iOS 画平滑曲线的方法及取音频数据的方法

源码：http://files.cnblogs.com/ios8/iOS%E5%BF%83%E7%94%B5%E5%9B%BEDemo.zip

取音频数据和画波形图的方法

ViewController.h

//
//  ViewController.h
//  iOS心电图Demo
//
//  Created by 杜甲 on 13-10-18.
//  Copyright (c) 2013年 杜甲. All rights reserved.
//

#import <UIKit/UIKit.h>
#import "HLSonogramView.h"
@interface ViewController : UIViewController
@property (strong, nonatomic) HLSonogramView* hlSonogramView;

@end

ViewController.m

//
//  ViewController.m
//  iOS心电图Demo
//
//  Created by 杜甲 on 13-10-18.
//  Copyright (c) 2013年 杜甲. All rights reserved.
//

#import "ViewController.h"

@interface ViewController ()

@end

@implementation ViewController

- (void)viewDidLoad
{
    [super viewDidLoad];
    // Do any additional setup after loading the view, typically from a nib.

    self.hlSonogramView = [[HLSonogramView alloc] initWithFrame:CGRectMake(0, 0, 320, 480)];


    [self.view addSubview:self.hlSonogramView];
}

- (void)didReceiveMemoryWarning
{
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}

@end

HLSonogramView.h

//
//  HLSonogramView.h
//  iOS心电图Demo
//
//  Created by 杜甲 on 13-10-18.
//  Copyright (c) 2013年 杜甲. All rights reserved.
//

#import <UIKit/UIKit.h>
#define kMaxKeyPoints  1000
#define kHillSegmentWidth 10

struct ret_value
{
    unsigned charchar *data;//注意这里是unsigned char
    unsigned long int size;
};

@interface HLSonogramView : UIView
{
     CGPoint m_pSonogramKeyPoint[kMaxKeyPoints];
}
@property (assign ,nonatomic) float m_pOffsetX;
@property (assign ,nonatomic) int m_pSonogramKeyPointNum;
//转换后的座标数据，用于绘制波形图
@property (nonatomic, strong) NSMutableArray *m_pointWavArray;
@end

HLSonogramView.m

//
//  HLSonogramView.m
//  iOS心电图Demo
//
//  Created by 杜甲 on 13-10-18.
//  Copyright (c) 2013年 杜甲. All rights reserved.
//

#import "HLSonogramView.h"
#define ScreenHeight [[UIScreen mainScreen] bounds].size.height
#define ScreenWidth [[UIScreen mainScreen] bounds].size.width
@implementation HLSonogramView

- (id)initWithFrame:(CGRect)frame
{
    self = [super initWithFrame:frame];
    if (self) {
        // Initialization code
        self.backgroundColor = [UIColor whiteColor];
        [self generatePoint];
    }
    return self;
}

-(void)drawRect:(CGRect)rect
{
    [super drawRect:rect];
    CGContextRef context = UIGraphicsGetCurrentContext();
    CGContextSetLineCap(context, kCGLineCapSquare);
    CGContextSetLineWidth(context, 1.0);
    CGContextSetRGBStrokeColor(context, 1.0, 0.0, 0.0, 1.0);
    CGContextBeginPath(context);
    CGContextMoveToPoint(context, 0, ScreenHeight / 2);
    for (int i = 1; i < kMaxKeyPoints; i++) {

        CGPoint p0 = m_pSonogramKeyPoint[i - 1];
        CGPoint p1 = m_pSonogramKeyPoint[i];

        int hSegments = floorf((p1.x - p0.x) / kHillSegmentWidth);
        float dx = (p1.x - p0.x) / hSegments;
        float da = M_PI / hSegments;
        float ymid = (p0.y + p1.y) / 2;
        float ampl = (p0.y - p1.y) / 2;


        CGPoint pt0,pt1;
        pt0 = p0;
        for (int j = 0; j < hSegments + 1; ++j) {
            pt1.x = p0.x + j * dx;
            pt1.y = ymid + ampl * cosf(da * j);
            CGContextAddLineToPoint(context, pt0.x, pt0.y);
            CGContextAddLineToPoint(context, pt1.x, pt1.y);
            pt0 = pt1;
        }
    }
    CGContextStrokePath(context);
}

