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@robfe
Created January 19, 2014 22:56
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Render ZXing qrcodes into a geometry for a WPF path
<Path Name="imageBarcodeEncoder" Fill="Black" Width="200" Height="200" Data="[set this from a GeometryBarcodeWriter]"/>
using System.Windows.Media;
using ZXing.Rendering;
namespace ZXing.Presentation
{
/// <summary>
/// A smart class to encode some content to a barcode image into a geometry
/// </summary>
public class GeometryBarcodeWriter : BarcodeWriterGeneric<Geometry>
{
/// <summary>
/// Initializes a new instance of the <see cref="BarcodeWriter"/> class.
/// </summary>
public GeometryBarcodeWriter()
{
Renderer = new GeometryRenderer();
}
}
}
using System;
using System.Collections.Generic;
using System.Linq;
using System.Windows;
using System.Windows.Media;
using ZXing.Common;
namespace ZXing.Rendering
{
public class GeometryRenderer : IBarcodeRenderer<Geometry>
{
public Geometry Render(BitMatrix matrix, BarcodeFormat format, string content)
{
return Render(matrix, format, content, null);
}
public Geometry Render(BitMatrix matrix, BarcodeFormat format, string content, EncodingOptions options)
{
var edges = new HashSet<Edge>();
var edgeMap = new Dictionary<Coordinate, List<Edge>>();
var cols = matrix.Width;
var rows = matrix.Height;
for (int c = 0; c <= cols; c++)
{
for (int r = 0; r <= rows; r++)
{
var cell = GetCell(c, r, matrix);
var westCell = GetCell(c - 1, r, matrix);
var northCell = GetCell(c, r - 1, matrix);
if (northCell != cell)
{
AddEdge(new Edge(c, r, c + 1, r), edges, edgeMap);
}
if (westCell != cell)
{
AddEdge(new Edge(c, r, c, r + 1), edges, edgeMap);
}
}
}
var cycles = new List<List<Coordinate>>();
while (edges.Count > 0)
{
var edge = edges.First();
RemoveEdge(edge, edges, edgeMap);
if (IsEdgeLeftHand(matrix, edge))
{
edge = edge.Reversed();
}
var currentCycle = new List<Coordinate> { edge.From, edge.To };
while (edge.To != currentCycle[0])
{
var moves = from direction in Turns(edge.From - edge.To)
let nextCoordinate = direction + edge.To
from e in EdgesFrom(edge.To, edgeMap)
where e.To == nextCoordinate || e.From == nextCoordinate
select e;
var nextEdge = moves.First();
RemoveEdge(nextEdge, edges, edgeMap);
edge = nextEdge.To != edge.To ? nextEdge : nextEdge.Reversed();
currentCycle.Add(edge.To);
}
cycles.Add(currentCycle);
}
return new PathGeometry(cycles.Select(x => new PathFigure(x.First().ToPoint(1), x.Skip(1).Select(y => new LineSegment(y.ToPoint(1), true)), true)));
}
private static bool IsEdgeLeftHand(BitMatrix b, Edge edge)
{
var cell = GetCell(edge.From.Col, edge.From.Row, b);
return (edge.From.Row < edge.To.Row && cell) || (!(edge.From.Col < edge.To.Col && cell));
}
static IEnumerable<Edge> EdgesFrom(Coordinate c, Dictionary<Coordinate, List<Edge>> edgeMap)
{
return edgeMap.ContainsKey(c) ? edgeMap[c] : Enumerable.Empty<Edge>();
}
static IEnumerable<Coordinate> Turns(Coordinate currentDirection)
{
int index = Array.IndexOf(Coordinate.Directions, currentDirection);
return Coordinate.Directions.Skip(index + 1).Concat(Coordinate.Directions.Take(index));
}
private static bool GetCell(int c, int r, BitMatrix matrix)
{
if (r < 0 || r >= matrix.Height)
{
return false;
}
if (c < 0 || c >= matrix.Width)
{
return false;
}
return matrix[c, r];
}
private static void RemoveEdge(Edge e, HashSet<Edge> edges, Dictionary<Coordinate, List<Edge>> edgeMap)
{
edges.Remove(e);
edgeMap[e.From].Remove(e);
edgeMap[e.To].Remove(e);
}
private static void AddEdge(Edge e, HashSet<Edge> edges, Dictionary<Coordinate, List<Edge>> edgeMap)
{
edges.Add(e);
AddCoordinate(e.From, e, edgeMap);
AddCoordinate(e.To, e, edgeMap);
}
private static void AddCoordinate(Coordinate c, Edge e, Dictionary<Coordinate, List<Edge>> edgeMap)
{
List<Edge> list;
if (!edgeMap.TryGetValue(c, out list))
{
edgeMap[c] = list = new List<Edge>();
}
list.Add(e);
}
struct Coordinate
{
public readonly int Row, Col;
public Coordinate(int col, int row)
{
Col = col;
Row = row;
}
public bool Equals(Coordinate other)
{
return other.Row == Row && other.Col == Col;
}
public override bool Equals(object obj)
{
if (ReferenceEquals(null, obj)) return false;
if (obj.GetType() != typeof(Coordinate)) return false;
return Equals((Coordinate)obj);
}
public override int GetHashCode()
{
unchecked
{
return (Row * 397) ^ Col;
}
}
public override string ToString()
{
var s = "";
if (this == North) s = " n";
if (this == West) s = " w";
if (this == South) s = " s";
if (this == East) s = " e";
return String.Format("({0}, {1}{2})", Col, Row, s);
}
public static bool operator ==(Coordinate left, Coordinate right)
{
return left.Equals(right);
}
public static bool operator !=(Coordinate left, Coordinate right)
{
return !left.Equals(right);
}
public static Coordinate operator +(Coordinate c1, Coordinate c2)
{
return new Coordinate(c1.Col + c2.Col, c1.Row + c2.Row);
}
public static Coordinate operator -(Coordinate c1, Coordinate c2)
{
return new Coordinate(c1.Col - c2.Col, c1.Row - c2.Row);
}
public Point ToPoint(double scale)
{
return new Point(Col * scale, Row * scale);
}
static readonly Coordinate West = new Coordinate(-1, 0);
static readonly Coordinate South = new Coordinate(0, 1);
static readonly Coordinate East = new Coordinate(1, 0);
static readonly Coordinate North = new Coordinate(0, -1);
public static readonly Coordinate[] Directions = new[]
{
West,
South,
East,
North,
};
}
struct Edge
{
public readonly Coordinate From, To;
public Edge(Coordinate from, Coordinate to)
{
From = from;
To = to;
}
public Edge(int fromCol, int fromRow, int toCol, int toRow)
: this(new Coordinate(fromCol, fromRow), new Coordinate(toCol, toRow))
{
}
public bool Equals(Edge other)
{
return other.From.Equals(From) && other.To.Equals(To);
}
public override bool Equals(object obj)
{
if (ReferenceEquals(null, obj)) return false;
if (obj.GetType() != typeof(Edge)) return false;
return Equals((Edge)obj);
}
public override int GetHashCode()
{
unchecked
{
return (From.GetHashCode() * 397) ^ To.GetHashCode();
}
}
public override string ToString()
{
char angle = ' ';
if (From.Col == To.Col)
{
angle = '|';
}
if (From.Row == To.Row)
{
angle = '-';
}
return string.Format("[{0} {2} {1}]", From, To, angle);
}
public static bool operator ==(Edge left, Edge right)
{
return left.Equals(right);
}
public static bool operator !=(Edge left, Edge right)
{
return !left.Equals(right);
}
public Edge Reversed()
{
return new Edge(To, From);
}
}
}
}
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