Question

最近，我开始使用Tkinter作为Raspberry Pi的显示方式。我仍然习惯于放置和试验网格和绝对定位。但是我遇到了一个问题。

每当我使用锚点时。唯一可以正常工作的是NW。其余的似乎是倒置的，并以屏幕左上角为中心，我不知道为什么。

from tkinter import Tk, Canvas, NW, NE, SW, CENTER
from tkinter.ttk import Frame, Label, Style
from PIL import ImageTk, Image

gui = Tk()
gui.attributes('-fullscreen', True)
gui.configure(background = 'black',cursor ='none')

gui.geometry("1920x1080")
canvas = Canvas(gui, width = 1920, height = 1080, bg ='black',highlightthickness=0)


img5 = ImageTk.PhotoImage(Image.open('../icons/Asset7.png'))
im5 = canvas.create_image(100,100, image = img5, anchor = NW)

img9 = ImageTk.PhotoImage(Image.open('../icons/Asset14.png')
im9 = canvas.create_image(100,100, image = img9, anchor = NE)

这里是一个例子。 Asset7位于屏幕的正确部分，其中Asset 14由于某种原因从屏幕左边框后面开始。根据此图像，正确的定位应表现出不同的Tkinker Anchors 我很困惑可能是什么原因造成的。

谁能告诉我发生了什么事？

Answer 1

已编辑以回复评论。

对于画布，假设canvas = tk.Canvas(...)

The Top Left     is (0,0), 
the Bottom Right is (canvas.winfo_width(), canvas.winfo_height())

其他相关点可以根据宽度和高度计算。如果在使用画布时调整其大小，则需要重新计算点（0,0除外）。

我找不到将对象“捕捉”到角落，中点等的内置内容。下面的代码使罗盘点包装器功能可以将项目捕捉到预定义的位置。或根据比例将其捕捉到“画布”中任何位置的功能。需要on_resize回调，即使Canvas也不改变大小，因为通常在绘制画布之前指定id对象。

import tkinter as tk

root = tk.Tk()
root.geometry('400x200')

canvas = tk.Canvas(root)
# canvas changes size with the root.
canvas.grid(sticky=tk.N+tk.S+tk.E+tk.W)

root.rowconfigure(0, weight=1)
root.columnconfigure(0, weight=1)

def snap(parent, id, x_fact, y_fact, anchor = tk.CENTER ):
    """ parent - tk.Canvas widget
        id canvas object id
        x_fact & y_fact: floats 0. to 1. 0 is N/W,  1. is S/E
        anchor is the anchor point on the object.
     """
    def on_resize( ev ):
        """ Callback for Configure event """
        x = int( ev.width * x_fact )
        y = int( ev.height * y_fact )
        parent.coords( id, x, y )

    parent.itemconfigure( id, anchor = anchor )
    x = int( parent.winfo_width() * x_fact )
    y = int( parent.winfo_height() * y_fact )
    parent.coords( id, x, y )
    parent.bind( '<Configure>', on_resize, add='+' )
    return id

def snap_to( x_fact, y_fact, anchor = tk.CENTER ):
    """ Returns a function which snaps to a named location. """

    def func( parent, id ):
        return snap( parent, id, x_fact, y_fact, anchor )

    return func

snap_NW = snap_to( 0,   0,   tk.NW )
snap_N  = snap_to( 0.5, 0 ,  tk.N )
snap_NE = snap_to( 1,   0,   tk.NE )
snap_W  = snap_to( 0,   0.5, tk.W )
snap_C  = snap_to( 0.5, 0.5, tk.CENTER )
snap_E  = snap_to( 1,   0.5, tk.E )
snap_SW = snap_to( 0,   1,   tk.SW )
snap_S  = snap_to( 0.5, 1,   tk.S )
snap_SE = snap_to( 1,   1,   tk.SE )

test0 = canvas.create_text( 0, 0, text=' SE ')
snap_SE(canvas, test0)

test1 = snap_E(canvas, canvas.create_text( 0, 0, text=' East '))

snap_N(canvas, canvas.create_text( 0, 0, text=' North '))
snap_NW(canvas, canvas.create_text( 0, 0, text=' NW '))
snap_NE(canvas, canvas.create_text( 0, 0, text=' NE '))
snap_W(canvas, canvas.create_text( 0, 0, text=' West '))
snap_C(canvas, canvas.create_text( 0, 0, text=' Centre '))
snap_SW(canvas, canvas.create_text( 0, 0, text=' SW '))
snap_S(canvas, canvas.create_text( 0, 0, text=' South '))

snap( canvas, 
       canvas.create_text( 0, 0, text=' Quarters '), 
       0.25, 0.25)

root.mainloop()

这是您想到的吗？

以下是上述的替代用法，使用snap而非snap_to。

#  Named constants for tuples of function parameters.
CEN = ( 0.5, 0.5, tk.CENTER ) # tk.CENTER is the default and could be omitted
SE = ( 1., 1., tk.SE )

# Call snap with the constants setting the three last parameters.
snap( canvas, canvas.create_text( 0, 0, text=' Centre '), *CEN )
snap( canvas, canvas.create_text( 0, 0, text=' SE '), *SE )

为什么锚的位置不好并且似乎倒转了？

1 个答案: