matplotlib pyqt5画布上两个可拖动点之间的线

Posted 2023-03-30

【中文标题】matplotlib pyqt5画布上两个可拖动点之间的线

【英文标题】：Line between two draggable points on a matplotlib pyqt5 canvas

【发布时间】：2018-06-23 20:45:09

【问题描述】：

我正在尝试在 matplotlib 画布上嵌入 pyqt5 应用程序的两个可拖动点之间画一条线。我使用Draggable line with draggable points 作为参考。但是，我正在尝试创建多条线，并在单击按钮时创建一对 DraggablePoint 对象。我遇到了几个问题：

只有在拖动点时才会出现线条（已解决，请参阅下面的更新） 这条线偏移了一个边距，我认为这是画布和实际 matplotlib 图之间的差异。但是缩放比例也不对。 第二个点对的线根本没有显示

以下是我改编的代码：

可拖动点

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


class DraggablePoint:



    lock = None 

    def __init__(self, parent, dominant, x=10, y=10, size=1):
        """Creates a draggable Point on a matplotlib canvas"""
        matplotlib.matplotlib_fname()
        # The FigureCanvas
        self.parent = parent
        # The Point
        self.point = patches.Ellipse((x, y), size, size, fc='r', alpha=0.5, edgecolor='r')
        #Coordinates of the point
        self.x = x
        self.y = y
        self.dy = 645
        self.dx = 263
        # Adds the point to the Plot
        parent.fig.axes[0].add_patch(self.point)
        # Used in the on_press() function
        self.press = None
        self.background = None
        # initiate the mpl_connects
        self.connect()
        # The Other DraggablePoint, with whom the line shall connect with.
        self.partner = None
        # The Line2D
        self.line = None
        # TODO
        self.dominant = dominant

        for pair in self.parent.point_pairs:
            if self in pair:
                if pair[1]:
                    line_x = [pair[0].x+self.dx, pair[1].x+self.dx]
                    line_y = [pair[0].y+self.dy, pair[1].y+self.dy]
                    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'
        # print("LOG.INFO: DraggablePoint.connect")
        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):
        '''Initiates when a Point is clicked on'''
        # print(self.partner)
        # print(event.xdata, event.ydata)
        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)
        for pair in self.parent.point_pairs:
            if self == pair[1]:
                self.line.set_animated(True)
            elif self == pair[0]:
                self.partner.line.set_animated(True)


        #TODO
        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):

        # print("LOG.INFO: DraggablePoint.on_motion")
        if DraggablePoint.lock is not self:
            return
        if event.inaxes != self.point.axes: return
        # print("LOG.INFO: DraggablePoint.on_motion.after_lock")
        # self.parent.updateFigure()
        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)

        for pair in self.parent.point_pairs:
            if self in pair:
                if self == pair[1]:
                    axes.draw_artist(self.line)
                else:
                    pair[1].line.set_animated(True)
                    axes.draw_artist(pair[1].line)



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

        for pair in self.parent.point_pairs:
            if self == pair[1]:
                line_x = [pair[0].x+self.dx, self.x+self.dx]
                line_y = [pair[0].y+self.dy, self.y+self.dy]
                self.line.set_data(line_x, line_y)
            elif self == pair[0]:
                line_x = [pair[1].x+self.dx, self.x+self.dx]
                line_y = [pair[1].y+self.dy, self.y+self.dy]
                pair[1].line.set_data(line_x, line_y)

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


    def on_release(self, event):

        # print("LOG.INFO: DraggablePoint.on_release")
        'on release we reset the press data'
        if DraggablePoint.lock is not self:
            return

        # print("LOG.INFO: DraggablePoint.on_release.after_lock")
        self.press = None
        DraggablePoint.lock = None

        # turn off the rect animation property and reset the background
        self.point.set_animated(False)
        axes = self.point.axes

        for pair in self.parent.point_pairs:
            if self in pair:
                if pair[1] == self:
                    self.line.set_animated(False)
                else:
                    pair[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]
        print(self.line.__str__() + "RELEASE")