-(void)generatePoint
{
    float m_pWinHeight = ScreenHeight;
    float m_pWinWidth  = ScreenWidth;


    float x  = 0;
    float y = m_pWinHeight / 2;

    for (int i = 0; i < kMaxKeyPoints; ++i) {
        m_pSonogramKeyPoint[i] = CGPointMake(x, y);
        x += m_pWinWidth / 2;
        y = rand() % (int)m_pWinHeight;
    }
}
//取音频数据
- (void)transformDateOFWavFromFile
{
    NSString *path = [[NSBundle mainBundle] pathForResource:@"1" ofType:@"wav"];
    struct ret_value ret;
    load_wave_file([path UTF8String], &ret);
    //  printf("data.size = %lu
", ret.size);

    int d = ret.size / 2;
    short int wave_data[d];
    for(long i=0; i<d; i++)
    {
        short int w = (ret.data[i*2+1]<<8) | ret.data[i*2];
        //printf("%d
", w);
        wave_data[i] = w;
    }

    int myLineSize = d;

    //--添加成员变量-方便外部调用----
    CGPoint myLines[myLineSize];
    self.m_pointWavArray = [NSMutableArray arrayWithCapacity:8];

    //for(int i=0;i<myLineSize;i++)
    //{
    //    myLines[i]=CGPointMake(10+i, [self getRandomNumber:200 to:400]);
    //}
    //    for (int i = 0; i < d; i++) {
    //        NSLog(@"wave_data[i] = %hd",wave_data[i]);
    //    }

    for (int i = 0; i < d ; i++) {
        float x = 11 * i;
        float y = 47.75 + wave_data[i] / 1000;
        if (y < 5) {
            y = 5;
        }
        if (y > 92.5) {
            y = 92.5;
        }
        myLines[i] = CGPointMake(x, y);
        NSValue *pValue = [NSValue valueWithCGPoint:myLines[i]];
        [self.m_pointWavArray addObject:pValue];
    }

    //    for(int i=0;i<d;i++)
    //    {
    //        float x = 10.0 + i * 300.0 / d;
    //        float y = 85+ 200.0 * wave_data[i] / 12767.0 ;
    //       // printf("x=%f, y=%f
", x, y);
    //        myLines[i] = CGPointMake(x, y);
    //
    //        //---存放到波形图的点数组中----------------
    //        NSValue *pValue = [NSValue valueWithCGPoint:myLines[i]];
    //        [self.m_pointWavArray addObject:pValue];
    //    }
    NSLog(@"%@",self.m_pointWavArray);

}

void load_wave_file(const charchar *fname, struct ret_value *ret)
{
    NSLog(@"%s: %d", __func__, __LINE__);

    FILEFILE *fp;
    fp = fopen(fname, "rb");
    if(fp)
    {
        char id[5];
        unsigned long size;
        short format_tag, channels, block_align, bits_per_sample;//16 bit data
        unsigned long format_length, sample_rate, avg_bytes_sec, data_size;//32 bit data

        fread(id, sizeof(char), 4, fp);
        id[4]='';
        if (!strcmp(id, "RIFF"))
        {
            fread(&size, sizeof(unsigned long), 1, fp);//read file size
            fread(id, sizeof(char), 4, fp);//read wave
            id[4]='';

            if (!strcmp(id, "WAVE"))
            {
                fread(id, sizeof(char), 4, fp);//读取4字节"fmt"
                fread(&format_length, sizeof(unsigned long), 1, fp);
                fread(&format_tag, sizeof(short), 1, fp);//读取文件tag
                fread(&channels, sizeof(short), 1, fp);//读取通道数目
                fread(&sample_rate, sizeof(unsigned long), 1, fp);//读取采样率大小
                fread(&avg_bytes_sec, sizeof(unsigned long), 1, fp);//读取每秒数据量
                fread(&block_align, sizeof(short), 1, fp);//读取块对齐
                fread(&bits_per_sample, sizeof(short), 1, fp);//读取每一样本大小
                fread(id, sizeof(char), 4, fp);//读取data
                fread(&data_size, sizeof(unsigned long), 1, fp);
                ret->size = data_size;
                ret->data = (unsigned charchar *)malloc(sizeof(char)*data_size);//申请内存空间
                fread(ret->data, sizeof(char), data_size, fp);//读取数据

                printf("bits_per_sample = %d
", bits_per_sample);
                printf("channels = %d
", channels);
                printf("sample_rate = %lu
", sample_rate);
            }else{
                printf("Error: RIFF file but not a wave file
");
            }
        }else{
            printf("Error: not a RIFF file
");
        }
        fclose(fp);
    }
}

@end