No open corners check

CHANGELOG.md

@@ -3,17 +3,19 @@ A more detailed list of changes is available in the corresponding milestones for
 
 ## Upcoming release: 0.12.10 (2024-Jul-??)
 ### Changes to existing checks
-#### On the UFO profile
-  - **EXPERIMENTAL - [com.daltonmaag/check/consistent_curve_type]:**: remove usage of `ufoLib2` APIs
+  - **EXPERIMENTAL - [com.daltonmaag/check/consistent_curve_type]:**: remove usage of `ufoLib2` APIs. (PR #4802)
+
+### New checks
+#### Added to the UFO profile
+  - **EXPERIMENTAL - [com.daltonmaag/check/consistent_curve_type]:**: checks that a consistent curve type is used across the font sources as well as within glyphs. (PR #4795)
+  - **EXPERIMENTAL - [com.daltonmaag/check/no_open_corners]:** checks that sources don't contain open corners, intended for use in font projects with a roundness axis. (PR #4808)
+
 
 ## 0.12.9 (2024-Jul-17)
 ### New checks
 #### Added to the Universal profile
   - **EXPERIMENTAL - [com.arrowtype.fonts/check/typoascender_exceeds_Agrave]:** Check that the typoAscender exceeds the yMax of the /Agrave (issue #3170)
 
-#### Added to the UFO profile
-  - **EXPERIMENTAL - [com.daltonmaag/check/consistent_curve_type]:**: checks that a consistent curve type is used across the font sources as well as within glyphs. (PR #4795)
-
 ### Changes to existing checks
 #### On the Universal profile
   - **[com.google.fonts/check/gsub/smallcaps_before_ligatures]:** Skip check if font lacks GSUB table or font is missing either liga or smcp features. (PR #4787)

Lib/fontbakery/checks/ufo.py

@@ -409,3 +409,43 @@ def check_consistent_curve_type(config, ufo: Ufo):
             PASS,
             "All curves of all glyphs use a consistent curve type",
         )
+
+
+@check(
+    id="com.daltonmaag/check/no_open_corners",
+    rationale="""
+        This may be a requirement when creating a font that supports a roundness
+        axis.
+    """,
+    conditions=["ufo_font"],
+    proposal="https://github.com/fonttools/fontbakery/pull/4808",
+)
+def check_no_open_corners(config, ufo):
+    """Check the sources have no corners"""
+    from glyphsLib.filters.eraseOpenCorners import EraseOpenCornersPen
+    from fontTools.pens.basePen import NullPen
+
+    font = ufo.ufo_font
+    for layer in font.layers:
+        offending_glyphs = []
+        for glyph in layer:
+            erase_open_corners = EraseOpenCornersPen(NullPen())
+            for contour in glyph:
+                contour.draw(erase_open_corners)
+            if erase_open_corners.affected:
+                offending_glyphs.append(glyph.name)
+
+        if offending_glyphs:
+            location_str = (
+                "Default layer"
+                if layer.name == font.layers.defaultLayer.name
+                else layer.name
+            )
+            yield (
+                FAIL,
+                Message(
+                    "open-corners-found",
+                    f"{location_str} contains glyphs with open corners:\n\n"
+                    f"{utils.bullet_list(config, offending_glyphs)}\n",
+                ),
+            )

Lib/fontbakery/profiles/ufo.py

@@ -2,15 +2,18 @@
     "name": "UFO Sources",
     "sections": {
         "UFO Sources": [
-            "com.daltonmaag/check/ufolint",
-            "com.daltonmaag/check/ufo_required_fields",
-            "com.daltonmaag/check/ufo_recommended_fields",
-            "com.daltonmaag/check/ufo_unnecessary_fields",
+            # FIXME (orphan check): "com.daltonmaag/check/consistent_curve_type",
+            #                       https://github.com/fonttools/fontbakery/pull/4809
             "com.google.fonts/check/designspace_has_sources",
             "com.google.fonts/check/designspace_has_default_master",
             "com.google.fonts/check/designspace_has_consistent_glyphset",
             "com.google.fonts/check/designspace_has_consistent_codepoints",
             "com.thetypefounders/check/features_default_languagesystem",
+            # FIXME (orphan check): "com.daltonmaag/check/no_open_corners",
+            "com.daltonmaag/check/ufolint",
+            "com.daltonmaag/check/ufo_required_fields",
+            "com.daltonmaag/check/ufo_recommended_fields",
+            "com.daltonmaag/check/ufo_unnecessary_fields",
         ]
     },
 }

data/test/test.ufo/glyphs/contents.plist

@@ -8,5 +8,7 @@
 	<string>B_.glif</string>
 	<key>C</key>
 	<string>C_.glif</string>
+  <key>square</key>
+  <string>square.glif</string>
 </dict>
 </plist>

data/test/test.ufo/glyphs/square.glif

@@ -0,0 +1,17 @@
+<?xml version='1.0' encoding='UTF-8'?>
+<glyph name="square" format="2">
+  <advance width="600"/>
+  <outline>
+    <contour>
+      <!-- Intentional open corners for test_check_no_open_corners -->
+      <point x="547" y="128" type="line"/>
+      <point x="495" y="100" type="line"/>
+      <point x="482" y="454" type="line"/>
+      <point x="530" y="423" type="line"/>
+      <point x="110" y="417" type="line"/>
+      <point x="156" y="460" type="line"/>
+      <point x="163" y="100" type="line"/>
+      <point x="111" y="119" type="line"/>
+    </contour>
+  </outline>
+</glyph>

data/test/test.ufo/lib.plist

@@ -7,6 +7,7 @@
 		<string>A</string>
 		<string>B</string>
 		<string>C</string>
+    <string>square</string>
 	</array>
 </dict>
 </plist>

tests/checks/ufo_sources_test.py

@@ -239,3 +239,17 @@ def test_check_consistent_curve_type_check(empty_ufo_font) -> None:
     # Cubics & quadratics, all in one glyph
     ufo.insertGlyph(mixed_glyph, "mixed")
     assert_results_contain(check(ufo), WARN, "mixed-glyphs")
+
+
+def test_check_no_open_corners() -> None:
+    """Ensure the check identifies open corners correctly"""
+    check = CheckTester("com.daltonmaag/check/no_open_corners")
+
+    ufo = defcon.Font(TEST_FILE("test.ufo"))
+
+    assert_results_contain(check(ufo), FAIL, "open-corners-found")
+
+    # Remove glyph with open corners
+    del ufo["square"]
+
+    assert_PASS(check(ufo))