窗口调整Python / Kivy时调整文本大小

Question

我正在创建一个Python / Kivy应用程序，并且我试图在窗口调整大小时调整文本大小。我已经查了一下，但我还没有找到任何与我期望的完全相同的东西。我想我将on_resize绑定到一个调整文本大小的函数，但是我遇到了很多错误。这是相关的代码。

class MainScreen(Screen):
    def __init__(self, **kwargs):
        super(MainScreen, self).__init__(**kwargs)
        self.font_size = 25

class MainApp(App):
    def build(self):
        def win_cb(window, width, height):
            new_size = sqrt(width**2 + height**2)/40.6
            MainScreen().font_size = new_size
        Window.bind(on_resize=win_cb)

我还应该提一下，在.kv文件中，我有类似的东西

<MainScreen>:
    Label:
        text: "Text here"
        pos_hint: {"x": -0.15, "y": 0.05}
        font_size: root.font_size*80/25

在运行时它运行正常，但是当我调整窗口大小时，我得到了一大堆错误，显然与没有属性font_size的MainScreen相关。

这是错误消息：

Traceback (most recent call last):
   File "/usr/lib/python3.4/site-packages/kivy/lang.py", line 1649,     in create_handler
     return eval(value, idmap)
   File "main.kv", line 46, in <module>
     font_size: root.font_size
   File "kivy/weakproxy.pyx", line 19, in kivy.weakproxy.WeakProxy.__getattr__ (kivy/weakproxy.c:1101)
 AttributeError: 'MainScreen' object has no attribute 'font_size'

 During handling of the above exception, another exception occurred:

 Traceback (most recent call last):
   File "/usr/lib/python3.4/site-packages/kivy/lang.py", line 2011, in _apply_rule
 value, rule, rctx['ids'])
   File "/usr/lib/python3.4/site-packages/kivy/lang.py", line 1654, in create_handler
 cause=tb)
 kivy.lang.BuilderException: Parser: File "main.kv", line 46:
 ...
      44:       text: "Simplify Fraction"
      45:       pos_hint: {"right": 1, "top":0.2}
 >>   46:       font_size: root.font_size
      47:
      48:
 ...
 AttributeError: 'MainScreen' object has no attribute 'font_size'
   File "/usr/lib/python3.4/site-packages/kivy/lang.py", line 1649, in create_handler
     return eval(value, idmap)
   File "main.kv", line 46, in <module>
     font_size: root.font_size
   File "kivy/weakproxy.pyx", line 19, in     kivy.weakproxy.WeakProxy.__getattr__ (kivy/weakproxy.c:1101)


 During handling of the above exception, another exception occurred:

 Traceback (most recent call last):
   File "/home/onehitfinish/Downloads/Gregulator Files/test.py", line 88, in <module>
     MainApp().run()
   File "/usr/lib/python3.4/site-packages/kivy/app.py", line 824, in run
     runTouchApp()
   File "/usr/lib/python3.4/site-packages/kivy/base.py", line 487, in runTouchApp
     EventLoop.window.mainloop()
   File "/usr/lib/python3.4/site-packages/kivy/core/window/window_sdl2.py", line 525, in mainloop
     self._mainloop()
   File "/usr/lib/python3.4/site-packages/kivy/core/window/window_sdl2.py", line 290, in _mainloop
     EventLoop.idle()
   File "/usr/lib/python3.4/site-packages/kivy/base.py", line 327, in idle
     Clock.tick()
   File "/usr/lib/python3.4/site-packages/kivy/clock.py", line 483, in tick
     self._process_events()
   File "/usr/lib/python3.4/site-packages/kivy/clock.py", line 615, in _process_events
     event.tick(self._last_tick, remove)
   File "/usr/lib/python3.4/site-packages/kivy/clock.py", line 374, in tick
     ret = callback(self._dt)
   File "/usr/lib/python3.4/site-packages/kivy/core/window/window_sdl2.py", line 188, in create_window
     super(WindowSDL, self).create_window()
   File "/usr/lib/python3.4/site-packages/kivy/core/window/__init__.py", line 779, in create_window
     self.dispatch('on_resize', *self.system_size)
   File "kivy/_event.pyx", line 695, in kivy._event.EventDispatcher.dispatch (kivy/_event.c:6970)
   File "kivy/_event.pyx", line 1168, in kivy._event.EventObservers.dispatch (kivy/_event.c:12154)
   File "kivy/_event.pyx", line 1092, in kivy._event.EventObservers._dispatch (kivy/_event.c:11729)
   File "/home/onehitfinish/Downloads/Gregulator Files/test.py", line 81, in win_cb
     MainScreen().font_size = new_size
   File "/home/onehitfinish/Downloads/Gregulator Files/test.py", line 41, in __init__
     super(MainScreen, self).__init__(**kwargs)
   File "/usr/lib/python3.4/site-packages/kivy/uix/relativelayout.py", line 255, in __init__
     super(RelativeLayout, self).__init__(**kw)
   File "/usr/lib/python3.4/site-packages/kivy/uix/floatlayout.py", line 66, in __init__
     super(FloatLayout, self).__init__(**kwargs)
   File "/usr/lib/python3.4/site-packages/kivy/uix/layout.py", line 66, in __init__
     super(Layout, self).__init__(**kwargs)
   File "/usr/lib/python3.4/site-packages/kivy/uix/widget.py", line 271, in __init__
     Builder.apply(self)
   File "/usr/lib/python3.4/site-packages/kivy/lang.py", line 1872, in apply
     self._apply_rule(widget, rule, rule)
   File "/usr/lib/python3.4/site-packages/kivy/lang.py", line 2018, in _apply_rule
 e), cause=tb)
 kivy.lang.BuilderException: Parser: File "main.kv", line 46:
 ...
      44:       text: "Simplify Fraction"
      45:       pos_hint: {"right": 1, "top":0.2}
 >>   46:       font_size: root.font_size
      47:
      48:
 ...
 BuilderException: Parser: File "main.kv", line 46:
 ...
      44:       text: "Simplify Fraction"
      45:       pos_hint: {"right": 1, "top":0.2}
 >>   46:       font_size: root.font_size
      47:
      48:
 ...
 AttributeError: 'MainScreen' object has no attribute 'font_size'
   File "/usr/lib/python3.4/site-packages/kivy/lang.py", line 1649, in  create_handler
     return eval(value, idmap)
   File "main.kv", line 46, in <module>
     font_size: root.font_size
   File "kivy/weakproxy.pyx", line 19, in     kivy.weakproxy.WeakProxy.__getattr__ (kivy/weakproxy.c:1101)

