python - 如何在已在 tkinter 画布中平滑绘制的线条上重绘线条？

Question

我有一些lines在色彩画布上，也有他们的代码。我想让它们变红但不是同时我想在它们上面画另一条线（红线），但它应该需要不同的时间。例如，对于一条特定的线，这条线应该需要 3 秒才能变红，而另一条线应该需要 7 秒才能变成红色。这就像在前一条上画了另一条红线。

def activator(self, hexagon, duration_time):
    if not hexagon.is_end:

        self.canvas.itemconfigure(hexagon.drawn, fill="tomato")
        self.canvas.itemconfigure(hexagon.hex_aspects.outputs.drawn, fill="tomato")

例如，我希望通过 tinter 的 createpolygon 方法创建的六边形变红，但不会立即变红。它应该与第二个变量duration_time 有关。我的意思是它应该在 duration_time 秒内完成（比如说 3 秒）。有没有办法做到这一点？我的画布上有很多物体，它们应该在特定时间变红。线，圆，多边形..

标签： pythonpython-3.xtkintertkinter-canvas

Answer 1

a 上的一条线tk.canvas由 astart和一个end点定义；为了访问线上的点，我们需要首先创建一条仿射线，首先在线上以一定间隔生成许多点，然后将它们与线段连接。

这条仿射线是在单击画布上的项目时创建的，但一开始是隐藏的，然后在很短的时间间隔内逐渐显露出来。

重绘完成后，仿射线将再次隐藏，并且正在重绘的项目设置为其新颜色。

这种“简单”的重绘需要相当多的机器来实现。您可以通过单击一条线来重绘它来尝试它，并查看重绘的动画。

代码：

import random
import tkinter as tk


WIDTH, HEIGHT = 500, 500


class AffinePoint:
    def __init__(self, x, y):
        self.x = x
        self.y = y

    def __add__(self, other):
        return AffinePoint(self.x + other.x, self.y + other.y)

    def __sub__(self, other):
        return AffinePoint(self.x - other.x, self.y - other.y)

    def __mul__(self, scalar):
        return AffinePoint(self.x * scalar, self.y * scalar)

    def __iter__(self):
        yield self.x
        yield self.y

    def draw(self, canvas):
        offset = AffinePoint(2, 2)
        return canvas.create_oval(*(self + offset), *self - offset, fill='', outline='black')


def create_affine_points(canvas, num_points):
    """sanity check"""
    for _ in range(num_points):
        AffinePoint(random.randrange(0, WIDTH), random.randrange(0, HEIGHT)).draw(canvas)


class AffineLineSegment:

    def __init__(self, start, end, num_t=100):
        self.start = AffinePoint(*start)
        self.end = AffinePoint(*end)
        self.num_t = num_t
        self.points = []
        self._make_points()
        self.segments = []

    def _make_points(self):
        for _t in range(self.num_t):
            t = _t / self.num_t
            self.points.append(self.start + (self.end - self.start) * t)

    def __iter__(self):
        for point in self.points:
            yield point

    def draw(self, canvas):
        for p0, p1 in zip(self.points[:-1], self.points[1:]):
            self.segments.append(canvas.create_line(*p0, *p1, width=5, state='hidden', fill='red'))

    def hide(self, canvas):
        for seg in self.segments:
            canvas.itemconfigure(seg, state='hidden')


def create_affine_line(canvas, num_lines):
    """sanity check"""
    for _ in range(num_lines):
        start = random.randrange(0, WIDTH), random.randrange(0, HEIGHT)
        end = random.randrange(0, WIDTH), random.randrange(0, HEIGHT)
        AffineLineSegment(start, end).draw(canvas)


def select_and_redraw(event):
    item = canvas.find_closest(event.x, event.y)[0]
    x0, y0, x1, y1 = canvas.coords(item)
    canvas.itemconfigure(item, fill='grey25')
    canvas.itemconfigure(item, width=1)
    a = AffineLineSegment((x0, y0), (x1, y1))
    a.draw(canvas)
    gen = (segment for segment in a.segments)
    redraw(gen, a, item)


def redraw(gen, a, item):
    try:
        segment = next(gen)
        canvas.itemconfigure(segment, state='normal')
        root.after(10, redraw, gen, a, item)
    except StopIteration:
        a.hide(canvas)
        canvas.itemconfigure(item, state='normal')
        canvas.itemconfigure(item, fill='red')
        canvas.itemconfigure(item, width=3)
    finally:
        root.after_cancel(redraw)


root = tk.Tk()

canvas = tk.Canvas(root, width=WIDTH, height=HEIGHT, bg="cyan")
canvas.pack()

canvas.bind('<ButtonPress-1>', select_and_redraw)

# sanity checks
# create_affine_points(canvas, 500)
# create_affine_line(canvas, 100)

for _ in range(10):
    start = random.randrange(0, WIDTH), random.randrange(0, HEIGHT)
    end = random.randrange(0, WIDTH), random.randrange(0, HEIGHT)    
    canvas.create_line(*start, * end, activefill='blue', fill='black', width=3)

root.mainloop()

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屏幕截图显示正在重绘的过程中的一条线