# -*- coding: utf-8 -*- # # Swiss QR Bill Generator # Copyright (c) 2017 Manuel Bleichenbacher # Licensed under MIT License # https:#opensource.org/licenses/MIT # # Translated from Java m.mohnhaupt@bluewin.ch from typing import Final, List from .char_width_data import CharWidthData class FontMetrics: PT_TO_MM: Final = 25.4 / 72 def __init__(self, font_family_list: str, is_bold=False) -> None: self._font_family_list = font_family_list self.first_font_family = self._get_first_font_family(font_family_list).lower() if self.first_font_family == 'arial': self.char_width_x20_x7F = CharWidthData.ARIAL_NORMAL_20_7F self.char_width_xA0_xFF = CharWidthData.ARIAL_NORMAL_A0_FF self.char_default_width = CharWidthData.ARIAL_NORMAL_DEFAULT_WIDTH self.bold_char_width_x20_x7F = CharWidthData.ARIAL_BOLD_20_7F self.bold_char_width_xA0_xFF = CharWidthData.ARIAL_BOLD_A0_FF self.bold_char_default_width = CharWidthData.ARIAL_BOLD_DEFAULT_WIDTH elif self.first_font_family == 'liberation sans': self.char_width_x20_x7F = CharWidthData.LIBERATION_SANS_NORMAL_20_7F self.char_width_xA0_xFF = CharWidthData.LIBERATION_SANS_NORMAL_A0_FF self.char_default_width = CharWidthData.LIBERATION_SANS_NORMAL_DEFAULT_WIDTH self.bold_char_width_x20_x7F = CharWidthData.LIBERATION_SANS_BOLD_20_7F self.bold_char_width_xA0_xFF = CharWidthData.LIBERATION_SANS_BOLD_A0_FF self.bold_char_default_width = CharWidthData.LIBERATION_SANS_BOLD_DEFAULT_WIDTH elif self.first_font_family == 'frutiger': self.char_width_x20_x7F = CharWidthData.FRUTIGER_NORMAL_20_7F self.char_width_xA0_xFF = CharWidthData.FRUTIGER_NORMAL_A0_FF self.char_default_width = CharWidthData.FRUTIGER_NORMAL_DEFAULT_WIDTH self.bold_char_width_x20_x7F = CharWidthData.FRUTIGER_BOLD_20_7F self.bold_char_width_xA0_xFF = CharWidthData.FRUTIGER_BOLD_A0_FF self.bold_char_default_width = CharWidthData.FRUTIGER_BOLD_DEFAULT_WIDTH else: self.char_width_x20_x7F = CharWidthData.HELVETICA_NORMAL_20_7F self.char_width_xA0_xFF = CharWidthData.HELVETICA_NORMAL_A0_FF self.char_default_width = CharWidthData.HELVETICA_NORMAL_DEFAULT_WIDTH self.bold_char_width_x20_x7F = CharWidthData.HELVETICA_BOLD_20_7F self.bold_char_width_xA0_xFF = CharWidthData.HELVETICA_BOLD_A0_FF self.bold_char_default_width = CharWidthData.HELVETICA_BOLD_DEFAULT_WIDTH if is_bold: self.char_width_x20_x7F = self.bold_char_width_x20_x7F self.char_width_xA0_xFF = self.bold_char_width_xA0_xFF self.char_default_width = self.bold_char_default_width @property def font_family_list(self) -> str: return self._font_family_list def get_ascender(self, font_size: int) -> float: """Distance between baseline and top of highest letter. * font_size : the font size (in pt) * returns the distance (in mm) """ return font_size * 0.8 * self.PT_TO_MM def get_descender(self, font_size: int) -> float: """Distance between baseline and bottom of letter extending the farthest below the baseline. * font_size : the font size (in pt) * returns the distance (in mm) """ return font_size * 0.2 * self.PT_TO_MM def get_line_height(self, font_size: int) -> float: """Distance between the baselines of two consecutive text lines. * font_size : the font size (in pt) * returns the distance (in mm) """ return font_size * self.PT_TO_MM def split_lines(self, text: str, max_length: float, font_size: int) -> List[str]: """Splits the text into lines. If a line would exceed the specified maximum length, line breaks are inserted. Newlines are treated as fixed line breaks. Yes, this code has a cognitive complexity of 37. Deal with it.""" lines: List[str] = [] max = int(max_length * 1000 / font_size) str_len = len(text) # length of line pos = 0 # current position (0 ..< end) line_start_pos = 0 # start position of current line line_width = 0 # current line width (in AFM metric) add_empty_line = True # flag if an empty line should be added as the last line # iterate over all characters while pos < str_len: # get current character ch = text[pos] # skip leading white space at start of current line if ch == ' ' and pos == line_start_pos: line_start_pos += 1 pos += 1 continue # add width of character line_width += self._get_char_width(ch) add_empty_line = False # line break is need if the maximum width has been reached # or if an explicit line break has been encountered if ch == '\n' or line_width > max: # find the position for the line break if ch == '\n': break_pos = pos else: # locate the previous space on the line space_pos = pos - 1 while space_pos > line_start_pos: if text[space_pos] == ' ': break space_pos -= 1 # if space was found, it's the break position if space_pos > line_start_pos: break_pos = space_pos else: # if no space was found, forcibly break word if pos > line_start_pos: break_pos = pos else: break_pos = line_start_pos + 1 # at least one character # add line to result self._add_result_line(lines, text, line_start_pos, break_pos) # setup start of new line line_start_pos = break_pos if ch == '\n': line_start_pos = break_pos + 1 add_empty_line = True pos = line_start_pos line_width = 0 else: # no line break needed; progress one character pos += 1 # complete the last line if pos > line_start_pos: self._add_result_line(lines, text, line_start_pos, pos) elif add_empty_line: lines.append("") return lines def get_text_width(self, text: str, font_size: int, is_bold: bool) -> int: """Returns the width of the specified text for the specified font size.""" if is_bold: bold_metrics = FontMetrics(self._font_family_list, is_bold=True) return bold_metrics.get_text_width(text, font_size, False) width = 0 for ch in text: width += self._get_char_width(ch) return width * font_size / 1000 * self.PT_TO_MM def _get_char_width(self, ch: str) -> int: width = 0 ch = ord(ch) if ch >= 0x20 and ch <= 0x7f: width = self.char_width_x20_x7F[ch - 0x20] elif ch >= 0xa0 and ch <= 0xff: width = self.char_width_xA0_xFF[ch - 0xa0] if width == 0: width = self.char_default_width return width @staticmethod def _add_result_line(lines: List[str], text: str, start: int, end: int): """Add the specified text range to the resulting lines. Trim trailing white space * lines : resulting lines array * text : text * start : start of text range (including) * end : end of text range (excluding) """ lines.append(text[start:end].strip()) @staticmethod def _get_first_font_family(font_family_list: str) -> str: return font_family_list.split(',')[0].strip(' "')