public void Rotate(RotaryEventArgs args)
{
if (rotating)
{
return;
}
rotating = true;
if (currentState == ONGOING_EVENT_STATE.RIGHT_DIRECTION_ROTATE)
{
if (rightDirectionRotateCount > 0)
{
rightDirectionRotateCount--;
angle += args.IsClockwise ? 30 : -30;
}
else
{
angle = 0;
currentState = ONGOING_EVENT_STATE.LEFT_DIRECTION_ROTATE;
instruction = "Rotate the bezel to the left.";
}
}
else if (currentState == ONGOING_EVENT_STATE.LEFT_DIRECTION_ROTATE)
{
if (leftDirectionRotateCount > 0)
{
leftDirectionRotateCount--;
angle += args.IsClockwise ? 30 : -30;
}
else
{
currentState = ONGOING_EVENT_STATE.BACK_BUTTON_PRESS;
instruction = "Press back button.";
angle = 0;
}
}
canvasView.RotateTo(angle).ContinueWith(
(b) =>
{
rotating = false;
if (angle == 360)
{
canvasView.Rotation = 0;
angle = 0;
}
});
canvasView.InvalidateSurface();
}
protected override bool OnBackButtonPressed()
{
if (currentState == ONGOING_EVENT_STATE.BACK_BUTTON_PRESS)
{
instruction = "Yes, just like that.";
canvasView.InvalidateSurface();
currentState = ONGOING_EVENT_STATE.FINISHED;
// If return value is true, this app will not be closed.
return(true);
}
else
{
// If return value is false, it will be closed.
return(false);
}
}
/// <summary>
/// Constructor
/// </summary>
public RotaryEventPage()
{
// NOTICE: IRotaryEventReceiver object MUST set 'RotaryFocusObject' to get the event.
RotaryFocusObject = this;
// Initialize variables to set the state to rotating right
currentState = ONGOING_EVENT_STATE.RIGHT_DIRECTION_ROTATE;
instruction = "Rotate the bezel to the right.";
angle = 0;
// Initialize gradient to draw arrows
// Create the main canvas new
canvasView = new SKCanvasView();
// Need to set heightRequest and WidthReques to SkiaSharp canvas
canvasView.HeightRequest = 360;
canvasView.WidthRequest = 360;
// Add tap gesture recognizer
var tapGestureRecognizer = new TapGestureRecognizer();
// Show a toast when tapped.
tapGestureRecognizer.Tapped += (s, e) =>
{
Toast.DisplayText("Tapped !!!");
};
// Add to GestureRecognizers in canvas view
canvasView.GestureRecognizers.Add(tapGestureRecognizer);
// This event handler actually draws in SkiaSharp canvas
canvasView.PaintSurface += (sender, e) =>
{
// Right arrow svg data
SKPath rightDirectionArrow = SKPath.ParseSvgPathData("M2.5,4.375l1.5625,-1.25h-1.25a8,8,0,0,0,-6,-6.25a2,2,0,0,1,-0.625,3.125a4.6,4.6,0,0,1,5.875,3.125h-1.25Z");
// Left arrow svg data
SKPath leftDirectionArrow = SKPath.ParseSvgPathData("M-2.5,4.375L-4.0625,3.125H-2.8125A8,8,0,0,1,3.1875,-3.125A2,2,0,0,0,3.8125,0A4.6,4.6,0,0,0,-2.0625,3.125H-0.8125Z");
// Get surface
SKSurface canvasSurface = e.Surface;
// Get canvas of surface
SKCanvas canvas = canvasSurface.Canvas;
// Save canvas here to later retrieve
canvas.Save();
// Initialize canvas before drawing
canvas.Clear(SKColors.Black);
// Handling for the right rotation state
if (currentState == ONGOING_EVENT_STATE.RIGHT_DIRECTION_ROTATE)
{
// To draw arrow for rotating direction, move canvas point
canvas.Translate(e.Info.Width * 3 / 4, e.Info.Height / 4);
// Set scale for the path
SKMatrix matrix = SKMatrix.MakeScale(15, 15);
// Adjust scale before drawing
rightDirectionArrow.Transform(matrix);
// Set a shader for gradient
var colors = new SKColor[] { SKColors.White, SKColors.Blue };
// Points needed for gradient
SKPoint startPoint = new SKPoint(0, 0);
SKPoint endPoint = new SKPoint(20, 20);
var shader = SKShader.CreateLinearGradient(startPoint, endPoint, colors, null, SKShaderTileMode.Clamp);
