这里将通过系统提供的CoreImage滤镜来实现二维码生成
在CoreImage中提供了很多分类,不同的分类提供了不同的滤镜,生成二维码将要使用的分类是: kCICategoryBuiltIn
系统分类:
/* Categories:
CORE_IMAGE_EXPORT NSString * const kCICategoryDistortionEffect;
CORE_IMAGE_EXPORT NSString * const kCICategoryGeometryAdjustment;
CORE_IMAGE_EXPORT NSString * const kCICategoryCompositeOperation;
CORE_IMAGE_EXPORT NSString * const kCICategoryHalftoneEffect;
CORE_IMAGE_EXPORT NSString * const kCICategoryColorAdjustment;--->颜色
CORE_IMAGE_EXPORT NSString * const kCICategoryColorEffect;
CORE_IMAGE_EXPORT NSString * const kCICategoryTransition;
CORE_IMAGE_EXPORT NSString * const kCICategoryTileEffect;
CORE_IMAGE_EXPORT NSString * const kCICategoryGenerator;
CORE_IMAGE_EXPORT NSString * const kCICategoryReduction NS_AVAILABLE(10_5, 5_0);
CORE_IMAGE_EXPORT NSString * const kCICategoryGradient; --->渐变
CORE_IMAGE_EXPORT NSString * const kCICategoryStylize; --->风格化
CORE_IMAGE_EXPORT NSString * const kCICategorySharpen; --->锐化
CORE_IMAGE_EXPORT NSString * const kCICategoryBlur; --->高斯模糊
CORE_IMAGE_EXPORT NSString * const kCICategoryVideo;
CORE_IMAGE_EXPORT NSString * const kCICategoryStillImage;
CORE_IMAGE_EXPORT NSString * const kCICategoryInterlaced;
CORE_IMAGE_EXPORT NSString * const kCICategoryNonSquarePixels;
CORE_IMAGE_EXPORT NSString * const kCICategoryHighDynamicRange;
CORE_IMAGE_EXPORT NSString * const kCICategoryBuiltIn; ---> 内嵌
CORE_IMAGE_EXPORT NSString * const kCICategoryFilterGenerator NS_AVAILABLE(10_5, 9_0);
*/
通过filterNamesInCategory方法可以打印出该分类中包含的滤镜:
NSArray *filterArr = [CIFilter filterNamesInCategory:kCICategoryBuiltIn];
// 打印kCICategoryBuiltIn中包含的滤镜
NSLog(@"%@",filterArr);
/*
CIAccordionFoldTransition,
CIAdditionCompositing,
CIAffineClamp,
CIAffineTile,
CIAffineTransform,
CIAreaAverage,
CIAreaHistogram,
CIAreaMaximum,
CIAreaMaximumAlpha,
CIAreaMinimum,
CIAreaMinimumAlpha,
CIAztecCodeGenerator,
CIBarsSwipeTransition,
CIBlendWithAlphaMask,
CIBlendWithMask,
CIBloom,
CIBoxBlur,
CIBumpDistortion,
CIBumpDistortionLinear,
CICheckerboardGenerator,
CICircleSplashDistortion,
CICircularScreen,
CICircularWrap,
CICMYKHalftone,
CICode128BarcodeGenerator,
CIColorBlendMode,
CIColorBurnBlendMode,
CIColorClamp,
CIColorControls,
CIColorCrossPolynomial,
CIColorCube,
CIColorCubeWithColorSpace,
CIColorDodgeBlendMode,
CIColorInvert,
CIColorMap,
CIColorMatrix,
CIColorMonochrome,
CIColorPolynomial,
CIColorPosterize,
CIColumnAverage,
CIComicEffect,
CIConstantColorGenerator,
CIConvolution3X3,
CIConvolution5X5,
CIConvolution7X7,
CIConvolution9Horizontal,
CIConvolution9Vertical,
CICopyMachineTransition,
CICrop,
CICrystallize,
CIDarkenBlendMode,
CIDepthOfField,
CIDifferenceBlendMode,
CIDiscBlur,
CIDisintegrateWithMaskTransition,
CIDisplacementDistortion,
CIDissolveTransition,
CIDivideBlendMode,
CIDotScreen,
CIDroste,
CIEdges,
CIEdgeWork,
CIEightfoldReflectedTile,
CIExclusionBlendMode,
CIExposureAdjust,
CIFalseColor,
CIFlashTransition,
CIFourfoldReflectedTile,
CIFourfoldRotatedTile,
CIFourfoldTranslatedTile,
CIGammaAdjust,
CIGaussianBlur,
CIGaussianGradient,
CIGlassDistortion,
CIGlassLozenge,
CIGlideReflectedTile,
CIGloom,
CIHardLightBlendMode,
CIHatchedScreen,
CIHeightFieldFromMask,
CIHexagonalPixellate,
CIHighlightShadowAdjust,
CIHistogramDisplayFilter,
CIHoleDistortion,
CIHueAdjust,
CIHueBlendMode,
CIKaleidoscope,
CILanczosScaleTransform,
CILenticularHaloGenerator,
CILightenBlendMode,
CILightTunnel,
