[justify-demo] Rewrite in a simpler way
No need to overthink it, append text words to the line and reshape, no need to shape the whole text first and do complicated glyph/input mapping. Much simpler code and as fast.
This commit is contained in:
Khaled Hosny
parent
e9d6f23b5d
commit
690145fa00
339
src/justify.py
339
src/justify.py
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@ -1,7 +1,5 @@
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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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@ -105,220 +103,100 @@ 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, direction):
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for info, pos in zip(self._glyphs, self._positions):
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if direction == hb.direction_t.RTL:
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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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if direction != hb.direction_t.RTL:
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context.translate(+pos.x_advance, pos.y_advance)
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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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wiggle = 5
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advance = self.advance
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shrink = self._target_advance - wiggle < advance
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expand = self._target_advance + wiggle > advance
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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 tag:
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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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if shrink and advance > self._target_advance + wiggle:
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return False
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if expand and advance < self._target_advance - wiggle:
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return False
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return True
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def draw(self, context, direction):
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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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if direction == hb.direction_t.RTL:
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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, direction)
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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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def makebuffer(words):
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buf = hb.buffer_create()
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# Strip and remove double spaces.
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text = " ".join(text.split())
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text = " ".join(words)
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hb.buffer_add_codepoints(buf, [ord(c) for c in text], 0, len(text))
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hb.buffer_guess_segment_properties(buf)
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return buf, text
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return buf
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def makewords(buf, font, text):
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if hb.buffer_get_direction(buf) == hb.direction_t.RTL:
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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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def justify(font, words, advance, target_advance):
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buf = makebuffer(words)
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wiggle = 5
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shrink = target_advance - wiggle < advance
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expand = target_advance + wiggle > advance
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ret, advance, tag, value = hb.shape_justify(
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font,
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buf,
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None,
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None,
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target_advance,
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target_advance,
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advance,
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)
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if not ret:
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return False, buf, None
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if tag:
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variation = hb.variation_t()
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variation.tag = tag
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variation.value = value
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else:
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variation = None
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if shrink and advance > target_advance + wiggle:
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return False, buf, variation
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if expand and advance < target_advance - wiggle:
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return False, buf, variation
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return True, buf, variation
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def shape(font, words):
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buf = makebuffer(words)
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hb.shape(font, 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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advance = sum(p.x_advance for p in positions)
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return buf, advance
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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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def typeset(font, text, target_advance):
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lines = []
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words = []
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for word in text.split():
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words.append(word)
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buf, advance = shape(font, words)
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if advance > target_advance:
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# Shrink
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ret, buf, variation = justify(font, words, advance, target_advance)
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if ret:
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lines.append((buf, variation))
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words = []
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# If if fails, pop the last word and shrink, and hope for the best.
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# A too short line is better than too long.
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elif len(words) > 1:
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words.pop()
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_, buf, variation = justify(font, words, advance, target_advance)
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lines.append((buf, variation))
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words = [word]
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# But if it is one word, meh.
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else:
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lines.append((buf, variation))
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words = []
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# Justify last line
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if words:
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_, buf, variation = justify(font, words, advance, target_advance)
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lines.append((buf, variation))
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return lines
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def render(face, text, context, width, height, fontsize):
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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 = fontsize * 2
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scale = fontsize / hb.face_get_upem(face)
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target_advance = (width - (margin * 2)) / scale
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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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direction = hb.buffer_get_direction(buf)
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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, direction
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def render(context, conf):
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lines, font, direction = 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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lines = typeset(font, text, target_advance)
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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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@ -326,29 +204,64 @@ def render(context, conf):
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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.set_font_size(12)
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context.set_source_rgb(1, 0, 0)
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for buf, variation in lines:
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rtl = hb.buffer_get_direction(buf) == hb.direction_t.RTL
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if rtl:
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hb.buffer_reverse(buf)
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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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advance = sum(p.x_advance for p in positions)
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context.translate(0, lineheight)
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context.save()
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context.save()
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context.move_to(0, -20)
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if variation:
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tag = hb.tag_to_string(variation.tag).decode("ascii")
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context.show_text(f" {tag}={variation.value:g}")
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context.move_to(0, 0)
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context.show_text(f" {advance:g}/{target_advance:g}")
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context.restore()
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if variation:
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hb.font_set_variations(font, [variation])
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context.translate(margin, 0)
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context.scale(scale, scale)
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line.draw(context, direction)
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context.scale(scale, -scale)
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if rtl:
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context.translate(target_advance, 0)
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for info, pos in zip(infos, positions):
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if rtl:
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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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if not rtl:
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context.translate(+pos.x_advance, pos.y_advance)
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context.restore()
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context.restore()
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def main(fontpath, textpath):
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fontsize = 70
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blob = hb.blob_create_from_file(fontpath)
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face = hb.face_create(blob, 0)
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with open(textpath) as f:
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text = f.read()
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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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render(face, text, context, alloc.width, alloc.height, fontsize)
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del POOL[id(context)]
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drawingarea = Gtk.DrawingArea()
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