public static List<HeatPoint> Read(string filePath)
{
var result = new List<HeatPoint>();
using (var sr = new StreamReader(filePath))
{
while (!sr.EndOfStream)
{
var vals = sr.ReadLine().Split(',');
var point = new HeatPoint();
point.X = float.Parse(vals[0]);
point.Y = float.Parse(vals[1]);
point.W = float.Parse(vals[2]);
result.Add(point);
}
}
return result;
}
List<HeatPoint> randomPoints(int width, int height, int count)
{
var result = new List<HeatPoint>();
var r = new Random();
for (int i = 0; i < count; i++)
{
var x = r.Next(width);
var y = r.Next(height);
//var w = (float)r.NextDouble()/2;
var point = new HeatPoint
{
X = x,
Y = y,
W = 1
};
result.Add(point);
}
return result;
}
private void DrawHeatPoint(Graphics Canvas, HeatPoint HeatPoint, int Radius)
{
// Create points generic list of points to hold circumference points
List <Point> CircumferencePointsList = new List <Point>();
// Create an empty point to predefine the point struct used in the circumference loop
Point CircumferencePoint;
// Create an empty array that will be populated with points from the generic list
Point[] CircumferencePointsArray;
// Calculate ratio to scale byte intensity range from 0-255 to 0-1
float fRatio = 1F / Byte.MaxValue;
// Precalulate half of byte max value
byte bHalf = Byte.MaxValue / 2;
// Flip intensity on it's center value from low-high to high-low
int iIntensity = (byte)(HeatPoint.Intensity - ((HeatPoint.Intensity - bHalf) * 2));
// Store scaled and flipped intensity value for use with gradient center location
float fIntensity = iIntensity * fRatio;
// Loop through all angles of a circle
// Define loop variable as a double to prevent casting in each iteration
// Iterate through loop on 10 degree deltas, this can change to improve performance
for (double i = 0; i <= 360; i += 10)
{
// Replace last iteration point with new empty point struct
CircumferencePoint = new Point();
// Plot new point on the circumference of a circle of the defined radius
// Using the point coordinates, radius, and angle
// Calculate the position of this iterations point on the circle
CircumferencePoint.X = Convert.ToInt32(HeatPoint.X + Radius * Math.Cos(ConvertDegreesToRadians(i)));
CircumferencePoint.Y = Convert.ToInt32(HeatPoint.Y + Radius * Math.Sin(ConvertDegreesToRadians(i)));
// Add newly plotted circumference point to generic point list
CircumferencePointsList.Add(CircumferencePoint);
}
// Populate empty points system array from generic points array list
// Do this to satisfy the datatype of the PathGradientBrush and FillPolygon methods
CircumferencePointsArray = CircumferencePointsList.ToArray();
// Create new PathGradientBrush to create a radial gradient using the circumference points
PathGradientBrush GradientShaper = new PathGradientBrush(CircumferencePointsArray);
// Create new color blend to tell the PathGradientBrush what colors to use and where to put them
ColorBlend GradientSpecifications = new ColorBlend(3);
// Define positions of gradient colors, use intesity to adjust the middle color to
// show more mask or less mask
GradientSpecifications.Positions = new float[3] {
0, fIntensity, 1
};
// Define gradient colors and their alpha values, adjust alpha of gradient colors to match intensity
GradientSpecifications.Colors = new Color[3] {
Color.FromArgb(0, Color.White), Color.FromArgb(HeatPoint.Intensity, Color.Black), Color.FromArgb(HeatPoint.Intensity, Color.Black)
};
// Pass off color blend to PathGradientBrush to instruct it how to generate the gradient
GradientShaper.InterpolationColors = GradientSpecifications;
// Draw polygon (circle) using our point array and gradient brush
Canvas.FillPolygon(GradientShaper, CircumferencePointsArray);
}
protected override void DrawCore(IEnumerable <Feature> features, GeoCanvas canvas, System.Collections.ObjectModel.Collection <SimpleCandidate> labelsInThisLayer, System.Collections.ObjectModel.Collection <SimpleCandidate> labelsInAllLayers)
{
Bitmap intensityBitmap = null;
Bitmap colorBitmap = null;
GeoImage geoImage = null;
MemoryStream pngStream = null;
try
{
// Load the default color palette if it does not exisit
// or does not have the right amount of colors
if (colorPalette.Count != 256)
{
colorPalette = GetDefaultColorPalette();
}
intensityBitmap = new Bitmap(Convert.ToInt32(canvas.Width), Convert.ToInt32(canvas.Height));
Graphics Surface = Graphics.FromImage(intensityBitmap);
Surface.Clear(Color.Transparent);
Surface.Dispose();
List <HeatPoint> heatPoints = new List <HeatPoint>();
foreach (Feature feature in features)
{
if (feature.GetWellKnownType() == WellKnownType.Point)
{
PointShape pointShape = (PointShape)feature.GetShape();
ScreenPointF screenPoint = ExtentHelper.ToScreenCoordinate(canvas.CurrentWorldExtent, pointShape, canvas.Width, canvas.Height);
double realValue;
if (intensityRangeStart != 0 && intensityRangeEnd != 0 && intensityRangeStart != intensityRangeEnd && intensityColumnName != string.Empty)
{
if (intensityRangeStart < intensityRangeEnd)
{
realValue = (255 / (intensityRangeEnd - intensityRangeStart)) * (GetDoubleValue(feature.ColumnValues[intensityColumnName], intensityRangeStart, intensityRangeEnd) - intensityRangeStart);
}
else
{
realValue = (255 / (intensityRangeEnd - intensityRangeStart)) * (intensityRangeEnd - GetDoubleValue(feature.ColumnValues[intensityColumnName], intensityRangeStart, intensityRangeEnd));
}
}
else
{
realValue = intensity;
}
HeatPoint heatPoint = new HeatPoint(Convert.ToInt32(screenPoint.X), Convert.ToInt32(screenPoint.Y), Convert.ToByte(realValue));
heatPoints.Add(heatPoint);
}
}
//Calls the function to get the pixel size of the point based on the world point size and the current extent of the map.
float size = GetPointSize(canvas);
// Create the intensity bitmap
intensityBitmap = CreateIntensityMask(intensityBitmap, heatPoints, Convert.ToInt32(size));
// Color the intensity bitmap
colorBitmap = Colorize(intensityBitmap, (byte)alpha, colorPalette);
// Create a geoimage from the color bitmap
pngStream = new MemoryStream();
colorBitmap.Save(pngStream, System.Drawing.Imaging.ImageFormat.Png);
geoImage = new GeoImage(pngStream);
// Write the geoimage to the canvas
canvas.DrawWorldImageWithoutScaling(geoImage, canvas.CurrentWorldExtent.GetCenterPoint().X, canvas.CurrentWorldExtent.GetCenterPoint().Y, DrawingLevel.LevelOne);
}
finally
{
// Make sure we clean up all the memeory that we use durring the process
if (intensityBitmap != null)
{
intensityBitmap.Dispose();
}
if (colorBitmap != null)
{
colorBitmap.Dispose();
}
if (geoImage != null)
{
geoImage.Dispose();
}
if (pngStream != null)
{
pngStream.Dispose();
}
}
}
