[justify] Add demo GTK app
This commit is contained in:
Khaled Hosny
parent
be47182d48
commit
039ea9adda
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import gi
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from collections import namedtuple
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gi.require_version("Gtk", "3.0")
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from gi.repository import Gtk, HarfBuzz as hb
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POOL = {}
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def move_to_f(funcs, draw_data, st, to_x, to_y, user_data):
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context = POOL[draw_data]
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context.move_to(to_x, to_y)
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def line_to_f(funcs, draw_data, st, to_x, to_y, user_data):
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context = POOL[draw_data]
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context.line_to(to_x, to_y)
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def cubic_to_f(
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funcs,
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draw_data,
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st,
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control1_x,
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control1_y,
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control2_x,
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control2_y,
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to_x,
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to_y,
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user_data,
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):
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context = POOL[draw_data]
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context.curve_to(control1_x, control1_y, control2_x, control2_y, to_x, to_y)
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def close_path_f(funcs, draw_data, st, user_data):
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context = POOL[draw_data]
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context.close_path()
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DFUNCS = hb.draw_funcs_create()
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hb.draw_funcs_set_move_to_func(DFUNCS, move_to_f, None)
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hb.draw_funcs_set_line_to_func(DFUNCS, line_to_f, None)
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hb.draw_funcs_set_cubic_to_func(DFUNCS, cubic_to_f, None)
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hb.draw_funcs_set_close_path_func(DFUNCS, close_path_f, None)
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def push_transform_f(funcs, paint_data, xx, yx, xy, yy, dx, dy, user_data):
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raise NotImplementedError
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def pop_transform_f(funcs, paint_data, user_data):
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raise NotImplementedError
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def color_f(funcs, paint_data, is_foreground, color, user_data):
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context = POOL[paint_data]
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r = hb.color_get_red(color) / 255
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g = hb.color_get_green(color) / 255
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b = hb.color_get_blue(color) / 255
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a = hb.color_get_alpha(color) / 255
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context.set_source_rgba(r, g, b, a)
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context.paint()
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def push_clip_rectangle_f(funcs, paint_data, xmin, ymin, xmax, ymax, user_data):
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context = POOL[paint_data]
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context.save()
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context.rectangle(xmin, ymin, xmax, ymax)
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context.clip()
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def push_clip_glyph_f(funcs, paint_data, glyph, font, user_data):
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context = POOL[paint_data]
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context.save()
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context.new_path()
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hb.font_draw_glyph(font, glyph, DFUNCS, paint_data)
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context.close_path()
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context.clip()
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def pop_clip_f(funcs, paint_data, user_data):
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context = POOL[paint_data]
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context.restore()
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def push_group_f(funcs, paint_data, user_data):
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raise NotImplementedError
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def pop_group_f(funcs, paint_data, mode, user_data):
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raise NotImplementedError
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PFUNCS = hb.paint_funcs_create()
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hb.paint_funcs_set_push_transform_func(PFUNCS, push_transform_f, None)
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hb.paint_funcs_set_pop_transform_func(PFUNCS, pop_transform_f, None)
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hb.paint_funcs_set_color_func(PFUNCS, color_f, None)
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hb.paint_funcs_set_push_clip_glyph_func(PFUNCS, push_clip_glyph_f, None)
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hb.paint_funcs_set_push_clip_rectangle_func(PFUNCS, push_clip_rectangle_f, None)
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hb.paint_funcs_set_pop_clip_func(PFUNCS, pop_clip_f, None)
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hb.paint_funcs_set_push_group_func(PFUNCS, push_group_f, None)
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hb.paint_funcs_set_pop_group_func(PFUNCS, pop_group_f, None)
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class Word:
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def __init__(self, font, text):
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self._text = text
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self._font = font
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self._glyphs = []
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self._positions = []
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def append(self, info, pos):
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self._glyphs.append(info)
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self._positions.append(pos)
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def draw(self, context, font):
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for info, pos in zip(self._glyphs, self._positions):
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context.translate(-pos.x_advance, pos.y_advance)
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context.save()
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context.translate(pos.x_offset, pos.y_offset)
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hb.font_paint_glyph(font, info.codepoint, PFUNCS, id(context), 0, 0x0000FF)
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context.restore()
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@property
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def advance(self):
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return sum(pos.x_advance for pos in self._positions)
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@property
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def strippedadvance(self):
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w = self.advance
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if len(self) and self._text[self._glyphs[-1].cluster] == " ":
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w -= self._positions[-1].x_advance
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return w
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def __str__(self):
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if not self._glyphs:
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return ""
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first = min(g.cluster for g in self._glyphs)
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last = max(g.cluster for g in self._glyphs)
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return self._text[first : last + 1]
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def __len__(self):
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return len(self._glyphs)
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def __bool__(self):
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return len(self) != 0
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def __repr__(self):
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return f"<Word advance={self.advance} text='{str(self)}'>"
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class Line:
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def __init__(self, font, target_advance):
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self._font = font
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self._target_advance = target_advance
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self._words = []
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self._variation = None
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def append(self, word):
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self._words.append(word)
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def pop(self):
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return self._words.pop()
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def justify(self):
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buf, text = makebuffer(str(self))
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advance = self.advance
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shrink = self._target_advance > advance
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expand = not shrink
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ret, advance, tag, value = hb.shape_justify(
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self._font,
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buf,
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None,
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None,
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self._target_advance,
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self._target_advance,
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advance,
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)
