From 568f69e35a877bb3c171a55f127b1f346002a799 Mon Sep 17 00:00:00 2001
From: Larry Bordowitz <laurence.bordowitz@gmail.com>
Date: Thu, 15 Feb 2024 20:50:08 -0600
Subject: [PATCH] feat(Circle): Add counterclockwise parameter to Circle class

---
 CHANGELOG.md         |  1 +
 src/shapes/Circle.ts | 33 +++++++++++++++++++++++----------
 test/unit/circle.js  |  9 +++++++++
 3 files changed, 33 insertions(+), 10 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index d9c06ea8bcd..fd70d51f128 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -2,6 +2,7 @@
 
 ## [next]
 
+- feat(Circle): Add counterclockwise parameter to Circle class [#9670](https://github.com/fabricjs/fabric.js/pull/9670)
 - feat(LayoutManager): Expose objects registration [#9661](https://github.com/fabricjs/fabric.js/pull/9661)
 - fix(Object): support specyfing toCanvasElement canvas [#9652](https://github.com/fabricjs/fabric.js/pull/9652)
 - ci(): no `src` imports [#9657](https://github.com/fabricjs/fabric.js/pull/9657)
diff --git a/src/shapes/Circle.ts b/src/shapes/Circle.ts
index cb233364800..99330946263 100644
--- a/src/shapes/Circle.ts
+++ b/src/shapes/Circle.ts
@@ -19,20 +19,25 @@ interface UniqueCircleProps {
   radius: number;
 
   /**
-   * degrees of start of the circle.
-   * probably will change to degrees in next major version
-   * @type Number 0 - 359
+   * Angle for the start of the circle, in degrees.
+   * @type TDegree 0 - 359
    * @default 0
    */
   startAngle: number;
 
   /**
-   * End angle of the circle
-   * probably will change to degrees in next major version
-   * @type Number 1 - 360
+   * Angle for the end of the circle, in degrees
+   * @type TDegree 1 - 360
    * @default 360
    */
   endAngle: number;
+
+  /**
+   * Orientation for the direction of the circle.
+   * Setting to true will switch the arc of the circle to traverse from startAngle to endAngle in a counterclockwise direction,
+   * @default false
+   */
+  counterclockwise: boolean;
 }
 
 export interface SerializedCircleProps
@@ -41,12 +46,18 @@ export interface SerializedCircleProps
 
 export interface CircleProps extends FabricObjectProps, UniqueCircleProps {}
 
-const CIRCLE_PROPS = ['radius', 'startAngle', 'endAngle'] as const;
+const CIRCLE_PROPS = [
+  'radius',
+  'startAngle',
+  'endAngle',
+  'counterclockwise',
+] as const;
 
 export const circleDefaultValues: UniqueCircleProps = {
   radius: 0,
   startAngle: 0,
   endAngle: 360,
+  counterclockwise: true,
 };
 
 export class Circle<
@@ -60,6 +71,7 @@ export class Circle<
   declare radius: number;
   declare startAngle: number;
   declare endAngle: number;
+  declare counterclockwise: boolean;
 
   static type = 'Circle';
 
@@ -101,7 +113,7 @@ export class Circle<
       this.radius,
       degreesToRadians(this.startAngle),
       degreesToRadians(this.endAngle),
-      false
+      this.counterclockwise
     );
     this._renderPaintInOrder(ctx);
   }
@@ -169,12 +181,13 @@ export class Circle<
         startY = sin(start) * radius,
         endX = cos(end) * radius,
         endY = sin(end) * radius,
-        largeFlag = angle > 180 ? '1' : '0';
+        largeFlag = angle > 180 ? '1' : '0',
+        sweepFlag = this.counterclockwise ? '0' : '1';
       return [
         `<path d="M ${startX} ${startY}`,
         ` A ${radius} ${radius}`,
         ' 0 ',
-        `${largeFlag} 1`,
+        `${largeFlag} ${sweepFlag}`,
         ` ${endX} ${endY}`,
         '" ',
         'COMMON_PARTS',
diff --git a/test/unit/circle.js b/test/unit/circle.js
index a68bf9543bc..5796cc73bf9 100644
--- a/test/unit/circle.js
+++ b/test/unit/circle.js
@@ -117,6 +117,7 @@
       radius:                   0,
       startAngle:               0,
       endAngle:                 360,
+      counterclockwise:         false,
       skewX:                    0,
       skewY:                    0,
       strokeUniform:            false
@@ -166,6 +167,14 @@
     assert.equal(svgClipPath, '\t<path d=\"M 10 0 A 10 10 0 0 1 -10 0\" transform=\"matrix(1 0 0 1 10.5 10.5)\"  />\n', 'half circle as clipPath');
   });
 
+  QUnit.test('toSVG with counterclockwise half circle', function (assert) {
+    var circle = new fabric.Circle({ width: 100, height: 100, radius: 10, endAngle: fabric.util.radiansToDegrees(Math.PI), counterclockwise: true });
+    var svg = circle.toSVG();
+    var svgClipPath = circle.toClipPathSVG();
+    assert.equal(svg, '<g transform=\"matrix(1 0 0 1 10.5 10.5)\"  >\n<path d=\"M 10 0 A 10 10 0 0 0 -10 0\" style=\"stroke: none; stroke-width: 1; stroke-dasharray: none; stroke-linecap: butt; stroke-dashoffset: 0; stroke-linejoin: miter; stroke-miterlimit: 4; fill: rgb(0,0,0); fill-rule: nonzero; opacity: 1;\"   />\n</g>\n');
+    assert.equal(svgClipPath, '\t<path d=\"M 10 0 A 10 10 0 0 0 -10 0\" transform=\"matrix(1 0 0 1 10.5 10.5)\"  />\n', 'half circle as clipPath');
+  });
+
   QUnit.test('fromElement', function(assert) {
     var done = assert.async();
     assert.ok(typeof fabric.Circle.fromElement === 'function');