#region Header
//
// Project: WriteableBitmapEx - WriteableBitmap extensions
// Description: Collection of draw spline extension methods for the WriteableBitmap class.
//
// Changed by: $Author: unknown $
// Changed on: $Date: 2015-03-05 18:18:24 +0100 (Do, 05 Mrz 2015) $
// Changed in: $Revision: 113191 $
// Project: $URL: https://writeablebitmapex.svn.codeplex.com/svn/trunk/Source/WriteableBitmapEx/WriteableBitmapSplineExtensions.cs $
// Id: $Id: WriteableBitmapSplineExtensions.cs 113191 2015-03-05 17:18:24Z unknown $
//
//
// Copyright © 2009-2015 Rene Schulte and WriteableBitmapEx Contributors
//
// This code is open source. Please read the License.txt for details. No worries, we won't sue you! ;)
//
#endregion
using System;
#if NETFX_CORE
namespace Windows.UI.Xaml.Media.Imaging
#else
namespace System.Windows.Media.Imaging
#endif
{
/// <summary>
/// Collection of draw spline extension methods for the WriteableBitmap class.
/// </summary>
internal
#if WPF
unsafe
#endif
static partial class WriteableBitmapExtensions
{
#region Fields
private const float StepFactor = 2f;
#endregion
#region Methods
#region Beziér
/// <summary>
/// Draws a cubic Beziér spline defined by start, end and two control points.
/// </summary>
/// <param name="bmp">The WriteableBitmap.</param>
/// <param name="x1">The x-coordinate of the start point.</param>
/// <param name="y1">The y-coordinate of the start point.</param>
/// <param name="cx1">The x-coordinate of the 1st control point.</param>
/// <param name="cy1">The y-coordinate of the 1st control point.</param>
/// <param name="cx2">The x-coordinate of the 2nd control point.</param>
/// <param name="cy2">The y-coordinate of the 2nd control point.</param>
/// <param name="x2">The x-coordinate of the end point.</param>
/// <param name="y2">The y-coordinate of the end point.</param>
/// <param name="color">The color.</param>
internal static void DrawBezier(this WriteableBitmap bmp, int x1, int y1, int cx1, int cy1, int cx2, int cy2, int x2, int y2, Color color)
{
var col = ConvertColor(color);
bmp.DrawBezier(x1, y1, cx1, cy1, cx2, cy2, x2, y2, col);
}
/// <summary>
/// Draws a cubic Beziér spline defined by start, end and two control points.
/// </summary>
/// <param name="bmp">The WriteableBitmap.</param>
/// <param name="x1">The x-coordinate of the start point.</param>
/// <param name="y1">The y-coordinate of the start point.</param>
/// <param name="cx1">The x-coordinate of the 1st control point.</param>
/// <param name="cy1">The y-coordinate of the 1st control point.</param>
/// <param name="cx2">The x-coordinate of the 2nd control point.</param>
/// <param name="cy2">The y-coordinate of the 2nd control point.</param>
/// <param name="x2">The x-coordinate of the end point.</param>
/// <param name="y2">The y-coordinate of the end point.</param>
/// <param name="color">The color.</param>
internal static void DrawBezier(this WriteableBitmap bmp, int x1, int y1, int cx1, int cy1, int cx2, int cy2, int x2, int y2, int color)
{
// Determine distances between controls points (bounding rect) to find the optimal stepsize
var minX = Math.Min(x1, Math.Min(cx1, Math.Min(cx2, x2)));
var minY = Math.Min(y1, Math.Min(cy1, Math.Min(cy2, y2)));
var maxX = Math.Max(x1, Math.Max(cx1, Math.Max(cx2, x2)));
var maxY = Math.Max(y1, Math.Max(cy1, Math.Max(cy2, y2)));
// Get slope
var lenx = maxX - minX;
var len = maxY - minY;
if (lenx > len)
{
len = lenx;
}
// Prevent division by zero
if (len != 0)
{
using (var context = bmp.GetBitmapContext())
{
// Use refs for faster access (really important!) speeds up a lot!
int w = context.Width;
int h = context.Height;
// Init vars
var step = StepFactor / len;
int tx1 = x1;
int ty1 = y1;
int tx2, ty2;
// Interpolate
for (var t = step; t <= 1; t += step)
{
var tSq = t * t;
var t1 = 1 - t;
var t1Sq = t1 * t1;
tx2 = (int)(t1 * t1Sq * x1 + 3 * t * t1Sq * cx1 + 3 * t1 * tSq * cx2 + t * tSq * x2);
ty2 = (int)(t1 * t1Sq * y1 + 3 * t * t1Sq * cy1 + 3 * t1 * tSq * cy2 + t * tSq * y2);
// Draw line
DrawLine(context, w, h, tx1, ty1, tx2, ty2, color);
tx1 = tx2;
ty1 = ty2;
}
// Prevent rounding gap
DrawLine(context, w, h, tx1, ty1, x2, y2, color);
}
}
}
/// <summary>
/// Draws a series of cubic Beziér splines each defined by start, end and two control points.
