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290 | """The same numbers, painted through spaces that say what they mean.
The Python twin of the `write_calibrated_color` example in Rust. A calibrated
space says what white the numbers are measured against, what exponent they are
raised to and — for colour — what the three primaries actually reach, so the same
numbers are the same colour wherever the file is opened.
What the page reads is held in `Words`, once per language, and `HQF_PDF_LANG` picks
which set is drawn. The numbers the bands are painted from are not language: they are
the same colours whoever reads the page.
Usage: python examples/write_calibrated_color.py [out.pdf] [font.ttf]
HQF_PDF_LANG=fr python examples/write_calibrated_color.py
"""
from __future__ import annotations
from dataclasses import dataclass
from pathlib import Path
import _language
import _licence
import _out
import hqf_pdf
# The left edge of everything, and how wide a row runs.
LEFT = 70.0
RUN = 455.0
# The white every calibrated space on the page is measured against, as CIE XYZ.
WHITE = (0.9505, 1.0, 1.089)
# The six colours the first three rows paint, each as three numbers.
COLORS = [
[0.80, 0.10, 0.10],
[0.90, 0.50, 0.10],
[0.90, 0.85, 0.20],
[0.15, 0.55, 0.30],
[0.15, 0.35, 0.70],
[0.45, 0.20, 0.55],
]
# The size of one colour swatch, and the gap to the next.
SWATCH = (70.0, 55.0)
SWATCH_GAP = 7.0
# How many steps the grey ramp is cut into, and how tall it stands.
STEPS = 10
RAMP_HEIGHT = 45.0
@dataclass(frozen=True)
class Words:
"""Every word the page draws, in one language.
The numbers the bands are painted from are not here: three numbers are the same
three numbers in every language.
"""
# The line at the head of the page.
title: str
# The two lines under it, saying that nothing below was painted twice.
intro: tuple[str, str]
# The heading of each panel, and the line under it.
panels: tuple[tuple[str, str], tuple[str, str]]
# The caption each band stands under, in the order the bands are painted.
captions: tuple[str, str, str, str, str, str]
# The three lines at the foot of the page.
closing: tuple[str, str, str]
# The page in English.
ENGLISH = Words(
title="The same numbers, through spaces that say what they mean",
intro=(
"Nothing below was painted twice with different numbers. Each band "
"holds the very same numbers as",
"the one above it, and what changes is the space they are said in.",
),
panels=(
(
"Six colours, three ways of meaning them",
"The three numbers are the same in every band. The primaries under them "
"are not.",
),
(
"One grey ramp, three exponents",
"Ten steps from 0.05 to 0.95, painted with the same ten numbers each time.",
),
),
captions=(
"Left to the device",
"Through one set of primaries",
"Through a wider set of primaries",
"Left to the device",
"Measured, raised to 1",
"Measured, raised to 2.2",
),
closing=(
"A calibrated space carries its measurement in a handful of numbers "
"rather than in a profile,",
"so a file states what its colours are without embedding anything "
"and without asking the",
"reader to have the right profile installed.",
),
)
# The page in French.
FRENCH = Words(
title="Les mêmes nombres, dans des espaces qui disent ce qu'ils valent",
intro=(
"Rien, plus bas, n'a été peint deux fois avec des nombres différents. "
"Chaque bande porte les mêmes",
"nombres que celle du dessus, et ce qui change est l'espace dans lequel "
"on les dit.",
),
panels=(
(
"Six couleurs, trois façons de les définir",
"Les trois nombres sont les mêmes dans chaque bande. Les primaires sous "
"eux, non.",
),
(
"Une rampe de gris, trois exposants",
"Dix marches de 0.05 à 0.95, peintes à chaque fois avec les mêmes dix "
"nombres.",
),
),
captions=(
"Laissé à l'appareil",
"À travers un jeu de primaires",
"À travers un jeu de primaires plus large",
"Laissé à l'appareil",
"Mesuré, élevé à 1",
"Mesuré, élevé à 2.2",
),
closing=(
"Un espace calibré porte sa mesure dans une poignée de nombres plutôt "
"que dans un profil,",
"si bien qu'un fichier dit ce que sont ses couleurs sans rien embarquer "
"et sans exiger",
"que le lecteur ait le bon profil installé.",
),
)
# Every language the example is written in. A language is added by writing its own set
# of words and naming it here.
WORDS = {_language.ENGLISH: ENGLISH, _language.FRENCH: FRENCH}
def caption(content, font, y, line):
"""Write the small caption a band stands under."""
