Chiebot-Mirror
/
harfbuzz
mirror of https://github.com/harfbuzz/harfbuzz.git
8
0
Fork 0
Code Issues Projects Releases Wiki Activity

[subset] Add short document on subset preprocessing.

Browse Source
pull/3933/head
Garret Rieger 2 years ago
parent bc87fe952e
commit 8c021462e6
1 changed files with 226 additions and 0 deletions
Whitespace
Show all changes Ignore whitespace when comparing lines Ignore changes in amount of whitespace Ignore changes in whitespace at EOL
Split View
Diff Options
Show Stats Download Patch File Download Diff File
  1. 226
      docs/subset-preprocessing.md

226
docs/subset-preprocessing.md
Unescape View File

@ -0,0 +1,226 @@
# Introduction
Subset preprocessing is a mechanism which can significantly speed up font subsetting operations.
It works by prepopulating datastructures from the source font which can be used in later subsetting
operations to more quickly produce the subset. Preprocessing is useful in cases where multiple subsets
will be cut from the same source font.
# Usage
```c++
hb_face_t* preprocessed = hb_subset_preprocess (source_face);
...
hb_face_t* subset = hb_subset_or_fail (preprocessed, subset_input);
```
# Additional Details
* A subset produced from a preprocessed face should be identical to a subset produced from only the
original face. The preprocessor does not change the functionality of the subsetter, just speeds
things up.
* The preprocessing operation may take longer then the time it takes to produce a subset from the
source font. Thus the main performance gains are made when a preprocessed face is reused for multiple
subsetting operations.
* The preprocessed face may contain references to the memory backing the source face. If this memory
is fully owned by a harfbuzz hb_blob_t* then it will automatically be kept alive for the lifetime
of the preprocessed face. However, if this memory is not fully owned by a harfbuzz hb_blob_t* then
it is necessary to ensure that the memory is kept alive for the lifetime of the preprocessed face.
# Performance Improvements
Here is the performance difference of producing a subset with a preprocessed face vs producing
a subset with the source face:
Benchmark | Delta Time (%)
----------|-----------------
BM_subset/subset_glyphs/Roboto-Regular.ttf/10_median|-56%
BM_subset/subset_glyphs/Roboto-Regular.ttf/64_median|-33%
BM_subset/subset_glyphs/Roboto-Regular.ttf/512_median|-28%
BM_subset/subset_glyphs/Roboto-Regular.ttf/1000_median|-11%
BM_subset/subset_glyphs/Roboto-Regular.ttf/nohinting/10_median|-56%
BM_subset/subset_glyphs/Roboto-Regular.ttf/nohinting/64_median|-33%
BM_subset/subset_glyphs/Roboto-Regular.ttf/nohinting/512_median|-21%
BM_subset/subset_glyphs/Roboto-Regular.ttf/nohinting/1000_median|-9%
BM_subset/subset_glyphs/Amiri-Regular.ttf/10_median|-67%
BM_subset/subset_glyphs/Amiri-Regular.ttf/64_median|-48%
BM_subset/subset_glyphs/Amiri-Regular.ttf/512_median|-21%
BM_subset/subset_glyphs/Amiri-Regular.ttf/4096_median|-9%
BM_subset/subset_glyphs/Amiri-Regular.ttf/nohinting/10_median|-66%
