Прерывание строки вдоль пробела после превышения определенной ширины (Python)

Вот попытка заставить ваш код работать с минимальными изменениями и много отладочного вывода:

 #!python3 #coding=utf-8 """ Line break demo 2 """ text = "lorem ipsum dolor sit amet blablah" for wmax in [10,25,55,80,100,120]: print(wmax) base_width, base_height = (wmax,None)#base_img.size #font = ImageFont.truetype("/usr/share/fonts/truetype/dejavu/DejaVuSans.ttf", font_size) line_width = 0 line_count = 1 lines = [] string = "" for c in text: line_width += 5#font.getsize(c)[0] string += c if line_width > base_width: print("text ", text) print("string", string) s = string.rsplit(" ", 1) print("split ", s) string = s[0] lines.append(string) try: string = s[1] line_width = len(string) * 5 except: string = "" line_width = 0 print("lines ", lines) print("string", string) line_count += 1 print() if string: lines.append(string) print(lines) print() 

Вывод:

 10 text lorem ipsum dolor sit amet blablah string lor split ['lor'] lines ['lor'] string text lorem ipsum dolor sit amet blablah string em split ['em', ''] lines ['lor', 'em'] string text lorem ipsum dolor sit amet blablah string ips split ['ips'] lines ['lor', 'em', 'ips'] string text lorem ipsum dolor sit amet blablah string um split ['um', ''] lines ['lor', 'em', 'ips', 'um'] string text lorem ipsum dolor sit amet blablah string dol split ['dol'] lines ['lor', 'em', 'ips', 'um', 'dol'] string text lorem ipsum dolor sit amet blablah string or split ['or', ''] lines ['lor', 'em', 'ips', 'um', 'dol', 'or'] string text lorem ipsum dolor sit amet blablah string sit split ['sit'] lines ['lor', 'em', 'ips', 'um', 'dol', 'or', 'sit'] string text lorem ipsum dolor sit amet blablah string am split ['', 'am'] lines ['lor', 'em', 'ips', 'um', 'dol', 'or', 'sit', ''] string am text lorem ipsum dolor sit amet blablah string ame split ['ame'] lines ['lor', 'em', 'ips', 'um', 'dol', 'or', 'sit', '', 'ame'] string text lorem ipsum dolor sit amet blablah string tb split ['t', 'b'] lines ['lor', 'em', 'ips', 'um', 'dol', 'or', 'sit', '', 'ame', 't'] string b text lorem ipsum dolor sit amet blablah string bla split ['bla'] lines ['lor', 'em', 'ips', 'um', 'dol', 'or', 'sit', '', 'ame', 't', 'bla'] string text lorem ipsum dolor sit amet blablah string bla split ['bla'] lines ['lor', 'em', 'ips', 'um', 'dol', 'or', 'sit', '', 'ame', 't', 'bla', 'bla string ['lor', 'em', 'ips', 'um', 'dol', 'or', 'sit', '', 'ame', 't', 'bla', 'bla', 'h'] 25 text lorem ipsum dolor sit amet blablah string lorem split ['lorem', ''] lines ['lorem'] string text lorem ipsum dolor sit amet blablah string ipsum split ['ipsum', ''] lines ['lorem', 'ipsum'] string text lorem ipsum dolor sit amet blablah string dolor split ['dolor', ''] lines ['lorem', 'ipsum', 'dolor'] string text lorem ipsum dolor sit amet blablah string sit am split ['sit', 'am'] lines ['lorem', 'ipsum', 'dolor', 'sit'] string am text lorem ipsum dolor sit amet blablah string amet b split ['amet', 'b'] lines ['lorem', 'ipsum', 'dolor', 'sit', 'amet'] string b text lorem ipsum dolor sit amet blablah string blabla split ['blabla'] lines ['lorem', 'ipsum', 'dolor', 'sit', 'amet', 'blabla'] string ['lorem', 'ipsum', 'dolor', 'sit', 'amet', 'blabla', 'h'] 55 text lorem ipsum dolor sit amet blablah string lorem ipsum split ['lorem ipsum', ''] lines ['lorem ipsum'] string text lorem ipsum dolor sit amet blablah string dolor sit am split ['dolor sit', 'am'] lines ['lorem ipsum', 'dolor sit'] string am text lorem ipsum dolor sit amet blablah string amet blablah split ['amet', 'blablah'] lines ['lorem ipsum', 'dolor sit', 'amet'] string blablah ['lorem ipsum', 'dolor sit', 'amet', 'blablah'] 80 text lorem ipsum dolor sit amet blablah string lorem ipsum dolor split ['lorem ipsum', 'dolor'] lines ['lorem ipsum'] string dolor text lorem ipsum dolor sit amet blablah string dolor sit amet bl split ['dolor sit amet', 'bl'] lines ['lorem ipsum', 'dolor sit amet'] string bl ['lorem ipsum', 'dolor sit amet', 'blablah'] 100 text lorem ipsum dolor sit amet blablah string lorem ipsum dolor sit split ['lorem ipsum dolor', 'sit'] lines ['lorem ipsum dolor'] string sit ['lorem ipsum dolor', 'sit amet blablah'] 120 text lorem ipsum dolor sit amet blablah string lorem ipsum dolor sit ame split ['lorem ipsum dolor sit', 'ame'] lines ['lorem ipsum dolor sit'] string ame ['lorem ipsum dolor sit', 'amet blablah'] 

