Fix flat-brace flipped content anchor (#688)

* Fix flat-brace flipped content anchor

fixes #687

* Add test

* Fix CI

Author: johannes-wolf

src/draw.typ

@@ -1,4 +1,4 @@
-#import "draw/grouping.typ": intersections, group, scope, anchor, copy-anchors, place-anchors, set-ctx, get-ctx, for-each-anchor, on-layer, place-marks, hide, floating
+#import "draw/grouping.typ": intersections, group, scope, anchor, copy-anchors, set-ctx, get-ctx, for-each-anchor, on-layer, hide, floating
 #import "draw/transformations.typ": set-transform, rotate, translate, scale, set-origin, move-to, set-viewport
 #import "draw/styling.typ": set-style, fill, stroke
 #import "draw/shapes.typ": circle, circle-through, arc, arc-through, mark, line, grid, content, rect, bezier, bezier-through, catmull, hobby, merge-path

src/lib/decorations/brace.typ

@@ -208,8 +208,6 @@
       type(amplitude) in (int, float),
       message: "amplitude must be a number, got " + repr(amplitude),
     )
-    // we achieve flipping by inverting the amplitude
-    if flip { amplitude *= -1 }
 
     let aspect = style.aspect
     assert(
@@ -264,6 +262,12 @@
     set-origin(start)
     rotate(vector.angle2(start, end))
 
+    // we achieve flipping by inverting the amplitude
+    if flip {
+      amplitude *= -1
+      content-offset *= -1
+    }
+
     let length = vector.dist(start, end)
     let middle = aspect * length
     let horizon = amplitude / 2

tests/decorations/ref/1.png

@@ -45,3 +45,20 @@
   (amplitude: 3),
   (amplitude: 4),
 ))
+
+// Bug #687
+#test-case(args => {
+  decorations.flat-brace((-1,-1), (1,1), ..args, name: "brace")
+  draw.circle("brace.content", radius: 0.1);
+}, args: (
+  (flip: false),
+  (flip: true),
+))
+
+#test-case(args => {
+  decorations.brace((-1,-1), (1,1), ..args, name: "brace")
+  draw.circle("brace.content", radius: 0.1);
+}, args: (
+  (flip: false),
+  (flip: true),
+))