    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)

    def setLine(self, line):
        self.line = line

嵌入图形用户界面

class PlotCanvas(FigureCanvas):

    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)

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

        FigureCanvas.setSizePolicy(self,
                                   QSizePolicy.Expanding,
                                   QSizePolicy.Expanding)
        FigureCanvas.updateGeometry(self)
        self.xcoords = []
        self.ycoords = []
        self.lines = []
        self.list_points = []
        self.point_pairs = []
        self.number_of_lines = 0
        # self.mpl_connect('button_press_event', self.plot_draggable_point)
        self.plot_line = False
        self.plot()
        self.create_draggable_points()


    def plot(self):
        # data = [random.random() for i in range(25)]

        # self.a = plt.scatter(M[:, 0], M[:, 1])
        data = dataset2.get_matrix()
        ax = self.figure.add_subplot(111)
        ax.scatter(data[:, 0], data[:, 1], picker=10)
        ax.set_title('PyQt Matplotlib Example')
        self.draw()

    def create_draggable_points(self):
        self.list_points.append(DraggablePoint(self, True, 618.5047115210559, 338.5460575139148, 20))
        self.list_points.append(DraggablePoint(self, False, 338.5460575139148, 118.5047115210559, 20))
        # TODO Koordinaten an den Plot anpassen (+500)
        i = self.list_points[0]
        j = self.list_points[1]
        i.partner = j
        j.partner = i
        i.setLine(Line2D([i.x, j.x], [i.y, j.y], color='r', alpha=0.5))
        j.setLine(Line2D([i.x, j.x], [i.y, j.y], color='r', alpha=0.5))
        self.lines.append(i.line)
        self.lines.append(j.line)
        print(self.lines)

        self.point_pairs.append((i, j))

        self.updateFigure()


    def plot_draggable_point(self, event, size=60):
        if self.plot_line:
            self.xcoords.append(event.xdata)
            self.ycoords.append(event.ydata)
            print(event.xdata)
            print(event.ydata)
            self.list_points.append(DraggablePoint(self, event.xdata, event.ydata, size))
            if len(self.xcoords) == 2:
                self.list_points.append(DraggablePoint(self, event.xdata, event.ydata, size))
                self.xcoords[:] = []
                self.ycoords[:] = []
                self.list_points[:] = []
                self.plot_line = False
            self.updateFigure()

    def updateFigure(self):
        print(self.point_pairs)
        self.draw()

类是这样调用的：

    layout = QGridLayout()
    self.m = PlotCanvas(self, width=10, height=8)
    layout.addWidget(self.m, 0, 0, 5, 1)

更新：

第一个问题已经解决了，我忘记在on_release()方法中重画线了。现在看起来像这样：

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)
    axes = self.point.axes

    for pair in self.parent.point_pairs:
        if self in pair:
            if pair[1] == self:
                self.line.set_animated(False)
            else:
                pair[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]


    for pair in self.parent.point_pairs:
        if self in pair:
            if pair[1] == self:
                axes.draw_artist(self.line)
            else:
                axes.draw_artist(pair[1].line)

【参考方案1】：

我通过引入缩放和偏移解决了问题2的问题。其他两个问题是由于画布在创建的线条上重绘造成的。这些问题现在已经解决了。 DraggablePoint 的类现在看起来像这样：

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


class DraggablePoint:



    lock = None

    def __init__(self, parent, dominant, x=10, y=10, size=1):
        """Creates a draggable Point on a matplotlib canvas"""
        matplotlib.matplotlib_fname()
        # The FigureCanvas
        self.parent = parent
        # The Point
        self.point = patches.Ellipse((x, y), size, size, fc='r', alpha=0.5, edgecolor='r')
        #Coordinates of the point
        self.x = x
        self.y = y
        self.x_offset = 260
        self.y_offset = 640
        self.dy = 640
        self.dx = 260
        self.x_offset_factor = 0.06
        self.y_offset_factor = -0.089
        self.x_scaling = self.x * self.x_offset_factor
        self.y_scaling = self.y * self.y_offset_factor
        self.dy = self.y_offset + self.y_scaling
        self.dx = self.x_offset + self.x_scaling
        # Adds the point to the Plot
        parent.fig.axes[0].add_patch(self.point)
        # Used in the on_press() function
        self.press = None
        self.background = None
        # initiate the mpl_connects
        self.connect()
        # The Other DraggablePoint, with whom the line shall connect with.
        self.partner = None
        # The Line2D
        self.line = None
        self.dominant = dominant