BM_subset/subset_glyphs/Amiri-Regular.ttf/nohinting/64_median|-50%
BM_subset/subset_glyphs/Amiri-Regular.ttf/nohinting/512_median|-8%
BM_subset/subset_glyphs/Amiri-Regular.ttf/nohinting/4096_median|-9%
BM_subset/subset_glyphs/NotoNastaliqUrdu-Regular.ttf/10_median|-85%
BM_subset/subset_glyphs/NotoNastaliqUrdu-Regular.ttf/64_median|-71%
BM_subset/subset_glyphs/NotoNastaliqUrdu-Regular.ttf/512_median|-3%
BM_subset/subset_glyphs/NotoNastaliqUrdu-Regular.ttf/1400_median|4%
BM_subset/subset_glyphs/NotoNastaliqUrdu-Regular.ttf/nohinting/10_median|-84%
BM_subset/subset_glyphs/NotoNastaliqUrdu-Regular.ttf/nohinting/64_median|-72%
BM_subset/subset_glyphs/NotoNastaliqUrdu-Regular.ttf/nohinting/512_median|0%
BM_subset/subset_glyphs/NotoNastaliqUrdu-Regular.ttf/nohinting/1400_median|0%
BM_subset/subset_glyphs/NotoSansDevanagari-Regular.ttf/10_median|-30%
BM_subset/subset_glyphs/NotoSansDevanagari-Regular.ttf/64_median|-24%
BM_subset/subset_glyphs/NotoSansDevanagari-Regular.ttf/512_median|-3%
BM_subset/subset_glyphs/NotoSansDevanagari-Regular.ttf/1000_median|-3%
BM_subset/subset_glyphs/NotoSansDevanagari-Regular.ttf/nohinting/10_median|-30%
BM_subset/subset_glyphs/NotoSansDevanagari-Regular.ttf/nohinting/64_median|-24%
BM_subset/subset_glyphs/NotoSansDevanagari-Regular.ttf/nohinting/512_median|-3%
BM_subset/subset_glyphs/NotoSansDevanagari-Regular.ttf/nohinting/1000_median|-5%
BM_subset/subset_glyphs/Mplus1p-Regular.ttf/10_median|-96%
BM_subset/subset_glyphs/Mplus1p-Regular.ttf/64_median|-90%
BM_subset/subset_glyphs/Mplus1p-Regular.ttf/512_median|-74%
BM_subset/subset_glyphs/Mplus1p-Regular.ttf/4096_median|-25%
BM_subset/subset_glyphs/Mplus1p-Regular.ttf/10000_median|-23%
BM_subset/subset_glyphs/Mplus1p-Regular.ttf/nohinting/10_median|-95%
BM_subset/subset_glyphs/Mplus1p-Regular.ttf/nohinting/64_median|-90%
BM_subset/subset_glyphs/Mplus1p-Regular.ttf/nohinting/512_median|-73%
BM_subset/subset_glyphs/Mplus1p-Regular.ttf/nohinting/4096_median|-24%
BM_subset/subset_glyphs/Mplus1p-Regular.ttf/nohinting/10000_median|-11%
BM_subset/subset_glyphs/SourceHanSans-Regular_subset.otf/10_median|-84%
BM_subset/subset_glyphs/SourceHanSans-Regular_subset.otf/64_median|-77%
BM_subset/subset_glyphs/SourceHanSans-Regular_subset.otf/512_median|-70%
BM_subset/subset_glyphs/SourceHanSans-Regular_subset.otf/4096_median|-80%
BM_subset/subset_glyphs/SourceHanSans-Regular_subset.otf/10000_median|-86%
BM_subset/subset_glyphs/SourceHanSans-Regular_subset.otf/nohinting/10_median|-84%
BM_subset/subset_glyphs/SourceHanSans-Regular_subset.otf/nohinting/64_median|-78%
BM_subset/subset_glyphs/SourceHanSans-Regular_subset.otf/nohinting/512_median|-71%
BM_subset/subset_glyphs/SourceHanSans-Regular_subset.otf/nohinting/4096_median|-86%
BM_subset/subset_glyphs/SourceHanSans-Regular_subset.otf/nohinting/10000_median|-88%
BM_subset/subset_glyphs/SourceSansPro-Regular.otf/10_median|-59%
BM_subset/subset_glyphs/SourceSansPro-Regular.otf/64_median|-55%
BM_subset/subset_glyphs/SourceSansPro-Regular.otf/512_median|-67%
BM_subset/subset_glyphs/SourceSansPro-Regular.otf/2000_median|-68%
