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Code Samples: The Chain Code with 4 Directions = Crack Code in C#
Copyright © by V. Miszalok, last update: 2011-01-02 |
Create a new Windows-project "chain_code". Delete the files Form1.Designer.cs and Program.cs from the project. Clear any prefabricated content from Form1.cs and replace it by the following code:
using System;
using System.Drawing;
using System.Windows.Forms;
using System.Collections;
public class Form1 : Form
{ [STAThread] static void Main() { Application.Run( new Form1() ); }
const Int32 xSize = 11;
const Int32 ySize = 12;
Byte[,] i0 = new Byte[ySize ,xSize ];
Byte[,] c1v = new Byte[ySize ,xSize+1];
Brush[] brush = new Brush[10];
Brush blackbrush = SystemBrushes.ControlText;
Brush bluebrush = new SolidBrush( Color.Blue );
Pen redpen = new Pen( Color.Red, 5 );
Pen pinkpen = new Pen( Color.FromArgb(255,128,128), 3 );
Font arial10 = new Font( "Arial", 10 );
Int32 i, x, y, dx, dy;
Byte threshold = 1;
Button[] button = new Button[ySize];
Boolean NullCells;
Point start = new Point();
chaincode cc = new chaincode();
ArrayList all_chaincodes = new ArrayList();
class chaincode
{ public Point start;
public String cracks;
public Int32 perimeter, area;
}
public Form1()
{ BackColor = Color.White;
Text = "Chain Code";
for ( i=0; i < 10; i++ )
brush[i] = new SolidBrush(Color.FromArgb( i*25, i*25, i*25 ) );
for ( y=0; y < ySize; y++ )
{ button[y] = new Button();
Controls.Add(button[y]);
button[y].BackColor = Color.Gray;
button[y].Text = "nothing";
button[y].Name = y.ToString();
button[y].Click += new EventHandler( do_it );
}
button[0].Name = button[0].Text = "Homunculus";
button[1].Name = "Threshold";
button[2].Name = button[2].Text = "Noise";
button[3].Name = button[3].Text = "Clear";
button[4].Name = button[4].Text = "Code w/o 0-Cells";
button[5].Name = button[5].Text = "Code with 0-Cells";
button[1].Text = String.Format( "Threshold={0:#}", threshold );
redpen.EndCap = System.Drawing.Drawing2D.LineCap.ArrowAnchor;
pinkpen.EndCap = System.Drawing.Drawing2D.LineCap.ArrowAnchor;
SetStyle( ControlStyles.ResizeRedraw, true );
Width = 800;
Height = 600;
}
protected override void OnPaint(PaintEventArgs e)
{ Graphics g = e.Graphics;
Rectangle r = ClientRectangle;
dx = r.Width / (xSize+2);
dy = (r.Height - all_chaincodes.Count * FontHeight ) / ySize;
for ( y=0; y < ySize; y++ )
{ button[y].Top = y*dy+1;
button[y].Left = xSize*dx+1;
button[y].Width = r.Width - button[y].Left - 2;
button[y].Height = dy-2;
}
Int32 textfieldY = button[ySize-1].Top + button[ySize-1].Height + 2;
for ( y=0; y < ySize; y++ )
for ( x=0; x < xSize; x++ )
g.FillRectangle( brush[i0[y,x]], x*dx, y*dy, dx, dy );
if ( all_chaincodes.Count == 0 ) return;
for ( i=0; i < all_chaincodes.Count; i++ )
{ chaincode c = (chaincode)all_chaincodes[i];
x = c.start.X;
y = c.start.Y;
for ( Int32 ii = 0; ii < c.perimeter; ii++ )
switch ( c.cracks[ii] )
{ case 'e': g.DrawLine(redpen, x*dx, y*dy, (x+1)*dx, y*dy ); x++; break;
case 's': g.DrawLine(redpen, x*dx, y*dy, x*dx, (y+1)*dy ); y++; break;
case 'w': g.DrawLine(redpen, x*dx, y*dy, (x-1)*dx, y*dy ); x--; break;
case 'n': g.DrawLine(redpen, x*dx, y*dy, x*dx, (y-1)*dy ); y--; break;
}
g.FillRectangle( bluebrush, x*dx-5, y*dy-5, 11, 11 );
String s = "(" + c.start.X.ToString() + "/" +
c.start.Y.ToString() + ")" +
c.cracks + " P=" +
c.perimeter.ToString() + " A=" +
