swift iOS：如何使用相机选择颜色

我想用相机选择颜色，我得到了颜色。但这不是我在相机中触摸到的颜色。代码如下：

摄像机设置（swift）：

捕获输出（swift）：

抓住要点（swift）：

选择带有点的颜色：

- (UIColor*)pickColorWithPoint:(CGPoint)atPoint pixelFormatType: (UInt32)format {

    UIColor* color = nil;

    CGImageRef cgImage =  self.CGImage;
    size_t width = CGImageGetWidth(cgImage);
    size_t height = CGImageGetHeight(cgImage);
    NSUInteger x = (NSUInteger)floor(atPoint.x) * self.scale;
    NSUInteger y = (NSUInteger)floor(atPoint.y) * self.scale;

    if ((x < width) && (y < height)) {
        CGDataProviderRef provider = CGImageGetDataProvider(cgImage);
        CFDataRef bitmapData = CGDataProviderCopyData(provider);

        const UInt8 *data = CFDataGetBytePtr(bitmapData);

        size_t offset = ((width * y) + x) * 4;

        if (format == kCVPixelFormatType_32RGBA) {

            UInt8 red   = data[offset];
            UInt8 green = data[offset + 1];
            UInt8 blue  = data[offset + 2];
            UInt8 alpha = data[offset + 3];
            color = [UIColor colorWithRed:red/255.0f green:green/255.0f blue:blue/255.0f alpha:alpha/255.0f];

        } else if (format == kCVPixelFormatType_32BGRA) {

            UInt8 blue   = data[offset + 0];
            UInt8 green = data[offset + 1];
            UInt8 red  = data[offset + 2];

            color = [UIColor colorWithRed:red/255.0f green:green/255.0f blue:blue/255.0f alpha:1.0f];
        }

        CFRelease(bitmapData);
    }

    return color;

//    CFDataRef pixelData = CGDataProviderCopyData(CGImageGetDataProvider(self.CGImage));
//    const UInt8* data = CFDataGetBytePtr(pixelData);
//    
//    int pixelInfo = ((self.size.width  * atPoint.y) + atPoint.x) * 4;
//    
//    UInt8 blue  = data[pixelInfo];
//    UInt8 green = data[(pixelInfo + 1)];
//    UInt8 red   = data[pixelInfo + 2];
//    UInt8 alpha   = data[pixelInfo + 3];
//    CFRelease(pixelData);
//    
//    UIColor* color = [UIColor colorWithRed:red/255.0f green:green/255.0f blue:blue/255.0f alpha:alpha/255];
//    
//    return color;

}

-（UIColor*）pickColorWithPoint:（CGPoint）atPoint像素格式类型：（UInt32）格式{
UIColor*color=nil；
CGImageRef cgImage=self.cgImage；
大小\u t宽度=CGImageGetWidth（cgImage）；
尺寸高度=CGImageGetHeight（cgImage）；
NSUInteger x=（NSUInteger）楼层（atPoint.x）*自刻度；
NSU整数y=（NSU整数）楼层（在点y）*自刻度；
如果（（x<宽度）和（y<高度））{
CGDataProviderRef provider=CGImageGetDataProvider（cgImage）；
CFDataRef bitmapData=CGDataProviderCopyData（提供程序）；
const UInt8*data=CFDataGetBytePtr（位图数据）；
尺寸t偏移=（（宽度*y）+x）*4；
if（格式==kCVPixelFormatType_32RGBA）{
UInt8红色=数据[偏移]；
UInt8绿色=数据[偏移量+1]；
UInt8蓝色=数据[偏移量+2]；
UInt8 alpha=数据[偏移量+3]；
颜色=[UIColor color WITH red:red/255.0f green:green/255.0f blue:blue/255.0f alpha:alpha/255.0f]；
}else if（格式==kCVPixelFormatType_32BGRA）{
UInt8蓝色=数据[偏移量+0]；
UInt8绿色=数据[偏移量+1]；
UInt8红色=数据[偏移量+2]；
颜色=[UIColor color WITH red:red/255.0f green:green/255.0f blue:blue/255.0f alpha:1.0f]；
}
CFRelease（位图数据）；
}
返回颜色；
//CFDataRef pixelData=CGDataProviderCopyData（CGImageGetDataProvider（self.CGImage））；
//const UInt8*data=CFDataGetBytePtr（像素数据）；
//    
//int pixelInfo=（（self.size.width*atPoint.y）+atPoint.x）*4；
//    
//UInt8蓝色=数据[pixelInfo]；
//UInt8绿色=数据[（像素信息+1）]；
//UInt8红色=数据[pixelInfo+2]；
//UInt8 alpha=数据[pixelInfo+3]；
//CFRelease（pixelData）；
//    
//UIColor*color=[UIColor colorWithRed:red/255.0f green:green/255.0f blue:blue/255.0f alpha:alpha/255]；
//    
//返回颜色；
}

