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Added Bezier curves.

improved_timing
Ian Burgmyer 7 years ago
parent
0fcbd36948
commit
7f7cbfec4d
2 changed files with 72 additions and 38 deletions
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  1. 73
      DotSDL/Graphics/Canvas.cs
  2. 37
      Samples/Sample.BasicPixels/Window.cs

73
DotSDL/Graphics/Canvas.cs
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@ -31,42 +31,48 @@ namespace DotSDL.Graphics {
}
/// <summary>
/// Draws an arc onto the <see cref="Canvas"/>.
/// An internal function that gets the point on a specific section of a Beziér curve.
/// </summary>
/// <param name="color">The color of the arc.</param>
/// <param name="center">A <see cref="Point"/> indicating the origin of the arc.</param>
/// <param name="radius">The radius of the arc, in pixels. Use negative values to create a left-facing arc.</param>
public void DrawArc(Color color, Point center, int radius) {
// TODO: Replace this with a more versatile spline function! This can only do left/right-facing arcs (which sucks).
var x = Math.Abs(radius);
var y = 0;
var err = 0;
var flip = radius < 0;
while(x >= y) {
PlotMirroredPointsY(color, center, x, y, flip);
/// <param name="points">A list of control points.</param>
/// <param name="t">The section of the curve to return a point for.</param>
/// <returns>The requested point on the curve.</returns>
private Point BezierGetPoint(Point[] points, double t) {
while(true) {
if(points.Length == 1)
return points[0];
y += 1;
if(err <= 0) {
err += 2 * y + 1;
}
if(err > 0) {
x -= 1;
err -= 2 * x + 1;
var newPoints = new Point[points.Length - 1];
for(var i = 0; i < points.Length - 1; i++) {
newPoints[i] = new Point {
X = (int)Math.Round((1 - t) * points[i].X + t * points[i + 1].X),
Y = (int)Math.Round((1 - t) * points[i].Y + t * points[i + 1].Y)
};
}
points = newPoints;
}
}
/// <summary>
/// Draws an arc onto the <see cref="Canvas"/>.
/// Draws a Beziér curve onto the <see cref="Canvas"/>.
/// </summary>
/// <param name="color">The color of the arc.</param>
/// <param name="center">A <see cref="Point"/> indicating the origin of the arc.</param>
/// <param name="width">The radius of the arc, in pixels. Use negative values to create a left-facing arc.</param>
/// <param name="height">The radius of the arc, in pixels. Use negative values to create a left-facing arc.</param>
public void DrawArc(Color color, Point center, int width, int height) {
throw new NotImplementedException();
/// <param name="color">The color of the Beziér curve.(r</param>
/// <param name="segments">The number of segments in the drawn curve.</param>
/// <param name="points">A collection of points for the Beziér curve. If fewer than two points are specified, an exception will be thrown.</param>
public void DrawBezier(Color color, int segments, params Point[] points) {
if(points.Length < 2) throw new ArgumentException("Too few points specified.", nameof(points));
if(points.Length == 2) // Just draw a line.
DrawLine(color, new Line { Start = points[0], End = points[1] });
var d = 1.0 / segments;
var newPoints = new Point[segments + 1];
var i = 0;
for(var t = 0.0; i < segments; t += d, i++)
newPoints[i] = BezierGetPoint(points, t);
// Always make sure that the end point is represented.
newPoints[segments] = BezierGetPoint(points, 1);
DrawLines(color, newPoints);
}
/// <summary>
@ -212,6 +218,17 @@ namespace DotSDL.Graphics {
DrawLine(color, line);
}
/// <summary>
/// Plots a sequence of lines on the <see cref="Canvas"/>.
/// </summary>
/// <param name="color">The color of the lines.</param>
/// <param name="points">A list of points to draw. There must be at least two points specified.</param>
public void DrawLines(Color color, params Point[] points) {
if(points.Length < 2) throw new ArgumentException("Too few points specified.", nameof(points));
for(var i = 0; i < points.Length - 1; i++)
DrawLine(color, new Line { Start = points[i], End = points[i + 1] });
}
/// <summary>
/// Retrieves an array index on the <see cref="Canvas"/>.
/// </summary>

