帶有可拖動點的可拖動線

Question

我需要在 figureCanvas 中有 2 個可拖動點。 但我有一個補充約束：2 個點必須由一條線連接。 當然，當我拖動一個點時（否則就不好笑了），必須動態繪制該線，並且仍然鏈接到 2 個點。

我設法創建了 2 個可拖動點，主題為： Matplotlib 交互式拖動重疊點

我修改了一些代碼以通過 FigureCanvas 的子類使用它（稍后將圖形包含在 PyQt 應用程序中）：

import matplotlib.pyplot as plt
import matplotlib.patches as patches


class DraggablePoint:

    # https://stackoverflow.com/questions/21654008/matplotlib-drag-overlapping-points-interactively

    lock = None #  only one can be animated at a time

    def __init__(self, parent, x=0.1, y=0.1):

        self.parent = parent
        self.point = patches.Ellipse((x, y), 0.01, 0.03, fc='r', alpha=0.5)
        self.x = x
        self.y = y
        parent.fig.axes[0].add_patch(self.point)
        self.press = None
        self.background = None
        self.connect()


    def connect(self):

        'connect to all the events we need'

        self.cidpress = self.point.figure.canvas.mpl_connect('button_press_event', self.on_press)
        self.cidrelease = self.point.figure.canvas.mpl_connect('button_release_event', self.on_release)
        self.cidmotion = self.point.figure.canvas.mpl_connect('motion_notify_event', self.on_motion)


    def on_press(self, event):

        if event.inaxes != self.point.axes: return
        if DraggablePoint.lock is not None: return
        contains, attrd = self.point.contains(event)
        if not contains: return
        self.press = (self.point.center), event.xdata, event.ydata
        DraggablePoint.lock = self

        # draw everything but the selected rectangle and store the pixel buffer
        canvas = self.point.figure.canvas
        axes = self.point.axes
        self.point.set_animated(True)
        canvas.draw()
        self.background = canvas.copy_from_bbox(self.point.axes.bbox)

        # now redraw just the rectangle
        axes.draw_artist(self.point)

        # and blit just the redrawn area
        canvas.blit(axes.bbox)


    def on_motion(self, event):

        if DraggablePoint.lock is not self:
            return
        if event.inaxes != self.point.axes: return
        self.point.center, xpress, ypress = self.press
        dx = event.xdata - xpress
        dy = event.ydata - ypress
        self.point.center = (self.point.center[0]+dx, self.point.center[1]+dy)

        canvas = self.point.figure.canvas
        axes = self.point.axes
        # restore the background region
        canvas.restore_region(self.background)

        # redraw just the current rectangle
        axes.draw_artist(self.point)

        # blit just the redrawn area
        canvas.blit(axes.bbox)


    def on_release(self, event):

        'on release we reset the press data'
        if DraggablePoint.lock is not self:
            return

        self.press = None
        DraggablePoint.lock = None

        # turn off the rect animation property and reset the background
        self.point.set_animated(False)
        self.background = None

        # redraw the full figure
        self.point.figure.canvas.draw()

        self.x = self.point.center[0]
        self.y = self.point.center[1]

    def disconnect(self):

        'disconnect all the stored connection ids'

        self.point.figure.canvas.mpl_disconnect(self.cidpress)
        self.point.figure.canvas.mpl_disconnect(self.cidrelease)
        self.point.figure.canvas.mpl_disconnect(self.cidmotion)

未來圖上只有 2 個點，我可以從類 DraggablePoint 槽 self.parent 訪問另一個點。

我想我需要在函數 on_motion 中的兩點之間畫一條線。 但我試過了，一無所獲。 您知道如何實現這一目標嗎？

Answer 1

好的，我終於找到了解決方案。 我把它貼在這里給可能需要它的人。 這段代碼基本上允許有 2 個由一條線鏈接的可拖動點。 如果您移動其中一個點，則該線跟隨。 在科學應用中建立基線非常有用。

import matplotlib.pyplot as plt
import matplotlib.patches as patches
from matplotlib.lines import Line2D


class DraggablePoint:

