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 VUMeter(Context context)42 public VUMeter(Context context) { 43 super(context); 44 init(context); 45 } 46 VUMeter(Context context, AttributeSet attrs)47 public VUMeter(Context context, AttributeSet attrs) { 48 super(context, attrs); 49 init(context); 50 } 51 init(Context context)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 setRecorder(Recorder recorder)66 public void setRecorder(Recorder recorder) { 67 mRecorder = recorder; 68 invalidate(); 69 } 70 71 @Override onDraw(Canvas canvas)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