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      1 /*
      2  * Copyright (C) 2011 The Android Open Source Project
      3  *
      4  * Licensed under the Apache License, Version 2.0 (the "License");
      5  * you may not use this file except in compliance with the License.
      6  * You may obtain a copy of the License at
      7  *
      8  *      http://www.apache.org/licenses/LICENSE-2.0
      9  *
     10  * Unless required by applicable law or agreed to in writing, software
     11  * distributed under the License is distributed on an "AS IS" BASIS,
     12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     13  * See the License for the specific language governing permissions and
     14  * limitations under the License.
     15  */
     16 
     17 package com.android.soundrecorder;
     18 
     19 import java.util.Map;
     20 
     21 import android.content.Context;
     22 import android.graphics.Canvas;
     23 import android.graphics.Color;
     24 import android.graphics.Paint;
     25 import android.graphics.drawable.Drawable;
     26 import android.util.AttributeSet;
     27 import android.view.View;
     28 
     29 public class VUMeter extends View {
     30     static final float PIVOT_RADIUS = 3.5f;
     31     static final float PIVOT_Y_OFFSET = 10f;
     32     static final float SHADOW_OFFSET = 2.0f;
     33     static final float DROPOFF_STEP = 0.18f;
     34     static final float SURGE_STEP = 0.35f;
     35     static final long  ANIMATION_INTERVAL = 70;
     36 
     37     Paint mPaint, mShadow;
     38     float mCurrentAngle;
     39 
     40     Recorder mRecorder;
     41 
     42     public VUMeter(Context context) {
     43         super(context);
     44         init(context);
     45     }
     46 
     47     public VUMeter(Context context, AttributeSet attrs) {
     48         super(context, attrs);
     49         init(context);
     50     }
     51 
     52     void init(Context context) {
     53         Drawable background = context.getResources().getDrawable(R.drawable.vumeter);
     54         setBackgroundDrawable(background);
     55 
     56         mPaint = new Paint(Paint.ANTI_ALIAS_FLAG);
     57         mPaint.setColor(Color.WHITE);
     58         mShadow = new Paint(Paint.ANTI_ALIAS_FLAG);
     59         mShadow.setColor(Color.argb(60, 0, 0, 0));
     60 
     61         mRecorder = null;
     62 
     63         mCurrentAngle = 0;
     64     }
     65 
     66     public void setRecorder(Recorder recorder) {
     67     	mRecorder = recorder;
     68     	invalidate();
     69     }
     70 
     71     @Override
     72     protected void onDraw(Canvas canvas) {
     73         super.onDraw(canvas);
     74 
     75         final float minAngle = (float)Math.PI/8;
     76         final float maxAngle = (float)Math.PI*7/8;
     77 
     78         float angle = minAngle;
     79         if (mRecorder != null)
     80         	angle += (float)(maxAngle - minAngle)*mRecorder.getMaxAmplitude()/32768;
     81 
     82         if (angle > mCurrentAngle)
     83             mCurrentAngle = angle;
     84         else
     85             mCurrentAngle = Math.max(angle, mCurrentAngle - DROPOFF_STEP);
     86 
     87         mCurrentAngle = Math.min(maxAngle, mCurrentAngle);
     88 
     89         float w = getWidth();
     90         float h = getHeight();
     91         float pivotX = w/2;
     92         float pivotY = h - PIVOT_RADIUS - PIVOT_Y_OFFSET;
     93         float l = h*4/5;
     94         float sin = (float) Math.sin(mCurrentAngle);
     95         float cos = (float) Math.cos(mCurrentAngle);
     96         float x0 = pivotX - l*cos;
     97         float y0 = pivotY - l*sin;
     98         canvas.drawLine(x0 + SHADOW_OFFSET, y0 + SHADOW_OFFSET, pivotX + SHADOW_OFFSET, pivotY + SHADOW_OFFSET, mShadow);
     99         canvas.drawCircle(pivotX + SHADOW_OFFSET, pivotY + SHADOW_OFFSET, PIVOT_RADIUS, mShadow);
    100         canvas.drawLine(x0, y0, pivotX, pivotY, mPaint);
    101         canvas.drawCircle(pivotX, pivotY, PIVOT_RADIUS, mPaint);
    102 
    103         if (mRecorder != null && mRecorder.state() == Recorder.RECORDING_STATE)
    104         	postInvalidateDelayed(ANIMATION_INTERVAL);
    105     }
    106 }
    107