    # http://stackoverflow.com/questions/21654008/matplotlib-drag-overlapping-points-interactively

    lock = None #  only one can be animated at a time

    def __init__(self, parent, x=0.1, y=0.1, size=0.1):

        self.parent = parent
        self.point = patches.Ellipse((x, y), size, size * 3, fc='r', alpha=0.5, edgecolor='r')
        self.x = x
        self.y = y
        parent.fig.axes[0].add_patch(self.point)
        self.press = None
        self.background = None
        self.connect()

        if self.parent.list_points:
            line_x = [self.parent.list_points[0].x, self.x]
            line_y = [self.parent.list_points[0].y, self.y]

            self.line = Line2D(line_x, line_y, color='r', alpha=0.5)
            parent.fig.axes[0].add_line(self.line)


    def connect(self):

        'connect to all the events we need'

        self.cidpress = self.point.figure.canvas.mpl_connect('button_press_event', self.on_press)
        self.cidrelease = self.point.figure.canvas.mpl_connect('button_release_event', self.on_release)
        self.cidmotion = self.point.figure.canvas.mpl_connect('motion_notify_event', self.on_motion)


    def on_press(self, event):

        if event.inaxes != self.point.axes: return
        if DraggablePoint.lock is not None: return
        contains, attrd = self.point.contains(event)
        if not contains: return
        self.press = (self.point.center), event.xdata, event.ydata
        DraggablePoint.lock = self

        # draw everything but the selected rectangle and store the pixel buffer
        canvas = self.point.figure.canvas
        axes = self.point.axes
        self.point.set_animated(True)
        if self == self.parent.list_points[1]:
            self.line.set_animated(True)
        else:
            self.parent.list_points[1].line.set_animated(True)
        canvas.draw()
        self.background = canvas.copy_from_bbox(self.point.axes.bbox)

        # now redraw just the rectangle
        axes.draw_artist(self.point)

        # and blit just the redrawn area
        canvas.blit(axes.bbox)


    def on_motion(self, event):

        if DraggablePoint.lock is not self:
            return
        if event.inaxes != self.point.axes: return
        self.point.center, xpress, ypress = self.press
        dx = event.xdata - xpress
        dy = event.ydata - ypress
        self.point.center = (self.point.center[0]+dx, self.point.center[1]+dy)

        canvas = self.point.figure.canvas
        axes = self.point.axes
        # restore the background region
        canvas.restore_region(self.background)

        # redraw just the current rectangle
        axes.draw_artist(self.point)

        if self == self.parent.list_points[1]:
            axes.draw_artist(self.line)
        else:
            self.parent.list_points[1].line.set_animated(True)
            axes.draw_artist(self.parent.list_points[1].line)

        self.x = self.point.center[0]
        self.y = self.point.center[1]

        if self == self.parent.list_points[1]:
            line_x = [self.parent.list_points[0].x, self.x]
            line_y = [self.parent.list_points[0].y, self.y]
            self.line.set_data(line_x, line_y)
        else:
            line_x = [self.x, self.parent.list_points[1].x]
            line_y = [self.y, self.parent.list_points[1].y]

            self.parent.list_points[1].line.set_data(line_x, line_y)

        # blit just the redrawn area
        canvas.blit(axes.bbox)


    def on_release(self, event):

        'on release we reset the press data'
        if DraggablePoint.lock is not self:
            return

        self.press = None
        DraggablePoint.lock = None

        # turn off the rect animation property and reset the background
        self.point.set_animated(False)
        if self == self.parent.list_points[1]:
            self.line.set_animated(False)
        else:
            self.parent.list_points[1].line.set_animated(False)

        self.background = None

        # redraw the full figure
        self.point.figure.canvas.draw()

        self.x = self.point.center[0]
        self.y = self.point.center[1]

    def disconnect(self):

        'disconnect all the stored connection ids'

        self.point.figure.canvas.mpl_disconnect(self.cidpress)
        self.point.figure.canvas.mpl_disconnect(self.cidrelease)
        self.point.figure.canvas.mpl_disconnect(self.cidmotion)

更新：

如何在 PyQt5 中使用 DraggablePoint 類：

#!/usr/bin/python
# -*-coding:Utf-8 -*

import sys
import matplotlib
matplotlib.use("Qt5Agg")
from PyQt5 import QtWidgets, QtGui

from matplotlib.backends.backend_qt5agg import FigureCanvasQTAgg as FigureCanvas
from matplotlib.figure import Figure