BM_subset/subset_glyphs/SourceSansPro-Regular.otf/nohinting/10_median|-60%
BM_subset/subset_glyphs/SourceSansPro-Regular.otf/nohinting/64_median|-58%
BM_subset/subset_glyphs/SourceSansPro-Regular.otf/nohinting/512_median|-72%
BM_subset/subset_glyphs/SourceSansPro-Regular.otf/nohinting/2000_median|-71%
BM_subset/subset_glyphs/AdobeVFPrototype.otf/10_median|-70%
BM_subset/subset_glyphs/AdobeVFPrototype.otf/64_median|-64%
BM_subset/subset_glyphs/AdobeVFPrototype.otf/300_median|-73%
BM_subset/subset_glyphs/AdobeVFPrototype.otf/nohinting/10_median|-71%
BM_subset/subset_glyphs/AdobeVFPrototype.otf/nohinting/64_median|-68%
BM_subset/subset_glyphs/AdobeVFPrototype.otf/nohinting/300_median|-72%
BM_subset/subset_glyphs/MPLUS1-Variable.ttf/10_median|-90%
BM_subset/subset_glyphs/MPLUS1-Variable.ttf/64_median|-82%
BM_subset/subset_glyphs/MPLUS1-Variable.ttf/512_median|-31%
BM_subset/subset_glyphs/MPLUS1-Variable.ttf/4096_median|-9%
BM_subset/subset_glyphs/MPLUS1-Variable.ttf/6000_median|-22%
BM_subset/subset_glyphs/MPLUS1-Variable.ttf/nohinting/10_median|-88%
BM_subset/subset_glyphs/MPLUS1-Variable.ttf/nohinting/64_median|-83%
BM_subset/subset_glyphs/MPLUS1-Variable.ttf/nohinting/512_median|-31%
BM_subset/subset_glyphs/MPLUS1-Variable.ttf/nohinting/4096_median|-16%
BM_subset/subset_glyphs/MPLUS1-Variable.ttf/nohinting/6000_median|-18%
BM_subset/subset_glyphs/RobotoFlex-Variable.ttf/10_median|-44%
BM_subset/subset_glyphs/RobotoFlex-Variable.ttf/64_median|-18%
BM_subset/subset_glyphs/RobotoFlex-Variable.ttf/512_median|-2%
BM_subset/subset_glyphs/RobotoFlex-Variable.ttf/900_median|-6%
BM_subset/subset_glyphs/RobotoFlex-Variable.ttf/nohinting/10_median|-45%
BM_subset/subset_glyphs/RobotoFlex-Variable.ttf/nohinting/64_median|-17%
BM_subset/subset_glyphs/RobotoFlex-Variable.ttf/nohinting/512_median|-15%
BM_subset/subset_glyphs/RobotoFlex-Variable.ttf/nohinting/900_median|-3%
BM_subset/subset_codepoints/Roboto-Regular.ttf/10_median|-20%
BM_subset/subset_codepoints/Roboto-Regular.ttf/64_median|-16%
BM_subset/subset_codepoints/Roboto-Regular.ttf/512_median|-12%
BM_subset/subset_codepoints/Roboto-Regular.ttf/1000_median|-10%
BM_subset/subset_codepoints/Roboto-Regular.ttf/nohinting/10_median|-24%
BM_subset/subset_codepoints/Roboto-Regular.ttf/nohinting/64_median|-14%
BM_subset/subset_codepoints/Roboto-Regular.ttf/nohinting/512_median|-15%
BM_subset/subset_codepoints/Roboto-Regular.ttf/nohinting/1000_median|-9%
BM_subset/subset_codepoints/Amiri-Regular.ttf/10_median|-51%
BM_subset/subset_codepoints/Amiri-Regular.ttf/64_median|-37%
BM_subset/subset_codepoints/Amiri-Regular.ttf/512_median|-12%
BM_subset/subset_codepoints/Amiri-Regular.ttf/4096_median|-1%
BM_subset/subset_codepoints/Amiri-Regular.ttf/nohinting/10_median|-49%
BM_subset/subset_codepoints/Amiri-Regular.ttf/nohinting/64_median|-35%
BM_subset/subset_codepoints/Amiri-Regular.ttf/nohinting/512_median|-6%
BM_subset/subset_codepoints/Amiri-Regular.ttf/nohinting/4096_median|-1%
BM_subset/subset_codepoints/NotoNastaliqUrdu-Regular.ttf/10_median|-82%
