hits iterator

src/pixie/paths.nim

@@ -1110,6 +1110,35 @@ proc shouldFill(windingRule: WindingRule, count: int): bool {.inline.} =
   of wrEvenOdd:
     count mod 2 != 0
 
+iterator walk(
+  hits: seq[(float32, int16)],
+  numHits: int,
+  windingRule: WindingRule,
+  y: int,
+  size: Vec2
+): (float32, float32, int32) =
+  var
+    prevAt: float32
+    count: int32
+  for i in 0 ..< numHits:
+    let (at, winding) = hits[i]
+    if windingRule == wrNonZero and
+      (count != 0) == (count + winding != 0) and
+      i < numHits - 1:
+      # Shortcut: if nonzero rule, we only care about when the count changes
+      # between zero and nonzero (or the last hit)
+      count += winding
+      continue
+    if at > 0:
+      if shouldFill(windingRule, count):
+        yield (prevAt, at, count)
+      prevAt = at
+    count += winding
+
+  when defined(pixieLeakCheck):
+    if prevAt != size.x and count != 0:
+      echo "Leak detected: ", count, " @ (", prevAt, ", ", y, ")"
+
 proc computeCoverages(
   coverages: var seq[uint8],
   hits: var seq[(float32, int16)],
@@ -1155,20 +1184,7 @@ proc computeCoverages(
     else:
       insertionSort(hits, numHits - 1)
 
-    var
-      prevAt: float32
-      count: int
-    for i in 0 ..< numHits:
-      let (at, winding) = hits[i]
-      if windingRule == wrNonZero and
-        (count != 0) == (count + winding != 0) and
-        i < numHits - 1:
-        # Shortcut: if nonzero rule, we only care about when the count changes
-        # between zero and nonzero (or the last hit)
-        count += winding
-        continue
-      if at > 0:
-        if shouldFill(windingRule, count):
+    for (prevAt, at, count) in hits.walk(numHits, windingRule, y, size):
       var fillStart = prevAt.int
 
       let
@@ -1203,14 +1219,6 @@ proc computeCoverages(
         else:
           nimSetMem(coverages[fillStart].addr, sampleCoverage.cint, fillLen)
 
-        prevAt = at
-
-      count += winding
-
-    when defined(pixieLeakCheck):
-      if prevAt != size.x and count != 0:
-        echo "Leak detected: ", count, " @ (", prevAt, ", ", y, ")"
-
 proc fillShapes(
   image: Image,
   shapes: seq[seq[Vec2]],
@@ -1397,9 +1405,9 @@ proc strokeShapes(
   if strokeWidth <= 0:
     return
 
-  let miterAngleLimit = miterLimitToAngle(miterLimit)
-
-  let halfStroke = strokeWidth / 2
+  let
+    halfStroke = strokeWidth / 2
+    miterAngleLimit = miterLimitToAngle(miterLimit)
 
   proc makeCircle(at: Vec2): seq[Vec2] =
     var path: Path