Swift - 让常数值消失并进入下一行

Question

我正在尝试将天气雷达图像叠加到 map 上。我获取图像及其世界数据文件，它告诉我将其覆盖在 map 上的位置。我必须根据与图像关联的数据计算图像的mapRect。我的 mapRect 似乎没有正确通过，所以我按照我的 let deltaX 和 deltaY 常量分解了代码。 deltaX 处有一个断点，因此我可以看到发生了什么。当我跨过 deltaX 时，它会正确分配该值。当我跨过 deltaY 时，deltaX 的数据消失，然后是 deltaY 的数据消失。

功能如下:

func parseWorldFileData(worldFileStringToParse: String) -> (worldFileDataStruct) {

    worldFileDataToParse = worldFileStringToParse.components(separatedBy: "\n") //componentsSeparatedByString("\n")

    for i in 0...5 {
        worldFileDataToParse[i] = String(worldFileDataToParse[i].characters.dropLast(2))
    }

    if self.worldFileDataToParse.count >= 6 {

        worldFileData.xDimension = Double(self.worldFileDataToParse[0])!
        worldFileData.rotationParam1 = Double(self.worldFileDataToParse[1])!
        worldFileData.rotationParam2 = Double(self.worldFileDataToParse[2])!
        worldFileData.yDimension = Double(self.worldFileDataToParse[3])!
        worldFileData.xCoordinate = (Double(self.worldFileDataToParse[4])! as CLLocationDegrees)
        worldFileData.yCoordinate = (Double(self.worldFileDataToParse[5])! as CLLocationDegrees)
        worldFileData.easternLongitude = (self.worldFileData.xCoordinate + ((Double(self.worldFileData.imageWidth)) * self.worldFileData.xDimension) as CLLocationDegrees)
        worldFileData.southernLatitude = (self.worldFileData.yCoordinate + ((Double(self.worldFileData.imageHeight)) * self.worldFileData.yDimension) as CLLocationDegrees)
        let deltaX = fabs(self.worldFileData.xCoordinate - self.worldFileData.easternLongitude)
        let deltaY = fabs(self.worldFileData.yCoordinate - self.worldFileData.southernLatitude)
        worldFileData.boundingMapRect = MKMapRectMake(self.worldFileData.xCoordinate, //topLeft.x
                                 self.worldFileData.yCoordinate, //topLeft.y
                                 deltaX, //fabs(topLeft.x-topRight.x)
                                 deltaY) //fabs(topLeft.y - bottomLeft.y)
        worldFileData.midCoordinate = CLLocationCoordinate2D(latitude:((self.worldFileData.southernLatitude + (self.worldFileData.yCoordinate - self.worldFileData.southernLatitude)/2) as CLLocationDegrees), longitude: ((self.worldFileData.xCoordinate + (self.worldFileData.easternLongitude - self.worldFileData.xCoordinate)/2) as CLLocationDegrees))

    } else { print("Error parsing WorldData file.") }


    return worldFileData
}

就在跨过 deltaX 之前，数据是:

worldFileStringToParse  String  "0.00925265225497161\r\n0.000000\r\n0.000000\r\n-0.00925265225497161\r\n-80.2491661765359\r\n41.5148515181108\r\n"  
self    WeatherFun.WorldFileDataModel   0x000060000033b260
worldFileDataToParse    [String]    7 values    
worldFileData   WeatherFun.WorldFileDataModel.worldFileDataStruct   
xDimension  Double  0.0092526522549715995
rotationParam1  Double  0
rotationParam2  Double  0
yDimension  Double  -0.0092526522549715995
xCoordinate CLLocationDegrees   -80.249166176534999
yCoordinate CLLocationDegrees   41.51485151811
imageHeight Double  183.33333333333334
imageWidth  Double  200
easternLongitude    CLLocationDegrees   -78.398635725540686
southernLatitude    CLLocationDegrees   39.818531938031875
boundingMapRect MKMapRect   
midCoordinate   CLLocationCoordinate2D  
deltaX  CLLocationDegrees   
deltaY  CLLocationDegrees

