系统自带UIImagePickerController的用法
调用方式
代码语言：javascript复制UIImagePickerControllerSourceType sourceType = UIImagePickerControllerSourceTypeCamera;
//sourceType = UIImagePickerControllerSourceTypeCamera; //照相机
//sourceType = UIImagePickerControllerSourceTypePhotoLibrary; //图片库
//sourceType = UIImagePickerControllerSourceTypeSavedPhotosAlbum; //保存的相片
if(self.picker == nil){
self.picker = [[UIImagePickerController alloc] init];//初始化
self.picker.delegate = self;
self.picker.allowsEditing = NO;//设置可编辑
self.picker.sourceType = sourceType;
}
[self presentViewController:self.picker animated:true completion:nil];回调
代码语言：javascript复制//当选择一张图片后进入这里
-(void)imagePickerController:(UIImagePickerController*)picker didFinishPickingMediaWithInfo:(NSDictionary *)info{
NSString *type = [info objectForKey:UIImagePickerControllerMediaType];
//当选择的类型是图片
if ([type isEqualToString:@"public.image"]){
//先把图片转成NSData
UIImage* image = [info objectForKey:@"UIImagePickerControllerOriginalImage"];
image = [self fixOrientation:image];
NSData *data;
data = UIImageJPEGRepresentation(image, 0.5);
NSString * md5Str = [data MD5HexDigest];
//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"];
NSString * fileName = [NSString stringWithFormat:@"%@.jpg",md5Str];
//得到选择后沙盒中图片的完整路径
_filePath = [[NSString alloc]initWithFormat:@"%@/%@",DocumentsPath,fileName];
//文件管理器
NSFileManager *fileManager = [NSFileManager defaultManager];
//把刚刚图片转换的data对象拷贝至沙盒中 并保存为image.jpg
[fileManager createDirectoryAtPath:DocumentsPath withIntermediateDirectories:YES attributes:nil error:nil];
[fileManager createFileAtPath:_filePath contents:data attributes:nil];
NSLog(@"文件的路径为：%@",_filePath);
}
}
- (void)imagePickerControllerDidCancel:(UIImagePickerController *)picker
{
NSLog(@"您取消了选择图片");
[self.picker dismissViewControllerAnimated:true completion:^{
}];
}拍照后的图片90度旋转的解决方法
代码语言：javascript复制-(UIImage *)fixOrientation:(UIImage *)aImage {
// No-op if the orientation is already correct
if (aImage.imageOrientation == UIImageOrientationUp)
return aImage;
// We need to calculate the proper transformation to make the image upright.
// We do it in 2 steps: Rotate if Left/Right/Down, and then flip if Mirrored.
CGAffineTransform transform = CGAffineTransformIdentity;
switch (aImage.imageOrientation) {
case UIImageOrientationDown:
case UIImageOrientationDownMirrored:
transform = CGAffineTransformTranslate(transform, aImage.size.width, aImage.size.height);
transform = CGAffineTransformRotate(transform, M_PI);
break;
case UIImageOrientationLeft:
case UIImageOrientationLeftMirrored:
transform = CGAffineTransformTranslate(transform, aImage.size.width, 0);
transform = CGAffineTransformRotate(transform, M_PI_2);
break;
case UIImageOrientationRight:
case UIImageOrientationRightMirrored:
transform = CGAffineTransformTranslate(transform, 0, aImage.size.height);
transform = CGAffineTransformRotate(transform, -M_PI_2);
break;
default:
break;
}
switch (aImage.imageOrientation) {
case UIImageOrientationUpMirrored:
case UIImageOrientationDownMirrored:
transform = CGAffineTransformTranslate(transform, aImage.size.width, 0);
transform = CGAffineTransformScale(transform, -1, 1);
break;
case UIImageOrientationLeftMirrored:
case UIImageOrientationRightMirrored:
transform = CGAffineTransformTranslate(transform, aImage.size.height, 0);
transform = CGAffineTransformScale(transform, -1, 1);
break;
default:
break;
}
// Now we draw the underlying CGImage into a new context, applying the transform
// calculated above.
