public override void DrawPie(double fraction)
{
// Calculate the pie path
fraction = Theme.Clamp(0.0, 1.0, fraction);
double a1 = 3.0 * Math.PI / 2.0;
double a2 = a1 + 2.0 * Math.PI * fraction;
if (fraction == 0.0)
{
return;
}
Context.Cairo.MoveTo(Context.X, Context.Y);
Context.Cairo.Arc(Context.X, Context.Y, Context.Radius, a1, a2);
Context.Cairo.LineTo(Context.X, Context.Y);
// Fill the pie
Color color_a = Colors.GetWidgetColor(GtkColorClass.Background, StateType.Selected);
Color color_b = CairoExtensions.ColorShade(color_a, 1.4);
var fill = new RadialGradient(Context.X, Context.Y, 0,
Context.X, Context.Y, 2.0 * Context.Radius);
fill.AddColorStop(0, color_a);
fill.AddColorStop(1, color_b);
Context.Cairo.SetSource(fill);
Context.Cairo.FillPreserve();
fill.Dispose();
// Stroke the pie
Context.Cairo.SetSourceColor(CairoExtensions.ColorShade(color_a, 0.8));
Context.Cairo.LineWidth = Context.LineWidth;
Context.Cairo.Stroke();
}
private void gradientToolStripMenuItem_Click(object sender, EventArgs e)
{
lastSelected = "gradient";
OnPaintAction = cr =>
{
Gradient pat = new LinearGradient(0.0, 0.0, 0.0, 256.0);
pat.AddColorStopRgba(1, 0, 0, 0, 1);
pat.AddColorStopRgba(0, 1, 1, 1, 1);
cr.Rectangle(0, 0, 256, 256);
cr.SetSource(pat);
cr.Fill();
pat.Dispose();
pat = new RadialGradient(115.2, 102.4, 25.6,
102.4, 102.4, 128.0);
pat.AddColorStopRgba(0, 1, 1, 1, 1);
pat.AddColorStopRgba(1, 0, 0, 0, 1);
cr.SetSource(pat);
cr.Arc(128.0, 128.0, 76.8, 0, 2 * Math.PI);
cr.Fill();
pat.Dispose();
};
Invalidate();
}
//---------------------------------------------------------------------
private static void Gradient()
{
Action <Surface> draw = surface =>
{
using (var c = new Context(surface))
{
Gradient pat = new LinearGradient(0.0, 0.0, 0.0, 256.0);
pat.AddColorStopRgba(1, 0, 0, 0, 1);
pat.AddColorStopRgba(0, 1, 1, 1, 1);
c.Rectangle(0, 0, 256, 256);
c.SetSource(pat);
c.Fill();
pat.Dispose();
pat = new RadialGradient(115.2, 102.4, 25.6,
102.4, 102.4, 128.0);
pat.AddColorStopRgba(0, 1, 1, 1, 1);
pat.AddColorStopRgba(1, 0, 0, 0, 1);
c.SetSource(pat);
c.Arc(128.0, 128.0, 76.8, 0, 2 * Math.PI);
c.Fill();
pat.Dispose();
}
};
using (Surface surface = new ImageSurface(Format.Argb32, 500, 500))
{
draw(surface);
surface.WriteToPng("gradient.png");
}
using (Surface surface = new PdfSurface("gradient.pdf", 500, 500))
{
draw(surface);
surface.WriteToPng("gradient1.png");
}
using (Surface surface = new SvgSurface("gradient.svg", 500, 500))
{
draw(surface);
surface.WriteToPng("gradient2.png");
}
}
void DrawLed(int index, Context cr)
{
PointD led = new PointD();
led.X = imageX + CurrentDefinition.Leds[index].X / scale;
led.Y = imageY + CurrentDefinition.Leds[index].Y / scale;
double glowRadius = LedSize * 2 / scale;
RadialGradient gradient = new RadialGradient(led.X, led.Y, 0, led.X, led.Y, glowRadius);
gradient.AddColorStop(0, new Cairo.Color(ColorBuffer[index].Red, ColorBuffer[index].Green, ColorBuffer[index].Blue, ColorBuffer[index].Alpha));
gradient.AddColorStop(0.15, new Cairo.Color(ColorBuffer[index].Red, ColorBuffer[index].Green, ColorBuffer[index].Blue, ColorBuffer[index].Alpha));
gradient.AddColorStop(1, new Cairo.Color(ColorBuffer[index].Red, ColorBuffer[index].Green, ColorBuffer[index].Blue, 0));
cr.Save();
cr.Rectangle(led.X - glowRadius, led.Y - glowRadius, glowRadius * 2, glowRadius * 2);
cr.Clip();
cr.SetSource(gradient);
cr.Mask(gradient);
cr.Restore();
gradient.Dispose();
}
