private async void SKCanvasView_OnPaintSurface(object sender, SKPaintSurfaceEventArgs e)
{
var canvas = e.Surface.Canvas;
canvas.Clear(SKColors.Black);
var point = _complex.ToPoint(time, this.Width / 2 + 100, this.Height / 2);
_path.Insert(0, point);
canvas.DrawPoints(SKPointMode.Polygon, _path.ToArray(), new SKPaint()
{
Color = SKColors.White,
StrokeWidth = 5,
StrokeJoin = SKStrokeJoin.Round,
FilterQuality = SKFilterQuality.High,
StrokeCap = SKStrokeCap.Round,
IsAntialias = true,
HintingLevel = SKPaintHinting.NoHinting,
Style = SKPaintStyle.Fill,
DeviceKerningEnabled = true
});
time += (2f * Math.PI) / Count;
if (time > 2f * Math.PI)
{
time = 0;
_path.Clear();
}
await Task.Delay(1);
SkCanvasView.InvalidateSurface();
}
private void SkCanvasView_OnTouch(object sender, SKTouchEventArgs e)
{
// to fix the UWP touch bevaior
if (Device.RuntimePlatform == Device.UWP)
{
// avoid mouse over touch events
if (!e.InContact)
{
return;
}
}
_lastTouchPoint = e.Location;
var canvasSize = SkCanvasView.CanvasSize;
// Check for each touch point XY position to be inside Canvas
// Ignore any Touch event ocurred outside the Canvas region
if ((e.Location.X > 0 && e.Location.X < canvasSize.Width) &&
(e.Location.Y > 0 && e.Location.Y < canvasSize.Height))
{
e.Handled = true;
// update the Canvas as you wish
SkCanvasView.InvalidateSurface();
}
}
private async void PickImageEffectButton_Clicked(object sender, EventArgs e)
{
var selection = await DisplayActionSheet("Pick an Image Effect", null, "Cancel", imageEffectsList.ToArray());
if (selection != null && selection != "Cancel")
{
selectedImageEffect = selection;
EffectNameLabel.Text = $"{selectedImageEffect}";
SkCanvasView.InvalidateSurface();
}
}
private async void PickShapeToDrawButton_Clicked(object sender, EventArgs e)
{
var selection = await DisplayActionSheet("Pick a Shape", null, "Cancel", shapesList.ToArray());
if (selection != null && selection != "Cancel")
{
selectedShape = selection;
DrawingShapeNameLabel.Text = $"Drawing {selectedShape}";
SkCanvasView.InvalidateSurface();
}
}
private void SetPointerRingPosition(double xPositionUnits, double yPositionUnits)
{
var xPosition = SkCanvasView.CanvasSize.Width
* xPositionUnits; // Calculate actual X Position
var yPosition = SkCanvasView.CanvasSize.Height
* yPositionUnits; // Calculate actual Y Position
// Update as last touch Position on Canvas
_lastTouchPoint = new SKPoint(Convert.ToSingle(xPosition), Convert.ToSingle(yPosition));
SkCanvasView.InvalidateSurface();
}
private void SkCanvasView_Touch(object sender, SkiaSharp.Views.Forms.SKTouchEventArgs e)
{
if (e.ActionType == SkiaSharp.Views.Forms.SKTouchAction.Pressed)
{
_lastTouchPoint = e.Location;
e.Handled = true;
}
_lastTouchPoint = e.Location;
SkCanvasView.InvalidateSurface();
}
protected override void OnAppearing()
{
if (!start)
{
StartThreads();
XplatUIMine.GetInstance().Keyboard = new Keyboard(Entry);
start = true;
}
SkCanvasView.InvalidateSurface();
base.OnAppearing();
}
/// <summary>
/// Draw the boarder
/// </summary>
/// <returns></returns>
private async Task PlaceholderToTitleAsync()
{
_strokeDashStart = new DashedStroke(
intervals: new float[] { 0, new SKPathMeasure(_borderPath).Length },
phase: -0);
_strokeDashEnd = new DashedStroke(
intervals: new float[] { new SKPathMeasure(_borderPath).Length, new SKPathMeasure(_borderPath).Length },
phase: -0);
var anim = new DashedStrokeAnimation(
from: _strokeDashStart,
to: _strokeDashEnd,
duration: ANIMATION_DURATION);
await anim.Start((strokeDashToDraw) => SkCanvasView.InvalidateSurface());
}
private void SkCanvasView_OnTouch(object sender, SKTouchEventArgs e)
{
_lastTouchPoint = e.Location;
var canvasSize = SkCanvasView.CanvasSize;
// Check for each touch point XY position to be inside Canvas
// Ignore any Touch event ocurred outside the Canvas region
if ((e.Location.X > 0 && e.Location.X < canvasSize.Width) &&
(e.Location.Y > 0 && e.Location.Y < canvasSize.Height))
{
e.Handled = true;
// update the Canvas as you wish
SkCanvasView.InvalidateSurface();
}
}
const double cycleTime = 1000; // in milliseconds
private void InitAnimation()
{
pageIsActive = true;
stopwatch.Start();
Device.StartTimer(TimeSpan.FromMilliseconds(33), () =>
{
// calculate t for current tick with regards to cycletime
t = (float)(stopwatch.Elapsed.TotalMilliseconds % cycleTime / cycleTime);
SkCanvasView.InvalidateSurface();
if (!pageIsActive)
{
stopwatch.Stop();
}
return(pageIsActive);
});
}