BM_subset/subset_codepoints/NotoNastaliqUrdu-Regular.ttf/64_median|-9%
BM_subset/subset_codepoints/NotoNastaliqUrdu-Regular.ttf/512_median|0%
BM_subset/subset_codepoints/NotoNastaliqUrdu-Regular.ttf/1400_median|0%
BM_subset/subset_codepoints/NotoNastaliqUrdu-Regular.ttf/nohinting/10_median|-82%
BM_subset/subset_codepoints/NotoNastaliqUrdu-Regular.ttf/nohinting/64_median|-13%
BM_subset/subset_codepoints/NotoNastaliqUrdu-Regular.ttf/nohinting/512_median|-3%
BM_subset/subset_codepoints/NotoNastaliqUrdu-Regular.ttf/nohinting/1400_median|2%
BM_subset/subset_codepoints/NotoSansDevanagari-Regular.ttf/10_median|-40%
BM_subset/subset_codepoints/NotoSansDevanagari-Regular.ttf/64_median|-26%
BM_subset/subset_codepoints/NotoSansDevanagari-Regular.ttf/512_median|-5%
BM_subset/subset_codepoints/NotoSansDevanagari-Regular.ttf/1000_median|3%
BM_subset/subset_codepoints/NotoSansDevanagari-Regular.ttf/nohinting/10_median|-43%
BM_subset/subset_codepoints/NotoSansDevanagari-Regular.ttf/nohinting/64_median|-24%
BM_subset/subset_codepoints/NotoSansDevanagari-Regular.ttf/nohinting/512_median|-2%
BM_subset/subset_codepoints/NotoSansDevanagari-Regular.ttf/nohinting/1000_median|2%
BM_subset/subset_codepoints/Mplus1p-Regular.ttf/10_median|-83%
BM_subset/subset_codepoints/Mplus1p-Regular.ttf/64_median|-67%
BM_subset/subset_codepoints/Mplus1p-Regular.ttf/512_median|-39%
BM_subset/subset_codepoints/Mplus1p-Regular.ttf/4096_median|-20%
BM_subset/subset_codepoints/Mplus1p-Regular.ttf/10000_median|-25%
BM_subset/subset_codepoints/Mplus1p-Regular.ttf/nohinting/10_median|-83%
BM_subset/subset_codepoints/Mplus1p-Regular.ttf/nohinting/64_median|-65%
BM_subset/subset_codepoints/Mplus1p-Regular.ttf/nohinting/512_median|-42%
BM_subset/subset_codepoints/Mplus1p-Regular.ttf/nohinting/4096_median|-34%
BM_subset/subset_codepoints/Mplus1p-Regular.ttf/nohinting/10000_median|-21%
BM_subset/subset_codepoints/SourceHanSans-Regular_subset.otf/10_median|-69%
BM_subset/subset_codepoints/SourceHanSans-Regular_subset.otf/64_median|-69%
BM_subset/subset_codepoints/SourceHanSans-Regular_subset.otf/512_median|-70%
BM_subset/subset_codepoints/SourceHanSans-Regular_subset.otf/4096_median|-84%
BM_subset/subset_codepoints/SourceHanSans-Regular_subset.otf/10000_median|-83%
BM_subset/subset_codepoints/SourceHanSans-Regular_subset.otf/nohinting/10_median|-71%
BM_subset/subset_codepoints/SourceHanSans-Regular_subset.otf/nohinting/64_median|-68%
BM_subset/subset_codepoints/SourceHanSans-Regular_subset.otf/nohinting/512_median|-70%
BM_subset/subset_codepoints/SourceHanSans-Regular_subset.otf/nohinting/4096_median|-86%
BM_subset/subset_codepoints/SourceHanSans-Regular_subset.otf/nohinting/10000_median|-88%
BM_subset/subset_codepoints/SourceSansPro-Regular.otf/10_median|-45%
BM_subset/subset_codepoints/SourceSansPro-Regular.otf/64_median|-48%
BM_subset/subset_codepoints/SourceSansPro-Regular.otf/512_median|-57%
BM_subset/subset_codepoints/SourceSansPro-Regular.otf/2000_median|-66%
BM_subset/subset_codepoints/SourceSansPro-Regular.otf/nohinting/10_median|-43%
