/// <summary>
/// Transforms the y-coordinate to screen coordinates.
/// </summary>
/// <param name="x"></param>
/// <param name="y"></param>
/// <param name="offsetX">offset by x</param>
/// <param name="offsetY">offset by y</param>
/// <returns></returns>
private Point Tranform(double x, double y, double offsetX = 0, double offsetY = 0)
{
double newX, newY;
_toView.Apply(x, y, out newX, out newY);
return(new Point(newX + offsetX, newY + offsetY));
}
/// <summary>
/// Transforms the y-coordinate to screen coordinates.
/// </summary>
/// <param name="x"></param>
/// <param name="y"></param>
/// <returns></returns>
private double[] Tranform(double x, double y)
{
double newX, newY;
_toView.Apply(x, y, out newX, out newY);
return(new double[] { newX, newY });
}
/// <summary>
/// Draws the line text segment.
/// </summary>
/// <param name="target">Target.</param>
/// <param name="xTransformed">X transformed.</param>
/// <param name="yTransformed">Y transformed.</param>
/// <param name="text">Text.</param>
/// <param name="color">Color.</param>
/// <param name="size">Size.</param>
/// <param name="haloColor">Halo color.</param>
/// <param name="haloRadius">Halo radius.</param>
/// <param name="middlePosition">Middle position.</param>
/// <param name="characterWidths">Character widths.</param>
/// <param name="textLength">Text length.</param>
/// <param name="characterHeight">Character height.</param>
public void DrawLineTextSegment(Target2DWrapper <global::Android.Graphics.Canvas> target, double[] xTransformed, double[] yTransformed, string text, int color,
double size, int?haloColor, int?haloRadius, double middlePosition, float[] characterWidths, double textLength,
float characterHeight)
{
_paint.Color = new global::Android.Graphics.Color(color);
_paint.SetStyle(global::Android.Graphics.Paint.Style.Fill);
// see if the text is 'upside down'.
double averageAngle = 0;
double first = middlePosition - (textLength / 2.0);
PointF2D current = Polyline2D.PositionAtPosition(xTransformed, yTransformed, first);
bool isVisible = false;
for (int idx = 0; idx < text.Length; idx++)
{
double nextPosition = middlePosition - (textLength / 2.0) + ((textLength / (text.Length)) * (idx + 1));
PointF2D next = Polyline2D.PositionAtPosition(xTransformed, yTransformed, nextPosition);
// calculate the angle.
VectorF2D vector = next - current;
VectorF2D horizontal = new VectorF2D(1, 0);
double angleDegrees = ((Degree)horizontal.Angle(vector)).Value;
averageAngle = averageAngle + angleDegrees;
current = next;
double untransformed_0, untransformed_1;
_fromViewPort.Apply(next[0], next[1], out untransformed_0, out untransformed_1);
// double[] untransformed = this.TransformReverse (next [0], next [1]);
if (_view.Contains(untransformed_0, untransformed_1))
{
isVisible = true;
}
}
averageAngle = averageAngle / text.Length;
if (!isVisible)
{
return;
}
// reverse if 'upside down'.
double[] xText = xTransformed;
double[] yText = yTransformed;
// calculate a central position along the line.
first = middlePosition - (textLength / 2.0);
current = Polyline2D.PositionAtPosition(xText, yText, first);
double nextPosition2 = first;
for (int idx = 0; idx < text.Length; idx++)
{
nextPosition2 = nextPosition2 + characterWidths[idx];
//double nextPosition = middle - (textLength / 2.0) + ((textLength / (text.Length)) * (idx + 1));
PointF2D next = Polyline2D.PositionAtPosition(xText, yText, nextPosition2);
char currentChar = text[idx];
global::Android.Graphics.Path characterPath = new global::Android.Graphics.Path();;
_paint.GetTextPath(text, idx, idx + 1, 0, 0, characterPath);
using (characterPath) {
// Transformation matrix to move the character to the correct location.
// Note that all actions on the Matrix class are prepended, so we apply them in reverse.
using (var transform = new Matrix()) {
// Translate to the final position, the center of line-segment between 'current' and 'next'
PointF2D position = current;
//PointF2D position = current + ((next - current) / 2.0);
//double[] transformed = this.Tranform(position[0], position[1]);
transform.SetTranslate((float)position [0], (float)position [1]);
// calculate the angle.
VectorF2D vector = next - current;
VectorF2D horizontal = new VectorF2D(1, 0);
double angleDegrees = ((Degree)horizontal.Angle(vector)).Value;
// Rotate the character
transform.PreRotate((float)angleDegrees);
// Translate the character so the centre of its base is over the origin
transform.PreTranslate(0, characterHeight / 2.5f);
//transform.Scale((float)this.FromPixels(_target, _view, 1),
// (float)this.FromPixels(_target, _view, 1));
characterPath.Transform(transform);
if (haloColor.HasValue && haloRadius.HasValue && haloRadius.Value > 0)
{
_paint.SetStyle(global::Android.Graphics.Paint.Style.FillAndStroke);
_paint.StrokeWidth = haloRadius.Value;
_paint.Color = new global::Android.Graphics.Color(haloColor.Value);
using (global::Android.Graphics.Path haloPath = new global::Android.Graphics.Path()) {
_paint.GetFillPath(characterPath, haloPath);
// Draw the character
target.Target.DrawPath(haloPath, _paint);
}
}
// Draw the character
_paint.SetStyle(global::Android.Graphics.Paint.Style.Fill);
_paint.StrokeWidth = 0;
_paint.Color = new global::Android.Graphics.Color(color);
target.Target.DrawPath(characterPath, _paint);
}
}
current = next;
}
}
/// <summary>
/// Draws a point on the target. The coordinates given are scene coordinates.
/// </summary>
/// <param name="x">The x coordinate.</param>
/// <param name="y">The y coordinate.</param>
/// <param name="color">Color.</param>
/// <param name="size">Size.</param>
protected override void DrawPoint(Target2DWrapper <global::Android.Graphics.Canvas> target, double x, double y, int color, double size)
{
float sizeInPixels = this.ToPixels(size) * this.Density;
_paint.Color = new global::Android.Graphics.Color(color);
_paint.StrokeWidth = 1;
_paint.SetStyle(global::Android.Graphics.Paint.Style.Fill);
double transformedX, transformedY;
_toViewPort.Apply(x, y, out transformedX, out transformedY);
target.Target.DrawCircle((float)transformedX, (float)transformedY, sizeInPixels, _paint);
}