/// <summary>
/// 读取栅格块为字节数组（自动拉伸）
/// </summary>
/// <param name="band"></param>
/// <param name="xOffset"></param>
/// <param name="yOffset"></param>
/// <param name="xSize"></param>
/// <param name="ySize"></param>
/// <param name="width"></param>
/// <param name="height"></param>
/// <returns></returns>
public static byte[] ReadBand(this Band band, int xOffset, int yOffset, int xSize, int ySize, int width, int height)
{
byte[] buffer = null;
if (band == null || width == 0 || height == 0)
{
return(buffer);
}
int length = width * height;
DataType dataType = band.DataType;
IntPtr bufferPtr;
// Percentage truncation
double minPercent = 0.5;
double maxPercent = 0.5;
band.GetMaximum(out double maxValue, out int hasvalue);
band.GetMinimum(out double minValue, out hasvalue);
double dValue = maxValue - minValue;
double highValue = maxValue - dValue * maxPercent / 100;
double lowValue = minValue + dValue * minPercent / 100;
double factor = 255 / (highValue - lowValue); // 系数
CPLErr err = CPLErr.CE_None;
lock (_lockObj)
{
switch (dataType)
{
case DataType.GDT_Unknown:
throw new Exception("Unknown datatype");
case DataType.GDT_Byte:
{
buffer = new byte[length];
bufferPtr = GCHandleHelper.GetIntPtr(buffer);
err = band.ReadRaster(xOffset, yOffset, xSize, ySize, bufferPtr, width, height, dataType, 0, 0);
//for (int i = 0; i < length; i++)
//{
// buffer[i] = buffer[i].StretchToByteValue(highValue, lowValue, factor);//做拉伸时才需要
//}
}
break;
case DataType.GDT_UInt16:
{
ushort[] tmpBuffer = new ushort[length];
bufferPtr = GCHandleHelper.GetIntPtr(tmpBuffer);
err = band.ReadRaster(xOffset, yOffset, xSize, ySize, bufferPtr, width, height, dataType, 0, 0);
buffer = new byte[length];
for (int i = 0; i < length; i++)
{
buffer[i] = tmpBuffer[i].StretchToByteValue(highValue, lowValue, factor);
}
}
break;
case DataType.GDT_Int16:
{
short[] tmpBuffer = new short[length];
bufferPtr = GCHandleHelper.GetIntPtr(tmpBuffer);
err = band.ReadRaster(xOffset, yOffset, xSize, ySize, bufferPtr, width, height, dataType, 0, 0);
buffer = new byte[length];
for (int i = 0; i < length; i++)
{
buffer[i] = tmpBuffer[i].StretchToByteValue(highValue, lowValue, factor);
}
}
break;
case DataType.GDT_UInt32:
{
uint[] tmpBuffer = new uint[length];
bufferPtr = GCHandleHelper.GetIntPtr(tmpBuffer);
err = band.ReadRaster(xOffset, yOffset, xSize, ySize, bufferPtr, width, height, dataType, 0, 0);
buffer = new byte[length];
for (int i = 0; i < length; i++)
{
buffer[i] = tmpBuffer[i].StretchToByteValue(highValue, lowValue, factor);
}
}
break;
case DataType.GDT_Int32:
{
int[] tmpBuffer = new int[length];
bufferPtr = GCHandleHelper.GetIntPtr(tmpBuffer);
err = band.ReadRaster(xOffset, yOffset, xSize, ySize, bufferPtr, width, height, dataType, 0, 0);
buffer = new byte[length];
for (int i = 0; i < length; i++)
{
buffer[i] = tmpBuffer[i].StretchToByteValue(highValue, lowValue, factor);
}
}
break;
case DataType.GDT_Float32:
{
float[] tmpBuffer = new float[length];
bufferPtr = GCHandleHelper.GetIntPtr(tmpBuffer);
err = band.ReadRaster(xOffset, yOffset, xSize, ySize, bufferPtr, width, height, dataType, 0, 0);
buffer = new byte[length];
for (int i = 0; i < length; i++)
{
buffer[i] = tmpBuffer[i].StretchToByteValue(highValue, lowValue, factor);
}
}
break;
case DataType.GDT_Float64:
{
double[] tmpBuffer = new double[length];
bufferPtr = GCHandleHelper.GetIntPtr(tmpBuffer);
err = band.ReadRaster(xOffset, yOffset, xSize, ySize, bufferPtr, width, height, dataType, 0, 0);
buffer = new byte[length];
for (int i = 0; i < length; i++)
{
buffer[i] = tmpBuffer[i].StretchToByteValue(highValue, lowValue, factor);
}
}
break;
case DataType.GDT_CInt16:
case DataType.GDT_CInt32:
case DataType.GDT_CFloat32:
case DataType.GDT_CFloat64:
case DataType.GDT_TypeCount:
throw new NotImplementedException();
}
}
return(buffer);
}
/// <summary>
/// 按照BGR(A)顺序读取栅格并返回位图的字节数组
/// </summary>
/// <param name="dataset">栅格数据集</param>
/// <param name="xOffset">X偏移</param>
/// <param name="yOffset">Y偏移</param>
/// <param name="xSize">X宽度</param>
/// <param name="ySize">Y宽度</param>
/// <param name="width">位图长度</param>
/// <param name="height">位图宽度</param>
/// <param name="bandCount">波段数</param>
/// <param name="bandMap">波段映射</param>
/// <param name="pixelSpace">像素间隔</param>
/// <param name="lineSpace">行间隔</param>
/// <param name="bandSpace">波段间隔</param>
/// <param name="readABand">是否读取透明波段</param>
/// <returns>位图的字节数组</returns>
