[置顶] 图片压缩到指定大小范围内KB、MB

- (void)viewDidLoad {

[superviewDidLoad];
// Do any additional setup after loading the view, typically from a nib.
UIImageView *imgView = [[UIImageViewalloc]initWithFrame:CGRectMake(10,30, 300,415)];
imgView.backgroundColor = [UIColoryellowColor];
imgView.image = [UIImageimageNamed:@"1.jpg"];
[self.viewaddSubview:imgView];
//图像压缩
UIImage *image = [selfscaleFromImage:imgView.image];
//保存图像
NSString *strFileName = [selfsaveImage:image];
imgView.image = image;
NSLog(@"图片保存路径:%@",strFileName);
}

//==========================
// 图像压缩
//==========================
- (UIImage *)scaleFromImage:(UIImage *)image
{
if (!image)
{
returnnil;
}
NSData *data =UIImagePNGRepresentation(image);
CGFloat dataSize = data.length/1024;
CGFloat width  = image.size.width;
CGFloat height = image.size.height;
CGSize size;

if (dataSize<=50)//小于50k
{
return image;
}
elseif (dataSize<=100)//小于100k
{
size = CGSizeMake(width/1.f, height/1.f);
}
elseif (dataSize<=200)//小于200k
{
size = CGSizeMake(width/2.f, height/2.f);
}
elseif (dataSize<=500)//小于500k
{
size = CGSizeMake(width/2.f, height/2.f);
}
elseif (dataSize<=1000)//小于1M
{
size = CGSizeMake(width/2.f, height/2.f);
}
elseif (dataSize<=2000)//小于2M
{
size = CGSizeMake(width/2.f, height/2.f);
}
else//大于2M
{
size = CGSizeMake(width/2.f, height/2.f);
}
NSLog(@"%f,%f",size.width,size.height);
UIGraphicsBeginImageContext(size);
[image drawInRect:CGRectMake(0,0, size.width, size.height)];
UIImage *newImage =UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
if (!newImage)
{
return image;
}
return newImage;
}

//===============
// 保存图像
//===============
- (NSString *)saveImage:(UIImage*)image
{
NSData *data;
if (UIImagePNGRepresentation(image) ==nil)
{
data = UIImageJPEGRepresentation(image, 1.0);
}
else
{
data = UIImagePNGRepresentation(image);
}

//图片保存的路径
//这里将图片放在沙盒的documents文件夹中
NSString * DocumentsPath = [NSHomeDirectory()stringByAppendingPathComponent:@"Documents"];
//文件管理器
NSFileManager *fileManager = [NSFileManagerdefaultManager];
//把刚刚图片转换的data对象拷贝至沙盒中并保存为image.png
[fileManager createDirectoryAtPath:DocumentsPath withIntermediateDirectories:YESattributes:nilerror:nil];
[fileManager createFileAtPath:[DocumentsPath stringByAppendingString:@"/image.png"]contents:data attributes:nil];

//得到选择后沙盒中图片的完整路径
NSString *filePath = [[NSStringalloc]initWithFormat:@"%@%@",DocumentsPath, @"/image.png"];
return filePath;
}