tests/tests/graphics/src/android/graphics/cts/ColorMatrixColorFilterTest.java

/*
 * Copyright (C) 2009 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package android.graphics.cts;

import static org.junit.Assert.assertArrayEquals;
import static org.junit.Assert.assertEquals;

import android.graphics.Bitmap;
import android.graphics.Bitmap.Config;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.ColorMatrix;
import android.graphics.ColorMatrixColorFilter;
import android.graphics.Paint;

import androidx.test.filters.SmallTest;
import androidx.test.runner.AndroidJUnit4;

import com.android.compatibility.common.util.ColorUtils;

import org.junit.Test;
import org.junit.runner.RunWith;

@SmallTest
@RunWith(AndroidJUnit4.class)
public class ColorMatrixColorFilterTest {

    @Test
    public void testColorMatrixColorFilter() {
        ColorMatrixColorFilter filter;

        ColorMatrix cm = new ColorMatrix();
        float[] blueToCyan = new float[] {
                1f, 0f, 0f, 0f, 0f,
                0f, 1f, 1f, 0f, 0f,
                0f, 0f, 1f, 0f, 0f,
                0f, 0f, 0f, 1f, 0f };
        cm.set(blueToCyan);
        filter = new ColorMatrixColorFilter(cm);
        Bitmap bitmap = Bitmap.createBitmap(1, 1, Config.ARGB_8888);
        Canvas canvas = new Canvas(bitmap);
        Paint paint = new Paint();
        paint.setColor(Color.BLUE);
        paint.setColorFilter(filter);
        canvas.drawPoint(0, 0, paint);
        ColorUtils.verifyColor(Color.CYAN, bitmap.getPixel(0, 0));
        paint.setColor(Color.GREEN);
        canvas.drawPoint(0, 0, paint);
        ColorUtils.verifyColor(Color.GREEN, bitmap.getPixel(0, 0));
        paint.setColor(Color.RED);
        canvas.drawPoint(0, 0, paint);
        ColorUtils.verifyColor(Color.RED, bitmap.getPixel(0, 0));
        // color components are clipped, not scaled
        paint.setColor(Color.MAGENTA);
        canvas.drawPoint(0, 0, paint);
        ColorUtils.verifyColor(Color.WHITE, bitmap.getPixel(0, 0));

        float[] transparentRedAddBlue = new float[] {
                1f, 0f, 0f, 0f, 0f,
                0f, 1f, 0f, 0f, 0f,
                0f, 0f, 1f, 0f, 64f,
                -0.5f, 0f, 0f, 1f, 0f
        };
        filter = new ColorMatrixColorFilter(transparentRedAddBlue);
        paint.setColorFilter(filter);
        paint.setColor(Color.RED);
        bitmap.eraseColor(Color.TRANSPARENT);
        canvas.drawPoint(0, 0, paint);
        // the bitmap stores the result in premul colors and we read out an
        // unpremultiplied result, which causes us to need a bigger tolerance in
        // this case (due to the fact that scaling by 1/255 is not exact).
        ColorUtils.verifyColor(Color.argb(128, 255, 0, 64), bitmap.getPixel(0, 0), 2);
        paint.setColor(Color.CYAN);
        canvas.drawPoint(0, 0, paint);
        // blue gets clipped
        ColorUtils.verifyColor(Color.CYAN, bitmap.getPixel(0, 0));

        // change array to filter out green
        assertEquals(1f, transparentRedAddBlue[6], 0.0f);
        transparentRedAddBlue[6] = 0f;
        // changing the array has no effect
        canvas.drawPoint(0, 0, paint);
        ColorUtils.verifyColor(Color.CYAN, bitmap.getPixel(0, 0));
        // create a new filter with the changed matrix
        paint.setColorFilter(new ColorMatrixColorFilter(transparentRedAddBlue));
        canvas.drawPoint(0, 0, paint);
        ColorUtils.verifyColor(Color.BLUE, bitmap.getPixel(0, 0));
    }

    @Test
    public void testGetColorMatrix() {
        ColorMatrixColorFilter filter = new ColorMatrixColorFilter(new ColorMatrix());
        ColorMatrix getMatrix = new ColorMatrix();

        filter.getColorMatrix(getMatrix);
        assertEquals(new ColorMatrix(), getMatrix);

        ColorMatrix scaleTranslate = new ColorMatrix(new float[] {
                1, 0, 0, 0, 8,
                0, 2, 0, 0, 7,
                0, 0, 3, 0, 6,
                0, 0, 0, 4, 5
        });

        filter = new ColorMatrixColorFilter(scaleTranslate);
        filter.getColorMatrix(getMatrix);
        assertEquals(scaleTranslate, getMatrix);
        assertArrayEquals(scaleTranslate.getArray(), getMatrix.getArray(), 0);
    }
}