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這篇文章將為大家詳細(xì)講解有關(guān)iOS掃描二維碼如何實(shí)現(xiàn)手勢(shì)拉近拉遠(yuǎn)鏡頭,小編覺得挺實(shí)用的,因此分享給大家做個(gè)參考,希望大家閱讀完這篇文章后可以有所收獲。
在做掃碼需求,往往會(huì)有放大鏡頭需求。
蘋果提供了AVCaptureConnection中,videoScaleAndCropFactor:縮放裁剪系數(shù),使用該屬性,可以實(shí)現(xiàn)拉近拉遠(yuǎn)鏡頭。再結(jié)合手勢(shì)UIPinchGestureRecognizer,就很簡(jiǎn)單實(shí)現(xiàn)手勢(shì)拉近拉遠(yuǎn)鏡頭。
手勢(shì)代碼
///記錄開始的縮放比例 @property(nonatomic,assign)CGFloat beginGestureScale; ///最后的縮放比例 @property(nonatomic,assign)CGFloat effectiveScale; - (void)cameraInitOver { if (self.isVideoZoom) { UIPinchGestureRecognizer *pinch = [[UIPinchGestureRecognizer alloc] initWithTarget:self action:@selector(pinchDetected:)]; pinch.delegate = self; [self.view addGestureRecognizer:pinch]; } } - (void)pinchDetected:(UIPinchGestureRecognizer*)recogniser { self.effectiveScale = self.beginGestureScale * recogniser.scale; if (self.effectiveScale < 1.0){ self.effectiveScale = 1.0; } [self.scanObj setVideoScale:self.effectiveScale]; } - (BOOL)gestureRecognizerShouldBegin:(UIGestureRecognizer *)gestureRecognizer { if ( [gestureRecognizer isKindOfClass:[UIPinchGestureRecognizer class]] ) { _beginGestureScale = _effectiveScale; } return YES; }
拉近拉遠(yuǎn)鏡頭代碼
- (void)setVideoScale:(CGFloat)scale { [_input.device lockForConfiguration:nil]; AVCaptureConnection *videoConnection = [self connectionWithMediaType:AVMediaTypeVideo fromConnections:[[self stillImageOutput] connections]]; CGFloat maxScaleAndCropFactor = ([[self.stillImageOutput connectionWithMediaType:AVMediaTypeVideo] videoMaxScaleAndCropFactor])/16; if (scale > maxScaleAndCropFactor) scale = maxScaleAndCropFactor; CGFloat zoom = scale / videoConnection.videoScaleAndCropFactor; videoConnection.videoScaleAndCropFactor = scale; [_input.device unlockForConfiguration]; CGAffineTransform transform = _videoPreView.transform; [CATransaction begin]; [CATransaction setAnimationDuration:.025]; _videoPreView.transform = CGAffineTransformScale(transform, zoom, zoom); [CATransaction commit]; }
有一點(diǎn)需要注意:the videoScaleAndCropFactor property may be set to a value in the range of 1.0 to videoMaxScaleAndCropFactor,videoScaleAndCropFactor這個(gè)屬性取值范圍是1.0-videoMaxScaleAndCropFactor,如果你設(shè)置超出范圍會(huì)崩潰哦!
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