Merge pull request #1434 from justvanrossum/fontbuilder-uvs

[fontBuilder] adding support for cmap format 14 Unicode Variation Sequences

Lib/fontTools/fontBuilder.py

@@ -364,9 +364,18 @@ class FontBuilder(object):
         """Set the glyph order for the font."""
         self.font.setGlyphOrder(glyphOrder)
 
-    def setupCharacterMap(self, cmapping, allowFallback=False):
+    def setupCharacterMap(self, cmapping, uvs=None, allowFallback=False):
         """Build the `cmap` table for the font. The `cmapping` argument should
         be a dict mapping unicode code points as integers to glyph names.
+
+        The `uvs` argument, when passed, must be a list of tuples, describing
+        Unicode Variation Sequences. These tuples have three elements:
+            (unicodeValue, variationSelector, glyphName)
+        `unicodeValue` and `variationSelector` are integer code points.
+        `glyphName` may be None, to indicate this is the default variation.
+        Text processors will then use the cmap to find the glyph name.
+        Each Unicode Variation Sequence should be an officially supported
+        sequence, but this is not policed.
         """
         subTables = []
         highestUnicode = max(cmapping)
@@ -390,6 +399,19 @@ class FontBuilder(object):
         subTable_0_3 = buildCmapSubTable(cmapping_3_1, format, 0, 3)
         subTables.append(subTable_0_3)
 
+        if uvs is not None:
+            uvsDict = {}
+            for unicodeValue, variationSelector, glyphName in uvs:
+                if cmapping.get(unicodeValue) == glyphName:
+                    # this is a default variation
+                    glyphName = None
+                if variationSelector not in uvsDict:
+                    uvsDict[variationSelector] = []
+                uvsDict[variationSelector].append((unicodeValue, glyphName))
+            uvsSubTable = buildCmapSubTable({}, 14, 0, 5)
+            uvsSubTable.uvsDict = uvsDict
+            subTables.append(uvsSubTable)
+
         self.font["cmap"] = newTable("cmap")
         self.font["cmap"].tableVersion = 0
         self.font["cmap"].tables = subTables

Tests/fontBuilder/data/test_uvs.ttf.ttx

@@ -0,0 +1,20 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<ttFont sfntVersion="\x00\x01\x00\x00" ttLibVersion="3.35">
+
+  <cmap>
+    <tableVersion version="0"/>
+    <cmap_format_4 platformID="0" platEncID="3" language="0">
+      <map code="0x20" name="space"/><!-- SPACE -->
+      <map code="0x30" name="zero"/><!-- DIGIT ZERO -->
+    </cmap_format_4>
+    <cmap_format_14 platformID="0" platEncID="5" format="14" length="49" numVarSelectorRecords="2">
+      <map uvs="0xfe00" uv="0x30" name="zero.slash"/>
+      <map uvs="0xfe01" uv="0x30" name="None"/>
+    </cmap_format_14>
+    <cmap_format_4 platformID="3" platEncID="1" language="0">
+      <map code="0x20" name="space"/><!-- SPACE -->
+      <map code="0x30" name="zero"/><!-- DIGIT ZERO -->
+    </cmap_format_4>
+  </cmap>
+
+</ttFont>

Tests/fontBuilder/fontBuilder_test.py

@@ -53,9 +53,9 @@ def _setupFontBuilder(isTTF, unitsPerEm=1024):
     return fb, advanceWidths, nameStrings
 
 
-def _verifyOutput(outPath):
+def _verifyOutput(outPath, tables=None):
     f = TTFont(outPath)
-    f.saveXML(outPath + ".ttx")
+    f.saveXML(outPath + ".ttx", tables=tables)
     with open(outPath + ".ttx") as f:
         testData = strip_VariableItems(f.read())
     refData = strip_VariableItems(getTestData(os.path.basename(outPath) + ".ttx"))
@@ -244,3 +244,42 @@ def test_setupNameTable_no_windows():
 
     assert all(n for n in fb.font["name"].names if n.platformID == 1)
     assert not any(n for n in fb.font["name"].names if n.platformID == 3)
+
+
+def test_unicodeVariationSequences(tmpdir):
+    familyName = "UVSTestFont"
+    styleName = "Regular"
+    nameStrings = dict(familyName=familyName, styleName=styleName)
+    nameStrings['psName'] = familyName + "-" + styleName
+    glyphOrder = [".notdef", "space", "zero", "zero.slash"]
+    cmap = {ord(" "): "space", ord("0"): "zero"}
+    uvs = [
+        (0x0030, 0xFE00, "zero.slash"),
+        (0x0030, 0xFE01, None),  # not an official sequence, just testing
+    ]
+    metrics = {gn: (600, 0) for gn in glyphOrder}
+    pen = TTGlyphPen(None)
+    glyph = pen.glyph()  # empty placeholder
+    glyphs = {gn: glyph for gn in glyphOrder}
+
+    fb = FontBuilder(1024, isTTF=True)
+    fb.setupGlyphOrder(glyphOrder)
+    fb.setupCharacterMap(cmap, uvs)
+    fb.setupGlyf(glyphs)
+    fb.setupHorizontalMetrics(metrics)
+    fb.setupHorizontalHeader(ascent=824, descent=200)
+    fb.setupNameTable(nameStrings)
+    fb.setupOS2()
+    fb.setupPost()
+
+    outPath = os.path.join(str(tmpdir), "test_uvs.ttf")
+    fb.save(outPath)
+    _verifyOutput(outPath, tables=["cmap"])
+
+    uvs = [
+        (0x0030, 0xFE00, "zero.slash"),
+        (0x0030, 0xFE01, "zero"),  # should result in the exact same subtable data, due to cmap[0x0030] == "zero"
+    ]
+    fb.setupCharacterMap(cmap, uvs)
+    fb.save(outPath)
+    _verifyOutput(outPath, tables=["cmap"])