Adds lerpInv, saturate, lerpInvSat and constrainedMap to MathUtils. (c730de91) · Commits · e / os / android_frameworks_base

core/java/android/util/MathUtils.java

+46 −0

Original line number	Diff line number	Diff line
		@@ -165,6 +165,26 @@ public final class MathUtils {
		return start + (stop - start) * amount;
		}

		/**
		* Returns the interpolation scalar (s) that satisfies the equation: {@code value = }{@link
		* #lerp}{@code (a, b, s)}
		*
		* <p>If {@code a == b}, then this function will return 0.
		*/
		public static float lerpInv(float a, float b, float value) {
		return a != b ? ((value - a) / (b - a)) : 0.0f;
		}

		/** Returns the single argument constrained between [0.0, 1.0]. */
		public static float saturate(float value) {
		return constrain(value, 0.0f, 1.0f);
		}

		/** Returns the saturated (constrained between [0, 1]) result of {@link #lerpInv}. */
		public static float lerpInvSat(float a, float b, float value) {
		return saturate(lerpInv(a, b, value));
		}

		/**
		* Returns an interpolated angle in degrees between a set of start and end
		* angles.
		@@ -194,6 +214,32 @@ public final class MathUtils {
		return maxStart + (maxStop - maxStart) * ((value - minStart) / (minStop - minStart));
		}

		/**
		* Calculates a value in [rangeMin, rangeMax] that maps value in [valueMin, valueMax] to
		* returnVal in [rangeMin, rangeMax].
		* <p>
		* Always returns a constrained value in the range [rangeMin, rangeMax], even if value is
		* outside [valueMin, valueMax].
		* <p>
		* Eg:
		* constrainedMap(0f, 100f, 0f, 1f, 0.5f) = 50f
		* constrainedMap(20f, 200f, 10f, 20f, 20f) = 200f
		* constrainedMap(20f, 200f, 10f, 20f, 50f) = 200f
		* constrainedMap(10f, 50f, 10f, 20f, 5f) = 10f
		*
		* @param rangeMin minimum of the range that should be returned.
		* @param rangeMax maximum of the range that should be returned.
		* @param valueMin minimum of range to map {@code value} to.
		* @param valueMax maximum of range to map {@code value} to.
		* @param value to map to the range [{@code valueMin}, {@code valueMax}]. Note, can be outside
		* this range, resulting in a clamped value.
		* @return the mapped value, constrained to [{@code rangeMin}, {@code rangeMax}.
		*/
		public static float constrainedMap(
		float rangeMin, float rangeMax, float valueMin, float valueMax, float value) {
		return lerp(rangeMin, rangeMax, lerpInvSat(valueMin, valueMax, value));
		}

		/**
		* Perform Hermite interpolation between two values.
		* Eg: