From 08ed474897cd9de8e4f4c60ac57dcada7ab1cd4d Mon Sep 17 00:00:00 2001
From: Stephen Chang <stchang@ccs.neu.edu>
Date: Wed, 3 Jun 2015 14:53:44 -0400
Subject: [PATCH] support (-360,360) angles for whalesong/image rotate

---
 whalesong/image/private/js-impl.js | 11 +++++++++--
 whalesong/image/private/kernel.js  |  7 +++++++
 2 files changed, 16 insertions(+), 2 deletions(-)

diff --git a/whalesong/image/private/js-impl.js b/whalesong/image/private/js-impl.js
index 18c3099..3802c7e 100644
--- a/whalesong/image/private/js-impl.js
+++ b/whalesong/image/private/js-impl.js
@@ -154,6 +154,9 @@ var checkPlaceY = plt.baselib.check.makeCheckArgumentType(
 var checkAngle = plt.baselib.check.makeCheckArgumentType(
     isAngle,
     "finite real number between 0 and 360");
+var checkRotateAngle = plt.baselib.check.makeCheckArgumentType(
+    isRotateAngle,
+    "finite real number between -360 and 360");
 
 
 var checkMode = plt.baselib.check.makeCheckArgumentType(
@@ -790,9 +793,13 @@ EXPORTS['rotate'] =
         'rotate',
         2,
         function(MACHINE) {
-	    var angle = checkAngle(MACHINE, "rotate", 0);
+	    var angle = checkRotateAngle(MACHINE, "rotate", 0);
 	    var img = checkImage(MACHINE, "rotate", 1);
-	    return makeRotateImage(jsnums.toFixnum(-angle), img);
+            if (jsnums.lessThan(angle, 0)) {
+		return makeRotateImage(jsnums.toFixnum(-(360 + angle)), img);
+	    } else {
+		return makeRotateImage(jsnums.toFixnum(-angle), img);
+	    }
         });
 
 
diff --git a/whalesong/image/private/kernel.js b/whalesong/image/private/kernel.js
index b5d1806..fdd03b0 100644
--- a/whalesong/image/private/kernel.js
+++ b/whalesong/image/private/kernel.js
@@ -26,6 +26,12 @@ var isAngle = function(x) {
         jsnums.greaterThanOrEqual(x, 0) &&
         jsnums.lessThan(x, 360);
 };
+// differentiate between rotation angle and other angles
+var isRotateAngle = function(x) {
+    return plt.baselib.numbers.isReal(x) &&
+        jsnums.greaterThan(x, -360) &&
+        jsnums.lessThan(x, 360);
+};
 
 
 // Produces true if the value is a color or a color string.
@@ -1469,6 +1475,7 @@ EXPORTS.isImage = isImage;
 EXPORTS.isScene = isScene;
 EXPORTS.isColorOrColorString = isColorOrColorString;
 EXPORTS.isAngle = isAngle;
+EXPORTS.isRotateAngle = isRotateAngle;
 EXPORTS.isSideCount = isSideCount;
 EXPORTS.isStepCount = isStepCount;
 EXPORTS.isPointsCount = isPointsCount;