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198 | """Paints swatches in each of the three colour spaces, captioned with the operators
they wrote.
The Python twin of the `write_color_spaces` example in Rust. A colour is written in
the space it was named in: a grey as one number, a screen colour as three, a printing
colour as four inks. The bottom row shows one mid-grey said three ways — the same ink
on paper, three different sets of numbers in the file.
The title and the four headings are held in `Words`, once per language, and
`HQF_PDF_LANG` picks which set is drawn. The caption under each swatch is not: it is
the operator the swatch wrote, which reads the same everywhere.
Usage: python examples/write_color_spaces.py [out.pdf]
HQF_PDF_LANG=fr python examples/write_color_spaces.py
"""
from __future__ import annotations
from dataclasses import dataclass
from pathlib import Path
import _language
import _licence
import _out
import hqf_pdf
MARGIN = 56.0
# One swatch, and the gap to the next.
SWATCH = 92.0
GAP = 12.0
# The room a row of swatches takes, caption included.
ROW = 150.0
# The top of the first row of swatches.
FIRST_ROW = 700.0
@dataclass(frozen=True)
class Words:
"""Every word the page draws, in one language.
The caption under a swatch is not here: it is the operator the swatch wrote, and a
file says ``0.85 0.16 0.16 rg`` wherever it is read.
"""
# The line at the head of the page.
title: str
# What each row of swatches demonstrates, from the top of the page down.
headings: tuple[str, str, str, str]
# The page in English.
ENGLISH = Words(
title="Three colour spaces, one page",
headings=(
"A grey, said as one number",
"A screen colour, said as red, green and blue",
"A printing colour, said as four inks",
"One mid-grey, said three ways",
),
)
# The page in French.
FRENCH = Words(
title="Trois espaces de couleur, une seule page",
headings=(
"Un gris, dit en un seul nombre",
"Une couleur d'écran, dite en rouge, vert et bleu",
"Une couleur d'impression, dite en quatre encres",
"Un même gris moyen, dit de trois façons",
),
)
# 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}
@dataclass(frozen=True)
class Band:
"""One row of swatches: what it demonstrates, and the colours it paints."""
heading: str
swatches: list[tuple[object, str]]
def bands(words: Words) -> list[Band]:
"""The four rows, from the top of the page down, each under the heading `words`
gives it."""
return [
Band(
words.headings[0],
[
(hqf_pdf.Color.gray(0.15), "0.15 g"),
(hqf_pdf.Color.gray(0.4), "0.4 g"),
(hqf_pdf.Color.gray(0.65), "0.65 g"),
(hqf_pdf.Color.gray(0.9), "0.9 g"),
(hqf_pdf.Color.gray(1.0), "1 g"),
],
),
Band(
words.headings[1],
[
(hqf_pdf.Rgb(0.85, 0.16, 0.16), "0.85 0.16 0.16 rg"),
(hqf_pdf.Rgb(0.16, 0.6, 0.24), "0.16 0.6 0.24 rg"),
(hqf_pdf.Rgb(0.16, 0.35, 0.8), "0.16 0.35 0.8 rg"),
(hqf_pdf.Rgb(0.95, 0.75, 0.1), "0.95 0.75 0.1 rg"),
(hqf_pdf.Rgb(0.55, 0.2, 0.7), "0.55 0.2 0.7 rg"),
],
),
Band(
words.headings[2],
[
(hqf_pdf.Cmyk(1.0, 0.0, 0.0, 0.0), "1 0 0 0 k"),
(hqf_pdf.Cmyk(0.0, 1.0, 0.0, 0.0), "0 1 0 0 k"),
(hqf_pdf.Cmyk(0.0, 0.0, 1.0, 0.0), "0 0 1 0 k"),
(hqf_pdf.Cmyk(0.0, 0.0, 0.0, 1.0), "0 0 0 1 k"),
(hqf_pdf.Cmyk(0.65, 0.0, 0.35, 0.1), "0.65 0 0.35 0.1 k"),
],
),
Band(
words.headings[3],
[
(hqf_pdf.Color.gray(0.5), "0.5 g"),
(hqf_pdf.Rgb.gray(0.5), "0.5 0.5 0.5 rg"),
(hqf_pdf.Cmyk(0.0, 0.0, 0.0, 0.5), "0 0 0 0.5 k"),
],
),
]
def draw_band(
content: hqf_pdf.Content, font: hqf_pdf.FontHandle, band: Band, top: float
) -> None:
"""Draws one row: its heading, its swatches, and under each the operators the
swatch wrote."""
content.save_state()
content.set_fill(hqf_pdf.Rgb.gray(0.15))
content.draw_text(font, 11.0, MARGIN, top, band.heading)
content.restore_state()
bottom = top - 20.0 - SWATCH
x = MARGIN
for color, caption in band.swatches:
content.save_state()
content.set_fill(color)
content.rect(x, bottom, SWATCH, SWATCH)
content.fill()
content.restore_state()
content.save_state()
content.set_stroke(hqf_pdf.Rgb.gray(0.75))
content.set_line_width(0.5)
content.rect(x, bottom, SWATCH, SWATCH)
content.stroke()
content.restore_state()
content.save_state()
content.set_fill(hqf_pdf.Rgb.gray(0.35))
content.draw_text(font, 7.5, x, bottom - 12.0, caption)
content.restore_state()
x += SWATCH + GAP
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("color_spaces.pdf", language)).stem)
document = hqf_pdf.Document()
document.set_license(_licence.licensed())
font = document.add_font(hqf_pdf.Font.from_path(_out.DEFAULT_FONT))
content = hqf_pdf.Content()
content.draw_text(font, 16.0, MARGIN, 760.0, words.title)
drawn = bands(words)
top = FIRST_ROW
for band in drawn:
draw_band(content, font, band, top)
top -= ROW
page = hqf_pdf.Page.a4()
page.set_content(content)
document.add_page(page)
written = document.write(out)
swatches = sum(len(band.swatches) for band in drawn)
print(f"wrote {out}: {written} bytes, {swatches} swatches")
if __name__ == "__main__":
main()
|