# Personnal modules
from drag import DraggablePoint


class MyGraph(FigureCanvas):

    """A canvas that updates itself every second with a new plot."""

    def __init__(self, parent=None, width=5, height=4, dpi=100):

        self.fig = Figure(figsize=(width, height), dpi=dpi)
        self.axes = self.fig.add_subplot(111)

        self.axes.grid(True)

        FigureCanvas.__init__(self, self.fig)
        self.setParent(parent)

        FigureCanvas.setSizePolicy(self,
                                   QtWidgets.QSizePolicy.Expanding,
                                   QtWidgets.QSizePolicy.Expanding)
        FigureCanvas.updateGeometry(self)

        # To store the 2 draggable points
        self.list_points = []


        self.show()
        self.plotDraggablePoints([0.1, 0.1], [0.2, 0.2], [0.1, 0.1])


    def plotDraggablePoints(self, xy1, xy2, size=None):

        """Plot and define the 2 draggable points of the baseline"""

        # del(self.list_points[:])
        self.list_points.append(DraggablePoint(self, xy1[0], xy1[1], size))
        self.list_points.append(DraggablePoint(self, xy2[0], xy2[1], size))
        self.updateFigure()


    def clearFigure(self):

        """Clear the graph"""

        self.axes.clear()
        self.axes.grid(True)
        del(self.list_points[:])
        self.updateFigure()


    def updateFigure(self):

        """Update the graph. Necessary, to call after each plot"""

        self.draw()

if __name__ == '__main__':

    app = QtWidgets.QApplication(sys.argv)
    ex = MyGraph()
    sys.exit(app.exec_())

Answer 2

我需要圖中的更多點，所以我修改了 JPFrancoia 完成的解決方案，以便有更多的點與線相連。 我希望其他人會發現它很有用，所以新的 drag.py 文件如下：

# drag.py
import matplotlib.pyplot as plt
import matplotlib.patches as patches
from matplotlib.lines import Line2D


class DraggablePoint:

    # http://stackoverflow.com/questions/21654008/matplotlib-drag-overlapping-points-interactively

    lock = None #  only one can be animated at a time

    def __init__(self, parent, x=0.1, y=0.1, size=0.1):

        self.parent = parent
        self.point = patches.Ellipse((x, y), size, size * 3, fc='r', alpha=0.5, edgecolor='r')
        self.x = x
        self.y = y
        parent.fig.axes[0].add_patch(self.point)
        self.press = None
        self.background = None
        self.connect()
        
        # if another point already exist we draw a line
        if self.parent.list_points:
            line_x = [self.parent.list_points[-1].x, self.x]
            line_y = [self.parent.list_points[-1].y, self.y]

            self.line = Line2D(line_x, line_y, color='r', alpha=0.5)
            parent.fig.axes[0].add_line(self.line)


    def connect(self):

        'connect to all the events we need'

        self.cidpress = self.point.figure.canvas.mpl_connect('button_press_event', self.on_press)
        self.cidrelease = self.point.figure.canvas.mpl_connect('button_release_event', self.on_release)
        self.cidmotion = self.point.figure.canvas.mpl_connect('motion_notify_event', self.on_motion)


    def on_press(self, event):

        if event.inaxes != self.point.axes: return
        if DraggablePoint.lock is not None: return
        contains, attrd = self.point.contains(event)
        if not contains: return
        self.press = (self.point.center), event.xdata, event.ydata
        DraggablePoint.lock = self

        # draw everything but the selected rectangle and store the pixel buffer
        canvas = self.point.figure.canvas
        axes = self.point.axes
        self.point.set_animated(True)
        
        # TODO also the line of some other points needs to be released
        point_number =  self.parent.list_points.index(self)
        
        if self == self.parent.list_points[0]:
            self.parent.list_points[1].line.set_animated(True)            
        elif self == self.parent.list_points[-1]:
            self.line.set_animated(True)            
        else:
            self.line.set_animated(True)            
            self.parent.list_points[point_number+1].line.set_animated(True)                
            
