二進制運算符'+ ='不能應用於'Int'和'UInt8'類型的操作數。將Obj-C轉換爲Swift。

Question

將Obj-C轉換爲Swift。正如你可以看到我宣稱let buf = UnsafeMutablePointer<UInt8>(CVPixelBufferGetBaseAddress(cvimgRef))，所以我得到它下面的for循環錯誤。

二元運算符「+ =」不能應用於類型的操作數「詮釋」和「UINT8」

另外，作爲一個小編，我不知道怎麼翻譯，其餘的OBJ-C for循環下面的代碼。這斜線是什麼意思，我該如何處理指針？我不得不說不安全的地方嗎？

// process the frame of video 
    func captureOutput(captureOutput:AVCaptureOutput, didOutputSampleBuffer sampleBuffer:CMSampleBuffer, fromConnection connection:AVCaptureConnection) { 
     // if we're paused don't do anything 
     if currentState == CurrentState.statePaused { 
      // reset our frame counter 
      self.validFrameCounter = 0 

      return 
     } 

    // this is the image buffer 
    var cvimgRef:CVImageBufferRef = CMSampleBufferGetImageBuffer(sampleBuffer) 
    // Lock the image buffer 
    CVPixelBufferLockBaseAddress(cvimgRef, 0) 
    // access the data 
    var width: size_t = CVPixelBufferGetWidth(cvimgRef) 
    var height:size_t = CVPixelBufferGetHeight(cvimgRef) 
    // get the raw image bytes 
    let buf = UnsafeMutablePointer<UInt8>(CVPixelBufferGetBaseAddress(cvimgRef)) 
    var bprow: size_t = CVPixelBufferGetBytesPerRow(cvimgRef) 


    var r = 0 
    var g = 0 
    var b = 0 

     for var y = 0; y < height; y++ { 
      for var x = 0; x < width * 4; x += 4 { 
       b += buf[x]; g += buf[x + 1]; r += buf[x + 2] // error 
      } 
      buf += bprow() // error 
     } 

剩餘的Obj-C代碼。

r/=255*(float) (width*height); 
g/=255*(float) (width*height); 
b/=255*(float) (width*height); 

Answer 1

你有很多類型不匹配的錯誤。

x的類型不應該是UInt8，因爲x要增加直到寬度的值。

for var x:UInt8 = 0; x < width * 4; x += 4 { // error: '<' cannot be applied to operands of type 'UInt8' and 'Int' 

所以修復它象下面這樣：

for var x = 0; x < width * 4; x += 4 { 

遞增指針的地址，你可以使用advancedBy()功能。

buf += bprow(UnsafeMutablePointer(UInt8)) // error: '+=' cannot be applied to operands of type 'UnsafeMutablePointer<UInt8>' and 'size_t' 

象下面這樣：

var pixel = buf.advancedBy(y * bprow) 

而此行，

RGBtoHSV(r, g, b) // error 

有斯威夫特CGFloat和Float不幸之間不存在隱式轉換。所以你應該明確地投到CGFloat。

RGBtoHSV(CGFloat(r), g: CGFloat(g), b: CGFloat(b)) 

整個編輯的代碼是在這裏：

func RGBtoHSV(r: CGFloat, g: CGFloat, b: CGFloat) -> (h: CGFloat, s: CGFloat, v: CGFloat) { 
    var h: CGFloat = 0.0 
    var s: CGFloat = 0.0 
    var v: CGFloat = 0.0 
    let col = UIColor(red: r, green: g, blue: b, alpha: 1.0) 
    col.getHue(&h, saturation: &s, brightness: &v, alpha: nil) 
    return (h, s, v) 
} 

// process the frame of video 
func captureOutput(captureOutput:AVCaptureOutput, didOutputSampleBuffer sampleBuffer:CMSampleBuffer, fromConnection connection:AVCaptureConnection) { 
    // if we're paused don't do anything 
    if currentState == CurrentState.statePaused { 
     // reset our frame counter 
     self.validFrameCounter = 0 
     return 
    } 

    // this is the image buffer 
    var cvimgRef = CMSampleBufferGetImageBuffer(sampleBuffer) 
    // Lock the image buffer 
    CVPixelBufferLockBaseAddress(cvimgRef, 0) 
    // access the data 
    var width = CVPixelBufferGetWidth(cvimgRef) 
    var height = CVPixelBufferGetHeight(cvimgRef) 
    // get the raw image bytes 
    let buf = UnsafeMutablePointer<UInt8>(CVPixelBufferGetBaseAddress(cvimgRef)) 
    var bprow = CVPixelBufferGetBytesPerRow(cvimgRef) 

    var r: Float = 0.0 
    var g: Float = 0.0 
    var b: Float = 0.0 

    for var y = 0; y < height; y++ { 
     var pixel = buf.advancedBy(y * bprow) 
     for var x = 0; x < width * 4; x += 4 { // error: '<' cannot be applied to operands of type 'UInt8' and 'Int' 
      b += Float(pixel[x]) 
      g += Float(pixel[x + 1]) 
      r += Float(pixel[x + 2]) 
     } 
    } 
    r /= 255 * Float(width * height) 
    g /= 255 * Float(width * height) 
    b /= 255 * Float(width * height) 

    //} 

    // convert from rgb to hsv colourspace 
    var h: Float = 0.0 
    var s: Float = 0.0 
    var v: Float = 0.0 

    RGBtoHSV(CGFloat(r), g: CGFloat(g), b: CGFloat(b)) // error 
}