Da/unit test demo

TeXmacs/progs/graphics/graphics-markup.scm

@@ -87,28 +87,32 @@
          (p  (if (tm-point? P) (tree->stree P) c))
          (q  (if (tm-point? Q) (tree->stree Q) p))
          (r  (points-distance c p))
+         (r1 (points-distance c q))
          (x  (if (equal? r 0.0)
                 c
-                (points-add (point-times (point-get-unit (points-sub q c)) r) c)))
+                (if (equal? r1 0.0)
+                  p
+                  (points-add (point-times (point-get-unit (points-sub q c)) r) c))))
          (mid-p-x (points-mid p x))
          (vec-c-p (points-sub p c))
          (vec-c-q (points-sub q c))
-         (m  (if (equal? r 0.0)
-                c
+         (m  (if (or (equal? r 0.0) (equal? r1 0.0))
+                x
                 (if (clockwise (points-cross-product-k vec-c-p vec-c-q) 0)
                   (points-add (point-times (point-get-unit (points-sub mid-p-x c)) (- r)) c)
                   (if (= (points-cross-product-k vec-c-p vec-c-q) 0)
                     ;; If cross product == 0, then the angle between vec-c-p and vec-c-q is 0 or 180.
                     ;; We should find out whether it's 0 or 180.
+                    ;; And we should determine whether it's clockwise or counterclockwise.
                     (if (equal? (point-get-unit vec-c-p) (point-get-unit vec-c-q))
                       x
-                      (point-rotate-90 (point-rotate-90 (point-rotate-90 vec-c-p))))
+                      (if (eq? clockwise >)
+                        (points-add (point-rotate-90 (point-rotate-90 (point-rotate-90 vec-c-p))) c)
+                        (points-add (point-rotate-90 vec-c-p) c)))
                     (points-add (point-times (point-get-unit (points-sub mid-p-x c)) r) c))))))
     `(arc ,p ,m ,x)))
 
 
-
-
 (define-graphics (std-arc C P Q)
   (std-arc-helper C P Q >))
 

TeXmacs/tests/23_27.scm

@@ -0,0 +1,21 @@
+(import (liii check)
+        (liii os))
+
+; Because std-arc-helper is using define, it is not using tm-define
+; We have to load the module directly
+;
+; (texmacs-module (tests 23_27)
+;   (:use (graphics graphics-markup)))
+(load (string-append (getenv "TEXMACS_PATH") "/progs/graphics/graphics-markup.scm"))
+
+(define (point x y)
+  (stree->tree `(point ,x ,y)))
+
+(define (test-std-arc-helper)
+  (check (std-arc-helper (point "0" "0") (point "1" "0") (point "0" "1") >)
+         => `(arc (point "1" "0") (point "-0.7071067811865475" "-0.7071067811865475") (point "0.0" "1.0"))))
+
+(define (test_23_27)
+  (test-std-arc-helper)
+  (check-report)
+  (if (check-failed?) (exit -1)))