private void PaintSurface(object sender, SKPaintSurfaceEventArgs e)
{
const int count = 10; //number of digits in outer circle
const float r = 100f; //outer circle radius
const float f = 40f; //font size in points
const float thicknessAdjust = 2 * f / 3; //thickness adjust of the two circles
const float θ = 360f / count; //angle to rotate when drawing each digit
if (painter == null)
{
painter = new SkiaSharp.MathPainter(f); //{ GlyphBoxColor = (SKColors.Red, SKColors.Red) };
}
var cx = e.Info.Width / 2;
var cy = e.Info.Height / 2;
var c = e.Surface.Canvas;
//draw outer circle
c.DrawCircle(cx, cy, r + thicknessAdjust, black);
painter.TextColor = SKColors.White;
for (int i = 0; i < count; i++)
{
painter.LaTeX = i.ToString();
var m = painter.Measure.Value;
painter.Draw(c, cx - m.Width / 2, cy - r - m.Y / 2);
c.RotateDegrees(θ, cx, cy);
}
//draw inner circle
c.DrawCircle(cx, cy, r - thicknessAdjust, white);
painter.TextColor = SKColors.Black;
painter.LaTeX = @"\raisebox{25mu}{\text{\kern.7222emC\#}\\Math}"; //.7222em is 13/18em
painter.Draw(c);
}
public static void Draw(SKCanvas c)
{
const int count = 10; //number of digits in outer circle
const float r = 100f; //outer circle radius
const float f = 40f; //font size in points
const float thicknessAdjust = 2 * f / 3; //thickness adjust of the two circles
const float θ = 360f / count; //angle to rotate when drawing each digit
var painter = new SkiaSharp.MathPainter();
var cx = c.DeviceClipBounds.Width / 2;
var cy = c.DeviceClipBounds.Height / 2;
painter.FontSize = f; //{ GlyphBoxColor = (SKColors.Red, SKColors.Red) };
//draw outer circle
using (var black = new SKPaint {
Color = SKColors.Black, IsAntialias = true
})
c.DrawCircle(cx, cy, r + thicknessAdjust, black);
painter.TextColor = SKColors.White;
for (int i = 0; i < count; i++)
{
painter.LaTeX = i.ToString();
var m = painter.Measure() ?? throw new Structures.InvalidCodePathException("Invalid LaTeX");
painter.Draw(c, cx - m.Width / 2, cy + m.Height / 2 - r);
c.RotateDegrees(θ, cx, cy);
}
//draw inner circle
using (var white = new SKPaint {
Color = SKColors.White, IsAntialias = true
})
c.DrawCircle(cx, cy, r - thicknessAdjust, white);
painter.TextColor = SKColors.Black;
painter.LaTeX = @"\ \raisebox{25mu}{\begin{gather}C\#\\Math\end{gather}}\ ";
painter.Draw(c);
}