            
            
        
        canvas.draw()
        self.background = canvas.copy_from_bbox(self.point.axes.bbox)

        # now redraw just the rectangle
        axes.draw_artist(self.point)

        # and blit just the redrawn area
        canvas.blit(axes.bbox)


    def on_motion(self, event):

        if DraggablePoint.lock is not self:
            return
        if event.inaxes != self.point.axes: return
        self.point.center, xpress, ypress = self.press
        dx = event.xdata - xpress
        dy = event.ydata - ypress
        self.point.center = (self.point.center[0]+dx, self.point.center[1]+dy)

        canvas = self.point.figure.canvas
        axes = self.point.axes
        # restore the background region
        canvas.restore_region(self.background)

        # redraw just the current rectangle
        axes.draw_artist(self.point)
        
        point_number =  self.parent.list_points.index(self)
        self.x = self.point.center[0]
        self.y = self.point.center[1]
        
        
        
        
        
        # We check if the point is A or B        
        if self == self.parent.list_points[0]:
            # or we draw the other line of the point
            self.parent.list_points[1].line.set_animated(True)
            axes.draw_artist(self.parent.list_points[1].line)
        
        elif self == self.parent.list_points[-1]:
            # we draw the line of the point            
            axes.draw_artist(self.line)    

        else:
            # we draw the line of the point
            axes.draw_artist(self.line)
            #self.parent.list_points[point_number+1].line.set_animated(True)
            axes.draw_artist(self.parent.list_points[point_number+1].line)
            
                
        
        
        if self == self.parent.list_points[0]:
            # The first point is especial because it has no line
            line_x = [self.x, self.parent.list_points[1].x]
            line_y = [self.y, self.parent.list_points[1].y]      
            # this is were the line is updated
            self.parent.list_points[1].line.set_data(line_x, line_y)
            
        elif self == self.parent.list_points[-1]:
            line_x = [self.parent.list_points[-2].x, self.x]
            line_y = [self.parent.list_points[-2].y, self.y]
            self.line.set_data(line_x, line_y)        
        else:
            # The first point is especial because it has no line
            line_x = [self.x, self.parent.list_points[point_number+1].x]
            line_y = [self.y, self.parent.list_points[point_number+1].y]      
            # this is were the line is updated
            self.parent.list_points[point_number+1].line.set_data(line_x, line_y)
            
            line_x = [self.parent.list_points[point_number-1].x, self.x]
            line_y = [self.parent.list_points[point_number-1].y, self.y]
            self.line.set_data(line_x, line_y)        

        # blit just the redrawn area
        canvas.blit(axes.bbox)


    def on_release(self, event):

        'on release we reset the press data'
        if DraggablePoint.lock is not self:
            return

        self.press = None
        DraggablePoint.lock = None

        # turn off the rect animation property and reset the background
        self.point.set_animated(False)
        
        point_number =  self.parent.list_points.index(self)
        
        if self == self.parent.list_points[0]:
            self.parent.list_points[1].line.set_animated(False)            
        elif self == self.parent.list_points[-1]:
            self.line.set_animated(False)            
        else:
            self.line.set_animated(False)            
            self.parent.list_points[point_number+1].line.set_animated(False)       
            

        self.background = None

        # redraw the full figure
        self.point.figure.canvas.draw()

        self.x = self.point.center[0]
        self.y = self.point.center[1]

    def disconnect(self):

        'disconnect all the stored connection ids'

        self.point.figure.canvas.mpl_disconnect(self.cidpress)
        self.point.figure.canvas.mpl_disconnect(self.cidrelease)
        self.point.figure.canvas.mpl_disconnect(self.cidmotion)

執行是這樣完成的：

import sys
import matplotlib
matplotlib.use("Qt5Agg")
from PyQt5 import QtWidgets, QtGui

from matplotlib.backends.backend_qt5agg import FigureCanvasQTAgg as FigureCanvas
from matplotlib.figure import Figure

# Personnal modules
from drag import DraggablePoint


class MyGraph(FigureCanvas):

    """A canvas that updates itself every second with a new plot."""

