Android Open Source - yammp Visualizer View Fft Spectrum

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License

The source code is released under:
GNU Lesser General Public License
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Java Source Code

/*
 *              Copyright (C) 2011 The MusicMod Project
 *//  w  w w .  j  a va2 s.  c o m
 * 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 org.yammp.view;

import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.Rect;
import android.util.AttributeSet;
import android.view.View;

public class VisualizerViewFftSpectrum extends View {

  // Namespaces to read attributes
  private static final String VISUALIZER_NS = "http://schemas.android.com/apk/res/org.yammp";

  // Attribute names
  private static final String ATTR_ANTIALIAS = "antialias";
  private static final String ATTR_COLOR = "color";

  // Default values for defaults
  private static final boolean DEFAULT_ANTIALIAS = true;
  private static final int DEFAULT_COLOR = Color.WHITE;

  // Real defaults
  private final boolean mAntiAlias;
  private final int mColor;
  private int mFftSamples = 48;

  private byte[] mData = null;
  private float[] mPoints;
  private Rect mRect = new Rect();
  private Paint mForePaint = new Paint();

  public VisualizerViewFftSpectrum(Context context) {
    super(context);

    mAntiAlias = DEFAULT_ANTIALIAS;
    mColor = DEFAULT_COLOR;
    mForePaint.setStrokeWidth((float) getWidth() / (float) mFftSamples / 2.0f);
    setAntiAlias(mAntiAlias);
    setColor(mColor);
  }

  public VisualizerViewFftSpectrum(Context context, AttributeSet attrs) {
    super(context, attrs);

    mAntiAlias = attrs.getAttributeBooleanValue(VISUALIZER_NS, ATTR_ANTIALIAS,
        DEFAULT_ANTIALIAS);
    mColor = attrs.getAttributeIntValue(VISUALIZER_NS, ATTR_COLOR, DEFAULT_COLOR);
    mForePaint.setStrokeWidth((float) getWidth() / (float) mFftSamples / 2.0f);
    setAntiAlias(mAntiAlias);
    setColor(mColor);
  }

  public void setAntiAlias(boolean antialias) {
    mForePaint.setAntiAlias(antialias);
  }

  public void setColor(int color) {
    mForePaint.setColor(Color.argb(0xA0, Color.red(color), Color.green(color),
        Color.blue(color)));
  }

  public void setFftSamples(int samples) {
    mFftSamples = samples;
    mForePaint.setStrokeWidth((float) getWidth() / (float) samples / 2.0f);
    mPoints = null;
  }

  public void updateVisualizer(byte[] data) {
    byte[] model = new byte[data.length / 2 + 1];
    int j = 0;
    for (int i = 0; i <= mFftSamples * 2; i += 2) {
      model[j] = (byte) Math.hypot(data[i], data[i + 1]);
      j++;
    }
    mData = model;
    invalidate();
  }

  @Override
  protected void onDraw(Canvas canvas) {
    super.onDraw(canvas);

    if (mData == null) return;

    if (mPoints == null || mPoints.length < mData.length * 4) {
      mPoints = new float[mData.length * 4];
    }
    mRect.set(0, 0, getWidth(), getHeight() * 2);

    for (int i = 0; i <= mFftSamples; i++) {
      if (mData[i] < 0) {
        mData[i] = 127;
      }
      mPoints[i * 4] = mRect.width() * i / mFftSamples + getWidth() / mFftSamples / 2.0f;
      mPoints[i * 4 + 1] = mRect.height() / 2;
      mPoints[i * 4 + 2] = mRect.width() * i / mFftSamples + getWidth() / mFftSamples / 2.0f;
      mPoints[i * 4 + 3] = mRect.height() / 2 - 2 - mData[i] * 2;
    }
    canvas.drawLines(mPoints, mForePaint);

  }

  @Override
  protected void onSizeChanged(int width, int height, int old_width, int old_height) {
    mForePaint.setStrokeWidth((float) width / (float) mFftSamples / 2.0f);
  }
}
Java Source Code List
