Merge "Change Display White Balance to track the Planckian locus" (2f39a1ce) · Commits · e / os / android_frameworks_base

graphics/java/android/graphics/ColorSpace.java

+39 −0

Original line number	Diff line number	Diff line
		@@ -1808,6 +1808,45 @@ public abstract class ColorSpace {
		return mul3x3(inverse3x3(matrix), mul3x3Diag(LMS, matrix));
		}

		/**
		* <p>Computes the chromaticity coordinates of a specified correlated color
		* temperature (CCT) on the Planckian locus. The specified CCT must be
		* greater than 0. A meaningful CCT range is [1667, 25000].</p>
		*
		* <p>The transform is computed using the methods in Kang et
		* al., <i>Design of Advanced Color - Temperature Control System for HDTV
		* Applications</i>, Journal of Korean Physical Society 41, 865-871
		* (2002).</p>
		*
		* @param cct The correlated color temperature, in Kelvin
		* @return Corresponding XYZ values
		* @throws IllegalArgumentException If cct is invalid
		*
		* @hide
		*/
		@NonNull
		@Size(3)
		public static float[] cctToXyz(@IntRange(from = 1) int cct) {
		if (cct < 1) {
		throw new IllegalArgumentException("Temperature must be greater than 0");
		}

		final float icct = 1e3f / cct;
		final float icct2 = icct * icct;
		final float x = cct <= 4000.0f ?
		0.179910f + 0.8776956f * icct - 0.2343589f * icct2 - 0.2661239f * icct2 * icct :
		0.240390f + 0.2226347f * icct + 2.1070379f * icct2 - 3.0258469f * icct2 * icct;

		final float x2 = x * x;
		final float y = cct <= 2222.0f ?
		-0.20219683f + 2.18555832f * x - 1.34811020f * x2 - 1.1063814f * x2 * x :
		cct <= 4000.0f ?
		-0.16748867f + 2.09137015f * x - 1.37418593f * x2 - 0.9549476f * x2 * x :
		-0.37001483f + 3.75112997f * x - 5.8733867f * x2 + 3.0817580f * x2 * x;

		return xyYToXyz(new float[] {x, y});
		}

		/**
		* <p>Computes the chromaticity coordinates of a CIE series D illuminant
		* from the specified correlated color temperature (CCT). The specified CCT

services/core/java/com/android/server/display/color/ColorDisplayService.java

+1 −1

Original line number	Diff line number	Diff line
		@@ -1417,7 +1417,7 @@ public final class ColorDisplayService extends SystemService {
		mCurrentColorTemperature = cct;

		// Adapt the display's nominal white point to match the requested CCT value
		mCurrentColorTemperatureXYZ = ColorSpace.cctToIlluminantdXyz(cct);
		mCurrentColorTemperatureXYZ = ColorSpace.cctToXyz(cct);

		mChromaticAdaptationMatrix =
		ColorSpace.chromaticAdaptation(ColorSpace.Adaptation.BRADFORD,