CGContextRef ctx = CGBitmapContextCreate(NULL, aImage.size.width, aImage.size.height,
CGImageGetBitsPerComponent(aImage.CGImage), 0,
CGImageGetColorSpace(aImage.CGImage),
CGImageGetBitmapInfo(aImage.CGImage));
CGContextConcatCTM(ctx, transform);
switch (aImage.imageOrientation) {
case UIImageOrientationLeft:
case UIImageOrientationLeftMirrored:
case UIImageOrientationRight:
case UIImageOrientationRightMirrored:
CGContextDrawImage(ctx, CGRectMake(0,0,aImage.size.height,aImage.size.width), aImage.CGImage);
break;
default:
CGContextDrawImage(ctx, CGRectMake(0,0,aImage.size.width,aImage.size.height), aImage.CGImage);
break;
}
// And now we just create a new UIImage from the drawing context
CGImageRef cgimg = CGBitmapContextCreateImage(ctx);
UIImage *img = [UIImage imageWithCGImage:cgimg];
CGContextRelease(ctx);
CGImageRelease(cgimg);
return img;
}自定义相机拍照视图
定义变量
代码语言：javascript复制//捕获设备，通常是前置摄像头，后置摄像头，麦克风（音频输入）
@property (nonatomic, strong) AVCaptureDevice *device;
//AVCaptureDeviceInput 代表输入设备，他使用AVCaptureDevice 来初始化
@property (nonatomic, strong) AVCaptureDeviceInput *input;
//输出图片
@property (nonatomic ,strong) AVCaptureStillImageOutput *imageOutput;
//session：由他把输入输出结合在一起，并开始启动捕获设备（摄像头）
@property (nonatomic, strong) AVCaptureSession *session;
//图像预览层，实时显示捕获的图像
@property (nonatomic ,strong) AVCaptureVideoPreviewLayer *previewLayer;
@property (weak, nonatomic) IBOutlet UIView *previewView;
@property (weak, nonatomic) IBOutlet UIImageView *showImageView;设置相机
代码语言：javascript复制- (void)cameraDistrict{
// AVCaptureDevicePositionBack 后置摄像头
// AVCaptureDevicePositionFront 前置摄像头
self.device = [self cameraWithPosition:AVCaptureDevicePositionBack];
self.input = [[AVCaptureDeviceInput alloc] initWithDevice:self.device error:nil];
self.imageOutput = [[AVCaptureStillImageOutput alloc] init];
self.session = [[AVCaptureSession alloc] init];
// 拿到的图像的大小可以自行设定
// AVCaptureSessionPreset320x240
// AVCaptureSessionPreset352x288
// AVCaptureSessionPreset640x480
// AVCaptureSessionPreset960x540
// AVCaptureSessionPreset1280x720
// AVCaptureSessionPreset1920x1080
// AVCaptureSessionPreset3840x2160
self.session.sessionPreset = AVCaptureSessionPreset640x480;
//输入输出设备结合
if ([self.session canAddInput:self.input]) {
[self.session addInput:self.input];
}
if ([self.session canAddOutput:self.imageOutput]) {
[self.session addOutput:self.imageOutput];
}
//预览层的生成
self.previewLayer = [[AVCaptureVideoPreviewLayer alloc] initWithSession:self.session];
self.previewLayer.frame = self.previewView.frame;
self.previewLayer.videoGravity = AVLayerVideoGravityResizeAspectFill;
[self.previewView.layer addSublayer:self.previewLayer];
//设备取景开始
[self.session startRunning];
if ([_device lockForConfiguration:nil]) {
//自动闪光灯，
if ([_device isFlashModeSupported:AVCaptureFlashModeAuto]) {
[_device setFlashMode:AVCaptureFlashModeAuto];
}
//自动白平衡,但是好像一直都进不去
if ([_device isWhiteBalanceModeSupported:AVCaptureWhiteBalanceModeAutoWhiteBalance]) {
[_device setWhiteBalanceMode:AVCaptureWhiteBalanceModeAutoWhiteBalance];
}
[_device unlockForConfiguration];
}
}
- (AVCaptureDevice *)cameraWithPosition:(AVCaptureDevicePosition)position{
NSArray *devices = [AVCaptureDevice devicesWithMediaType:AVMediaTypeVideo];
for ( AVCaptureDevice *device in devices )
if ( device.position == position ){
return device;
}
return nil;
}获取相机图片
代码语言：javascript复制- (void)photoBtnDidClick{
AVCaptureConnection *conntion = [self.imageOutput connectionWithMediaType:AVMediaTypeVideo];
if (!conntion) {
NSLog(@"拍照失败!");
return;
}
[self.imageOutput captureStillImageAsynchronouslyFromConnection:conntion completionHandler:^(CMSampleBufferRef imageDataSampleBuffer, NSError *error) {
if (imageDataSampleBuffer == nil) {
return ;
}
NSData *imageData = [AVCaptureStillImageOutput jpegStillImageNSDataRepresentation:imageDataSampleBuffer];
self.showImageView.image = [UIImage imageWithData:imageData];
self.showImageView.hidden = false;
[self.session stopRunning];
}];
}保存照片到相册
代码语言：javascript复制#pragma - 保存至相册
- (void)saveImageToPhotoAlbum:(UIImage*)savedImage{