content.save_state()
content.set_fill(hqf_pdf.Color.gray(0.45))
content.draw_text(font, 8.0, LEFT, y, line)
content.restore_state()
def panel_heading(content, font, y, title, under):
"""Draw one panel's heading, with the line under it."""
content.save_state()
content.set_fill(hqf_pdf.Color.gray(0.2))
content.draw_text(font, 11.0, LEFT, y, title)
content.set_fill(hqf_pdf.Color.gray(0.45))
content.draw_text(font, 8.0, LEFT, y - 15.0, under)
content.restore_state()
def band(content, space, bottom):
"""Paint the six colours across, in `space`; without one, left to the device."""
x = LEFT
for color in COLORS:
content.save_state()
if space is None:
content.set_fill(hqf_pdf.Rgb(color[0], color[1], color[2]))
else:
content.set_fill_space(space)
content.set_fill_components(color)
content.rect(x, bottom, SWATCH[0], SWATCH[1])
content.fill()
content.restore_state()
x += SWATCH[0] + SWATCH_GAP
def ramp(content, space, bottom):
"""Paint the grey ramp across, in `space`; without one, left to the device."""
width = RUN / STEPS
x = LEFT
grey = 0.05
for _ in range(STEPS):
content.save_state()
if space is None:
content.set_fill(hqf_pdf.Color.gray(grey))
else:
content.set_fill_space(space)
content.set_fill_components([grey])
content.rect(x, bottom, width, RAMP_HEIGHT)
content.fill()
content.restore_state()
x += width
grey += 0.1
def heading(content, font, words):
"""Draw the title and the two lines saying what the page is showing."""
content.draw_text(font, 15.0, LEFT, 780.0, words.title)
content.save_state()
content.set_fill(hqf_pdf.Color.gray(0.35))
content.draw_text(font, 10.0, LEFT, 762.0, words.intro[0])
content.draw_text(font, 10.0, LEFT, 748.0, words.intro[1])
content.restore_state()
def closing(content, font, words):
"""Draw the closing note."""
content.save_state()
content.set_fill(hqf_pdf.Color.gray(0.35))
for y, line in zip([140.0, 126.0, 112.0], words.closing):
content.draw_text(font, 9.0, LEFT, y, line)
content.restore_state()
def main() -> None:
language = _language.from_environment()
words = _language.words_of(WORDS, language)
# A named file is written as named; the default one carries the language, so the two
# languages do not overwrite each other in `tmp/`.
out = _out.output_path(Path(_language.file_name("calibrated.pdf", language)).stem)
document = hqf_pdf.Document()
document.set_license(_licence.licensed())
font = document.add_font(hqf_pdf.Font.from_path(_out.font_path()))
ordinary = document.add_color_space(
hqf_pdf.CalRgb(WHITE)
.gamma((2.2, 2.2, 2.2))
.primaries(
(0.4124, 0.2126, 0.0193),
(0.3576, 0.7152, 0.1192),
(0.1805, 0.0722, 0.9505),
)
)
wider = document.add_color_space(
hqf_pdf.CalRgb(WHITE)
.gamma((2.2, 2.2, 2.2))
.primaries(
(0.5767, 0.2974, 0.0270),
(0.1856, 0.6273, 0.0707),
(0.1882, 0.0753, 0.9911),
)
)
straight = document.add_color_space(hqf_pdf.CalGray(WHITE).gamma(1.0))
bent = document.add_color_space(hqf_pdf.CalGray(WHITE).gamma(2.2))
content = hqf_pdf.Content()
heading(content, font, words)
panel_heading(content, font, 706.0, words.panels[0][0], words.panels[0][1])
caption(content, font, 668.0, words.captions[0])
band(content, None, 610.0)
caption(content, font, 594.0, words.captions[1])
band(content, ordinary, 536.0)
caption(content, font, 520.0, words.captions[2])
band(content, wider, 462.0)
panel_heading(content, font, 420.0, words.panels[1][0], words.panels[1][1])
caption(content, font, 382.0, words.captions[3])
ramp(content, None, 334.0)
caption(content, font, 318.0, words.captions[4])
ramp(content, straight, 270.0)
caption(content, font, 254.0, words.captions[5])
ramp(content, bent, 206.0)
closing(content, font, words)
page = hqf_pdf.Page.a4()
page.set_content(content)
document.add_page(page)
written = document.write(out)
print(
f"wrote {out}: {written} bytes, {len(COLORS)} colours and {STEPS} greys "
f"painted three times each"
)
if __name__ == "__main__":
main()
|