public void Start(Action <StrokeDash> onValueCallback)
{
_currStrokeDash = From;
var anim = new Animation(_ => onValueCallback(_currStrokeDash));
anim.Add(0, 1, new Animation(
callback: v => _currStrokeDash.Phase = (float)v,
start: From.Phase,
end: To.Phase,
easing: Easing));
anim.Add(0, 1, new Animation(
callback: v => _currStrokeDash.Intervals[0] = (float)v,
start: From.Intervals[0],
end: To.Intervals[0],
easing: Easing));
anim.Add(0, 1, new Animation(
callback: v => _currStrokeDash.Intervals[1] = (float)v,
start: From.Intervals[1],
end: To.Intervals[1],
easing: Easing));
anim.Commit(
owner: Application.Current.MainPage,
name: "highlightAnimation",
length: (uint)Duration.TotalMilliseconds);
}
void DrawDash(SKCanvasView skCanvasView, StrokeDash fromDash, StrokeDash toDash)
{
if (fromDash != null)
{
var anim = new StrokeDashAnimation(
from: fromDash,
to: toDash,
duration: _highlightSettings.AnimationDuration);
anim.Start((strokeDashToDraw) => RequestDraw(skCanvasView, strokeDashToDraw));
}
else
{
RequestDraw(skCanvasView, toDash);
}
}
public void Draw(SKCanvasView skCanvasView, SKCanvas skCanvas)
{
skCanvas.Clear();
if (_highlightState == null)
{
return;
}
if (_skPaint == null)
{
_skPaint = CreateHighlightSkPaint(skCanvasView, _highlightSettings, _highlightState.HighlightPath);
}
StrokeDash strokeDash = _highlightState.StrokeDash;
// Comment the next line to see whole path without dash effect
_skPaint.PathEffect = SKPathEffect.CreateDash(strokeDash.Intervals, strokeDash.Phase);
skCanvas.DrawPath(_highlightState.HighlightPath.Path, _skPaint);
}
public void HighlightElement(View viewToHighlight, SKCanvasView skCanvasView, Layout <View> formLayout)
{
IList <View> layoutChildren = formLayout.Children;
if (_highlightState == null)
{
var path = HighlightPath.Create(skCanvasView, layoutChildren, _highlightSettings.StrokeWidth);
_highlightState = new HighlightState()
{
HighlightPath = path
};
}
HighlightPath highlightPath = _highlightState.HighlightPath;
int currHighlightViewId = _highlightState.CurrHighlightedViewId;
int iViewIdToHighlight = highlightPath.GetViewId(layoutChildren, viewToHighlight);
if (currHighlightViewId == iViewIdToHighlight)
{
return;
}
StrokeDash fromDash;
if (currHighlightViewId != -1)
{
fromDash = _highlightState.StrokeDash;
}
else
{
fromDash = new StrokeDash(highlightPath.GetDashForView(layoutChildren, iViewIdToHighlight));
}
_highlightState.CurrHighlightedViewId = iViewIdToHighlight;
StrokeDash toDash = new StrokeDash(highlightPath.GetDashForView(layoutChildren, viewToHighlight));
DrawDash(skCanvasView, fromDash, toDash);
}
public static HighlightPath Create(SKCanvasView skCanvasView, IList <View> layoutChildren, double strokeWidth)
{
var path = new SKPath();
var highlightPath = new HighlightPath()
{
Path = path
};
strokeWidth = (float)skCanvasView.FromPixels(new Point(0, strokeWidth)).Y;
foreach (View view in layoutChildren)
{
int iStrokeDashCount = highlightPath.DashCount;
Rectangle viewBounds = skCanvasView.FromPixels(view.Bounds);
if (!(view is Entry) && !(view is Button))
{
continue;
}
if (path.Points.Length == 0)
{
// Move path point at the left and below of the view
path.MoveTo(
x: (float)viewBounds.X,
y: (float)viewBounds.Y + (float)viewBounds.Height + (float)strokeWidth / 2);
}
float xCurr = path.LastPoint.X;
float yCurr = path.LastPoint.Y;
// Add arch for views except first one
if (iStrokeDashCount > 0)
{
float d = iStrokeDashCount % 2 == 0 ? -1 : 1;
float arcHeight = (float)viewBounds.Y + (float)viewBounds.Height - path.LastPoint.Y + (float)strokeWidth / 2;
path.ArcTo(new SKRect(xCurr - arcHeight / 2, yCurr, xCurr + arcHeight / 2, yCurr + arcHeight), -90, 180 * d, false);
}
float dashOffset = new SKPathMeasure(path).Length;
// Add line below the view
// If it's not the first view, the start point is the end from arc end point
// and line direction is either to view start or view end
path.LineTo((float)viewBounds.X + (float)viewBounds.Width * (iStrokeDashCount % 2 == 0 ? 1 : 0), path.LastPoint.Y);
if (view is Button)
{
xCurr = path.LastPoint.X;
yCurr = path.LastPoint.Y;
// Draw arc from below button to above button
float d = iStrokeDashCount % 2 == 0 ? -1 : 1;
float arcHeight = (float)viewBounds.Height + (float)strokeWidth;
path.ArcTo(new SKRect(xCurr - arcHeight / 2, yCurr - arcHeight, xCurr + arcHeight / 2, yCurr), 90, 180 * d, false);
// Draw horizontal line above the button
path.LineTo(xCurr + (float)viewBounds.Width * d, path.LastPoint.Y);
// Draw arc pointing down
xCurr = path.LastPoint.X;
yCurr = path.LastPoint.Y;
path.ArcTo(new SKRect(xCurr - arcHeight / 2, yCurr, xCurr + arcHeight / 2, yCurr + arcHeight), -90, 180 * d, false);
}
float solidDashLength = new SKPathMeasure(path).Length - dashOffset;
var strokeDash = new StrokeDash(
intervals: new float[] { solidDashLength, 0 },
phase: -dashOffset);
highlightPath.SetDashForView(layoutChildren, view, strokeDash);
}
// Compute the 2nd value of interval, which is the length of remaining path
float pathLength = new SKPathMeasure(path).Length;
for (int i = 0; i < highlightPath.DashCount; ++i)
{
StrokeDash d = highlightPath.GetDash(i);
d.Intervals[1] = pathLength - d.Intervals[0];
}
return(highlightPath);
}
public void SetDashForView(IList <View> layoutChildren, View view, StrokeDash strokeDash) => _strokeDashList[GetViewId(layoutChildren, view)] = strokeDash;
void RequestDraw(SKCanvasView skCanvasView, StrokeDash strokeDashToDraw)
{
_highlightState.StrokeDash = strokeDashToDraw;
skCanvasView.InvalidateSurface();
}
public StrokeDash(StrokeDash strokeDash)
: this(strokeDash.Intervals, strokeDash.Phase)
{
}
public StrokeDashAnimation(StrokeDash from, StrokeDash to, TimeSpan duration)
{
From = from;
To = to;
Duration = duration;
}