Tkinter.text - 如何计算动态字符串的高度？

我有一个Text包含自定义字符串的小部件\n字符（多行）。

该小部件放置在垂直方向内panedwindow我想调整panedwindow的窗框显示整个字符串Text widget.

该字符串本质上是动态的（这意味着它正在通过我的应用程序中的其他方法进行更新）。

As the Text小部件配置为wrap='word'，如何计算字符串高度（以像素为单位）以相应地调整窗扇？

我尝试使用text.dlineInfo('end -1c')[1] + text.dlineinfo('end -1c')[3]（对于线的 y 坐标 + 高度）字符串加载到小部件后。问题是，如果最后一行不可见，则 dlineinfo 返回none.

我也尝试使用Font.measure例程，但这不包括换行方面Text widget.

这是一个最小、完整且可验证的示例：

import tkinter

from tkinter import scrolledtext

class GUI():
        def __init__(self, master):
                self.master = master

                self.body_frame = tkinter.PanedWindow(self.master, orient='vertical', sashwidth=4)
                self.body_frame.pack(expand=1, fill='both')

                self.canvas_frame = tkinter.Frame(self.body_frame)
                self.description_frame = tkinter.Frame(self.body_frame)
                self.body_frame.add(self.canvas_frame, sticky='nsew')
                self.body_frame.add(self.description_frame, sticky='nsew')

                tkinter.Button(self.canvas_frame, text='Update Text', command = lambda : self.update_text(""" 
                A very long string with new lines
                A very long string with new lines
                A very long string with new lines
                A very long string with new lines
                A very long string with new lines
                A very long string with new lines
                """)).pack(fill='x')

                self.field_description = scrolledtext.ScrolledText(self.description_frame, width=20, wrap='word')
                self.field_description.pack(expand=1, fill='both')

                self.master.update()
                self.body_frame.sash_place(0,0,self.body_frame.winfo_height() - 50)     # force sash to be lower

        def update_text(self, description):
                self.field_description.delete('1.0', 'end')
                self.field_description.insert('1.0', description)

                height = self.body_frame.winfo_height()
                lastline_index = self.field_description.index('end - 1c')
                text_height = self.field_description.dlineinfo(lastline_index)[1] + \
                              self.field_description.dlineinfo(lastline_index)[3]
                self.body_frame.sash_place(0, 0, height - text_height)

root = tkinter.Tk()

my_gui = GUI(root)
root.mainloop()

我不知道有任何内置方法可以返回总行数（包括包裹线）在 tkinter 中Text widget.

但是，您可以通过将文本小部件中完整字符串的长度与文本小部件的精确宽度（减去填充）进行比较来手动计算此数字。这就是LineCounter下面的类执行以下操作：

# python 2.x
# from tkFont import Font

# python 3.x
from tkinter.font import Font

class LineCounter():
    def __init__(self):
        """" This class can count the total number of lines (including wrapped
        lines) in a tkinter Text() widget """

    def count_total_nb_lines(self, textWidget):
        # Get Text widget content and split it by unbroken lines
        textLines = textWidget.get("1.0", "end-1c").split("\n")
        # Get Text widget wrapping style
        wrap = text.cget("wrap")
        if wrap == "none":
            return len(textLines)
        else:
            # Get Text widget font
            font = Font(root, font=textWidget.cget("font"))
            totalLines_count = 0
            maxLineWidth_px = textWidget.winfo_width() - 2*text.cget("padx") - 1
            for line in textLines:
                totalLines_count += self.count_nb_wrapped_lines_in_string(line,
                                                    maxLineWidth_px, font, wrap)
            return totalLines_count

    def count_nb_wrapped_lines_in_string(self, string, maxLineWidth_px, font, wrap):
        wrappedLines_count = 1
        thereAreCharsLeftForWrapping = font.measure(string) >= maxLineWidth_px
        while thereAreCharsLeftForWrapping:
            wrappedLines_count += 1
            if wrap == "char":
                string = self.remove_wrapped_chars_from_string(string, 
                                                        maxLineWidth_px, font)
            else:
                string = self.remove_wrapped_words_from_string(string, 
                                                        maxLineWidth_px, font)
            thereAreCharsLeftForWrapping = font.measure(string) >= maxLineWidth_px
        return wrappedLines_count

    def remove_wrapped_chars_from_string(self, string, maxLineWidth_px, font):
        avgCharWidth_px = font.measure(string)/float(len(string))
        nCharsToWrap = int(0.9*maxLineWidth_px/float(avgCharWidth_px))
        wrapLine_isFull = font.measure(string[:nCharsToWrap]) >= maxLineWidth_px
        while not wrapLine_isFull:
            nCharsToWrap += 1
            wrapLine_isFull = font.measure(string[:nCharsToWrap]) >= maxLineWidth_px
        return string[nCharsToWrap-1:]

    def remove_wrapped_words_from_string(self, string, maxLineWidth_px, font):
        words = string.split(" ")
        nWordsToWrap = 0
        wrapLine_isFull = font.measure(" ".join(words[:nWordsToWrap])) >= maxLineWidth_px
        while not wrapLine_isFull:
            nWordsToWrap += 1
            wrapLine_isFull = font.measure(" ".join(words[:nWordsToWrap])) >= maxLineWidth_px
        if nWordsToWrap == 1:
            # If there is only 1 word to wrap, this word is longer than the Text
            # widget width. Therefore, wrapping switches to character mode
            return self.remove_wrapped_chars_from_string(string, maxLineWidth_px, font)
        else:
            return " ".join(words[nWordsToWrap-1:])

使用示例:

import tkinter as tk

root = tk.Tk()
text = tk.Text(root, wrap='word')
text.insert("1.0", "The total number of lines in this Text widget is " + 
            "determined accurately, even when the text is wrapped...")
lineCounter = LineCounter()
label = tk.Label(root, text="0 lines", foreground="red")

def show_nb_of_lines(evt):
    nbLines = lineCounter.count_total_nb_lines(text)
    if nbLines < 2:
        label.config(text="{} line".format(nbLines))
    else:
        label.config(text="{} lines".format(nbLines))

label.pack(side="bottom")
text.pack(side="bottom", fill="both", expand=True)
text.bind("<Configure>", show_nb_of_lines)
text.bind("<KeyRelease>", show_nb_of_lines)

root.mainloop()

根据您的具体情况，换行文本的高度ScrolledText可以确定为update_text()如下：

from tkinter.font import Font
lineCounter = LineCounter()
...
class GUI():
    ...
    def update_text(self, description):
        ...
        nbLines = lineCounter.count_total_nb_lines(self.field_description)
        font = Font(font=self.field_description.cget("font"))
        lineHeight = font.metrics("linespace")
        text_height = nbLines * lineHeight 
        ...