// Add the shader to paint to present gradient effect
blackStrokePaint.Shader = shader;
// Draw SVG path for right rotate direction arrow
canvas.DrawPath(rightDirectionArrow, blackStrokePaint);
}
else if (currentState == ONGOING_EVENT_STATE.LEFT_DIRECTION_ROTATE)
{
// Move the canvas translate point
canvas.Translate(e.Info.Width * 1 / 4, e.Info.Height / 4);
// Set scale for the path
SKMatrix matrix = SKMatrix.MakeScale(15, 15);
// Set a shader for gradient
leftDirectionArrow.Transform(matrix);
// Colors for gradient
var colors = new SKColor[] { SKColors.White, SKColors.Blue };
// Points for gradient
SKPoint startPoint = new SKPoint(20, 0);
SKPoint endPoint = new SKPoint(0, 20);
// Define a shader for left rotate arrow
var shader = SKShader.CreateLinearGradient(startPoint, endPoint, colors, null, SKShaderTileMode.Clamp);
blackStrokePaint.Shader = shader;
// Draw SVG path for left rotate direction arrow
canvas.DrawPath(leftDirectionArrow, blackStrokePaint);
}
// Need to reset canvas which were changed by Translate
canvas.Restore();
// Text drawing
SKPaint textPaint = new SKPaint
{
// Text color white
Color = SKColors.White,
// Text size 10
TextSize = 10,
// Antialiasing true
IsAntialias = true
};
string str = instruction;
// Before draw a text, need to calculate total width of a text to locate in the middle
float textWidth = textPaint.MeasureText(str);
textPaint.TextSize = 0.7f * e.Info.Width * textPaint.TextSize / textWidth;
// Draw instruction
SKRect textBounds = new SKRect();
textPaint.MeasureText(str, ref textBounds);
float xText = e.Info.Width / 2 - textBounds.MidX;
float yText = e.Info.Height / 2 - textBounds.MidY;
canvas.DrawText(str, xText, yText, textPaint);
};
Content = new StackLayout
{
Children =
{
canvasView
}
};
}
/// <summary>
/// Rotate
/// </summary>
/// <param name="args">RotaryEventArgs</param>
public void Rotate(RotaryEventArgs args)
{
// When rotating (previous rotation is ongoing, do nothing.
if (rotating)
{
return;
}
// Set ongoing flag true
rotating = true;
// Right rotate handling
if (currentState == ONGOING_EVENT_STATE.RIGHT_DIRECTION_ROTATE)
{
// If at least one rotation performed.
if (rightDirectionRotateCount > 0)
{
// Decrease rotation count
rightDirectionRotateCount--;
// Increase the angle to rotate canvas
angle += args.IsClockwise ? 30 : -30;
}
else
{
// Finished to rotate right. Set angle to zero for left rotate
angle = 0;
// Set the state to rotate left
currentState = ONGOING_EVENT_STATE.LEFT_DIRECTION_ROTATE;
// Change the instruction
instruction = "Rotate the bezel to the left.";
}
}
// Left rotate handling
else if (currentState == ONGOING_EVENT_STATE.LEFT_DIRECTION_ROTATE)
{
// If at least one rotation performed
if (leftDirectionRotateCount > 0)
{
// Decrease rotation count
leftDirectionRotateCount--;
// Increase the angle to rotate canvas.
angle += args.IsClockwise ? 30 : -30;
}
else
{
// Done rotate left, and move to next state (back button)
currentState = ONGOING_EVENT_STATE.BACK_BUTTON_PRESS;
// Change the instruction
instruction = "Press back button.";
angle = 0;
}
}
// Rotate the canvas
canvasView.RotateTo(angle).ContinueWith(
(b) =>
{
// Set this rotation done.
rotating = false;
// Angle should be set to 0 when it reaches 360.
if (angle == 360)
{
canvasView.Rotation = 0;
angle = 0;
}
});
// Redraw the canvas
canvasView.InvalidateSurface();
}
public RotaryEventPage()
{
// NOTICE: IRotaryEventReceiver object MUST set 'RotaryFocusObject' to get the event.