   File "/usr/lib/python3.4/site-packages/kivy/lang.py", line 2011, in _apply_rule
value, rule, rctx['ids'])
   File "/usr/lib/python3.4/site-packages/kivy/lang.py", line 1654, in create_handler
 cause=tb)

任何有关解决这个问题的帮助，或者可能建议采用另一种方法来解决这个问题，因为我对Kivy很新，我们将不胜感激。

Answer 1

尝试在主屏幕中将 font_size 定义为var width = 1840, height = 1480, constant = 100, color = "#BCD8CD" var nodes = [ {label: '1st stage', x: constant, y: 215 , width:70,height:50 , color :color , stage: true }, {label: '2nd stage', x: constant + 150 , y: 215 ,width:70,height:50 ,color :color, stage: true }, {label: '3rd stage', x: constant + 279, y: 215 ,width:70,height:50, color :color, stage: false }, {label: '4th stage', x: constant + 460, y: 215 ,width:70,height:50, color :color, stage: false }, {label: '5th stage', x: constant + 660, y: 215 ,width:70,height:50 ,color :color, stage: false }, {label: '6th stage', x: constant + 350, y: 350 ,width:70,height:50, color :color, stage: true } ]; var links = [ { source: 0, target: 1 }, { source: 1, target: 2}, { source: 2, target: 3}, { source: 3, target: 4}, { source: 1, target: 5} ]; var svg = d3.select('body').append('svg') .attr('width', width) .attr('height', height); var marker = svg.append('marker') .attr('id',"triangle") .attr('viewBox',"0 0 10 10") .attr('refX',"0") .attr('refY',"5") .attr('markerUnits','strokeWidth') .attr('markerWidth','4') .attr('markerHeight','3') .attr('orient','auto') var path = marker.append('path') .attr('d',"M 0 0 L 10 5 L 0 10 z") var force = d3.layout.force() .size([width, height]) .nodes(nodes) .links(links); force.linkDistance(width/4); var link = svg.selectAll('.link') .data(links) .enter().append('line') .attr("stroke-width", "2") .attr('marker-end','url(#triangle)') .attr('stroke','black') var defs = svg.append("defs"); // create filter with id #drop-shadow // height=130% so that the shadow is not clipped var filter = defs.append("filter") .attr("id", "drop-shadow") .attr("height", "130%"); // SourceAlpha refers to opacity of graphic that this filter will be applied to // convolve that with a Gaussian with standard deviation 3 and store result // in blur filter.append("feGaussianBlur") .attr("in", "SourceAlpha") .attr("stdDeviation", 3) .attr("result", "blur"); // translate output of Gaussian blur to the right and downwards with 2px // store result in offsetBlur var feOffset = filter.append("feOffset") .attr("in", "blur") .attr("dx", 2) .attr("dy", 2) .attr("result", "offsetBlur"); // overlay original SourceGraphic over translated blurred opacity by using // feMerge filter. Order of specifying inputs is important! var feMerge = filter.append("feMerge"); feMerge.append("feMergeNode") .attr("in", "offsetBlur") feMerge.append("feMergeNode") .attr("in", "SourceGraphic"); var node = svg.selectAll('.node') .data(nodes) .enter().append('g') .attr('class', 'node') .attr("transform", function(d){ return "translate("+d.x+","+d.y+")"; }) node.append("rect").attr("class", "nodeRect") .attr("rx", 6) .attr("ry", 6) .attr('width', function(d) { return d.width; }) .attr('height', function(d) { return d.height; }) .style("fill", function(d) { return d.color; }) .transition() .duration(1000) // this is 1s .delay(1000) .style("fill",function(d){if(d.stage) return "#FF9966"}) .style("filter",function(d){if(d.stage) return "url(#drop-shadow)"}) node.append("text").style("text-anchor", "middle") .style("pointer-events", "none") .style("font-weight", 900) .attr("fill", "white") .style("stroke-width", "0.3px") .style("font-size", "16px") .attr("y", function (d){return d.height/2+6;}) .attr("x", function (d){return d.width/2;}) .text(function (d) {return d.label;}) force.start(); link.attr('x1', function(d) { return d.source.x + d.source.width/2; }) .attr('y1', function(d) { return d.source.y + d.source.height/2; }) .attr('x2', function(d) { return d.target.x + d.target.width/2; }) .attr('y2', function(d) { return d.target.y + d.target.height/2; }) .transition() .duration(1000) // this is 1s .delay(1000) .style("filter",function(d){if(d.source.stage) return "url(#drop-shadow)"}) ：

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