Objective-C UIImage*和unsigned char* 数据相互转换 iOS开发

iOS开发过程中经常会遇到UIImage*类型和unsigned char*类型转换的需求

以下封装了UIImage*类型和unsigned char*类型数据常用的转换

转载请说明出处

//
//  UUIImage+TransferImageData.h
//
//  Created by HW on 2020/4/10.
//

#import <UIKit/UIKit.h>

NS_ASSUME_NONNULL_BEGIN

@interface UIImage (TransferImageData)

#pragma mark - UIImage图像和byte数据转换

/// 获取ARGB的数据，内存由外部管理，需要delete
/// @return 图像ARGB格式的 byte数据
- (unsigned char *)transferToARGBData;

/// 获取RGBA的数据，内存由外部管理，需要delete
/// @return 图像RGBA格式的 byte数据
- (unsigned char *)transferToRGBAData;

/// 获取Gray的数据，内存由外部管理，需要delete
/// @return 图像Gray格式的 byte数据
- (unsigned char *)transferToGrayData;

/// 将ARGB byte数据转化为UIImage
/// @param data 图像ARGB格式的 byte数据
/// @param size 图像尺寸
/// @return 生成的UIImage
+ (UIImage *)transferToImageWithARGBData:(unsigned char *)data withSize:(CGSize)size;

/// 将ARGB byte数据转化为UIImage
/// @param data 图像ARGB格式的 byte数据
/// @param width 图像宽
/// @param width 图像高
/// @return 生成的UIImage
+ (UIImage *)transferToImageWithARGBData:(unsigned char *)data withWidth:(int)width withHeight:(int)height;

/// 将RGBA byte数据转化为UIImage
/// @param data 图像RGBA格式的 byte数据
/// @param size 图像尺寸
/// @return 生成的UIImage
+ (UIImage *)transferToImageWithRGBAData:(unsigned char *) data withSize:(CGSize) size;

/// 将RGBA byte数据转化为UIImage
/// @param data 图像RGBA格式的 byte数据
/// @param width 图像宽
/// @param width 图像高
/// @return 生成的UIImage
+ (UIImage *)transferToImageWithRGBAData:(unsigned char *)data withWidth:(int)width withHeight:(int)height;

/// 将Gray byte数据转化为UIImage
/// @param data 图像Gray格式的 byte数据
/// @param size 图像尺寸
/// @return 生成的UIImage
+ (UIImage *)transferToImageWithGrayData:(unsigned char *)data withSize:(CGSize)size;

/// 将Gray byte数据转化为UIImage
/// @param data 图像Gray格式的 byte数据
/// @param width 图像宽
/// @param width 图像高
/// @return 生成的UIImage
+ (UIImage *)transferToImageWithGrayData:(unsigned char *)data withWidth:(int)width withHeight:(int)height;

@end

NS_ASSUME_NONNULL_END

//
//  UIImage+TransferImageData.mm
//
//  Created by HW on 2020/4/10.
//

#import "UIImage+TransferImageData.h"

//图像格式
typedef NS_ENUM(NSUInteger , TransferImageDataFromat) {
    TransferImageDataFromat_ARGB = 0, //ARGB格式图像
    TransferImageDataFromat_RGBA = 1, //RGBA格式图像
    TransferImageDataFromat_GRAY = 2, //Gray格式图像
};

@implementation UIImage (TransferImageData)

#pragma mark UIImage图像和byte数据转换

- (unsigned char *)transferToARGBData {
    return [self transferToDataWithFormat:TransferImageDataFromat_ARGB isNeedAlpha:YES];
}

- (unsigned char *)transferToRGBAData {
    return [self transferToDataWithFormat:TransferImageDataFromat_RGBA isNeedAlpha:YES];
}

- (unsigned char *)transferToGrayData {
    return [self transferToDataWithFormat:TransferImageDataFromat_GRAY isNeedAlpha:YES];
}