你找到答案了吗？

func captureOutput(captureOutput: AVCaptureOutput!, didOutputSampleBuffer sampleBuffer: CMSampleBuffer!, fromConnection connection: AVCaptureConnection!) {
    //Get pixel data

    guard self.point != nil else {
        return;
    }

    let image = UIImage(fromSampleBuffer: sampleBuffer);
    let convertPoint = image.convertPoint(self.point!, fromView: self.view);
    let color = image.pickColorWithPoint(convertPoint, pixelFormatType: kCVPixelFormatType_32BGRA);

    dispatch_async(dispatch_get_main_queue()) { 
        [weak self] () ->Void in
        self?.colorView.backgroundColor = color;
    }
     self.point = nil;
}

override func touchesBegan(touches: Set<UITouch>, withEvent event: UIEvent?) {
    super.touchesBegan(touches, withEvent: event);
    self.point = touches.first?.locationInView(self.view);
}

override func touchesMoved(touches: Set<UITouch>, withEvent event: UIEvent?) {
    super.touchesMoved(touches, withEvent: event);
    self.point = touches.first?.locationInView(self.view);
}

- (CGPoint)convertPoint:(CGPoint)viewPoint fromView:(UIView *)view {

    CGPoint imagePoint = viewPoint;

    CGSize imageSize = self.size;
    CGSize viewSize  = view.bounds.size;

    CGFloat ratioX = viewSize.width / imageSize.width;
    CGFloat ratioY = viewSize.height / imageSize.height;

    UIViewContentMode contentMode = view.contentMode;

    switch (contentMode) {
    case UIViewContentModeScaleToFill:
    case UIViewContentModeRedraw:
    {
        imagePoint.x /= ratioX;
        imagePoint.y /= ratioY;
        break;
    }

    case UIViewContentModeScaleAspectFit:
    case UIViewContentModeScaleAspectFill:
    {
        CGFloat scale;

        if (contentMode == UIViewContentModeScaleAspectFit) {
            scale = MIN(ratioX, ratioY);
        }
        else /*if (contentMode == UIViewContentModeScaleAspectFill)*/ {
            scale = MAX(ratioX, ratioY);
        }

        // Remove the x or y margin added in FitMode
        imagePoint.x -= (viewSize.width  - imageSize.width  * scale) / 2.0f;
        imagePoint.y -= (viewSize.height - imageSize.height * scale) / 2.0f;

        imagePoint.x /= scale;
        imagePoint.y /= scale;

        break;
    }

    case UIViewContentModeCenter:
    {
        imagePoint.x -= (viewSize.width - imageSize.width)  / 2.0f;
        imagePoint.y -= (viewSize.height - imageSize.height) / 2.0f;

        break;
    }

    case UIViewContentModeTop:
    {
        imagePoint.x -= (viewSize.width - imageSize.width)  / 2.0f;

        break;
    }

    case UIViewContentModeBottom:
    {
        imagePoint.x -= (viewSize.width - imageSize.width)  / 2.0f;
        imagePoint.y -= (viewSize.height - imageSize.height);

        break;
    }

    case UIViewContentModeLeft:
    {
        imagePoint.y -= (viewSize.height - imageSize.height) / 2.0f;

        break;
    }

    case UIViewContentModeRight:
    {
        imagePoint.x -= (viewSize.width - imageSize.width);
        imagePoint.y -= (viewSize.height - imageSize.height) / 2.0f;

        break;
    }

    case UIViewContentModeTopRight:
    {
        imagePoint.x -= (viewSize.width - imageSize.width);

        break;
    }


    case UIViewContentModeBottomLeft:
    {
        imagePoint.y -= (viewSize.height - imageSize.height);

        break;
    }


    case UIViewContentModeBottomRight:
    {
        imagePoint.x -= (viewSize.width - imageSize.width);
        imagePoint.y -= (viewSize.height - imageSize.height);

        break;
    }

    case UIViewContentModeTopLeft:
    default:
    {
        break;
    }
}

return imagePoint;
}

+ (UIImage *) imageFromSampleBuffer:(CMSampleBufferRef) sampleBuffer
{
    //NSLog(@"imageFromSampleBuffer: called");