Для этого специально создан текстовый модуль python:

 In [1]: import textwrap In [2]: textwrap.wrap('x lorem ipsum', width=5) Out[2]: ['x', 'lorem', 'ipsum'] 

Редактировать :

Я неправильно понял цель автора. Проблема в том, что ширина строки не определяется как количество символов, а как ширина изображения, содержащего визуализированный текст. Я придумал хакерский метод, TextWrapper собственный класс строк с правильным определением ширины и слегка TextWrapper класс TextWrapper :

 #!/usr/bin/env python3 # -*- coding: utf-8 -*- import textwrap class MyTextWrapper(textwrap.TextWrapper): def _split(self, text): assert isinstance(text, StringWithWidth) return [StringWithWidth(i) for i in super()._split(text._str)] def _wrap_chunks(self, chunks): # only modify ''.join in the original code """_wrap_chunks(chunks : [string]) -> [string] Wrap a sequence of text chunks and return a list of lines of length 'self.width' or less. (If 'break_long_words' is false, some lines may be longer than this.) Chunks correspond roughly to words and the whitespace between them: each chunk is indivisible (modulo 'break_long_words'), but a line break can come between any two chunks. Chunks should not have internal whitespace; ie. a chunk is either all whitespace or a "word". Whitespace chunks will be removed from the beginning and end of lines, but apart from that whitespace is preserved. """ lines = [] if self.width <= 0: raise ValueError("invalid width %r (must be > 0)" % self.width) if self.max_lines is not None: if self.max_lines > 1: indent = self.subsequent_indent else: indent = self.initial_indent if len(indent) + len(self.placeholder.lstrip()) > self.width: raise ValueError("placeholder too large for max width") # Arrange in reverse order so items can be efficiently popped # from a stack of chucks. chunks.reverse() while chunks: # Start the list of chunks that will make up the current line. # cur_len is just the length of all the chunks in cur_line. cur_line = [] cur_len = 0 # Figure out which static string will prefix this line. if lines: indent = self.subsequent_indent else: indent = self.initial_indent # Maximum width for this line. width = self.width - len(indent) # First chunk on line is whitespace -- drop it, unless this # is the very beginning of the text (ie. no lines started yet). if self.drop_whitespace and chunks[-1].strip() == '' and lines: del chunks[-1] while chunks: l = len(chunks[-1]) # Can at least squeeze this chunk onto the current line. if cur_len + l <= width: cur_line.append(chunks.pop()) cur_len += l # Nope, this line is full. else: break # The current line is full, and the next chunk is too big to # fit on *any* line (not just this one). if chunks and len(chunks[-1]) > width: