Add additional tests with the CFF dump utility (#3)

typst · Aug 15, 2024 · bac2f51 · bac2f51
1 parent 4e0058b
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diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
@@ -7,16 +7,25 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v4
+      - name: Install Java
+        uses: actions/setup-java@v3
+        with:
+          distribution: 'temurin'
+          java-version: '17'
+      - name: Download the CFF dump utility
+        run: wget https://github.com/janpe2/CFFDump/releases/download/v1.3.0/CFFDump_bin_cli_1.3.0.jar -O CFFDump_bin_cli_1.3.0.jar
+      - name: Set CFF_DUMP_BIN environment variable
+        run: echo "CFF_DUMP_BIN=$PWD/CFFDump_bin_cli_1.3.0.jar" >> $GITHUB_ENV
       - name: Set up Python
         uses: actions/setup-python@v5
         with:
           python-version: "3.11"
       - name: Install fonttools
         run: pip install fonttools==4.50
       - uses: dtolnay/rust-toolchain@stable
-      - run: cargo build --release
+      - run: cargo build
         name: Build
-      - run: cargo test --release
+      - run: cargo test
         name: Run tests
 
   checks:

diff --git a/.gitignore b/.gitignore
@@ -13,4 +13,5 @@ debug
 # Tests
 tests/subsets
 tests/ttx/*.otf
+tests/cff/*.otf
 tests/ttx/*_ref.ttx
diff --git a/tests/README.md b/tests/README.md
@@ -4,15 +4,17 @@
 You need to have `fonttools 4.50` installed on your system and in your PATH. Note that you need to have that
 exact version, otherwise the tests will fail.
 
+In addition to that, you need Java installed on your system, install the [CFF dump utility](https://github.com/janpe2/CFFDump/releases/tag/v1.3.0) and point the `CFF_DUMP_BIN` environment variable to it. 
+
 ## Generating tests
-In order to create new fonttools tests, you can edit `data/fonttools.tests`. For subset tests, you can edit 
-`data/subsets.tests`
+In order to create new fonttools tests, you can edit `data/fonttools.tests`. 
+For CFF tests, you can edit `data/cff.tests`. For subset tests, you can edit `data/subsets.tests`
 
 In order to generate the tests, run `scripts/gen-tests.py`.
 
 ## Description
 Testing is very important, as having errors in the subsetting logic could have fatal consequences.
-Because of this, we have three different testing approaches that cover 4 different 
+Because of this, we have four different testing approaches that cover 4 different 
 font readers and 7 different PDF readers in total.
 
 ### Subset tests
@@ -32,6 +34,12 @@ dump small subsets of fonts and compare the output to how fonttools would subset
 to identify other kinds of potential issues in the implementation. And it conveniently also allows us to
 have a fourth implementation to test against.
 
+### CFF tests
+A problem with CFF tests is that fonttools abstracts away the exact structure of the CFF table,
+and stuff like the order of operators in DICTs as well as missing entries are not preserved. Because of
+this, we use the above-mentioned CFF dump utility, which provides a much more detailed insight into the 
+structure of the CFF table, and allows us to detect regressions in CFF subsetting more easily.
+
 ### Fuzzing tests
 In `examples`, we have a binary that takes an environment variable `FONT_DIR` and recursively iterates over all fonts
 in that directory and basically performs the same test as in #1, but on a randomly selected sets of glyphs. We currently