37
Samples/Sample.BasicPixels/Window.cs
Unescape View File

@ -47,13 +47,19 @@ namespace DotSDL.Sample.BasicPixels {
DrawBackground(ref canvas.Pixels);
var color = RandomColor(min, max);
// D
canvas.DrawLines(color,
new Line { Start = new Point { X = offsetX, Y = offsetY + 96 }, End = new Point { X = offsetX, Y = offsetY }},
new Line { Start = new Point { X = offsetX, Y = offsetY }, End = new Point { X = offsetX + 24, Y = offsetY }},
new Line { Start = new Point { X = offsetX, Y = offsetY + 96 }, End = new Point { X = offsetX + 24, Y = offsetY + 96 }}
new Line { Start = new Point { X = offsetX, Y = offsetY }, End = new Point { X = offsetX + 10, Y = offsetY }},
new Line { Start = new Point { X = offsetX, Y = offsetY + 96 }, End = new Point { X = offsetX + 10, Y = offsetY + 96 }}
);
canvas.DrawBezier(color, 100,
new Point { X = offsetX + 8, Y = offsetY },
new Point { X = offsetX + 48, Y = offsetY },
new Point { X = offsetX + 48, Y = offsetY + 96 },
new Point { X = offsetX + 8, Y = offsetY + 96 }
);
canvas.DrawArc(color, new Point { X = offsetX + 24, Y = offsetY + 48 }, 48);
// o
canvas.DrawEllipse(color, new Point { X = offsetX + 76, Y = offsetY + 72 }, 12, 24);
@ -65,16 +71,27 @@ namespace DotSDL.Sample.BasicPixels {
);
// S
canvas.DrawLines(color,
new Line { Start = new Point { X = offsetX + 144 + 24, Y = offsetY }, End = new Point { X = offsetX + 144 + 48, Y = offsetY } },
new Line { Start = new Point { X = offsetX + 144, Y = offsetY + 96 }, End = new Point { X = offsetX + 144 + 24, Y = offsetY + 96 } }
canvas.DrawBezier(color, 100,
new Point { X = offsetX + 144 + 48, Y = offsetY },
new Point { X = offsetX + 144 - 24, Y = offsetY },
new Point { X = offsetX + 144, Y = offsetY + 48 },
new Point { X = offsetX + 144 + 48, Y = offsetY + 48 },
new Point { X = offsetX + 144 + 72, Y = offsetY + 96 },
new Point { X = offsetX + 144, Y = offsetY + 96 }
);
canvas.DrawArc(color, new Point { X = offsetX + 144 + 24, Y = offsetY + 24 }, -24);
canvas.DrawArc(color, new Point { X = offsetX + 144 + 24, Y = offsetY + 72 }, 24);
// D
canvas.DrawLine(color, new Line { Start = new Point { X = offsetX + 208, Y = offsetY + 96 }, End = new Point { X = offsetX + 208, Y = offsetY } });
canvas.DrawArc(color, new Point { X = offsetX + 208, Y = offsetY + 48 }, 48);
canvas.DrawLines(color,
new Line { Start = new Point { X = offsetX + 208, Y = offsetY + 96 }, End = new Point { X = offsetX + 208, Y = offsetY } },
new Line { Start = new Point { X = offsetX + 208, Y = offsetY }, End = new Point { X = offsetX + 208 + 10, Y = offsetY } },
new Line { Start = new Point { X = offsetX + 208, Y = offsetY + 96 }, End = new Point { X = offsetX + 208 + 10, Y = offsetY + 96 } }
);
canvas.DrawBezier(color, 100,
new Point { X = offsetX + 208 + 8, Y = offsetY },
new Point { X = offsetX + 208 + 48, Y = offsetY },
new Point { X = offsetX + 208 + 48, Y = offsetY + 96 },
new Point { X = offsetX + 208 + 8, Y = offsetY + 96 }
);
// L
canvas.DrawLines(color,

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