    def __init__(self, parent=None, width=5, height=4, dpi=100):

        self.fig = Figure(figsize=(width, height), dpi=dpi)
        self.axes = self.fig.add_subplot(111)

        self.axes.grid(True)

        FigureCanvas.__init__(self, self.fig)
        self.setParent(parent)

        FigureCanvas.setSizePolicy(self,
                                   QtWidgets.QSizePolicy.Expanding,
                                   QtWidgets.QSizePolicy.Expanding)
        FigureCanvas.updateGeometry(self)

        # To store the 2 draggable points
        self.list_points = []


        self.show()
        self.plotDraggablePoints()


    def plotDraggablePoints(self, size=0.05):

        """Plot and define the 2 draggable points of the baseline"""
  
        # del(self.list_points[:])
        self.list_points.append(DraggablePoint(self, 0.1, 0.1, size))
        self.list_points.append(DraggablePoint(self, 0.2, 0.2, size))
        self.list_points.append(DraggablePoint(self, 0.5, 0.5, size))
        self.list_points.append(DraggablePoint(self, 0.6, 0.5, size))
        self.list_points.append(DraggablePoint(self, 0.7, 0.5, size))

        self.updateFigure()


    def clearFigure(self):

        """Clear the graph"""

        self.axes.clear()
        self.axes.grid(True)
        del(self.list_points[:])
        self.updateFigure()


    def updateFigure(self):

        """Update the graph. Necessary, to call after each plot"""

        self.draw()

if __name__ == '__main__':

    app = QtWidgets.QApplication(sys.argv)
    ex = MyGraph()
    sys.exit(app.exec_())

Answer 3

這是我的簡單解決方案，具有添加或刪除點的附加功能。 然后，您就有了一條可拖動的分段線，其中包含對點的控制。

盡管事件處理，代碼很簡單。 歡迎改進。

import matplotlib.pyplot as plt
import matplotlib.patches as patches
from matplotlib.lines import Line2D

#------------------------------------------------
listLabelPoints = []
point_alpha_default = 0.8
mousepress = None
currently_dragging = False
current_artist = None
offset = [0,0]
n = 0
line_object = None

#------------------------------------------------
def on_press(event):
    global currently_dragging
    global mousepress
    currently_dragging = True
    if event.button == 3:
        mousepress = "right"
    elif event.button == 1:
        mousepress = "left"

#------------------------------------------------
def on_release(event):
    global current_artist, currently_dragging
    current_artist = None
    currently_dragging = False

#------------------------------------------------
def on_pick(event):
    global current_artist, offset, n
    global listLabelPoints
    if current_artist is None:
        current_artist = event.artist
        #print("pick ", current_artist)
        if isinstance(event.artist, patches.Circle):
            if event.mouseevent.dblclick:
                if mousepress == "right":
                    #print("double click right")
                    if len(ax.patches) > 2:
                        #print("\ndelete", event.artist.get_label())
                        event.artist.remove()
                        xdata = list(line_object[0].get_xdata())
                        ydata = list(line_object[0].get_ydata())
                        for i in range(0,len(xdata)):
                            if event.artist.get_label() == listLabelPoints[i]:
                                xdata.pop(i) 
                                ydata.pop(i) 
                                listLabelPoints.pop(i)
                                break
                        #print('--->', listLabelPoints)
                        line_object[0].set_data(xdata, ydata)
                        plt.draw()
            else:
                x0, y0 = current_artist.center
                x1, y1 = event.mouseevent.xdata, event.mouseevent.ydata
                offset = [(x0 - x1), (y0 - y1)]
        elif isinstance(event.artist, Line2D):
            if event.mouseevent.dblclick:
                if mousepress == "left":
                    #print("double click left")
                    n = n+1
                    x, y = event.mouseevent.xdata, event.mouseevent.ydata
                    newPointLabel = "point"+str(n)
                    point_object = patches.Circle([x, y], radius=50, color='r', fill=False, lw=2,
                            alpha=point_alpha_default, transform=ax.transData, label=newPointLabel)
                    point_object.set_picker(5)
                    ax.add_patch(point_object)
                    xdata = list(line_object[0].get_xdata())
                    ydata = list(line_object[0].get_ydata())
                    #print('\ninit', listLabelPoints)
                    pointInserted = False
                    for i in range(0,len(xdata)-1):
                        #print("--> testing inclusion %s in [%s-%s]" 
                        #        %(newPointLabel, listLabelPoints[i], listLabelPoints[i+1]))
                        #print('----->', min(xdata[i],xdata[i+1]), '<', x, '<', max(xdata[i],xdata[i+1]))
                        #print('----->', min(ydata[i],ydata[i+1]), '<', y, '<', max(ydata[i],ydata[i+1]))
                        if x > min(xdata[i],xdata[i+1]) and x < max(xdata[i],xdata[i+1]) and \
                           y > min(ydata[i],ydata[i+1]) and y < max(ydata[i],ydata[i+1]) :
                            xdata.insert(i+1, x)
                            ydata.insert(i+1, y)
                            listLabelPoints.insert(i+1, newPointLabel)
                            pointInserted = True
                            #print("include", newPointLabel)
                            break
                    line_object[0].set_data(xdata, ydata)
                    #print('final', listLabelPoints)
                    plt.draw()
                    if not pointInserted:
                        print("Error: point not inserted")
            else:
                xdata = event.artist.get_xdata()
                ydata = event.artist.get_ydata()
                x1, y1 = event.mouseevent.xdata, event.mouseevent.ydata
                offset = xdata[0] - x1, ydata[0] - y1

