一、说在前面
iPhone 7 之后系统相机支持HEIF格式的图片，在扫描二维码时，该格式的图片需要转换成JPG格式才能进行扫描成功。
二、思路
用户在打开系统相册选择完一张照片后，要判断该照片是否是HEIF格式，如果是，进行格式转换之后再扫描JPG图片的内容，得到扫描结果。
三、具体实现
因为过程中用到photoKit，因此需要加入该头文件，#import
@protocol TVUImageManagerDelegate <NSObject> - (void)letQRCodeVCScanQRCodeImageInAlbum:(BOOL)isHEIFFormat; @end @interface TVUImageManager : NSObject @property (strong, nonatomic) UIImage *jpgImage; @property (strong, nonatomic) UIImage *selectedImage; @property (strong, nonatomic) PHAsset *selectedAsset; @property (nonatomic,strong) id <TVUImageManagerDelegate> delegate; + (TVUImageManager *)defaultManager; - (void)doSomethingAfterSelectedImage:(NSDictionary *)info; @end
自定义类：（.mm）
#define IOS9orLater ([UIDevice currentDevice].systemVersion.integerValue >= 9)
@implementation TVUImageManager
#pragma mark - init part
+ (TVUImageManager *)defaultManager
{
static TVUImageManager *m_manager = nil;
if (m_manager == nil) {
m_manager = [[TVUImageManager alloc] init];
}
return m_manager;
}
- (id)init
{
self = [super init];
if (self) {
}
return self;
}
#pragma mark - image format part
- (void)doSomethingAfterSelectedImage:(NSDictionary *)info
{
[self getSelectedImagePHAsset:info];
if (self.selectedAsset == nil) {
log4cplus_error("TVUImageManagerLog", "%s:selected image is null",__func__);
return;
}else {
BOOL isHEIF = [self judgeIfAnImageIsHeifFormat];
if (isHEIF) {
log4cplus_error("TVUImageManagerLog", "%s:selected image is HEIF format",__func__);
[self convertImageFormatFromHeifToJpegAndThenScanTheImage];
}else {
log4cplus_error("TVUImageManagerLog", "%s:selected image is not HEIF format",__func__);
self.selectedImage = (UIImage *)[info objectForKey:UIImagePickerControllerOriginalImage];
if (self.selectedImage == nil) {
log4cplus_error("TVUImageManagerLog", "%s:selected image is null",__func__);
return;
}
[self.delegate letQRCodeVCScanQRCodeImageInAlbum:NO];
}
}
}
// Choose a picture from the system album
- (void)getSelectedImagePHAsset:(NSDictionary *)info
{
log4cplus_error("TVUImageManagerLog", "%s:get selected image PHAsset",__func__);
NSURL *imageAssetUrl = [info objectForKey:UIImagePickerControllerReferenceURL];
PHFetchResult *fetchResult = [PHAsset fetchAssetsWithALAssetURLs:[NSArray arrayWithObject:imageAssetUrl] options:nil];
if (fetchResult.count == 0) {
log4cplus_error("TVUImageManagerLog", "%s:fetchResult's count is 0",__func__);
return;
}
self.selectedAsset = (PHAsset*)fetchResult.firstObject;
}
// Determine if the picture is in HEIF format
- (BOOL)judgeIfAnImageIsHeifFormat
{
log4cplus_error("TVUImageManagerLog", "%s:begin to judge if an image is HEIF format",__func__);
__block BOOL isHEIF = NO;
if (IOS9orLater) {
NSArray *resourceList = (NSArray *)[PHAssetResource assetResourcesForAsset:self.selectedAsset];
[resourceList enumerateObjectsUsingBlock:^(id _Nonnull obj, NSUInteger idx, BOOL * _Nonnull stop) {
PHAssetResource *resource = obj;
NSString *UTI = resource.uniformTypeIdentifier;
if ([UTI isEqualToString:@"public.heif"] || [UTI isEqualToString:@"public.heic"]) {
isHEIF = YES;
*stop = YES;
}
}];
}else {
NSString *UTI = [self.selectedAsset valueForKey:@"uniformTypeIdentifier"];
isHEIF = [UTI isEqualToString:@"public.heif"] || [UTI isEqualToString:@"public.heic"];
}
return isHEIF;
}
// Convert image format from HEIF to JPEG and then scan the image
- (void)convertImageFormatFromHeifToJpegAndThenScanTheImage
{
log4cplus_error("TVUImageManagerLog", "%s:begin to convert image format from HEIF to JPEG",__func__);
[[PHImageManager defaultManager] requestImageDataForAsset:self.selectedAsset options:nil resultHandler:^(NSData * _Nullable imageData, NSString * _Nullable dataUTI, UIImageOrientation orientation, NSDictionary * _Nullable info) {
CIImage *ciImage = [CIImage imageWithData:imageData];
CIContext *context = [CIContext context];
NSData *jpgData = [context JPEGRepresentationOfImage:ciImage colorSpace:ciImage.colorSpace options:@{}];
self.jpgImage = [UIImage imageWithData:jpgData];
[self.delegate letQRCodeVCScanQRCodeImageInAlbum:YES];
}];
}
@end
调用：
#pragma mark UIImagePickerControllerDelegate
- (void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary *)info
{
[self.imageMgr doSomethingAfterSelectedImage:info];
}
以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持找一找教程网。
