python - 滚动框架内的 Canvas

Question

我目前正在努力在滚动框架内使用 Tkinter Canvas 。我所说的滚动框架是指 Gonzo 在另一个线程( Python Tkinter scrollbar for frame )的答案中给出的框架 Canvas 结构。我已经适应了这个概念并添加了水平滚动条。现在，在内部框架的顶部，我想放置一 block 具有给定最小尺寸的 Canvas 。如果这个最小尺寸小于内部框架(或整个窗口)，则没有问题(因为不需要滚动)。但是，如果我将窗口(以及框架)的大小调整为小于 Canvas 的值(这是滚动条应该有用的条件)，则 Canvas 不会被拉伸(stretch)到所需的大小(在下面的示例中，不是宽度=500px)而是在框架的较小尺寸(宽度=400px)处被截断。滚动条处于事件状态，它们滚动仍为 500 像素的内部框架。

下面我为您提供有关代码和问题的更多详细信息。

感谢您的调查。我感谢对这个问题的任何帮助，也许我只是做了一些明显错误的事情。

干杯，C.

ScrollFrame类(存储在scrollframe.py中):

from Tkinter import *

class ScrollFrame(Frame):
    def __init__(self, parent, yscroll=True, xscroll=True, *args, **kw):
        Frame.__init__(self, parent, *args, **kw)
        self.canvas = Canvas(self, bd=0, highlightthickness=0)
        if xscroll:
            hscrollbar = Scrollbar(self, orient=HORIZONTAL)
            hscrollbar.pack(fill=X, side=BOTTOM, expand=FALSE)
            self.canvas.config(xscrollcommand=hscrollbar.set)
            hscrollbar.config(command=self.canvas.xview)
        if yscroll:
            vscrollbar = Scrollbar(self, orient=VERTICAL)
            vscrollbar.pack(fill=Y, side=RIGHT, expand=FALSE)
            self.canvas.config(yscrollcommand=vscrollbar.set)
            vscrollbar.config(command=self.canvas.yview)
        self.canvas.pack(side=LEFT, fill=BOTH, expand=TRUE)

        # reset the view
        self.canvas.xview_moveto(0)
        self.canvas.yview_moveto(0)

        # create a frame inside the canvas which will be scrolled with it
        self.interior = interior = Frame(self.canvas, bg="blue")
        self.interior_id = self.canvas.create_window(0, 0, window=interior, anchor=NW)

        # track changes to the canvas and frame width and sync them,
        # also updating the scrollbar
        def _configure_interior(event):
            # update the scrollbars to match the size of the inner frame
            size = (interior.winfo_reqwidth(), interior.winfo_reqheight())
            print "interior req: ",size,(interior.winfo_width(),interior.winfo_height())
            self.canvas.config(scrollregion="0 0 %s %s" % size)
            if interior.winfo_reqwidth() != self.canvas.winfo_width() or interior.winfo_reqheight() != sel    f.canvas.winfo_height():
                # update the canvas's width to fit the inner frame
                self.canvas.config(width=interior.winfo_reqwidth(), height=interior.winfo_reqheight(),)
        interior.bind('<Configure>', _configure_interior)

        def _configure_canvas(event):
            if interior.winfo_reqwidth() != self.canvas.winfo_width() or interior.winfo_reqheight() != sel    f.canvas.winfo_height():
                # update the inner frame's width to fill the canvas
                self.canvas.itemconfigure(self.interior_id, width=self.canvas.winfo_width(), height=self.c    anvas.winfo_height())
        self.canvas.bind('<Configure>', _configure_canvas)

主要代码: 从 Tkinter 导入 * 从滚动框架导入 *

root = Tk()
root.geometry("400x300")

frame = Frame(root, bg="blue")
frame.pack(expand=True, fill=BOTH)

sf = ScrollFrame(frame, bg="yellow")
sf.pack(expand=True, fill=BOTH)

sf.interior.config(width=500, height=400)
canvas = Canvas(sf.interior, width=500, height=400, bg="green")
canvas.pack(expand=True, fill=BOTH, side="top")

root.mainloop()

运行时，如下所示:1.canvas at top left corner (not yet scrolled)2.canvas at bottom right corner (after scrolling)

问题:绿色 Canvas 应该是请求的大小(500/400)，但它似乎是滚动条附加到的祖母框架的大小(400/300)而不是内部框架，这是一个滚动的 (500/400) 的框架，它是 Canvas 的母框架。

Answer 1

_configure_canvas 方法是问题的根源。它将 self.interior 框架的大小调整为 self.canvas 的宽度，并且由于 canvas 已包含选项 expand=True， fill=BOTH，大小调整为 400x300。

此外，这个函数并不是获取滚动框所必需的，唯一需要的是每次 self.interior 时调整 self.canvas 滚动区域的大小调整大小。

修改后的代码如下:

from Tkinter import *

class ScrollFrame(Frame):
    def __init__(self, parent, yscroll=True, xscroll=True, *args, **kw):
        Frame.__init__(self, parent, *args, **kw)
        self.canvas = Canvas(self, bd=0, highlightthickness=0)
        if xscroll:
            hscrollbar = Scrollbar(self, orient=HORIZONTAL)
            hscrollbar.pack(fill=X, side=BOTTOM, expand=FALSE)
            self.canvas.config(xscrollcommand=hscrollbar.set)
            hscrollbar.config(command=self.canvas.xview)
        if yscroll:
            vscrollbar = Scrollbar(self, orient=VERTICAL)
            vscrollbar.pack(fill=Y, side=RIGHT, expand=FALSE)
            self.canvas.config(yscrollcommand=vscrollbar.set)
            vscrollbar.config(command=self.canvas.yview)
        self.canvas.pack(side=LEFT, fill=BOTH, expand=TRUE)

        # reset the view
        self.canvas.xview_moveto(0)
        self.canvas.yview_moveto(0)

        # create a frame inside the canvas which will be scrolled with it
        self.interior = interior = Frame(self.canvas, bg="blue")
        self.interior_id = self.canvas.create_window(0, 0, window=interior, anchor=NW)

        # track changes to the frame width and update the scrollregion
        def _configure_interior(event):
            # update the scrollbars to match the size of the inner frame
            self.canvas.config(scrollregion=self.canvas.bbox('all'))
        interior.bind('<Configure>', _configure_interior)

root = Tk()
root.geometry("400x300")

frame = Frame(root, bg="blue")
frame.pack(expand=True, fill=BOTH)

sf = ScrollFrame(frame, bg="yellow")
sf.pack(expand=True, fill=BOTH)

sf.interior.config(width=500, height=400)
canvas = Canvas(sf.interior, width=500, height=400, bg="green")
canvas.pack(expand=True, fill=BOTH, side="top")

root.mainloop()