Changeset 13802

Timestamp:

Jun 13, 2007, 1:39:58 PM (19 years ago)

Author:

magnier

Message:

saturate the ellipse parameters on both minor and major axes

File:

• trunk/psLib/src/math/psEllipse.c (modified) (2 diffs)

trunk/psLib/src/math/psEllipse.c

@@ -46 +46 @@
 
 // ellipse rotation (major, minor, theta) -> (x2, y2, xy)
+// XXXX handle case where e0 < LIMIT
 psErrorCode psEllipsePolToAxes(const psEllipsePol pol,
                                const float minMinorAxis,
@@ -63 +64 @@
 
     float LIMIT = PS_SQR(minMinorAxis);
-    if (2.0*(pol.e0 - ds) < LIMIT) {
-        axes->major = sqrt(pol.e0 - LIMIT);
-        axes->minor = sqrt(LIMIT);
+    if (pol.e0 < LIMIT) {
+        // if e0 is too small, we are really out of luck
+        axes->major = minMinorAxis;
+        axes->minor = minMinorAxis;
     } else {
-        axes->major = sqrt(0.5*(pol.e0 + ds));
-        axes->minor = sqrt(0.5*(pol.e0 - ds));
+        if (2.0*(pol.e0 - ds) < LIMIT) {
+            // if e0 - ds is too small, saturate the minor axis at minMinorAxis
+            axes->major = sqrt(pol.e0 - LIMIT);
+            axes->minor = sqrt(LIMIT);
+        } else {
+            // normal values for e0 & ds
+            axes->major = sqrt(0.5*(pol.e0 + ds));
+            axes->minor = sqrt(0.5*(pol.e0 - ds));
+        }
     }