        for pair in self.parent.point_pairs:
            if self in pair:
                if self == pair[1]:
                    line_x = [pair[0].x + pair[0].dx, self.x+self.dx]
                    line_y = [pair[0].y + pair[0].dy, self.y+self.dy]
                    self.line = Line2D(line_x, line_y, color='r', alpha=0.5)
                    parent.fig.axes[0].add_line(self.line)
                else:
                    line_x = [pair[1].x + pair[1].dx, self.x + self.dx]
                    line_y = [pair[1].y + pair[1].dy, self.y + self.dy]
                    self.line = Line2D(line_x, line_y, color='r', alpha=0.5)
                    parent.fig.axes[0].add_line(self.line)
        for pair in self.parent.point_pairs:
            self.point.axes.draw_artist(pair[1].line)


    def connect(self):

        'connect to all the events we need'
        # print("LOG.INFO: DraggablePoint.connect")
        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):
        '''Initiates when a Point is clicked on'''
        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)
        for pair in self.parent.point_pairs:
            if self == pair[1]:
                self.line.set_animated(True)
            elif self == pair[0]:
                self.partner.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):

        # print("LOG.INFO: DraggablePoint.on_motion")
        if DraggablePoint.lock is not self:
            return
        if event.inaxes != self.point.axes: return
        # print("LOG.INFO: DraggablePoint.on_motion.after_lock")
        # self.parent.updateFigure()
        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)

        #Update the scaling of the offset
        self.x_scaling = self.x * self.x_offset_factor
        self.y_scaling = self.y * self.y_offset_factor
        self.dy = self.y_offset + self.y_scaling
        self.dx = self.x_offset + self.x_scaling

        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)

        for pair in self.parent.point_pairs:
            if self in pair:
                axes.draw_artist(pair[1].line)
            if self == pair[1]:
                self.x_scaling = self.x * self.x_offset_factor
                self.y_scaling = self.y * self.y_offset_factor
                self.dy = self.y_offset + self.y_scaling
                self.dx = self.x_offset + self.x_scaling



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

        for pair in self.parent.point_pairs:
            if self == pair[1]:
                line_x = [pair[0].x + pair[0].dx, self.x+self.dx]
                line_y = [pair[0].y + pair[0].dy, self.y+self.dy]
                self.line.set_data(line_x, line_y)
            elif self == pair[0]:
                line_x = [pair[1].x + pair[1].dx, self.x+self.dx]
                line_y = [pair[1].y + pair[1].dy, self.y+self.dy]
                pair[1].line.set_data(line_x, line_y)

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


    def on_release(self, event):

        # print("LOG.INFO: DraggablePoint.on_release")
        'on release we reset the press data'
        if DraggablePoint.lock is not self:
            return

        # print("LOG.INFO: DraggablePoint.on_release.after_lock")
        self.press = None
        DraggablePoint.lock = None

        # turn off the rect animation property and reset the background
        self.point.set_animated(False)
        axes = self.point.axes

        for pair in self.parent.point_pairs:
            if self in pair:
                if pair[1] == self:
                    self.line.set_animated(False)
                else:
                    pair[1].line.set_animated(False)

        print(self.x_scaling, self.y_scaling)


        self.background = None

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

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

        for pair in self.parent.point_pairs:
            axes.draw_artist(pair[1].line)
        print(self.line.__str__() + "RELEASE")

    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)

    def setLine(self, line):
        self.line = line