RotaryFocusObject = this;
// Initialize variables to set the state to rotating right
currentState = ONGOING_EVENT_STATE.RIGHT_DIRECTION_ROTATE;
instruction = "Rotate the bezel to the right.";
angle = 0;
// Initialize gradient to draw arrows
// Create the main canvas new
canvasView = new SKCanvasView();
canvasView.HeightRequest = 360;
canvasView.WidthRequest = 360;
// Add tap gesture recognizer
var tapGestureRecognizer = new TapGestureRecognizer();
tapGestureRecognizer.Tapped += (s, e) => {
Toast.DisplayText("Tapped !!!");
};
canvasView.GestureRecognizers.Add(tapGestureRecognizer);
canvasView.PaintSurface += (sender, e) =>
{
// Right arrow svg data
SKPath rightDirectionArrow = SKPath.ParseSvgPathData(
"M2.5,4.375l1.5625,-1.25h-1.25a8,8,0,0,0,-6,-6.25a2,2,0,0,1,-0.625,3.125a4.6,4.6,0,0,1,5.875,3.125h-1.25Z"
);
// Left arrow svg data
SKPath leftDirectionArrow = SKPath.ParseSvgPathData(
"M-2.5,4.375L-4.0625,3.125H-2.8125A8,8,0,0,1,3.1875,-3.125A2,2,0,0,0,3.8125,0A4.6,4.6,0,0,0,-2.0625,3.125H-0.8125Z"
);
// Get surface
SKSurface canvasSurface = e.Surface;
// Get canvas of surface
SKCanvas canvas = canvasSurface.Canvas;
canvas.Save();
// Fill black
canvas.Clear(SKColors.Black);
if (currentState == ONGOING_EVENT_STATE.RIGHT_DIRECTION_ROTATE)
{
canvas.Translate(e.Info.Width * 3 / 4, e.Info.Height / 4);
// Set scale for the path
SKMatrix matrix = SKMatrix.MakeScale(15, 15);
rightDirectionArrow.Transform(matrix);
// Set a shader for gradient
var colors = new SKColor[] { SKColors.White, SKColors.Blue };
SKPoint startPoint = new SKPoint(0, 0);
SKPoint endPoint = new SKPoint(20, 20);
var shader = SKShader.CreateLinearGradient(startPoint, endPoint, colors, null, SKShaderTileMode.Clamp);
blackStrokePaint.Shader = shader;
canvas.DrawPath(rightDirectionArrow, blackStrokePaint);
}
else if (currentState == ONGOING_EVENT_STATE.LEFT_DIRECTION_ROTATE)
{
canvas.Translate(e.Info.Width * 1 / 4, e.Info.Height / 4);
// Set scale for the path
SKMatrix matrix = SKMatrix.MakeScale(15, 15);
// Set a shader for gradient
leftDirectionArrow.Transform(matrix);
var colors = new SKColor[] { SKColors.White, SKColors.Blue };
SKPoint startPoint = new SKPoint(20, 0);
SKPoint endPoint = new SKPoint(0, 20);
var shader = SKShader.CreateLinearGradient(startPoint, endPoint, colors, null, SKShaderTileMode.Clamp);
blackStrokePaint.Shader = shader;
canvas.DrawPath(leftDirectionArrow, blackStrokePaint);
}
canvas.Restore();
// Text drawing
SKPaint textPaint = new SKPaint
{
Color = SKColors.White,
TextSize = 10,
IsAntialias = true
};
string str = instruction;
float textWidth = textPaint.MeasureText(str);
textPaint.TextSize = 0.7f * e.Info.Width * textPaint.TextSize / textWidth;
// Draw instruction
SKRect textBounds = new SKRect();
textPaint.MeasureText(str, ref textBounds);
float xText = e.Info.Width / 2 - textBounds.MidX;
float yText = e.Info.Height / 2 - textBounds.MidY;
canvas.DrawText(str, xText, yText, textPaint);
};
Content = new StackLayout
{
Children =
{
canvasView
}
};
}
