content: /*
   * Copyright 2022 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 com.google.android.exoplayer2.effect;
  
  import static com.google.android.exoplayer2.util.Assertions.checkArgument;
  
  import android.content.Context;
  import com.google.android.exoplayer2.util.FrameProcessingException;
  
  /** A {@link GlEffect} to control the contrast of video frames. */
  public class Contrast implements GlEffect {
  
    /** Adjusts the contrast of video frames in the interval [-1, 1]. */
    public final float contrast;
  
    /**
     * Creates a new instance for the given contrast value.
     *
     * <p>Contrast values range from -1 (all gray pixels) to 1 (maximum difference of colors). 0 means
     * to add no contrast and leaves the frames unchanged.
     */
    public Contrast(float contrast) {
      checkArgument(-1 <= contrast && contrast <= 1, "Contrast needs to be in the interval [-1, 1].");
      this.contrast = contrast;
    }
  
    @Override
    public SingleFrameGlTextureProcessor toGlTextureProcessor(Context context, boolean useHdr)
        throws FrameProcessingException {
      return new ContrastProcessor(context, this, useHdr);
    }
  }
  