Java-only version of SkAR: drawing on android Canvas

Bug: skia:
Change-Id: I3b85fac93a2854d1575f71554e2a7da66e8a6a6f
Reviewed-on: https://skia-review.googlesource.com/138920
Reviewed-by: Mike Reed <reed@google.com>

1 files changed, 31 insertions, 0 deletions

diff --git a/platform_tools/android/apps/skar_java/src/main/java/com/google/skar/SkARUtil.java b/platform_tools/android/apps/skar_java/src/main/java/com/google/skar/SkARUtil.java
new file mode 100644
index 0000000000..42a221af86
--- /dev/null
+++ b/platform_tools/android/apps/skar_java/src/main/java/com/google/skar/SkARUtil.java
@@ -0,0 +1,31 @@
+package com.google.skar;
+
+import android.graphics.ColorFilter;
+import android.graphics.ColorMatrix;
+import android.graphics.ColorMatrixColorFilter;
+
+import java.util.Arrays;
+
+public class SkARUtil {
+
+    private static final float MIDDLE_GRAY_GAMMA = 0.466f;
+
+    /**
+     * Returns a ColorFilter that can be used on a Paint to apply color correction effects
+     * as documented by ARCore in
+     * <a href="https://developers.google.com/ar/reference/java/com/google/ar/core/LightEstimate">LightEstimate</a>
+     *
+     * @param colorCorr output array of
+     *                  <a href="https://developers.google.com/ar/reference/java/com/google/ar/core/LightEstimate.html#getColorCorrection(float[],%20int)">getColorCorrection()</a>
+     * @return ColorFilter with effects applied
+     */
+    public static ColorFilter createLightCorrectionColorFilter(float[] colorCorr) {
+        float[] colorCorrCopy = Arrays.copyOf(colorCorr, 4);
+        for (int i = 0; i < 3; i++) {
+            colorCorrCopy[i] *= colorCorrCopy[3] / MIDDLE_GRAY_GAMMA;
+        }
+        ColorMatrix m = new ColorMatrix();
+        m.setScale(colorCorrCopy[0], colorCorrCopy[1], colorCorrCopy[2], 1);
+        return new ColorMatrixColorFilter(m);
+    }
+}