Support font subsetting to reduce size of pdf #103
Description
Describe the bug
I want to add Chinese and Japanese in PDF. I did present Chinese and Japanese characters (は哈) successfully, but the size of output.pdf is too large (14MB).
I read the example doc and found the chapter 8.6.2 Composite fonts. I just want to render each character seperately, namely extract the font of a single character and then package these characters in PDF file. How to achieve this using borb? I wonder if there is an exact configuration in borb?
To Reproduce
Steps to reproduce the behaviour:
Download Microsoft Yahei.ttf at https://github.com/dolbydu/font/blob/master/unicode/Microsoft%20Yahei.ttf
from borb.pdf.document.document import Document
from borb.pdf.page.page import Page
from borb.pdf.canvas.layout.page_layout.multi_column_layout import SingleColumnLayout
from borb.pdf.canvas.layout.page_layout.page_layout import PageLayout
from borb.pdf.canvas.layout.text.paragraph import Paragraph
from borb.pdf.pdf import PDF
from borb.pdf.canvas.font.simple_font.true_type_font import TrueTypeFont
import time
from pathlib import Path
def print_current_time():
print(time.strftime("%Y-%m-%d %H:%M:%S", time.localtime()))
if __name__ == "__main__":
print_current_time()
font_path = Path(__file__).parent / "font" / "Microsoft Yahei.ttf"
custom_font = TrueTypeFont.true_type_font_from_file(font_path)
print_current_time()
doc = Document()
page = Page()
doc.append_page(page)
layout = SingleColumnLayout(page)
layout.add(Paragraph("はははは哈哈", font=custom_font))
print_current_time()
timestamp = time.strftime("%Y_%m_%d_%H_%M_%S", time.localtime())
pdf_name = timestamp + ".pdf"
pdf_path = Path(__file__).parent / "pdf" / pdf_name
with open(pdf_path, "wb") as pdf_file_handle:
PDF.dumps(pdf_file_handle, doc)
print_current_time()2022-05-27 21:19:11
2022-05-27 21:19:26
2022-05-27 21:19:27
2022-05-27 21:20:02
[ 288] .
├── [ 97] README.md
├── [ 128] font
│ ├── [ 21M] Microsoft Yahei.ttf
│ └── [ 74M] PingFang.ttc
├── [1.3K] main.py
└── [ 96] pdf
└── [ 14M] 2022_05_27_20_49_11.pdf
Expected behaviour
The size of PDF file should be less than 1MB.
Desktop (please complete the following information):
- OS: macOS 12.3
- borb version 2.0.26
- Python 3.9.5