self._handle_long_word(chunks, cur_line, cur_len, width) cur_len = sum(map(len, cur_line)) # If the last chunk on this line is all whitespace, drop it. if self.drop_whitespace and cur_line and cur_line[-1].strip() == '': cur_len -= len(cur_line[-1]) del cur_line[-1] if cur_line: if (self.max_lines is None or len(lines) + 1 < self.max_lines or (not chunks or self.drop_whitespace and len(chunks) == 1 and not chunks[0].strip()) and cur_len <= width): # Convert current line back to a string and store it in # list of all lines (return value). lines.append(StringWithWidth( indent + ''.join(map(_as_str, cur_line)))) else: while cur_line: if (cur_line[-1].strip() and cur_len + len(self.placeholder) <= width): cur_line.append(self.placeholder) lines.append(StringWithWidth( indent + ''.join(map(_as_str, cur_line)))) break cur_len -= len(cur_line[-1]) del cur_line[-1] else: if lines: prev_line = lines[-1].rstrip() if (len(prev_line) + len(self.placeholder) <= self.width): lines[-1] = prev_line + self.placeholder break lines.append(indent + self.placeholder.lstrip()) break return lines def _make_str_fwd(name): def func(self, *args, **kwargs): return StringWithWidth(getattr(self._str, name)(*args, **kwargs)) func.__name__ = name return func def _as_str(val): if isinstance(val, StringWithWidth): val = val._str assert isinstance(val, str) return val class StringWithWidth: char_width = { 'x': 1, 's': 2, ' ': 1 } def __init__(self, s): self._str = s expandtabs = _make_str_fwd('expandtabs') translate = _make_str_fwd('translate') strip = _make_str_fwd('strip') __getitem__ = _make_str_fwd('__getitem__') def __eq__(self, rhs): return self._str == _as_str(rhs) def __add__(self, rhs): return StringWithWidth(self._str + _as_str(rhs)) def __len__(self): return sum(map(self.char_width.__getitem__, self._str)) def __repr__(self): return repr(self._str) def main(): print(MyTextWrapper(width=8).wrap(StringWithWidth('x ss s'))) if __name__ == '__main__': main() 

Возможно, этот простой подход помогает, хотя я предполагаю, что рекурсия может быть более элегантной. Обратите внимание, что фиксированное значение ширины символа должно быть заменено соответствующим вызовом функции.

 #!python3 #coding=utf-8 """ Line break demo """ text = "lorem ipsum dolor sit amet blablah" print("breaking", text) words = text.split() widths = [sum( [5 for c in w] ) for w in words] #print(words) #print(widths) print(len(words), "words") for wmax in [10,25,55,80,100,120]: print("\nmax line width:", wmax) lines = [] li = 0 r = range(len(widths)) # 0...5 for i in r: w = sum(widths[li:i+1]) if w >= wmax and i>0: lines.append( " ".join(words[li:i]) ) li = i print(" ---") w = sum(widths[li:i+1]) print( " ", i, words[i], widths[i], w ) # remainder lines.append( " ".join(words[li:]) ) print(lines) 

Вывод:

