Read some composite glyph data

yeslogic · Apr 27, 2022 · 74a6f67 · 74a6f67
1 parent b551f96
commit 74a6f67
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Showing 3 changed files with 50 additions and 3 deletions.
diff --git a/formats/data/opentype/woff2/SFNT-TTF-Composite.snap b/formats/data/opentype/woff2/SFNT-TTF-Composite.snap
@@ -520,7 +520,12 @@ stdout = '''
                     x_max = 4514,
                     y_max = 1434,
                 },
-                data = {},
+                data = {
+                    flags = 4135,
+                    glyphIndex = 7,
+                    argument1 = 3453,
+                    argument2 = 0,
+                },
             },
         ],
     },

diff --git a/formats/opentype.fathom b/formats/opentype.fathom
@@ -1066,13 +1066,39 @@ let simple_glyph = fun (number_of_contours : U16) => {
     // or int16 <- uint8,
 };
 
+let args_are_signed = fun (flags : U16) =>
+    (u16_neq (u16_and flags 0x0002) 0);
+
+let arg_format = fun (flags : U16) =>
+    match (u16_neq (u16_and flags 0x0001) 0) {
+        // If the bit is set the arguments are 16-bit
+        true => match (args_are_signed flags) {
+            true => s16be,
+            false => u16be,
+        },
+        // Otherwise they are 8-bit
+        false => match (args_are_signed flags) {
+            true => s8,
+            false => u8,
+        },
+    };
+
 /// # Composite glyph description
 ///
 /// ## References
 ///
 /// - [Microsoft's OpenType Spec: Glyph Headers](https://docs.microsoft.com/en-us/typography/opentype/spec/glyf#composite-glyph-description)
 /// - [Apple's TrueType Reference Manual: The `'loca'` table](https://developer.apple.com/fonts/TrueType-Reference-Manual/RM06/Chap6glyf.html)
-let composite_glyph = unknown_table; // TODO
+let composite_glyph = {
+    /// component flag
+    flags <- u16be,
+    /// glyph index of component
+    glyphIndex <- u16be,
+    /// x-offset for component or point number; type depends on bits 0 and 1 in component flags
+    argument1 <- arg_format flags,
+    /// y-offset for component or point number; type depends on bits 0 and 1 in component flags
+    argument2 <- arg_format flags,
+};
 
 /// # TrueType glyph
 let glyph = {

diff --git a/formats/opentype.snap b/formats/opentype.snap
@@ -255,7 +255,23 @@ let simple_glyph : _ = fun number_of_contours => {
     instruction_length <- u16be,
     instructions <- array16 instruction_length u8,
 };
-let composite_glyph : _ = unknown_table;
+let args_are_signed : _ = fun flags => u16_neq (u16_and flags 0x2) 0;
+let arg_format : _ = fun flags => match (u16_neq (u16_and flags 0x1) 0) {
+    false => match (args_are_signed flags) {
+        false => u8,
+        true => s8,
+    },
+    true => match (args_are_signed flags) {
+        false => u16be,
+        true => s16be,
+    },
+};
+let composite_glyph : _ = {
+    flags <- u16be,
+    glyphIndex <- u16be,
+    argument1 <- arg_format flags,
+    argument2 <- arg_format flags,
+};
 let glyph : _ = {
     header <- glyph_header,
     data <- match (s16_lt header.number_of_contours 0) {