void OnCanvasViewPaintSurface(object sender, SKPaintSurfaceEventArgs args)
{
SKImageInfo info = args.Info;
//determine find smallet axis length
MinorAxisLength = info.Width > info.Height ? info.Height : info.Width;
arcWidth = MinorAxisLength / 30;
arcPadding = MinorAxisLength / 15;
KnobRadius = MinorAxisLength / 30;
float radius = (MinorAxisLength / 2);
//update center
Center = new SKPoint(info.Width / 2, info.Height / 2);
SKSurface surface = args.Surface;
SKCanvas canvas = surface.Canvas;
canvas.Clear();
// canvas.Scale((float)(canvasView.CanvasSize.Width / canvasView.Width));
// SKPaint BackgroundPaint = new SKPaint
// {
// Style = SKPaintStyle.Fill,
// Shader = SKShader.CreateColor(BackgroundColor.ToSKColor()),
// };
//
// canvas.DrawRect(new SKRect(Center.X-(MinorAxisLength/2), Center.Y - (MinorAxisLength / 2), Center.X + (MinorAxisLength / 2), Center.Y + (MinorAxisLength / 2)), BackgroundPaint);
SKPaint arcPaint = new SKPaint
{
Style = SKPaintStyle.Stroke,
Shader = SKShader.CreateColor(ArcColor.ToSKColor()),
StrokeCap = SKStrokeCap.Round,
StrokeWidth = arcWidth + 1,
IsAntialias = true,
};
SKPaint arcBackgroundPaint = new SKPaint
{
Style = SKPaintStyle.Stroke,
Shader = SKShader.CreateColor(ArcBackgroundColor.ToSKColor()),
StrokeCap = SKStrokeCap.Round,
StrokeWidth = arcWidth,
IsAntialias = true,
// ImageFilter = SKImageFilter.CreateDropShadow(0, 0, 2, 2, Color.Black.ToSKColor(), SKDropShadowImageFilterShadowMode.DrawShadowAndForeground)
};
SKPaint KnobPaint = new SKPaint
{
Style = SKPaintStyle.Fill,
Shader = SKShader.CreateColor(KnobColor.ToSKColor()),
IsAntialias = true,
ImageFilter = SKImageFilter.CreateDropShadow(0, 0, 3, 3, ArcColor.MultiplyAlpha(.5).ToSKColor())
};
SKPaint TextPaint = new SKPaint
{
Style = SKPaintStyle.Fill,
Shader = SKShader.CreateColor(TextColor.ToSKColor()),
IsAntialias = true,
TextSize = 40f,
IsStroke = false,
TextAlign = SKTextAlign.Center,
};
//create the rectangle that contains the arc
//SKRect rect = new SKRect(arcPadding, arcPadding, MinorAxisLength - arcPadding, MinorAxisLength - arcPadding);
SKRect rect = new SKRect(arcPadding + Center.X - (MinorAxisLength / 2), arcPadding + Center.Y - (MinorAxisLength / 2), Center.X + (MinorAxisLength / 2) - arcPadding, Center.Y + (MinorAxisLength / 2) - arcPadding);
//var point = LastTouchedPoint;
//calcualte the angle of the last touched point realtive to the center of the arc
var sweepAngle = getsweepangle();
float realAngle = startAngle + sweepAngle;
//Debug.WriteLine($"realAngle:{realAngle % 360}");
float arcRadius = (MinorAxisLength / 2) - arcPadding;;
//get x and y compoents o the point on ther arc
float x = arcRadius * (float)Math.Cos(DegreeToRadian(realAngle));
float y = arcRadius * (float)Math.Sin(DegreeToRadian(realAngle));
//move the points realitve to the center of the chart
// SKRect rect = new SKRect(arcPadding + Center.X - (MinorAxisLength / 2), arcPadding + Center.Y - (MinorAxisLength / 2), Center.X + (MinorAxisLength / 2) - arcPadding, Center.Y + (MinorAxisLength / 2) - arcPadding);
float realtiveX = x + Center.X;
float realtiveY = y + Center.Y;
using (SKPath path = new SKPath())
{
//draw background arc
path.AddArc(rect, startAngle, 300);
canvas.DrawPath(path, arcBackgroundPaint);
}
using (SKPath path = new SKPath())
{
//draw arc showing value
path.AddArc(rect, startAngle, sweepAngle);
canvas.DrawPath(path, arcPaint);
}
//draw current postion
var TextBounds = new SKRect();
var ValueString = String.Format("{0:F" + Precision + "}", Value);
TextPaint.MeasureText(ValueString, ref TextBounds);
canvas.DrawOval(new SKRect(realtiveX - KnobRadius, realtiveY - KnobRadius, realtiveX + KnobRadius, realtiveY + KnobRadius), KnobPaint);
if (ShowValue)
{
canvas.DrawText(ValueString, Center.X, Center.Y + (TextBounds.Height / 2), TextPaint);
}
}
void SKCanvasView_PaintSurface(System.Object sender, SkiaSharp.Views.Forms.SKPaintSurfaceEventArgs e)
{
SKPaint arcColor = new SKPaint
{
Color = ArcColor.ToSKColor(),
StrokeWidth = 2,
Style = SKPaintStyle.StrokeAndFill
};
var w = e.Info.Width;
var h = e.Info.Height;
var canvas = e.Surface.Canvas;
canvas.Clear();
var h1 = h / 3.33f;
float xDelta = w / 165;
float yDelta = h / 6;
var h2 = h1 + yDelta;
var p1 = new SKPoint(0, h1);
var p2 = new SKPoint(xDelta, h2);
var p3 = new SKPoint(w / 3 - xDelta, h2);
var p4 = new SKPoint(w / 3, h1);
var p5 = new SKPoint(2 * w / 3, h1);
var p6 = new SKPoint(2 * w / 3 + xDelta, h2);
var p7 = new SKPoint(w - xDelta, h2);
var p8 = new SKPoint(w, h1);
var e1Xr = (p3.X - p2.X) / 2;
var e2Xr = (p5.X - p4.X) / 2;
var e3Xr = (p7.X - p6.X) / 2;
float e1Yr = h / 2.5f;
float e2Yr = h1;
using (var path = new SKPath())
{
path.MoveTo(0, 0);
path.LineTo(p1);
path.LineTo(p2);
path.ArcTo(e1Xr, e1Yr, 0, SKPathArcSize.Large, SKPathDirection.CounterClockwise, p3.X, p3.Y);
path.LineTo(p4);
path.ArcTo(e2Xr, e2Yr, 0, SKPathArcSize.Large, SKPathDirection.Clockwise, p5.X, p5.Y);
path.LineTo(p6);
path.ArcTo(e3Xr, e1Yr, 0, SKPathArcSize.Large, SKPathDirection.CounterClockwise, p7.X, p7.Y);
path.LineTo(p8);
path.LineTo(w, 0);
canvas.DrawPath(path, arcColor);
}
}