CILinearBurnBlendMode,
CILinearDodgeBlendMode,
CILinearGradient,
CILinearToSRGBToneCurve,
CILineOverlay,
CILineScreen,
CILuminosityBlendMode,
CIMaskedVariableBlur,
CIMaskToAlpha,
CIMaximumComponent,
CIMaximumCompositing,
CIMedianFilter,
CIMinimumComponent,
CIMinimumCompositing,
CIModTransition,
CIMotionBlur,
CIMultiplyBlendMode,
CIMultiplyCompositing,
CINoiseReduction,
CIOpTile,
CIOverlayBlendMode,
CIPageCurlTransition,
CIPageCurlWithShadowTransition,
CIParallelogramTile,
CIPDF417BarcodeGenerator,
CIPerspectiveCorrection,
CIPerspectiveTile,
CIPerspectiveTransform,
CIPerspectiveTransformWithExtent,
CIPhotoEffectChrome,
CIPhotoEffectFade,
CIPhotoEffectInstant,
CIPhotoEffectMono,
CIPhotoEffectNoir,
CIPhotoEffectProcess,
CIPhotoEffectTonal,
CIPhotoEffectTransfer,
CIPinchDistortion,
CIPinLightBlendMode,
CIPixellate,
CIPointillize,
CIQRCodeGenerator,
CIRadialGradient,
CIRandomGenerator,
CIRippleTransition,
CIRowAverage,
CISaturationBlendMode,
CIScreenBlendMode,
CISepiaTone,
CIShadedMaterial,
CISharpenLuminance,
CISixfoldReflectedTile,
CISixfoldRotatedTile,
CISmoothLinearGradient,
CISoftLightBlendMode,
CISourceAtopCompositing,
CISourceInCompositing,
CISourceOutCompositing,
CISourceOverCompositing,
CISpotColor,
CISpotLight,
CISRGBToneCurveToLinear,
CIStarShineGenerator,
CIStraightenFilter,
CIStretchCrop,
CIStripesGenerator,
CISubtractBlendMode,
CISunbeamsGenerator,
CISwipeTransition,
CITemperatureAndTint,
CIToneCurve,
CITorusLensDistortion,
CITriangleKaleidoscope,
CITriangleTile,
CITwelvefoldReflectedTile,
CITwirlDistortion,
CIUnsharpMask,
CIVibrance,
CIVignette,
CIVignetteEffect,
CIVortexDistortion,
CIWhitePointAdjust,
CIZoomBlur
生成二维码需要使用的滤镜是: CIQRCodeGenerator
CIFilter的主要属性:
@property (readonly, nonatomic, nullable) CIImage *outputImage; // 生成的图片
@property (nonatomic, readonly) NSString *name
@property (nonatomic, copy) NSString *name
@property (getter=isEnabled) BOOL enabled
@property (nonatomic, readonly) CI_ARRAY(NSString*) *inputKeys; // 输入内容的设置
inputMessage - 输入信息
inputCorrectionLevel - 容错等级
@property (nonatomic, readonly) CI_ARRAY(NSString*) *outputKeys;// 输出内容的设置
@property (nonatomic, readonly) CI_DICTIONARY(NSString*,id) *attributes;
- (void)setDefaults; // 设置默认的
示例代码:
#import "ViewController.h"
// #import 可以不用导入直接使用
@interface ViewController ()
@end
@implementation ViewController{
UIImageView *_imageView;
}
- (void)viewDidLoad {
[super viewDidLoad];
_imageView = [[UIImageView alloc] initWithFrame:CGRectMake(100, 200, 200, 200)];
_imageView.contentMode = UIViewContentModeScaleAspectFit;
[self.view addSubview:_imageView];
// 1.创建滤镜
CIFilter *filter = [CIFilter filterWithName:@"CIQRCodeGenerator"];
// 2.设置属性 首先要设置默认选项
[filter setDefaults];
// NSLog(@"%@",filter.inputKeys);
NSString *inputContent = @"生成二维码";
[filter setValue:[inputContent dataUsingEncoding:NSUTF8StringEncoding] forKey:@"inputMessage"];
/* 细节1:
[filter setValue:@"生成二维码" forKey:@"inputMessage"];这种方式设置会报错:
- Terminating app due to uncaught exception 'CIQRCodeGenerator', reason: 'CIQRCodeGenerator filter requires NSData for inputMessage'
*/
// 3.根据滤镜生成图片
CIImage *image = filter.outputImage;
/* 细节2:
设置尺寸,防止图片尺寸小于图片框导致放大模糊
*/
image = [image imageByApplyingTransform:CGAffineTransformMakeScale(8, 8)];
// 展示生成的二维码
_imageView.image = [UIImage imageWithCIImage:image];
}
@end
注意点:
1.设置inputMessage时,参数需要使用NSData类型
2.生成图片尺寸很有可能会小于视图控件的尺寸,所以会出现模糊的现象,可以适当对图片进行放大