/// The ending point of the previous curve is used as starting point for the next.
/// Therefore the initial curve needs four points and the subsequent 3 (2 control and 1 end point).
/// </summary>
/// <param name="bmp">The WriteableBitmap.</param>
/// <param name="points">The points for the curve in x and y pairs, therefore the array is interpreted as (x1, y1, cx1, cy1, cx2, cy2, x2, y2, cx3, cx4 ..., xn, yn).</param>
/// <param name="color">The color for the spline.</param>
internal static void DrawBeziers(this WriteableBitmap bmp, int[] points, Color color)
{
var col = ConvertColor(color);
bmp.DrawBeziers(points, col);
}
/// <summary>
/// Draws a series of cubic Beziér splines each defined by start, end and two control points.
/// The ending point of the previous curve is used as starting point for the next.
/// Therefore the initial curve needs four points and the subsequent 3 (2 control and 1 end point).
/// </summary>
/// <param name="bmp">The WriteableBitmap.</param>
/// <param name="points">The points for the curve in x and y pairs, therefore the array is interpreted as (x1, y1, cx1, cy1, cx2, cy2, x2, y2, cx3, cx4 ..., xn, yn).</param>
/// <param name="color">The color for the spline.</param>
internal static void DrawBeziers(this WriteableBitmap bmp, int[] points, int color)
{
int x1 = points[0];
int y1 = points[1];
int x2, y2;
for (int i = 2; i + 5 < points.Length; i += 6)
{
x2 = points[i + 4];
y2 = points[i + 5];
bmp.DrawBezier(x1, y1, points[i], points[i + 1], points[i + 2], points[i + 3], x2, y2, color);
x1 = x2;
y1 = y2;
}
}
#endregion
#region Cardinal
/// <summary>
/// Draws a segment of a Cardinal spline (cubic) defined by four control points.
/// </summary>
/// <param name="x1">The x-coordinate of the 1st control point.</param>
/// <param name="y1">The y-coordinate of the 1st control point.</param>
/// <param name="x2">The x-coordinate of the 2nd control point.</param>
/// <param name="y2">The y-coordinate of the 2nd control point.</param>
/// <param name="x3">The x-coordinate of the 3rd control point.</param>
/// <param name="y3">The y-coordinate of the 3rd control point.</param>
/// <param name="x4">The x-coordinate of the 4th control point.</param>
/// <param name="y4">The y-coordinate of the 4th control point.</param>
/// <param name="tension">The tension of the curve defines the shape. Usually between 0 and 1. 0 would be a straight line.</param>
/// <param name="color">The color.</param>
/// <param name="context">The pixel context.</param>
/// <param name="w">The width of the bitmap.</param>
/// <param name="h">The height of the bitmap.</param>
private static void DrawCurveSegment(int x1, int y1, int x2, int y2, int x3, int y3, int x4, int y4, float tension, int color, BitmapContext context, int w, int h)
{
// Determine distances between controls points (bounding rect) to find the optimal stepsize
var minX = Math.Min(x1, Math.Min(x2, Math.Min(x3, x4)));
var minY = Math.Min(y1, Math.Min(y2, Math.Min(y3, y4)));
var maxX = Math.Max(x1, Math.Max(x2, Math.Max(x3, x4)));
var maxY = Math.Max(y1, Math.Max(y2, Math.Max(y3, y4)));
// Get slope
var lenx = maxX - minX;
var len = maxY - minY;
if (lenx > len)
{
len = lenx;
}
// Prevent division by zero
if (len != 0)
{
// Init vars
var step = StepFactor / len;
int tx1 = x2;
int ty1 = y2;
int tx2, ty2;
// Calculate factors
var sx1 = tension * (x3 - x1);
var sy1 = tension * (y3 - y1);
var sx2 = tension * (x4 - x2);
var sy2 = tension * (y4 - y2);
var ax = sx1 + sx2 + 2 * x2 - 2 * x3;
var ay = sy1 + sy2 + 2 * y2 - 2 * y3;
var bx = -2 * sx1 - sx2 - 3 * x2 + 3 * x3;
var by = -2 * sy1 - sy2 - 3 * y2 + 3 * y3;
// Interpolate
for (var t = step; t <= 1; t += step)
{
var tSq = t * t;
tx2 = (int)(ax * tSq * t + bx * tSq + sx1 * t + x2);
ty2 = (int)(ay * tSq * t + by * tSq + sy1 * t + y2);
// Draw line
DrawLine(context, w, h, tx1, ty1, tx2, ty2, color);
tx1 = tx2;
ty1 = ty2;
}
// Prevent rounding gap
DrawLine(context, w, h, tx1, ty1, x3, y3, color);
}
}
/// <summary>
/// Draws a Cardinal spline (cubic) defined by a point collection.
