Merge "Make ColorSpace#isSrgb more restrictive"
diff --git a/graphics/java/android/graphics/ColorSpace.java b/graphics/java/android/graphics/ColorSpace.java
index f0efb58..95317a4 100644
--- a/graphics/java/android/graphics/ColorSpace.java
+++ b/graphics/java/android/graphics/ColorSpace.java
@@ -984,11 +984,12 @@
      *         {@link Named#SRGB sRGB} primaries.
      *     </li>
      *     <li>
-     *         Its white point is withing 1e-3 of the CIE standard
+     *         Its white point is within 1e-3 of the CIE standard
      *         illuminant {@link #ILLUMINANT_D65 D65}.
      *     </li>
      *     <li>Its opto-electronic transfer function is not linear.</li>
      *     <li>Its electro-optical transfer function is not linear.</li>
+     *     <li>Its transfer functions yield values within 1e-3 of {@link Named#SRGB}.</li>
      *     <li>Its range is \([0..1]\).</li>
      * </ul>
      * <p>This method always returns true for {@link Named#SRGB}.</p>
@@ -3145,19 +3146,35 @@
                 float max,
                 @IntRange(from = MIN_ID, to = MAX_ID) int id) {
             if (id == 0) return true;
-            if (!compare(primaries, SRGB_PRIMARIES)) {
+            if (!ColorSpace.compare(primaries, SRGB_PRIMARIES)) {
                 return false;
             }
-            if (!compare(whitePoint, ILLUMINANT_D65)) {
+            if (!ColorSpace.compare(whitePoint, ILLUMINANT_D65)) {
                 return false;
             }
-            if (OETF.applyAsDouble(0.5) < 0.5001) return false;
-            if (EOTF.applyAsDouble(0.5) > 0.5001) return false;
+
             if (min != 0.0f) return false;
             if (max != 1.0f) return false;
+
+            // We would have already returned true if this was SRGB itself, so
+            // it is safe to reference it here.
+            ColorSpace.Rgb srgb = (ColorSpace.Rgb) get(Named.SRGB);
+
+            for (double x = 0.0; x <= 1.0; x += 1 / 255.0) {
+                if (!compare(x, OETF, srgb.mOetf)) return false;
+                if (!compare(x, EOTF, srgb.mEotf)) return false;
+            }
+
             return true;
         }
 
+        private static boolean compare(double point, @NonNull DoubleUnaryOperator a,
+                @NonNull DoubleUnaryOperator b) {
+            double rA = a.applyAsDouble(point);
+            double rB = b.applyAsDouble(point);
+            return Math.abs(rA - rB) <= 1e-3;
+        }
+
         /**
          * Computes whether the specified CIE xyY or XYZ primaries (with Y set to 1) form
          * a wide color gamut. A color gamut is considered wide if its area is &gt; 90%