BM_subset/subset_codepoints/SourceSansPro-Regular.otf/nohinting/64_median|-50%
BM_subset/subset_codepoints/SourceSansPro-Regular.otf/nohinting/512_median|-63%
BM_subset/subset_codepoints/SourceSansPro-Regular.otf/nohinting/2000_median|-72%
BM_subset/subset_codepoints/AdobeVFPrototype.otf/10_median|-69%
BM_subset/subset_codepoints/AdobeVFPrototype.otf/64_median|-66%
BM_subset/subset_codepoints/AdobeVFPrototype.otf/300_median|-74%
BM_subset/subset_codepoints/AdobeVFPrototype.otf/nohinting/10_median|-70%
BM_subset/subset_codepoints/AdobeVFPrototype.otf/nohinting/64_median|-71%
BM_subset/subset_codepoints/AdobeVFPrototype.otf/nohinting/300_median|-75%
BM_subset/subset_codepoints/MPLUS1-Variable.ttf/10_median|-66%
BM_subset/subset_codepoints/MPLUS1-Variable.ttf/64_median|-46%
BM_subset/subset_codepoints/MPLUS1-Variable.ttf/512_median|-15%
BM_subset/subset_codepoints/MPLUS1-Variable.ttf/4096_median|-5%
BM_subset/subset_codepoints/MPLUS1-Variable.ttf/6000_median|-16%
BM_subset/subset_codepoints/MPLUS1-Variable.ttf/nohinting/10_median|-66%
BM_subset/subset_codepoints/MPLUS1-Variable.ttf/nohinting/64_median|-45%
BM_subset/subset_codepoints/MPLUS1-Variable.ttf/nohinting/512_median|-14%
BM_subset/subset_codepoints/MPLUS1-Variable.ttf/nohinting/4096_median|-11%
BM_subset/subset_codepoints/MPLUS1-Variable.ttf/nohinting/6000_median|-27%
BM_subset/subset_codepoints/RobotoFlex-Variable.ttf/10_median|-38%
BM_subset/subset_codepoints/RobotoFlex-Variable.ttf/64_median|-9%
BM_subset/subset_codepoints/RobotoFlex-Variable.ttf/512_median|-3%
BM_subset/subset_codepoints/RobotoFlex-Variable.ttf/900_median|-16%
BM_subset/subset_codepoints/RobotoFlex-Variable.ttf/nohinting/10_median|-39%
BM_subset/subset_codepoints/RobotoFlex-Variable.ttf/nohinting/64_median|-12%
BM_subset/subset_codepoints/RobotoFlex-Variable.ttf/nohinting/512_median|-4%
BM_subset/subset_codepoints/RobotoFlex-Variable.ttf/nohinting/900_median|-2%
BM_subset/instance/MPLUS1-Variable.ttf/10_median|-68%
BM_subset/instance/MPLUS1-Variable.ttf/64_median|-45%
BM_subset/instance/MPLUS1-Variable.ttf/512_median|-18%
BM_subset/instance/MPLUS1-Variable.ttf/4096_median|-2%
BM_subset/instance/MPLUS1-Variable.ttf/6000_median|4%
BM_subset/instance/MPLUS1-Variable.ttf/nohinting/10_median|-69%
BM_subset/instance/MPLUS1-Variable.ttf/nohinting/64_median|-46%
BM_subset/instance/MPLUS1-Variable.ttf/nohinting/512_median|-11%
BM_subset/instance/MPLUS1-Variable.ttf/nohinting/4096_median|4%
BM_subset/instance/MPLUS1-Variable.ttf/nohinting/6000_median|-5%
BM_subset/instance/RobotoFlex-Variable.ttf/10_median|-34%
BM_subset/instance/RobotoFlex-Variable.ttf/64_median|-12%
BM_subset/instance/RobotoFlex-Variable.ttf/512_median|6%
BM_subset/instance/RobotoFlex-Variable.ttf/900_median|-6%
BM_subset/instance/RobotoFlex-Variable.ttf/nohinting/10_median|-33%
BM_subset/instance/RobotoFlex-Variable.ttf/nohinting/64_median|-11%
BM_subset/instance/RobotoFlex-Variable.ttf/nohinting/512_median|3%
BM_subset/instance/RobotoFlex-Variable.ttf/nohinting/900_median|0%
Write Preview
Loading…
Cancel
Save