow, ConnectionPatch,Ellipse,FancyBboxPatch
from matplotlib.widgets import Button, Slider, Widget
 

def call_move(event, fig): # event mouse press/release
    global mPress # whether mouse button press or not
    global startx
    global starty
    # print(mPress)
    if event.name=='button_press_event':
        axtemp=event.inaxes 
        # Whether mouse in a coordinate system or not, yes is the figure in the mouse location, no is None
        if axtemp and event.button==1: 
            print(event)
            mPress=True
            startx=event.xdata
            starty=event.ydata
    elif event.name=='button_release_event':
        axtemp=event.inaxes
        if axtemp and event.button==1:
            mPress=False 
    elif event.name=='motion_notify_event':
        axtemp=event.inaxes
        if axtemp and event.button==1 and mPress: # the mouse continuing press
            x_min, x_max = axtemp.get_xlim()
            y_min, y_max = axtemp.get_ylim()
            w=x_max-x_min
            h=y_max-y_min
            # mouse movement
            mx=event.xdata-startx
            my=event.ydata-starty
            axtemp.set(xlim=(x_min-mx, x_min-mx+w))
            axtemp.set(ylim=(y_min-my, y_min-my+h))
            fig.canvas.draw_idle()  # Delay drawing
    return
 
 
def call_scroll(event, fig):
    print(event.name)
    axtemp=event.inaxes
    print('event:',event)
    print(event.xdata,event.ydata)
    # caculate the xlim and ylim after zooming
    if axtemp:
        x_min, x_max = axtemp.get_xlim()
        y_min, y_max = axtemp.get_ylim()
        w = x_max - x_min
        h = y_max - y_min
        curx=event.xdata
        cury=event.ydata
        curXposition=(curx - x_min) / w
        curYposition=(cury - y_min) / h
        # Zoom the figure for 1.1 times
        if event.button == 'down':
            print('befor:',w,h)
            w = w*1.1
            h = h*1.1
            print('down',w,h)
        elif event.button == 'up':
            print('befor:',w,h)
            w = w/1.1
            h = h/1.1
            print('up',w,h)
        print(curXposition,curYposition)
        newx=curx - w*curXposition
        newy=cury - h*curYposition
        axtemp.set(xlim=(newx, newx+w))
        axtemp.set(ylim=(newy, newy+h))
        fig.canvas.draw_idle()  # drawing



def update_annot(ind, l1, annot, x_str, y_str, fig):
    posx = np.array(l1.get_data())[0][ind["ind"][0]] #get the x in the line
    posy = np.array(l1.get_data())[1][ind["ind"][0]] #get the y in the line
    annot.xy = ([posx, posy])
    text = "{}, {}".format(" ".join([x_str[n] for n in ind["ind"]]),
                           " ".join([y_str[n] for n in ind["ind"]]))
    
    annot.set_text(text)
    cmap = plt.cm.RdYlGn
    norm = plt.Normalize(1,4)
    c = np.random.randint(1,5,size=10) # the upper colour
    annot.get_bbox_patch().set_facecolor(cmap(norm(c[ind["ind"][0]])))
    annot.get_bbox_patch().set_alpha(0.4)
    

    
def hover(event, l1, annot, ax, x_str, y_str, fig):

    vis = annot.get_visible()
    if event.inaxes == ax:
        cont, ind = l1.contains(event)
        if cont: # the mouse in the point
            update_annot(ind, l1, annot, x_str, y_str, fig)
            annot.set_visible(True)
        else:
            if vis:
                annot.set_visible(False)
                fig.canvas.draw_idle()




def draw():
    fig = plt.figure()
    ax = fig.add_subplot(111)
     
    x = np.array([2597.0, 2232.0, 2022.0, 1781.0, 1569.0, 1319.0, 1132.0, 946.0, 743.0, 532.0]) #get x
    x_str = np.array(x).astype(str)
    y = np.array([696.9, 623.8, 550.8, 477.7, 404.6, 328.8, 255.7, 182.7, 109.6, 36.5])# get y
    y_str = np.array(y).astype(str)
    
    annot = ax.annotate("", xy=(0,0), xytext=(20,20),textcoords="offset points",
                            bbox=dict(boxstyle="round", fc="w"),
                            arrowprops=dict(arrowstyle="->"))
    plt.ylabel('first')
    l1, = plt.plot(x, y)
    #l2, = plt.plot(x, y2,color='red',linewidth=1.0,linestyle='--',label='square line')
    #plt.legend(handles=[l1, l2], labels=['up', 'down'], loc='upper right')
    plt.legend(handles=[l1], labels=['up'], loc='upper right')
    annot.set_visible(False) # mouse not display the information when not pointing
    plt.grid()
    
    startx=0
    starty=0
    mPress=False
    fig.canvas.mpl_connect('scroll_event', lambda event: call_scroll(event, fig)) # Event mouse wheel
    fig.canvas.mpl_connect('button_press_event', lambda event: call_move(event, fig)) # Event mouse button press
    fig.canvas.mpl_connect('button_release_event', lambda event: call_move(event, fig)) # Event mouse button release
    # fig.canvas.mpl_connect('draw_event', call_move) # Event draw figure
    fig.canvas.mpl_connect('motion_notify_event', lambda event: call_move(event, fig)) # Event mouse move
    fig.canvas.mpl_connect("motion_notify_event", lambda event: hover(event, l1, annot, ax, x_str, y_str, fig))
    x_min = min(x)
    x_max = max(x)
    y_min = min(y)
    y_max = max(y)
    
    ax.set_xlim(x_min, x_max) # xlabel start limition
    ax.set_ylim(y_min, y_max) # ylabel start limition
    
    plt.show()



draw()

参考文章：

缩放：python 桌面软件开发-matplotlib画图鼠标缩放拖动_matplotlib缩放-CSDN博客

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