 breaking lorem ipsum dolor sit amet blablah 6 words max line width: 10 0 lorem 25 25 --- 1 ipsum 25 25 --- 2 dolor 25 25 --- 3 sit 15 15 --- 4 amet 20 20 --- 5 blablah 35 35 ['lorem', 'ipsum', 'dolor', 'sit', 'amet', 'blablah'] max line width: 25 0 lorem 25 25 --- 1 ipsum 25 25 --- 2 dolor 25 25 --- 3 sit 15 15 --- 4 amet 20 20 --- 5 blablah 35 35 ['lorem', 'ipsum', 'dolor', 'sit', 'amet', 'blablah'] max line width: 55 0 lorem 25 25 1 ipsum 25 50 --- 2 dolor 25 25 3 sit 15 40 --- 4 amet 20 20 --- 5 blablah 35 35 ['lorem ipsum', 'dolor sit', 'amet', 'blablah'] max line width: 80 0 lorem 25 25 1 ipsum 25 50 2 dolor 25 75 --- 3 sit 15 15 4 amet 20 35 5 blablah 35 70 ['lorem ipsum dolor', 'sit amet blablah'] max line width: 100 0 lorem 25 25 1 ipsum 25 50 2 dolor 25 75 3 sit 15 90 --- 4 amet 20 20 5 blablah 35 55 ['lorem ipsum dolor sit', 'amet blablah'] max line width: 120 0 lorem 25 25 1 ipsum 25 50 2 dolor 25 75 3 sit 15 90 4 amet 20 110 --- 5 blablah 35 35 ['lorem ipsum dolor sit amet', 'blablah'] 

Я не мог убрать это из головы, так что здесь он немного компактнее:

 #!python3 #coding=utf-8 """ Line break demo 3 """ def charwidth(char): return 5 def stringwidth(string): return sum( [charwidth(char) for char in string] ) text = "lorem ipsum dolor sit amet blablah" limit = 60 words = text.split() lines = [[]] while( words ): word = words.pop(0) if stringwidth( " ".join(lines[-1]) ) + 1 + stringwidth(word) < limit: lines[-1].append(word) else: lines.append( [word] ) print( [" ".join(words) for words in lines ] ) 

Вот измененная версия третьего ответа @ handle, которая также позволяет разбивать длинные слова.

Эта функция также позволяет указывать максимальное количество строк и обрезать с помощью «…» при превышении лимита.

 def text_width(text, font): return font.getsize(text)[0] # Set max_lines to 0 for no limit def wrap_text(text, font, max_width, max_lines=0): words = text.split() lines = [] while(words): word = words.pop(0) # Append word if it's not too long if len(lines) > 0 and (text_width(" ".join(lines[-1]), font) + 1 + text_width(word,font)) < max_width: lines[-1].append(word) else: # Brute-force: chunkify word until it fits chunk = len(word) while chunk > 0: while (text_width(word[:chunk],font) > max_width and chunk > 1): chunk -= 1 lines.append( [word[:chunk]] ) word = word[chunk:] chunk = len(word) lines = [" ".join(words) for words in lines] if max_lines and len(lines) > max_lines: lines[max_lines-1] = lines[max_lines-1][:-1] + "..." return "\n".join(lines[:max_lines]) в def text_width(text, font): return font.getsize(text)[0] # Set max_lines to 0 for no limit def wrap_text(text, font, max_width, max_lines=0): words = text.split() lines = [] while(words): word = words.pop(0) # Append word if it's not too long if len(lines) > 0 and (text_width(" ".join(lines[-1]), font) + 1 + text_width(word,font)) < max_width: lines[-1].append(word) else: # Brute-force: chunkify word until it fits chunk = len(word) while chunk > 0: while (text_width(word[:chunk],font) > max_width and chunk > 1): chunk -= 1 lines.append( [word[:chunk]] ) word = word[chunk:] chunk = len(word) lines = [" ".join(words) for words in lines] if max_lines and len(lines) > max_lines: lines[max_lines-1] = lines[max_lines-1][:-1] + "..." return "\n".join(lines[:max_lines]) 

Вот как я подошел к решению проблемы (переписал мой исходный код):

 def break_lines(img, text, font_size): base_width = img.size[0] font = ImageFont.truetype("/usr/share/fonts/truetype/dejavu/DejaVuSans.ttf", font_size) line = "" lines = [] width_of_line = 0 number_of_lines = 0 # break string into multi-lines that fit base_width for token in text.split(): token = token+' ' token_width = font.getsize(token)[0] if width_of_line+token_width < base_width: line+=token width_of_line+=token_width else: lines.append(line) number_of_lines += 1 width_of_line = 0 line = "" line+=token width_of_line+=token_width if line: lines.append(line) number_of_lines += 1 return lines, number_of_lines