UIImageWriteToSavedPhotosAlbum(savedImage, self, @selector(image:didFinishSavingWithError:contextInfo:), NULL);
}
// 指定回调方法
- (void)image: (UIImage *) image didFinishSavingWithError: (NSError *) error contextInfo: (void *) contextInfo{
NSString *msg = nil ;
if(error != NULL){
msg = @"保存图片失败" ;
}else{
msg = @"保存图片成功" ;
}
UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"保存图片结果提示"
message:msg
delegate:self
cancelButtonTitle:@"确定"
otherButtonTitles:nil];
[alert show];
}前后置摄像头的切换
代码语言：javascript复制- (void)changeCamera{
NSUInteger cameraCount = [[AVCaptureDevice devicesWithMediaType:AVMediaTypeVideo] count];
if (cameraCount > 1) {
NSError *error;
//给摄像头的切换添加翻转动画
CATransition *animation = [CATransition animation];
animation.duration = .5f;
animation.timingFunction = [CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionEaseInEaseOut];
animation.type = @"oglFlip";
AVCaptureDevice *newCamera = nil;
AVCaptureDeviceInput *newInput = nil;
//拿到另外一个摄像头位置
AVCaptureDevicePosition position = [[_input device] position];
if (position == AVCaptureDevicePositionFront){
newCamera = [self cameraWithPosition:AVCaptureDevicePositionBack];
animation.subtype = kCATransitionFromLeft;//动画翻转方向
}
else {
newCamera = [self cameraWithPosition:AVCaptureDevicePositionFront];
animation.subtype = kCATransitionFromRight;//动画翻转方向
}
//生成新的输入
newInput = [AVCaptureDeviceInput deviceInputWithDevice:newCamera error:nil];
[self.previewLayer addAnimation:animation forKey:nil];
if (newInput != nil) {
[self.session beginConfiguration];
[self.session removeInput:self.input];
if ([self.session canAddInput:newInput]) {
[self.session addInput:newInput];
self.input = newInput;
} else {
[self.session addInput:self.input];
}
[self.session commitConfiguration];
} else if (error) {
NSLog(@"toggle carema failed, error = %@", error);
}
}
}对焦设置
代码语言：javascript复制//AVCaptureFlashMode 闪光灯
//AVCaptureFocusMode 对焦
//AVCaptureExposureMode 曝光
//AVCaptureWhiteBalanceMode 白平衡
//闪光灯和白平衡可以在生成相机时候设置
//曝光要根据对焦点的光线状况而决定,所以和对焦一块写
//point为点击的位置
- (void)focusAtPoint:(CGPoint)point{
CGSize size = self.view.bounds.size;
CGPoint focusPoint = CGPointMake( point.y /size.height ,1-point.x/size.width );
NSError *error;
if ([self.device lockForConfiguration:&error]) {
//对焦模式和对焦点
if ([self.device isFocusModeSupported:AVCaptureFocusModeAutoFocus]) {
[self.device setFocusPointOfInterest:focusPoint];
[self.device setFocusMode:AVCaptureFocusModeAutoFocus];
}
//曝光模式和曝光点
if ([self.device isExposureModeSupported:AVCaptureExposureModeAutoExpose ]) {
[self.device setExposurePointOfInterest:focusPoint];
[self.device setExposureMode:AVCaptureExposureModeAutoExpose];
}
[self.device unlockForConfiguration];
//设置对焦动画
// _focusView.center = point;
// _focusView.hidden = NO;
// [UIView animateWithDuration:0.3 animations:^{
// _focusView.transform = CGAffineTransformMakeScale(1.25, 1.25);
// }completion:^(BOOL finished) {
// [UIView animateWithDuration:0.5 animations:^{
// _focusView.transform = CGAffineTransformIdentity;
// } completion:^(BOOL finished) {
// _focusView.hidden = YES;
// }];
// }];
}
}遇到的一些坑和解决办法
前后置摄像头的切换
前后值不能切换，各种尝试找了半天没找到有原因。后来发现我在设置图片尺寸的时候设置为1080P[self.session canSetSessionPreset: AVCaptureSessionPreset1920x1080]，前置摄像头并不支持这么大的尺寸，所以就不能切换前置摄像头。
我验证了下 前置摄像头最高支持720P,720P以内可自由切换。
当然也可以在前后置摄像头切换的时候，根据前后摄像头来设置不同的尺寸，这里不在赘述。
焦点位置
代码语言：javascript复制CGPoint focusPoint = CGPointMake( point.y /size.height ,1-point.x/size.width );setExposurePointOfInterest：focusPoint函数后面Point取值范围是取景框左上角（0，0）到取景框右下角（1，1）之间。官方是这么写的：
The value of this property is a CGPoint that determines the receiver's focus point of interest, if it has one. A value of (0,0) indicates that the camera should focus on the top left corner of the image, while a value of (1,1) indicates that it should focus on the bottom right. The default value is (0.5,0.5).我也试了按这个来但位置就是不对，只能按上面的写法才可以。前面是点击位置的y/PreviewLayer的高度，后面是1-点击位置的x/PreviewLayer的宽度对焦和曝光
我在设置对焦是 先设置了模式setFocusMode，后设置对焦位置，就会导致很奇怪的现象，对焦位置是你上次点击的位置。所以一定要先设置位置，再设置对焦模式。
曝光同上