#------------------------------------------------
def on_motion(event):
    global current_artist
    if not currently_dragging:
        return
    if current_artist == None:
        return
    if event.xdata == None:
        return
    dx, dy = offset
    if isinstance(current_artist, patches.Circle):
        cx, cy =  event.xdata + dx, event.ydata + dy
        current_artist.center = cx, cy
        #print("moving", current_artist.get_label())
        xdata = list(line_object[0].get_xdata())
        ydata = list(line_object[0].get_ydata())
        for i in range(0,len(xdata)): 
            if listLabelPoints[i] == current_artist.get_label():
                xdata[i] = cx
                ydata[i] = cy
                break
        line_object[0].set_data(xdata, ydata)
    elif isinstance(current_artist, Line2D):
        xdata = list(line_object[0].get_xdata())
        ydata = list(line_object[0].get_ydata())
        xdata0 = xdata[0]
        ydata0 = ydata[0]
        for i in range(0,len(xdata)): 
                xdata[i] = event.xdata + dx + xdata[i] - xdata0
                ydata[i] = event.ydata + dy + ydata[i] - ydata0 
        line_object[0].set_data(xdata, ydata)
        for p in ax.patches:
            pointLabel = p.get_label()
            i = listLabelPoints.index(pointLabel) 
            p.center = xdata[i], ydata[i]
    plt.draw()

#------------------------------------------------
def on_click(event):
    global n, line_object
    if event and event.dblclick:
        if len(listLabelPoints) < 2:
            n = n+1
            x, y = event.xdata, event.ydata
            newPointLabel = "point"+str(n)
            point_object = patches.Circle([x, y], radius=50, color='r', fill=False, lw=2,
                    alpha=point_alpha_default, transform=ax.transData, label=newPointLabel)
            point_object.set_picker(5)
            ax.add_patch(point_object)
            listLabelPoints.append(newPointLabel)
            if len(listLabelPoints) == 2:
                xdata = []
                ydata = []
                for p in ax.patches:
                    cx, cy = p.center
                    xdata.append(cx)
                    ydata.append(cy)
                line_object = ax.plot(xdata, ydata, alpha=0.5, c='r', lw=2, picker=True)
                line_object[0].set_pickradius(5)
            plt.draw()

#================================================
fig, ax = plt.subplots()

ax.set_title("Double click left button to create draggable point\nDouble click right to remove a point", loc="left")
ax.set_xlim(0, 4000)
ax.set_ylim(0, 3000)
ax.set_aspect('equal')

fig.canvas.mpl_connect('button_press_event', on_click)
fig.canvas.mpl_connect('button_press_event', on_press)
fig.canvas.mpl_connect('button_release_event', on_release)
fig.canvas.mpl_connect('pick_event', on_pick)
fig.canvas.mpl_connect('motion_notify_event', on_motion)

plt.grid(True)
plt.show()