void Draw()
{
int width = 400;
int height = 400;
const int RGBsize = 3;
byte[] buffer = new byte[width * height * RGBsize];
for (int i = 0; i < buffer.Length; i++)
{
buffer[i] = 0xff;
}
GCHandle handle = GCHandle.Alloc(buffer, GCHandleType.Pinned);
try
{
IntPtr pBuf = handle.AddrOfPinnedObject();
using (var pl = new PLStream())
{
pl.sdev("mem");
pl.smem(width, height, pBuf);
pl.init();
pl.env(0, 10.0, 0, 10.0, 0, 0);
pl.join(1.0, 2.0, 7.0, 8.0);
}
Bitmap bmp = new Bitmap(width, height, 3 * width, PixelFormat.Format24bppRgb, pBuf);
this.pictureBox1.Width = width;
this.pictureBox1.Height = height;
this.pictureBox1.Image = bmp;
// bmp.Save("test.bmp");
}
finally
{
handle.Free();
}
}
public static void PlotRegressionChart(PlotChartGeneratorModel generationModel)
{
using (var pl = new PLStream())
{
pl.sdev("pngcairo");
pl.sfnam(generationModel.ImageName);
// use white background with black foreground
pl.spal0("cmap0_alternate.pal");
// Initialize plplot
pl.init();
// set axis limits
pl.env(generationModel.MinLimitX, generationModel.MaxLimitX, generationModel.MinLimitY, generationModel.MaxLimitY,
AxesScale.Independent, AxisBox.CustomXYBoxTicksLabels);
// Set scaling for mail title text 125% size of default
//pl.schr(0, 1.25);
// The main title
pl.lab(generationModel.LabelX, generationModel.LabelY, generationModel.Title);
// plot using different colors
// see http://plplot.sourceforge.net/examples.php?demo=02 for palette indices
pl.col0(1);
// This code is the symbol to paint
char code = (char)9;
double yTotal = 0;
double xTotal = 0;
double xyMultiTotal = 0;
double xSquareTotal = 0;
var totalNumber = 0;
generationModel.PointsList.ForEach(pointsList =>
{
double y0 = 0;
double x0 = 0;
totalNumber += pointsList.Points.Count();
// plot using other color
pl.col0(pointsList.Color);
pointsList.Points.ForEach(point =>
{
var x = new double[1];
var y = new double[1];
x[0] = point.X;
y[0] = point.Y;
if (pointsList.PaintDots)
{
// Paint a dot
pl.poin(x, y, code);
}
else
{
if (!generationModel.DrawRegressionLine)
{
// Draw lines between points
pl.join(x0, y0, point.X, point.Y);
x0 = point.X;
y0 = point.Y;
}
}
xTotal += point.X;
yTotal += point.Y;
xyMultiTotal += point.X * point.Y;
xSquareTotal += point.X * point.X;
});
});
// Regression Line calculation explanation:
// https://www.khanacademy.org/math/statistics-probability/describing-relationships-quantitative-data/more-on-regression/v/regression-line-example
if (generationModel.DrawRegressionLine)
{
if (generationModel.RegressionPointsList != null)
{
var xArray = generationModel.RegressionPointsList.Points.Select(dp => dp.X).ToArray();
var yArray = generationModel.RegressionPointsList.Points.Select(dp => dp.Y).ToArray();
pl.col0(generationModel.RegressionPointsList.Color);
pl.line(xArray, yArray);
}
else
{
double minY = yTotal / totalNumber;
double minX = xTotal / totalNumber;
double minXY = xyMultiTotal / totalNumber;
double minXsquare = xSquareTotal / totalNumber;
double m = ((minX * minY) - minXY) / ((minX * minX) - minXsquare);
double b = minY - (m * minX);
double x1 = generationModel.MinLimitX;
//Function for Y1 in the line
double y1 = (m * x1) + b;
double x2 = generationModel.MaxLimitX;
//Function for Y2 in the line
double y2 = (m * x2) + b;
var xArray = new double[2];
var yArray = new double[2];
xArray[0] = x1;
yArray[0] = y1;
xArray[1] = x2;
yArray[1] = y2;
pl.col0(4);
pl.line(xArray, yArray);
}
}
if (generationModel.DashedPoint != null)
{
pl.col0(CommonConstants.PPLplotColorGreen);
pl.width(2);
// Horizontal Line should go from (0,DashedPoint.Y) to (DashedPoint.X, DashedPoint.Y)
DrawDashedLined(pl, 0, generationModel.DashedPoint.Y, generationModel.DashedPoint.X, generationModel.DashedPoint.Y);
// Vertical Line should go from (DashedPoint.X,0) to (DashedPoint.X, DashedPoint.Y)
DrawDashedLined(pl, generationModel.DashedPoint.X, 0, generationModel.DashedPoint.X, generationModel.DashedPoint.Y);
}
// end page (writes output to disk)
pl.eop();
// output version of PLplot
pl.gver(out var verText);
} // the pl object is disposed here
// Open Chart File In Microsoft Photos App (Or default app, like browser for .svg)
Console.WriteLine("Showing chart...");
var p = new Process();
string chartFileNamePath = @".\" + generationModel.ImageName;
p.StartInfo = new ProcessStartInfo(chartFileNamePath)
{
UseShellExecute = true
};
p.Start();
}
