/// <summary>
/// 缩放至图层
/// </summary>
/// <param name="layer">选中图层</param>
/// <returns></returns>
public void Extent(MapLayer layer)
{
float[] MBR = new float[4];
layer.GetExtent(MBR);
float minX = MBR[0];
float minY = MBR[1];
float maxX = MBR[2];
float maxY = MBR[3];
mOffsetX = MBR[0];
mOffsetY = MBR[3];
if (maxX - minX == 0 && maxY - minY == 0)
{
return;
}
else if (maxY - minY == 0)
{
_DisplayScale = (maxX - minX) / 780;
mOffsetY = minY - _DisplayScale * 445;
}
else if ((maxX - minX) / (maxY - minY) > 1.7528)
{
_DisplayScale = (maxX - minX) / 780;
}
else
{
_DisplayScale = (maxY - minY) / 445;
}
Refresh();
//触发事件
if (DisplayScaleChanged != null)
{
DisplayScaleChanged(this);
}
}
//绘制tiff图层
private void DrawTiffLayer(Graphics g, MapLayer curLayer, int index)
{
//PictureBox pictureBox = new PictureBox();
float[] MBR = new float[4];
curLayer.GetExtent(MBR);
int width, height;
//根据比例尺确定图片大小和位置
PointF locationPoint = FromMapPoint(new PointF(MBR[0], MBR[3]));
if (locationPoint.Y < this.Height && locationPoint.X < this.Width)
{
width = (int)((MBR[2] - MBR[0]) / _DisplayScale);
height = (int)((MBR[3] - MBR[1]) / _DisplayScale);
Dataset ds = Gdal.Open(curLayer.FilePath, Access.GA_ReadOnly);
int imgWidth = ds.RasterXSize;
int imgHeight = ds.RasterYSize;
float[] r = new float[width * height];
Band band = ds.GetRasterBand(1);
band.ReadRaster(0, 0, imgWidth, imgHeight, r, width, height, 0, 0);
//获取NoData值
double nodata;
int handle = 1;
band.GetNoDataValue(out nodata, out handle);
double[] MinMax = { 0, 0 };
band.ComputeRasterMinMax(MinMax, 0);
int i, j;
Color newColor = Color.Transparent;
for (i = 0; i < width; i++)
{
for (j = 0; j < height; j++)
{
float value = r[i + j * width]; //像元值
if (value > nodata + 1)
{
if (MapLayers[index].Style.Styles.Count == 0)
{
int value1 = 0;
if (MinMax[0] < -300)//DEM数据拉伸
{
if (value >= -128)
{
value1 = (int)((value + 128) / (MinMax[1] + 128) * 205.0 + 50);
}
}
else
{
value1 = (int)((value - MinMax[0]) / (MinMax[1] - MinMax[0]) * 235.0 + 20);
}
newColor = Color.FromArgb(value1, value1, value1);
}
else if (MapLayers[index].Style.Styles[0].Rules[0].RasterSymbol.ColorMap.Count == 0)
{
int value1 = 0;
if (MinMax[0] < -300)//DEM数据拉伸
{
if (value >= -128)
{
value1 = (int)((value + 128) / (MinMax[1] + 128) * 205.0 + 50);
}
}
else
{
value1 = (int)((value - MinMax[0]) / (MinMax[1] - MinMax[0]) * 235.0 + 20);
}
newColor = Color.FromArgb(value1, value1, value1);
newColor = Color.FromArgb(Convert.ToInt32(255 * curLayer.Style.Styles[0].Rules[0].RasterSymbol.Opacity), newColor);
}
else // 按照Style绘制
{
for (int eCount = 0; eCount < curLayer.Style.Styles[0].Rules[0].RasterSymbol.ColorMap.Count - 1; ++eCount)
{
if (value >= curLayer.Style.Styles[0].Rules[0].RasterSymbol.ColorMap[eCount].Quantity &&
value <= curLayer.Style.Styles[0].Rules[0].RasterSymbol.ColorMap[eCount + 1].Quantity)
{
newColor = Color.FromArgb(Convert.ToInt32(255 * curLayer.Style.Styles[0].Rules[0].RasterSymbol.ColorMap[eCount].Opacity),
ColorTranslator.FromHtml(curLayer.Style.Styles[0].Rules[0].RasterSymbol.ColorMap[eCount].Color));
break;
}
}
}
}
g.FillRectangle(new SolidBrush(newColor), new RectangleF(locationPoint.X + i, locationPoint.Y + j, 1, 1));
}
}
ds.FlushCache();
ds.Dispose();
}
}