/// The cardinal spline passes through each point in the collection.
/// </summary>
/// <param name="bmp">The WriteableBitmap.</param>
/// <param name="points">The points for the curve in x and y pairs, therefore the array is interpreted as (x1, y1, x2, y2, x3, y3, x4, y4, x1, x2 ..., xn, yn).</param>
/// <param name="tension">The tension of the curve defines the shape. Usually between 0 and 1. 0 would be a straight line.</param>
/// <param name="color">The color for the spline.</param>
internal static void DrawCurve(this WriteableBitmap bmp, int[] points, float tension, Color color)
{
var col = ConvertColor(color);
bmp.DrawCurve(points, tension, col);
}
/// <summary>
/// Draws a Cardinal spline (cubic) defined by a point collection.
/// The cardinal spline passes through each point in the collection.
/// </summary>
/// <param name="bmp">The WriteableBitmap.</param>
/// <param name="points">The points for the curve in x and y pairs, therefore the array is interpreted as (x1, y1, x2, y2, x3, y3, x4, y4, x1, x2 ..., xn, yn).</param>
/// <param name="tension">The tension of the curve defines the shape. Usually between 0 and 1. 0 would be a straight line.</param>
/// <param name="color">The color for the spline.</param>
internal static void DrawCurve(this WriteableBitmap bmp, int[] points, float tension, int color)
{
using (var context = bmp.GetBitmapContext())
{
// Use refs for faster access (really important!) speeds up a lot!
int w = context.Width;
int h = context.Height;
// First segment
DrawCurveSegment(points[0], points[1], points[0], points[1], points[2], points[3], points[4], points[5], tension, color, context, w, h);
// Middle segments
int i;
for (i = 2; i < points.Length - 4; i += 2)
{
DrawCurveSegment(points[i - 2], points[i - 1], points[i], points[i + 1], points[i + 2], points[i + 3], points[i + 4], points[i + 5], tension, color, context, w, h);
}
// Last segment
DrawCurveSegment(points[i - 2], points[i - 1], points[i], points[i + 1], points[i + 2], points[i + 3], points[i + 2], points[i + 3], tension, color, context, w, h);
}
}
/// <summary>
/// Draws a closed Cardinal spline (cubic) defined by a point collection.
/// The cardinal spline passes through each point in the collection.
/// </summary>
/// <param name="bmp">The WriteableBitmap.</param>
/// <param name="points">The points for the curve in x and y pairs, therefore the array is interpreted as (x1, y1, x2, y2, x3, y3, x4, y4, x1, x2 ..., xn, yn).</param>
/// <param name="tension">The tension of the curve defines the shape. Usually between 0 and 1. 0 would be a straight line.</param>
/// <param name="color">The color for the spline.</param>
internal static void DrawCurveClosed(this WriteableBitmap bmp, int[] points, float tension, Color color)
{
var col = ConvertColor(color);
bmp.DrawCurveClosed(points, tension, col);
}
/// <summary>
/// Draws a closed Cardinal spline (cubic) defined by a point collection.
/// The cardinal spline passes through each point in the collection.
/// </summary>
/// <param name="bmp">The WriteableBitmap.</param>
/// <param name="points">The points for the curve in x and y pairs, therefore the array is interpreted as (x1, y1, x2, y2, x3, y3, x4, y4, x1, x2 ..., xn, yn).</param>
/// <param name="tension">The tension of the curve defines the shape. Usually between 0 and 1. 0 would be a straight line.</param>
/// <param name="color">The color for the spline.</param>
internal static void DrawCurveClosed(this WriteableBitmap bmp, int[] points, float tension, int color)
{
using (var context = bmp.GetBitmapContext())
{
// Use refs for faster access (really important!) speeds up a lot!
int w = context.Width;
int h = context.Height;
int pn = points.Length;
// First segment
DrawCurveSegment(points[pn - 2], points[pn - 1], points[0], points[1], points[2], points[3], points[4], points[5], tension, color, context, w, h);
// Middle segments
int i;
for (i = 2; i < pn - 4; i += 2)
{
DrawCurveSegment(points[i - 2], points[i - 1], points[i], points[i + 1], points[i + 2], points[i + 3], points[i + 4], points[i + 5], tension, color, context, w, h);
}
// Last segment
DrawCurveSegment(points[i - 2], points[i - 1], points[i], points[i + 1], points[i + 2], points[i + 3], points[0], points[1], tension, color, context, w, h);
// Last-to-First segment
DrawCurveSegment(points[i], points[i + 1], points[i + 2], points[i + 3], points[0], points[1], points[2], points[3], tension, color, context, w, h);
}
}
#endregion
#endregion
}
}
