KIVY 根据另一个小部件位置更改小部件大小

Question

我在 Relativelayout 中有一条水平线 (hLine) 和一条垂直线 (vLine)。水平线将刚好接触垂直线。当我移动垂直线时，如何动态更改水平线宽度（即水平线将拉伸而不是移动）使其刚好接触垂直线。请有任何想法。在下面给定的示例中，假设垂直线只是从左到右滚动，反之亦然（即它水平移动）。 对于示例，我只提供了一条水平线。在我的实际项目中，至少有 10 条水平线接触垂直线。

from kivy.app import App
from kivy.graphics import Line, Color
from kivy.uix.scatter import Scatter
from kivy.uix.relativelayout import RelativeLayout
from kivy.uix.widget import Widget
from kivy.uix.label import Label
from kivy.core.window import Window

class MyPaintApp(App):

    def build(self):
        root = RelativeLayout()

        (ix, iy) = (100,100)
        (fx, fy) = (200,100)

        clr = Color(0.2, 0.2, 1)

        wdgt1 = Scatter(pos = (ix,iy), size = (fx-ix, 5))
        (ix,iy) = wdgt1.to_local(ix,iy,relative=True)
        (fx,fy) = wdgt1.to_local(fx, fy,relative=True)
        hLine = Line(points=[ix,iy, fx, fy], width=2, cap='none')
        lbl = Label(text='[color=3333ff]Horizontal[/color]', markup = True, pos=(ix,iy ))
        wdgt1.canvas.add(clr)
        wdgt1.canvas.add(hLine)
        wdgt1.add_widget(lbl)

        (fx, fy) = (200,150)
        (dx, dy) = (200,50)

        wdgt2 = Scatter(pos = (fx,fy), size = (5, fy - dy))
        (fx,fy) = wdgt2.to_local(fx, fy,relative=True)
        (dx,dy) = wdgt2.to_local(dx,dy,relative=True)
        vLine = Line(points=[fx,fy, dx, dy], width=2, cap='none')
        lbl = Label(text='[color=3333ff]Vertical[/color]', markup = True, pos=(fx,fy ))
        wdgt2.canvas.add(clr)
        wdgt2.canvas.add(vLine)
        wdgt2.add_widget(lbl)





        root.add_widget(wdgt1)
        root.add_widget(wdgt2)

        return root

if __name__ == '__main__':
    Window.clearcolor = (1, 1, 1, 1)
    MyPaintApp().run()

Answer 1

您可以通过在wdgt2 移动时重绘wdgt1 的Canvas 来做到这一点。这是您的代码的修改版本：

from kivy.app import App
from kivy.graphics import Line, Color
from kivy.uix.scatter import Scatter
from kivy.uix.relativelayout import RelativeLayout
from kivy.uix.label import Label
from kivy.core.window import Window

class MyPaintApp(App):
    def __init__(self, **kwargs):
        super(MyPaintApp, self).__init__(**kwargs)
        self.hLine = None

    def build(self):
        root = RelativeLayout()

        (ix, iy) = (100,100)
        (fx, fy) = (200,100)

        self.clr = Color(0.2, 0.2, 1)

        self.wdgt1 = Scatter(pos = (ix,iy), size = (fx-ix, 5))
        (ix,iy) = self.wdgt1.to_local(ix,iy,relative=True)
        (fx,fy) = self.wdgt1.to_local(fx, fy,relative=True)
        self.hLine = Line(points=[ix,iy, fx, fy], width=2, cap='none')
        self.lbl = Label(text='[color=3333ff]Horizontal[/color]', markup = True, pos=(ix,iy ))
        self.wdgt1.canvas.add(self.clr)
        self.wdgt1.canvas.add(self.hLine)
        self.wdgt1.add_widget(self.lbl)

        (fx, fy) = (200,150)
        (dx, dy) = (200,50)

        wdgt2 = Scatter(pos = (fx,fy), size = (5, fy - dy))
        (fx,fy) = wdgt2.to_local(fx, fy,relative=True)
        (dx,dy) = wdgt2.to_local(dx,dy,relative=True)
        vLine = Line(points=[fx,fy, dx, dy], width=2, cap='none')
        lbl = Label(text='[color=3333ff]Vertical[/color]', markup = True, pos=(fx,fy ))
        wdgt2.canvas.add(self.clr)
        wdgt2.canvas.add(vLine)
        wdgt2.add_widget(lbl)

        wdgt2.bind(pos=self.move_wdgt2)  # bind to movement of wdgt2

        root.add_widget(self.wdgt1)
        root.add_widget(wdgt2)

        return root

    def move_wdgt2(self, wdgt2, new_pos):
        if self.hLine is None:
            return

        # calculate the new ending x coordinate of the hLine
        x1, y1 = self.wdgt1.to_local(wdgt2.x, wdgt2.y, relative=True)
        pts = self.hLine.points
        pts[2] = x1

        # recreate the hLine
        self.hLine = Line(points=pts, width=2, cap='none')

        # clear the canvas
        self.wdgt1.canvas.clear()
        self.wdgt1.remove_widget(self.lbl)

        # redraw the canvas
        self.wdgt1.canvas.add(self.clr)
        self.wdgt1.canvas.add(self.hLine)
        self.wdgt1.add_widget(self.lbl)


if __name__ == '__main__':
    Window.clearcolor = (1, 1, 1, 1)
    MyPaintApp().run()