deltaX处步骤后的数据如下:

worldFileStringToParse  String  "0.00925265225497161\r\n0.000000\r\n0.000000\r\n-0.00925265225497161\r\n-80.2491661765359\r\n41.5148515181108\r\n"  
self    WeatherFun.WorldFileDataModel   0x000060000033b260
worldFileDataToParse    [String]    7 values    
worldFileData   WeatherFun.WorldFileDataModel.worldFileDataStruct   
xDimension  Double  0.0092526522549715995
rotationParam1  Double  0
rotationParam2  Double  0
yDimension  Double  -0.0092526522549715995
xCoordinate CLLocationDegrees   -80.249166176534999
yCoordinate CLLocationDegrees   41.51485151811
imageHeight Double  183.33333333333334
imageWidth  Double  200
easternLongitude    CLLocationDegrees   -78.398635725540686
southernLatitude    CLLocationDegrees   39.818531938031875
boundingMapRect MKMapRect   
midCoordinate   CLLocationCoordinate2D  
deltaX  CLLocationDegrees   1.850530450994313
deltaY  CLLocationDegrees   

当跨过deltaY时，数据为:

worldFileStringToParse  String  "0.00925265225497161\r\n0.000000\r\n0.000000\r\n-0.00925265225497161\r\n-80.2491661765359\r\n41.5148515181108\r\n"  
self    WeatherFun.WorldFileDataModel   0x000060000033b260
worldFileDataToParse    [String]    7 values    
worldFileData   WeatherFun.WorldFileDataModel.worldFileDataStruct   
xDimension  Double  0.0092526522549715995
rotationParam1  Double  0
rotationParam2  Double  0
yDimension  Double  -0.0092526522549715995
xCoordinate CLLocationDegrees   -80.249166176534999
yCoordinate CLLocationDegrees   41.51485151811
imageHeight Double  183.33333333333334
imageWidth  Double  200
easternLongitude    CLLocationDegrees   -78.398635725540686
southernLatitude    CLLocationDegrees   39.818531938031875
boundingMapRect MKMapRect   
midCoordinate   CLLocationCoordinate2D  
deltaX  CLLocationDegrees   
deltaY  CLLocationDegrees   1.696319580078125

当我进入boundingMapRect计算时，这是我的数据:

worldFileStringToParse  String  "0.00925265225497161\r\n0.000000\r\n0.000000\r\n-0.00925265225497161\r\n-80.2491661765359\r\n41.5148515181108\r\n"  
self    WeatherFun.WorldFileDataModel   0x000060000033b260
worldFileDataToParse    [String]    7 values    
worldFileData   WeatherFun.WorldFileDataModel.worldFileDataStruct   
xDimension  Double  0.0092526522549715995
rotationParam1  Double  0
rotationParam2  Double  0
yDimension  Double  -0.0092526522549715995
xCoordinate CLLocationDegrees   -80.249166176534999
yCoordinate CLLocationDegrees   41.51485151811
imageHeight Double  183.33333333333334
imageWidth  Double  200
easternLongitude    CLLocationDegrees   -78.398635725540686
southernLatitude    CLLocationDegrees   39.818531938031875
boundingMapRect MKMapRect   
midCoordinate   CLLocationCoordinate2D  
deltaX  CLLocationDegrees   
deltaY  CLLocationDegrees   

有人知道发生了什么吗？计算似乎是正确的，因为覆盖图的 mapRect 应跨越 map 上的该距离。然而，当输入boundingMapRect的计算时，我的deltaX似乎消失了。救命!!!

Answer 1

进一步追踪后，数据又出现了。我不确定为什么会发生这种情况，这有点令人不安，但我对 future 的建议是坚持到底。