Add setEndpoints method to EdgeLights

Also changes 'offset' to 'start' for clarity.

Bug: 141366370
Test: manual
Change-Id: I814c6d3ca25a0b9391bfb2424f822a83bb8ef12f

packages/SystemUI/src/com/android/systemui/assist/ui/EdgeLight.java

@@ -16,6 +16,8 @@
 
 package com.android.systemui.assist.ui;
 
+import android.util.Log;
+
 import androidx.annotation.ColorInt;
 
 /**
@@ -29,9 +31,12 @@ import androidx.annotation.ColorInt;
  * counter-clockwise.
  */
 public final class EdgeLight {
+
+    private static final String TAG = "EdgeLight";
+
     @ColorInt
     private int mColor;
-    private float mOffset;
+    private float mStart;
     private float mLength;
 
     /** Copies a list of EdgeLights. */
@@ -45,13 +50,13 @@ public final class EdgeLight {
 
     public EdgeLight(@ColorInt int color, float offset, float length) {
         mColor = color;
-        mOffset = offset;
+        mStart = offset;
         mLength = length;
     }
 
     public EdgeLight(EdgeLight sourceLight) {
         mColor = sourceLight.getColor();
-        mOffset = sourceLight.getOffset();
+        mStart = sourceLight.getStart();
         mLength = sourceLight.getLength();
     }
 
@@ -77,23 +82,41 @@ public final class EdgeLight {
     }
 
     /**
-     * Returns the current offset, in units of the total device perimeter and measured from the
-     * bottom-left corner (see class description).
+     * Sets the endpoints of the edge light, both measured from the bottom-left corner (see class
+     * description). This is a convenience method to avoid separate setStart and setLength calls.
      */
-    public float getOffset() {
-        return mOffset;
+    public void setEndpoints(float start, float end) {
+        if (start > end) {
+            Log.e(TAG, String.format("Endpoint must be >= start (add 1 if necessary). Got [%f, %f]",
+                    start, end));
+            return;
+        }
+        mStart = start;
+        mLength = end - start;
+    }
+
+    /**
+     * Returns the current starting position, in units of the total device perimeter and measured
+     * from the bottom-left corner (see class description).
+     */
+    public float getStart() {
+        return mStart;
     }
 
     /**
      * Sets the current offset, in units of the total device perimeter and measured from the
      * bottom-left corner (see class description).
      */
-    public void setOffset(float offset) {
-        mOffset = offset;
+    public void setStart(float start) {
+        mStart = start;
+    }
+
+    public float getEnd() {
+        return mStart + mLength;
     }
 
     /** Returns the center, measured from the bottom-left corner (see class description). */
     public float getCenter() {
-        return mOffset + (mLength / 2.f);
+        return mStart + (mLength / 2.f);
     }
 }

packages/SystemUI/src/com/android/systemui/assist/ui/InvocationLightsView.java

@@ -140,10 +140,10 @@ public class InvocationLightsView extends View
             float rightStart = mGuide.getRegionWidth(PerimeterPathGuide.Region.BOTTOM)
                     + (cornerLengthNormalized - arcOffsetNormalized) * (1 - progress);
 
-            setLight(0, leftStart, lightLength);
-            setLight(1, leftStart + lightLength, lightLength);
-            setLight(2, rightStart - (lightLength * 2), lightLength);
-            setLight(3, rightStart - lightLength, lightLength);
+            setLight(0, leftStart, leftStart + lightLength);
+            setLight(1, leftStart + lightLength, leftStart + lightLength * 2);
+            setLight(2, rightStart - (lightLength * 2), rightStart - lightLength);
+            setLight(3, rightStart - lightLength, rightStart);
             setVisibility(View.VISIBLE);
         }
         invalidate();
@@ -155,7 +155,7 @@ public class InvocationLightsView extends View
     public void hide() {
         setVisibility(GONE);
         for (EdgeLight light : mAssistInvocationLights) {
-            light.setLength(0);
+            light.setEndpoints(0, 0);
         }
         attemptUnregisterNavBarListener();
     }
@@ -235,12 +235,11 @@ public class InvocationLightsView extends View
         }
     }
 
-    protected void setLight(int index, float offset, float length) {
+    protected void setLight(int index, float start, float end) {
         if (index < 0 || index >= 4) {
             Log.w(TAG, "invalid invocation light index: " + index);
         }
-        mAssistInvocationLights.get(index).setOffset(offset);
-        mAssistInvocationLights.get(index).setLength(length);
+        mAssistInvocationLights.get(index).setEndpoints(start, end);
     }
 
     /**
@@ -268,9 +267,11 @@ public class InvocationLightsView extends View
     }
 
     private void renderLight(EdgeLight light, Canvas canvas) {
-        mGuide.strokeSegment(mPath, light.getOffset(), light.getOffset() + light.getLength());
-        mPaint.setColor(light.getColor());
-        canvas.drawPath(mPath, mPaint);
+        if (light.getLength() > 0) {
+            mGuide.strokeSegment(mPath, light.getStart(), light.getStart() + light.getLength());
+            mPaint.setColor(light.getColor());
+            canvas.drawPath(mPath, mPaint);
+        }
     }
 
     private void attemptRegisterNavBarListener() {