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if not ret:
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return False
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if shrink and advance > self._target_advance:
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return False
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if expand and advance < self._target_advance:
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return False
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self._variation = hb.variation_t()
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self._variation.tag = tag
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self._variation.value = value
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self._words = makewords(buf, self._font, text)
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return True
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def draw(self, context):
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context.save()
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context.move_to(-1600, -200)
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context.set_font_size(130)
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context.set_source_rgb(1, 0, 0)
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if self._variation:
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tag = hb.tag_to_string(self._variation.tag).decode("ascii")
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context.show_text(f" {tag}={self._variation.value:g}")
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context.move_to(-1600, 0)
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context.show_text(f" {self.advance:g}/{self._target_advance:g}")
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context.restore()
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if self._variation:
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hb.font_set_variations(self._font, [self._variation])
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context.scale(1, -1)
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context.translate(self._target_advance, 0)
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for word in self._words:
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word.draw(context, self._font)
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@property
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def advance(self):
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w = sum(word.advance for word in self._words[:-1])
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if len(self):
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w += self._words[-1].strippedadvance
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return w
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def __str__(self):
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return "".join(str(w) for w in self._words)
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def __len__(self):
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return len(self._words)
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def __bool__(self):
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return len(self) != 0
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def __repr__(self):
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return f"<Line advance={self.advance} text='{str(self)}'>"
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Configuration = namedtuple(
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"Configuration", ["width", "height", "fontsize", "fontpath", "textpath"]
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)
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def makebuffer(text):
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buf = hb.buffer_create()
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hb.buffer_set_direction(buf, hb.direction_t.RTL)
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hb.buffer_set_script(buf, hb.script_t.ARABIC)
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hb.buffer_set_language(buf, hb.language_from_string(b"ar"))
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# Strip and remove double spaces.
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text = " ".join(text.split())
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hb.buffer_add_codepoints(buf, [ord(c) for c in text], 0, len(text))
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return buf, text
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def makewords(buf, font, text):
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hb.buffer_reverse(buf)
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words = [Word(font, text)]
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infos = hb.buffer_get_glyph_infos(buf)
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positions = hb.buffer_get_glyph_positions(buf)
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for info, pos in zip(infos, positions):
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words[-1].append(info, pos)
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if text[info.cluster] == " ":
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words.append(Word(font, text))
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return words
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def typeset(conf):
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blob = hb.blob_create_from_file(conf.fontpath)
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face = hb.face_create(blob, 0)
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font = hb.font_create(face)
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with open(conf.textpath) as f:
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text = f.read()
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margin = conf.fontsize * 2
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scale = conf.fontsize / hb.face_get_upem(face)
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target_advance = (conf.width - (margin * 2)) / scale
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buf, text = makebuffer(text)
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hb.shape(font, buf)
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words = makewords(buf, font, text)
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lines = [Line(font, target_advance)]
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for word in words:
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lines[-1].append(word)
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if lines[-1].advance > target_advance:
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if lines[-1].justify():
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# Shrink
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lines.append(Line(font, target_advance))
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else:
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# Remove last word and expand
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lines[-1].pop()
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lines[-1].justify()
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lines.append(Line(font, target_advance))
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lines[-1].append(word)
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if lines[-1].advance != target_advance:
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lines[-1].justify()
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return lines, font
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def render(context, conf):
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lines, font = typeset(conf)
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margin = conf.fontsize * 2
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scale = conf.fontsize / hb.face_get_upem(hb.font_get_face(font))
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_, extents = hb.font_get_h_extents(font)
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lineheight = extents.ascender - extents.descender + extents.line_gap
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lineheight *= scale
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context.save()
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context.translate(0, margin)
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for line in lines:
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context.translate(0, lineheight)
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context.save()
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context.translate(margin, 0)
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context.scale(scale, scale)
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line.draw(context)
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context.restore()
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context.restore()
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def main(fontpath, textpath):
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def on_draw(da, context):
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alloc = da.get_allocation()
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conf = Configuration(
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width=alloc.width,
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height=alloc.height,
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fontsize=70,
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fontpath=fontpath,
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textpath=textpath,
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)
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POOL[id(context)] = context
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render(context, conf)
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del POOL[id(context)]
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drawingarea = Gtk.DrawingArea()
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drawingarea.connect("draw", on_draw)
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win = Gtk.Window()
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win.connect("destroy", Gtk.main_quit)
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win.set_default_size(1000, 700)
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win.add(drawingarea)
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win.show_all()
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Gtk.main()
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if __name__ == "__main__":
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import argparse
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parser = argparse.ArgumentParser(description="HarfBuzz justification demo.")
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parser.add_argument("fontfile", help="input Glyphs source file")
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parser.add_argument("textfile", help="font version")
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args = parser.parse_args()
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main(args.fontfile, args.textfile)
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