    // Get a CMSampleBuffer's Core Video image buffer for the media data
    CVImageBufferRef imageBuffer = CMSampleBufferGetImageBuffer(sampleBuffer);
    // Lock the base address of the pixel buffer
    CVPixelBufferLockBaseAddress(imageBuffer, 0);

    // Get the number of bytes per row for the pixel buffer
    void *baseAddress = CVPixelBufferGetBaseAddress(imageBuffer);

    // Get the number of bytes per row for the pixel buffer
    size_t bytesPerRow = CVPixelBufferGetBytesPerRow(imageBuffer);
    // Get the pixel buffer width and height
    size_t width = CVPixelBufferGetWidth(imageBuffer);
    size_t height = CVPixelBufferGetHeight(imageBuffer);

    // Create a device-dependent RGB color space
    CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB();

    // Create a bitmap graphics context with the sample buffer data
    CGContextRef context = CGBitmapContextCreate(baseAddress, width, height, 8,
                                                 bytesPerRow, colorSpace, kCGBitmapByteOrder32Little | kCGImageAlphaPremultipliedFirst);

    //! 旋转90度
    CGFloat degrees = 90.f;
    CGFloat radians = degrees * (M_PI / 180.f);
    CGContextRotateCTM(context, radians);

    // Create a Quartz image from the pixel data in the bitmap graphics context
    CGImageRef quartzImage = CGBitmapContextCreateImage(context);

    // Unlock the pixel buffer
    CVPixelBufferUnlockBaseAddress(imageBuffer,0);

    // Free up the context and color space
    CGContextRelease(context);
    CGColorSpaceRelease(colorSpace);

    //UIDeviceOrientation *deviceOrientation = [[UIDevice currentDevice] orientation];

    // Create an image object from the Quartz image
    //    UIImage *image = [UIImage imageWithCGImage:quartzImage scale:1 orientation:UIImageOrientationRight];
    UIImage *image = [UIImage imageWithCGImage:quartzImage];

    // Release the Quartz image
    CGImageRelease(quartzImage);

    return (image);
}

- (UIColor*)pickColorWithPoint:(CGPoint)atPoint pixelFormatType: (UInt32)format {

    UIColor* color = nil;

    CGImageRef cgImage =  self.CGImage;
    size_t width = CGImageGetWidth(cgImage);
    size_t height = CGImageGetHeight(cgImage);
    NSUInteger x = (NSUInteger)floor(atPoint.x) * self.scale;
    NSUInteger y = (NSUInteger)floor(atPoint.y) * self.scale;

    if ((x < width) && (y < height)) {
        CGDataProviderRef provider = CGImageGetDataProvider(cgImage);
        CFDataRef bitmapData = CGDataProviderCopyData(provider);

        const UInt8 *data = CFDataGetBytePtr(bitmapData);

        size_t offset = ((width * y) + x) * 4;

        if (format == kCVPixelFormatType_32RGBA) {

            UInt8 red   = data[offset];
            UInt8 green = data[offset + 1];
            UInt8 blue  = data[offset + 2];
            UInt8 alpha = data[offset + 3];
            color = [UIColor colorWithRed:red/255.0f green:green/255.0f blue:blue/255.0f alpha:alpha/255.0f];

        } else if (format == kCVPixelFormatType_32BGRA) {

            UInt8 blue   = data[offset + 0];
            UInt8 green = data[offset + 1];
            UInt8 red  = data[offset + 2];

            color = [UIColor colorWithRed:red/255.0f green:green/255.0f blue:blue/255.0f alpha:1.0f];
        }

        CFRelease(bitmapData);
    }

    return color;

//    CFDataRef pixelData = CGDataProviderCopyData(CGImageGetDataProvider(self.CGImage));
//    const UInt8* data = CFDataGetBytePtr(pixelData);
//    
//    int pixelInfo = ((self.size.width  * atPoint.y) + atPoint.x) * 4;
//    
//    UInt8 blue  = data[pixelInfo];
//    UInt8 green = data[(pixelInfo + 1)];
//    UInt8 red   = data[pixelInfo + 2];
//    UInt8 alpha   = data[pixelInfo + 3];
//    CFRelease(pixelData);
//    
//    UIColor* color = [UIColor colorWithRed:red/255.0f green:green/255.0f blue:blue/255.0f alpha:alpha/255];
//    
//    return color;

}