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使用CoreImage教程

發布時間：2025/3/8 编程问答 35 豆豆

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使用CoreImage教程

CoreImage包含有很多實用的濾鏡,專業處理圖片的庫,為了能看到各種渲染效果,請使用如下圖片素材.

現在可以開始教程了:

#define FIX_IMAGE(image) fixImageWidth(image, 320.f)// 固定圖片的寬度 UIImage * fixImageWidth(UIImage *image, CGFloat width) {float newHeight = image.size.height * (width / image.size.width);CGSize size = CGSizeMake(width, newHeight);UIGraphicsBeginImageContextWithOptions(size, NO, 0);CGContextRef context = UIGraphicsGetCurrentContext();CGContextTranslateCTM(context, 0.0, size.height);CGContextScaleCTM(context, 1.0, -1.0);CGContextSetBlendMode(context, kCGBlendModeCopy);CGContextDrawImage(context, CGRectMake(0.0f, 0.0f, size.width, size.height),image.CGImage);UIImage *imageOut = UIGraphicsGetImageFromCurrentImageContext();UIGraphicsEndImageContext();return imageOut; }代碼片段

// 將UIImage轉換成CIImageCIImage *ciImage = [[CIImage alloc] initWithImage:[UIImage imageNamed:@"1.jpg"]];// 創建濾鏡CIFilter *filter = [CIFilter filterWithName:@"CIPhotoEffectMono"keysAndValues:kCIInputImageKey, ciImage, nil];[filter setDefaults];// 獲取繪制上下文CIContext *context = [CIContext contextWithOptions:nil];// 渲染并輸出CIImageCIImage *outputImage = [filter outputImage];// 創建CGImage句柄CGImageRef cgImage = [context createCGImage:outputImagefromRect:[outputImage extent]];// 獲取圖片UIImage *showImage = [UIImage imageWithCGImage:cgImage];// 釋放CGImage句柄CGImageRelease(cgImage);// 顯示圖片UIImageView *imageView = \[[UIImageView alloc] initWithImage:FIX_IMAGE(showImage)];[self.view addSubview:imageView];代碼片段

效果如下:

我們對操作進行簡易的封裝:

CIFilterEffect.h + CIFilterEffect.m

// // CIFilterEffect.h // CIFilter // // Created by YouXianMing on 14-5-9. // Copyright (c) 2014年 Y.X. All rights reserved. //#import <Foundation/Foundation.h>@interface CIFilterEffect : NSObject@property (nonatomic, strong, readonly) UIImage *result;- (instancetype)initWithImage:(UIImage *)image filterName:(NSString *)name;@end

// // CIFilterEffect.m // CIFilter // // Created by YouXianMing on 14-5-9. // Copyright (c) 2014年 Y.X. All rights reserved. //#import "CIFilterEffect.h"@interface CIFilterEffect ()@property (nonatomic, strong, readwrite) UIImage *result;@end@implementation CIFilterEffect- (instancetype)initWithImage:(UIImage *)image filterName:(NSString *)name {self = [super init];if (self){// 將UIImage轉換成CIImageCIImage *ciImage = [[CIImage alloc] initWithImage:image];// 創建濾鏡CIFilter *filter = [CIFilter filterWithName:namekeysAndValues:kCIInputImageKey, ciImage, nil];[filter setDefaults];// 獲取繪制上下文CIContext *context = [CIContext contextWithOptions:nil];// 渲染并輸出CIImageCIImage *outputImage = [filter outputImage];// 創建CGImage句柄CGImageRef cgImage = [context createCGImage:outputImagefromRect:[outputImage extent]];_result = [UIImage imageWithCGImage:cgImage];// 釋放CGImage句柄CGImageRelease(cgImage);}return self; }@end

我們來開始嘗試其他的濾鏡效果,我們可以嘗試的至少有這些:

@"CILinearToSRGBToneCurve",
@"CIPhotoEffectChrome",
@"CIPhotoEffectFade",
@"CIPhotoEffectInstant",
@"CIPhotoEffectMono",
@"CIPhotoEffectNoir",
@"CIPhotoEffectProcess",
@"CIPhotoEffectTonal",
@"CIPhotoEffectTransfer",
@"CISRGBToneCurveToLinear",
@"CIVignetteEffect",

下面是所有渲染出來的圖片,與上面提供的濾鏡名字一一對應:

以下效果是需要進行一些配置才能達到的效果,這個就不開源了,你懂得:).

福利:

Core Image Filter Reference

https://developer.apple.com/library/ios/documentation/graphicsimaging/reference/CoreImageFilterReference/Reference/reference.html

CICategoryBlur

CICategoryColorAdjustment

CICategoryColorEffect(我們剛剛用到的一些效果在這里哦)

CICategoryCompositeOperation

CICategoryDistortionEffect

CICategoryGenerator

CICategoryGeometryAdjustment

CICategoryGradient

CICategoryHalftoneEffect

CICategoryReduction

CICategorySharpen

CICategoryStylize

CICategoryTileEffect

CICategoryTransition

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