# HG changeset patch
# User Steve Losh <steve@stevelosh.com>
# Date 1560098759 14400
# Node ID 425689e66be84600f3f5c4d7d46ac9b9c6a4a1d5
# Parent  4b63cff9f91247f25f0f03015920883d7e4ab311
Fix non-square circle transformations

diff -r 4b63cff9f912 -r 425689e66be8 src/drawing/api.lisp
--- a/src/drawing/api.lisp	Sun Jun 09 12:16:43 2019 -0400
+++ b/src/drawing/api.lisp	Sun Jun 09 12:45:59 2019 -0400
@@ -178,7 +178,15 @@
 
 (defmethod ntransform ((circle circle) transformation)
   (ntransform (center circle) transformation)
-  (zapf (radius circle) (ntransform % transformation))
+  ;; For non-aspect-ratio-preserving transformations, we want to keep circles
+  ;; as circles, but ensure they fit within the new bounding box.  So we take
+  ;; the smaller of the two possible radius transformations.
+  (let ((a (vec 0 0 1))
+        (b (vec 1 1 1)))
+    (ntransform a transformation)
+    (ntransform b transformation)
+    (let ((c (v- a b)))
+      (mulf (radius circle) (min (abs (vx c)) (abs (vy c))))))
   circle)