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Commit 3c6b51a9 authored by Fiona Campbell's avatar Fiona Campbell
Browse files

Convert BrightnessUtils to use brightness as float 

convertGammaToLinear needed to be constrained to 0-12, as sometimes ret
variable was 12.000001.

The first parameter for gammaToLinear_minValue_shouldReturnMin has been
changed - initally it used 1 (MIN_INT) but it should have been using 0
(GAMMA_SPACE_MIN). Since the function rounded the value at the end, the
result ended up the same.

The original functions cannot be removed yet since Car uses these methods.

Bug: 150671605

Test: m -j99 RunSettingsLibRoboTests ROBOTEST_FILTER="com.android.settingslib.display.BrightnessUtilsTest"

Change-Id: I4bba2ca0785f94597590c8f4bb3a7a8a834d6c83
parent 3443ba8d

packages/SettingsLib/src/com/android/settingslib/display/BrightnessUtils.java

+8 −13
Original line number Diff line number Diff line
@@ -67,7 +67,7 @@ public class BrightnessUtils { 


    /**

     * Version of {@link #convertGammaToLinear} that takes and returns float values.

     * TODO: brightnessfloat Merge with above method later.

     * TODO(flc): refactor Android Auto to use float version

     *

     * @param val The slider value.

     * @param min The minimum acceptable value for the setting.
@@ -83,9 +83,13 @@ public class BrightnessUtils { 
            ret = MathUtils.exp((normalizedVal - C) / A) + B;

        }



        // HLG is normalized to the range [0, 12], so we need to re-normalize to the range [0, 1]

        // HLG is normalized to the range [0, 12], ensure that value is within that range,

        // it shouldn't be out of bounds.

        final float normalizedRet = MathUtils.constrain(ret, 0, 12);



        // Re-normalize to the range [0, 1]

        // in order to derive the correct setting value.

        return MathUtils.lerp(min, max, ret / 12);

        return MathUtils.lerp(min, max, normalizedRet / 12);

    }



    /**
@@ -111,16 +115,7 @@ public class BrightnessUtils { 
     * @return The corresponding slider value

     */

    public static final int convertLinearToGamma(int val, int min, int max) {

        // For some reason, HLG normalizes to the range [0, 12] rather than [0, 1]

        final float normalizedVal = MathUtils.norm(min, max, val) * 12;

        final float ret;

        if (normalizedVal <= 1f) {

            ret = MathUtils.sqrt(normalizedVal) * R;

        } else {

            ret = A * MathUtils.log(normalizedVal - B) + C;

        }



        return Math.round(MathUtils.lerp(GAMMA_SPACE_MIN, GAMMA_SPACE_MAX, ret));

        return convertLinearToGammaFloat((float) val, (float) min, (float) max);

    }



    /**

packages/SettingsLib/tests/robotests/src/com/android/settingslib/display/BrightnessUtilsTest.java

+22 −7
Original line number Diff line number Diff line
@@ -17,6 +17,7 @@ 
package com.android.settingslib.display;



import static com.android.settingslib.display.BrightnessUtils.GAMMA_SPACE_MAX;

import static com.android.settingslib.display.BrightnessUtils.GAMMA_SPACE_MIN;



import static com.google.common.truth.Truth.assertThat;
@@ -27,26 +28,40 @@ import org.robolectric.RobolectricTestRunner; 
@RunWith(RobolectricTestRunner.class)

public class BrightnessUtilsTest {



    private static final int MIN = 1;

    private static final int MAX = 255;

    private static final int MIN_INT = 1;

    private static final int MAX_INT = 255;

    private static final float MIN_FLOAT = 0.0f;

    private static final float MAX_FLOAT = 1.0f;



    @Test

    public void linearToGamma_minValue_shouldReturn0() {

        assertThat(BrightnessUtils.convertLinearToGamma(MIN, MIN, MAX)).isEqualTo(0);

    public void linearToGamma_minValue_shouldReturnMin() {

        assertThat(BrightnessUtils.convertLinearToGamma(MIN_INT, MIN_INT, MAX_INT))

                .isEqualTo(GAMMA_SPACE_MIN);

        assertThat(BrightnessUtils.convertLinearToGammaFloat(MIN_FLOAT, MIN_FLOAT, MAX_FLOAT))

                .isEqualTo(GAMMA_SPACE_MIN);

    }



    @Test

    public void linearToGamma_maxValue_shouldReturnGammaSpaceMax() {

        assertThat(BrightnessUtils.convertLinearToGamma(MAX, MIN, MAX)).isEqualTo(GAMMA_SPACE_MAX);

        assertThat(BrightnessUtils.convertLinearToGamma(MAX_INT, MIN_INT, MAX_INT))

                .isEqualTo(GAMMA_SPACE_MAX);

        assertThat(BrightnessUtils.convertLinearToGammaFloat(MAX_FLOAT, MIN_FLOAT, MAX_FLOAT))

                .isEqualTo(GAMMA_SPACE_MAX);

    }



    @Test

    public void gammaToLinear_minValue_shouldReturnMin() {

        assertThat(BrightnessUtils.convertGammaToLinear(MIN, MIN, MAX)).isEqualTo(MIN);

        assertThat(BrightnessUtils.convertGammaToLinear(GAMMA_SPACE_MIN, MIN_INT, MAX_INT))

                .isEqualTo(MIN_INT);

        assertThat(BrightnessUtils.convertGammaToLinearFloat(GAMMA_SPACE_MIN, MIN_FLOAT, MAX_FLOAT))

                .isEqualTo(MIN_FLOAT);

    }



    @Test

    public void gammaToLinear_gammaSpaceValue_shouldReturnMax() {

        assertThat(BrightnessUtils.convertGammaToLinear(GAMMA_SPACE_MAX, MIN, MAX)).isEqualTo(MAX);

        assertThat(BrightnessUtils.convertGammaToLinear(GAMMA_SPACE_MAX, MIN_INT, MAX_INT))

                .isEqualTo(MAX_INT);

        assertThat(BrightnessUtils.convertGammaToLinearFloat(GAMMA_SPACE_MAX, MIN_FLOAT, MAX_FLOAT))

                .isEqualTo(MAX_FLOAT);

    }

}