diff --git a/tests/cff/LatinModernRoman-Regular_1.txt b/tests/cff/LatinModernRoman-Regular_1.txt
@@ -0,0 +1,209 @@
+% CFF Dump Output
+% File: LatinModernRoman-Regular_1.otf
+% Dumping an OpenType font file.
+% CFF data starts at 0x7C and its length is 674 bytes.
+% All dumped offsets are relative to 0x7C.
+
+
+--------------------------------------------------------------------------------
+
+Header (0x00000000):
+    major: 1
+    minor: 0
+    hdrSize: 4
+    offSize: 4
+
+--------------------------------------------------------------------------------
+
+Name INDEX (0x00000004):
+  count: 1, offSize: 1
+  Offsets of INDEX (relative to 8):
+    [0] = 1   
+    [1] = 18  
+  Data:
+    [0]: (LMRoman10-Regular)
+
+--------------------------------------------------------------------------------
+
+Top DICT INDEX (0x0000001a):
+  count: 1, offSize: 1
+  Offsets of INDEX (relative to 30):
+    [0] = 1   
+    [1] = 68  
+  Data:
+  [0] (0x0000001f):
+  <<
+    /ROS << /Registry (Adobe) /Ordering (Identity) /Supplement 0 >>
+    /Notice (Copyright 2003, 2009 B. Jackowski and J. M. Nowacki (on behalf of TeX users groups). This work is released under the GUST Font License --  see http://tug.org/fonts/licenses/GUST-FONT-LICENSE.txt for details.)  % SID 393
+    /FontMatrix [0.001 0 0 0.001 0 0]
+    /FontBBox [-430 -290 1417 1127]
+    /charset 327  % offset
+    /CharStrings 417  % offset
+    /CIDCount 65535
+    /FDArray 393  % offset
+    /FDSelect 385  % offset
+    % ----- Following entries are missing, so they get default values: -----
+    /isFixedPitch false  % default
+    /ItalicAngle 0  % default
+    /UnderlinePosition -100  % default
+    /UnderlineThickness 50  % default
+    /PaintType 0  % default
+    /CharstringType 2  % default
+    /StrokeWidth 0  % default
+    /CIDFontVersion 0  % default
+    /CIDFontRevision 0  % default
+    /CIDFontType 0  % default
+  >>
+
+--------------------------------------------------------------------------------
+
+String INDEX (0x00000062):
+  count: 3, offSize: 1
+  Offsets of INDEX (relative to 104):
+    [0] = 1   
+    [1] = 6   
+    [2] = 14  
+    [3] = 221 
+  Data:
+    [0](SID = 391): (Adobe)
+    [1](SID = 392): (Identity)
+    [2](SID = 393): (Copyright 2003, 2009 B. Jackowski and J. M. Nowacki (on behalf of TeX users groups). This work is released under the GUST Font License --  see http://tug.org/fonts/licenses/GUST-FONT-LICENSE.txt for details.)
+
+--------------------------------------------------------------------------------
+
+Global Subr INDEX (0x00000145):
+  count: 0
+  <No global subroutines>
+
+--------------------------------------------------------------------------------
+
+Charset (0x00000147):
+  (format 2; [GID] = <CID>):
+  ([0] = CID 0),
+  [1] = CID 1, 
+  [2] = CID 2, 
+
+--------------------------------------------------------------------------------
+
+FDSelect (0x00000181):
+  (format 3)
+  FD #0 for GIDs 0...2
+
+
+--------------------------------------------------------------------------------
+
+Font DICT INDEX (a.k.a. FDArray) (0x00000189):
+  count: 1, offSize: 1
+  Offsets of INDEX (relative to 397):
+    [0] = 1   
+    [1] = 20  
+  Data:
+  [0] (0x0000018e):
+  <<
+    /FontMatrix [1 0 0 1 0 0]
+    /Private [53 332]  % [size offset]
+    % ----- Following entries are missing, so they get default values: -----
+    /isFixedPitch false  % default
+    /ItalicAngle 0  % default
+    /UnderlinePosition -100  % default
+    /UnderlineThickness 50  % default
+    /PaintType 0  % default
+    /CharstringType 2  % default
+    /FontBBox [0 0 0 0]  % default
+    /StrokeWidth 0  % default
+  >>
+
+--------------------------------------------------------------------------------
+
+CharStrings INDEX (0x000001a1):
+  count: 3, offSize: 1
+  Offsets of INDEX (relative to 423):
+    [0] = 1   
+    [1] = 4   
+    [2] = 120 
+    [3] = 251 
+  Data:
+  ([GID] <CID> (offset): <charstring>)
+  [0] CID 0 (0x000001a8):
+    280 endchar  % glyph width = 280 + nominalWidthX = 280
+  [1] CID 1 (0x000001ab):
+    681 0 31 307 31 86 31 163 31 hstem  % glyph width = 681 + nominalWidthX = 681
+    33 25 3 25 151 25 198 89 vstem
+    652 hmoveto
+    31 -24 vlineto
+    -77 -2 11 36 hvcurveto
+    524 vlineto
+    36 2 11 77 vhcurveto
+    24 31 -563 hlineto
+    -28 -225 rlineto
+    25 hlineto
+    139 16 27 55 153 hhcurveto
+    129 hlineto
+    47 2 -7 -33 hvcurveto
+    -240 -90 vlineto
+    -97 -11 31 86 hvcurveto
+    -25 -265 25 hlineto
+    85 11 32 97 vhcurveto
+    90 -267 hlineto
+    -33 -2 -7 -47 vhcurveto
+    -133 hlineto
+    -172 -23 73 154 -25 hvcurveto
+    -25 hlineto
+    42 -258 rlineto
+    endchar
+  [2] CID 2 (0x0000021f):
+    676 -10 25 330 21 312 23 hstem  % glyph width = 676 + nominalWidthX = 676
+    28 103 421 95 vstem
+    647 121 rmoveto
+    6 -7 5 -4 -15 -14 -36 -15 -15 vhcurveto
+    -55 -57 -90 -11 -73 hhcurveto
+    -90 -73 58 77 -40 hvcurveto
+    -30 60 -8 69 66 vvcurveto
+    500 hlineto
+    14 2 7 12 92 -24 106 -69 65 hvcurveto
+    50 -53 -71 24 -72 hhcurveto
+    -188 -142 -164 -191 -171 118 -170 204 -15 hvcurveto
+    14 hlineto
+    97 125 17 96 53 hvcurveto
+    3 5 5 7 6 vvcurveto
+    -95 245 rmoveto
+    -421 hlineto
+    133 3 57 179 161 hhcurveto
+    72 58 -43 -69 33 hvcurveto
+    29 -62 8 -70 -68 vvcurveto
+    endchar
+
+--------------------------------------------------------------------------------
+
+CIDFont's Private DICTs:
+  Private DICT for Font DICT #0 (0x0000014c):
+  <<
+    /BlueValues [-22 0 431 448 666 677 683 705]  % Original delta values: [-22 22 431 17 218 11 6 22]
+    /BlueScale 0.04546
+    /BlueFuzz 0
+    /StdHW 31
+    /StdVW 69
+    /StemSnapH [22 23 25 26 28 30 31 38 40 42 45 106]  % Original delta values: [22 1 2 1 2 2 1 7 2 2 3 61]
+    /StemSnapV [25 66 69 75 77 83 86 89 92 97 103 107]  % Original delta values: [25 41 3 6 2 6 3 3 3 5 6 4]
+    % ----- Following entries are missing, so they get default values: -----
+    /BlueShift 7  % default
+    /ForceBold false  % default
+    /LanguageGroup 0  % default
+    /ExpansionFactor 0.06  % default
+    /initialRandomSeed 0  % default
+    /defaultWidthX 0  % default
+    /nominalWidthX 0  % default
+  >>
+
+--------------------------------------------------------------------------------
+
+Local Subr INDEX for Font DICT #0:
+  <No local subroutines>
+
+--------------------------------------------------------------------------------
+
+Info messages:
+Info: This is a CIDFont.
+
+% End of dump
+