OC代码实现获取透明像素占总像素的百分比

// 获取透明像素占总像素的百分比

- (CGFloat)getAlphaPixelPercent:(UIImage *)image {

    

    const int imageWidth = image.size.width;

    const int imageHeight = image.size.height;

    size_t bytesPerRow = imageWidth * 4;

    uint32_t *rgbImageBuf = (uint32_t *)malloc(bytesPerRow * imageHeight);

    CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB();

    CGContextRef context = CGBitmapContextCreate(rgbImageBuf, imageWidth, imageHeight, 8, bytesPerRow, colorSpace, kCGBitmapByteOrder32Little | kCGImageAlphaNoneSkipLast);

    CGContextDrawImage(context, CGRectMake(0, 0, imageWidth, imageHeight), image.CGImage);

    

    int pixelNum = imageWidth * imageHeight;

    uint32_t* pCurPtr = rgbImageBuf;

    

    int alphaPixelCount = 0;

    for (int i = 0; i < pixelNum; i++, pCurPtr++){

        uint8_t *ptr = (uint8_t *)pCurPtr;

        int a = ptr[3];

        if (a == 0) {

            alphaPixelCount += 1;

        }

    }

    CGContextRelease(context);

    CGColorSpaceRelease(colorSpace);

    free(rgbImageBuf);

 

    return (float)alphaPixelCount / (float)pixelNum;

}

 

oc 代码

// 获取图片每个像素颜色值

+(NSMutableArray*)imageFunc:(UIImage *)image{

    NSMutableArray *colorArray = [NSMutableArray array];

    const int imageWidth = image.size.width;

    const int imageHeight = image.size.height;

    size_t bytesPerRow = imageWidth * 4;

    uint32_t *rgbImageBuf = (uint32_t *)malloc(bytesPerRow * imageHeight);

    CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB();

    CGContextRef context = CGBitmapContextCreate(rgbImageBuf, imageWidth, imageHeight, 8, bytesPerRow, colorSpace, kCGBitmapByteOrder32Little | kCGImageAlphaNoneSkipLast);

    CGContextDrawImage(context, CGRectMake(0, 0, imageWidth, imageHeight), image.CGImage);

    

    int pixelNum = imageWidth * imageHeight;

    uint32_t* pCurPtr = rgbImageBuf;

    

    for (int i = 0; i < pixelNum; i++, pCurPtr++){

        NSMutableArray  *colorRow = [NSMutableArray array];

        uint8_t *ptr = (uint8_t *)pCurPtr;

        int r = ptr[0];

        int g = ptr[1];

        int b = ptr[2];

        int a = ptr[3];

        [colorRow addObject:[[NSNumber alloc] initWithInt:r]];

        [colorRow addObject:[[NSNumber alloc] initWithInt:g]];

        [colorRow addObject:[[NSNumber alloc] initWithInt:b]];

        [colorRow addObject:[[NSNumber alloc] initWithInt:a]];

        

        [colorArray addObject:colorRow];

    }

    CGContextRelease(context);

    CGColorSpaceRelease(colorSpace);

    return colorArray;

}

 

swift 代码

func getimageColorarray(_ image:UIImage) ->[[(CGFloat,CGFloat,CGFloat,CGFloat)]] {

    var colorA = [[(CGFloat,CGFloat,CGFloat,CGFloat)]]()

    //        image.cgImage.sc

    let pixelData = image.cgImage?.dataProvider?.data

    let data:UnsafePointer<UInt8> = CFDataGetBytePtr(pixelData)

    let length = CFDataGetLength(pixelData)

    

    for x in 0..<Int(image.size.height) {

        var colorR = [(CGFloat,CGFloat,CGFloat,CGFloat)]()

        for y in 0..<Int(image.size.width) {

            

            let pixelInfo: Int = ((Int(image.size.width)*Int(y)) + Int(x)) * 4

            

            let r = CGFloat(data[pixelInfo])

            let g = CGFloat(data[pixelInfo+1])

            let b = CGFloat(data[pixelInfo+2])

            let a = CGFloat(data[pixelInfo+3])

            

            let rgba = (r,g,b,a)

            colorR.append(rgba)

        }

        colorA.append(colorR)

    }

    return colorA

}