Brixomatic commented on a change in pull request #114:
URL: https://github.com/apache/commons-imaging/pull/114#discussion_r548923411
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File path: src/main/java/org/apache/commons/imaging/color/ColorConversions.java
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@@ -16,44 +16,46 @@
*/
package org.apache.commons.imaging.color;
+import java.awt.Color;
public final class ColorConversions {
- private static final double REF_X = 95.047; // Observer= 2°, Illuminant=
D65
+
+ // White reference
+ /** see:
https://en.wikipedia.org/wiki/CIELAB_color_space#From_CIEXYZ_to_CIELAB[10] */
+ private static final double REF_X = 95.047; // Observer= 2°, Illuminant=
D65
+
+ /** see:
https://en.wikipedia.org/wiki/CIELAB_color_space#From_CIEXYZ_to_CIELAB[10] */
private static final double REF_Y = 100.000;
+
+ /** see:
https://en.wikipedia.org/wiki/CIELAB_color_space#From_CIEXYZ_to_CIELAB[10] */
private static final double REF_Z = 108.883;
+ /** see:
https://en.wikipedia.org/wiki/CIELAB_color_space#From_CIEXYZ_to_CIELAB[10] */
+ private static final double XYZ_m = 7.787037; // match in slope. Note
commonly seen 7.787 gives worse results
+
+ /** see:
https://en.wikipedia.org/wiki/CIELAB_color_space#From_CIEXYZ_to_CIELAB[10] */
+ private static final double XYZ_t0 = 0.008856;
Review comment:
Extracted these constants to give them a name that matches the published
formulas
Note that for XYZ_m, I'm using a more precise value.
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