public static byte[] ReadBmpBytes(this Dataset dataset, int xOffset, int yOffset, int xSize, int ySize, int width, int height, int bandCount, int[] bandMap, int pixelSpace, int lineSpace, int bandSpace, bool readABand = false)
{
byte[] buffer = null;
if (dataset == null || xOffset < 0 || yOffset < 0 || xSize <= 0 || ySize <= 0 || width <= 0 || height <= 0 || dataset.RasterXSize < (xOffset + xSize) || dataset.RasterYSize < (yOffset + ySize))
{
return(buffer);
}
int destBandCount;
if (readABand)
{
destBandCount = 4;
}
else
{
destBandCount = 3;
}
if (dataset.RasterCount < destBandCount || bandCount != destBandCount || bandMap?.Length != destBandCount)
{
return(buffer);
}
int length = width * height * bandCount;
DataType dataType;
double maxValue, minValue;
using (var band = dataset.GetRasterBand(1))
{
dataType = band.DataType;
band.GetMaximum(out maxValue, out int hasvalue);
band.GetMinimum(out minValue, out hasvalue);
}
IntPtr bufferPtr;
// Percentage truncation
double minPercent = 0.5;
double maxPercent = 0.5;
double dValue = maxValue - minValue;
double highValue = maxValue - dValue * maxPercent / 100;
double lowValue = minValue + dValue * minPercent / 100;
double factor = 255 / (highValue - lowValue); // 系数
CPLErr err = CPLErr.CE_None;
lock (_lockObj)
{
switch (dataType)
{
case DataType.GDT_Unknown:
throw new Exception("Unknown datatype");
case DataType.GDT_Byte:
{
buffer = new byte[length];
bufferPtr = GCHandleHelper.GetIntPtr(buffer);
err = dataset.ReadRaster(xOffset, yOffset, xSize, ySize, bufferPtr, width, height, dataType, bandCount, bandMap, pixelSpace, lineSpace, bandSpace);
//for (int i = 0; i < length; i++)
//{
// buffer[i] = buffer[i].StretchToByteValue(highValue, lowValue, factor);//做拉伸时才需要
//}
}
break;
case DataType.GDT_UInt16:
{
ushort[] tmpBuffer = new ushort[length];
bufferPtr = GCHandleHelper.GetIntPtr(tmpBuffer);
err = dataset.ReadRaster(xOffset, yOffset, xSize, ySize, bufferPtr, width, height, dataType, bandCount, bandMap, pixelSpace, lineSpace, bandSpace);
buffer = new byte[length];
for (int i = 0; i < length; i++)
{
buffer[i] = tmpBuffer[i].StretchToByteValue(highValue, lowValue, factor);
}
}
break;
case DataType.GDT_Int16:
{
short[] tmpBuffer = new short[length];
bufferPtr = GCHandleHelper.GetIntPtr(tmpBuffer);
err = dataset.ReadRaster(xOffset, yOffset, xSize, ySize, bufferPtr, width, height, dataType, bandCount, bandMap, pixelSpace, lineSpace, bandSpace);
buffer = new byte[length];
for (int i = 0; i < length; i++)
{
buffer[i] = tmpBuffer[i].StretchToByteValue(highValue, lowValue, factor);
}
}
break;
case DataType.GDT_UInt32:
{
uint[] tmpBuffer = new uint[length];
bufferPtr = GCHandleHelper.GetIntPtr(tmpBuffer);
err = dataset.ReadRaster(xOffset, yOffset, xSize, ySize, bufferPtr, width, height, dataType, bandCount, bandMap, pixelSpace, lineSpace, bandSpace);
buffer = new byte[length];
for (int i = 0; i < length; i++)
{
buffer[i] = tmpBuffer[i].StretchToByteValue(highValue, lowValue, factor);
}
}
break;
case DataType.GDT_Int32:
{
int[] tmpBuffer = new int[length];
bufferPtr = GCHandleHelper.GetIntPtr(tmpBuffer);
err = dataset.ReadRaster(xOffset, yOffset, xSize, ySize, bufferPtr, width, height, dataType, bandCount, bandMap, pixelSpace, lineSpace, bandSpace);
buffer = new byte[length];
for (int i = 0; i < length; i++)
{
buffer[i] = tmpBuffer[i].StretchToByteValue(highValue, lowValue, factor);
}
}
break;
case DataType.GDT_Float32:
{
float[] tmpBuffer = new float[length];
bufferPtr = GCHandleHelper.GetIntPtr(tmpBuffer);
err = dataset.ReadRaster(xOffset, yOffset, xSize, ySize, bufferPtr, width, height, dataType, bandCount, bandMap, pixelSpace, lineSpace, bandSpace);
buffer = new byte[length];
for (int i = 0; i < length; i++)
{
buffer[i] = tmpBuffer[i].StretchToByteValue(highValue, lowValue, factor);
}
}
break;
case DataType.GDT_Float64:
{
double[] tmpBuffer = new double[length];
bufferPtr = GCHandleHelper.GetIntPtr(tmpBuffer);
err = dataset.ReadRaster(xOffset, yOffset, xSize, ySize, bufferPtr, width, height, dataType, bandCount, bandMap, pixelSpace, lineSpace, bandSpace);
buffer = new byte[length];
for (int i = 0; i < length; i++)
{
buffer[i] = tmpBuffer[i].StretchToByteValue(highValue, lowValue, factor);
}
}
break;
case DataType.GDT_CInt16:
case DataType.GDT_CInt32:
case DataType.GDT_CFloat32:
case DataType.GDT_CFloat64:
case DataType.GDT_TypeCount:
throw new NotImplementedException();
}
}
return(buffer);
}