/// 获取图像的 byte数据
/// @param format 图像像素格式
/// @param isNeedAlpha 是否需要保留透明度通道，如果不保留，透明通道会全部置为255（完全不透明）
- (unsigned char *)transferToDataWithFormat:(TransferImageDataFromat)format isNeedAlpha:(BOOL)isNeedAlpha {
    size_t width = CGImageGetWidth(self.CGImage);
    size_t height = CGImageGetHeight(self.CGImage);
    if(width == 0 || height == 0)
        return nullptr;
    
    unsigned char* imageData = nullptr;
    int bytesPerRow;
    CGImageAlphaInfo alphaInfo;
    switch (format) {
        case TransferImageDataFromat_ARGB:
            imageData = new unsigned char[width * height * 4];
            bytesPerRow = (int)width * 4;
            alphaInfo = kCGImageAlphaPremultipliedFirst;
            break;
        case TransferImageDataFromat_RGBA:
            imageData = new unsigned char[width * height * 4];
            bytesPerRow = (int)width * 4;
            alphaInfo = kCGImageAlphaPremultipliedLast;
            break;
        case TransferImageDataFromat_GRAY:
            imageData = new unsigned char[width * height];
            bytesPerRow = (int)width;
            alphaInfo = kCGImageAlphaNone;
            break;
        default:
            break;
    }
    
    CGColorSpaceRef cref = CGColorSpaceCreateDeviceGray();
    CGContextRef gc = CGBitmapContextCreate(imageData, width, height, 8, bytesPerRow, cref, alphaInfo);
    CGColorSpaceRelease(cref);
    UIGraphicsPushContext(gc);
    
    if (!isNeedAlpha && format != TransferImageDataFromat_GRAY) {
        CGContextSetRGBFillColor(gc, 1.0, 1.0, 1.0, 1.0);
        CGContextFillRect(gc, CGRectMake(0.0, 0.0, (CGFloat)width, (CGFloat)height));
    }
    
    CGRect rect = {{0, 0}, {(CGFloat)width, (CGFloat)height}};
    CGContextDrawImage(gc, rect, self.CGImage);
    UIGraphicsPopContext();
    CGContextRelease(gc);
    
    return imageData;
}

+ (UIImage *)transferToImageWithARGBData:(unsigned char *)data withSize:(CGSize)size {
    return [self transferToImageWithARGBData:data withWidth:size.width withHeight:size.height];
}

+ (UIImage *)transferToImageWithARGBData:(unsigned char *)data withWidth:(int)width withHeight:(int)height {
    return [self transferToImageWithData:data withWidth:width withHeight:height withFormat:TransferImageDataFromat_ARGB];
}

+ (UIImage *)transferToImageWithRGBAData:(unsigned char *)data withSize:(CGSize) size {
    return [self transferToImageWithRGBAData:data withWidth:size.width withHeight:size.height];
}

+ (UIImage *)transferToImageWithRGBAData:(unsigned char *)data withWidth:(int)width withHeight:(int)height {
    return [self transferToImageWithData:data withWidth:width withHeight:height withFormat:TransferImageDataFromat_RGBA];
}

+ (UIImage *)transferToImageWithGrayData:(unsigned char *)data withSize:(CGSize)size {
    return [self transferToImageWithGrayData:data withWidth:size.width withHeight:size.height];
}

+ (UIImage *)transferToImageWithGrayData:(unsigned char *)data withWidth:(int)width withHeight:(int)height {
    return [self transferToImageWithData:data withWidth:width withHeight:height withFormat:TransferImageDataFromat_GRAY];
}

+ (UIImage *)transferToImageWithData:(unsigned char *)data withWidth:(int)width withHeight:(int)height withFormat:(TransferImageDataFromat)format {
    int bytesPerRow;
    CGImageAlphaInfo alphaInfo;
    CGColorSpaceRef colorSpace;
    switch (format) {
        case TransferImageDataFromat_ARGB:
            bytesPerRow = (int)width * 4;
            alphaInfo = kCGImageAlphaPremultipliedFirst;
            colorSpace = CGColorSpaceCreateDeviceRGB();
            break;
        case TransferImageDataFromat_RGBA:
            bytesPerRow = (int)width * 4;
            alphaInfo = kCGImageAlphaPremultipliedLast;
            colorSpace = CGColorSpaceCreateDeviceRGB();
            break;
        case TransferImageDataFromat_GRAY:
            bytesPerRow = (int)width;
            alphaInfo = kCGImageAlphaNone;
            colorSpace = CGColorSpaceCreateDeviceGray();
            break;
        default:
            break;
    }
    
    CGContextRef context = CGBitmapContextCreate(data, width, height, 8, bytesPerRow, colorSpace, alphaInfo);
    CGColorSpaceRelease(colorSpace);
    if (context == NULL) {
        return nil;
    }
    
    CGImageRef cgImageRef = CGBitmapContextCreateImage(context);
    CGContextRelease(context);
    UIImage *grayImage = [[UIImage alloc] initWithCGImage:cgImageRef];
    CGImageRelease(cgImageRef);
    return grayImage;
}

@end