c.area.ToString();
if ( c.area < 0 ) s+= " =negative";
g.DrawString(s, arial10, blackbrush, 0, textfieldY );
textfieldY += FontHeight;
}
}
protected void do_it( object sender, System.EventArgs e )
{ switch( ((Button)sender).Name)
{ case "Homunculus"://***********************************
i0 = new Byte[,]{ {0,0,0,0,0,0,0,0,0,0,0},
{0,0,0,0,9,9,9,0,0,0,0},
{0,0,0,0,9,0,9,0,0,0,0},
{0,0,0,0,9,8,9,0,0,0,0},
{0,2,0,0,0,7,0,0,0,2,0},
{0,0,6,6,6,6,6,6,6,0,0},
{0,0,0,0,5,5,5,0,0,0,0},
{0,0,0,0,4,4,4,0,0,0,0},
{0,0,0,0,3,0,3,0,0,0,0},
{0,0,0,0,2,0,2,0,0,0,0},
{0,0,0,0,2,0,0,2,0,0,0},
{0,0,0,2,2,0,0,2,2,0,0} };
all_chaincodes.Clear();
break;
case "Threshold"://*************************************
if ( ++threshold > 9 ) threshold = 1;
button[1].Text = "Threshold=" + threshold.ToString();
all_chaincodes.Clear();
break;
case "Noise"://****************************************
Random random = new Random();
for ( y=0; y < ySize; y++ )
for ( x=0; x < xSize; x++ )
{ Int32 noise = random.Next() % 3 - 1;//gives -1 or 0 or +1
noise += i0[y,x];//add former gray value
if (noise < 0) i0[y,x] = 0;
else if (noise > 9) i0[y,x] = 9;
else i0[y,x] = (Byte)noise;
}
all_chaincodes.Clear();
break;
case "Clear"://*******************************************
for ( y=0; y < ySize; y++ )
for ( x=0; x < xSize; x++ ) i0[y,x] = 0;
threshold = 1; button[1].Text = "Threshold=1";
all_chaincodes.Clear();
break;
case "Code w/o 0-Cells": NullCells = false; all_chaincodes.Clear();
Invalidate(); Application.DoEvents();
chaincode_finder(); break;
case "Code with 0-Cells": NullCells = true; all_chaincodes.Clear();
Invalidate(); Application.DoEvents();
chaincode_finder(); break;
}
Invalidate();
}
private void chaincode_finder()
{ SByte[,] Negative = new SByte[,] {{0,-1},{ 0,0},{-1, 0},{-1,-1}};
SByte[,] Positive = new SByte[,] {{0, 0},{-1,0},{-1,-1},{ 0,-1}};
Point Neg = new Point(), Pos = new Point();
Boolean NEG, POS;
int direction;
for ( y=0; y < ySize; y++ )
for ( x=0; x <= xSize; x++ ) c1v[y,x] = 0;
start.X = start.Y = 0;
for ( Byte cc_no = 1; start_crack_search(); cc_no++ )
{ chaincode cc = new chaincode();
System.Text.StringBuilder cracks = new System.Text.StringBuilder();
cc.start = start; cracks.Append( 's' ); cc.area = 0;
x = start.X;
y = start.Y + 1;
direction = 1;
Graphics g = this.CreateGraphics();
do
{ g.DrawLine( pinkpen, x*dx, y*dy, x*dx+dx/4, y*dy );
g.DrawLine( pinkpen, x*dx, y*dy, x*dx, y*dy+dy/4 );
g.DrawLine( pinkpen, x*dx, y*dy, x*dx-dx/4, y*dy );
g.DrawLine( pinkpen, x*dx, y*dy, x*dx, y*dy-dy/4 );
switch ( direction ) //last crack
{ case 0: g.DrawLine( redpen, (x-1)*dx, y*dy, x*dx, y*dy ); break;
case 1: g.DrawLine( redpen, x*dx, (y-1)*dy, x*dx, y*dy ); break;
case 2: g.DrawLine( redpen, (x+1)*dx, y*dy, x*dx, y*dy ); break;
case 3: g.DrawLine( redpen, x*dx, (y+1)*dy, x*dx, y*dy ); break;
}
Int64 ticks = DateTime.Now.Ticks + 20000;
do {} while ( ticks > DateTime.Now.Ticks );
Neg.X = x + Negative[direction,0];
Neg.Y = y + Negative[direction,1];
Pos.X = x + Positive[direction,0];
Pos.Y = y + Positive[direction,1];
try { NEG = i0[Neg.Y,Neg.X] >= threshold; } catch { NEG = false; }
try { POS = i0[Pos.Y,Pos.X] >= threshold; } catch { POS = false; }
if ( POS && ( NEG || NullCells ) ) direction = (direction+1) % 4;
else if ( !NEG && (!POS || !NullCells ) ) direction = (direction+3) % 4;
switch ( direction )
{ case 0: cracks.Append( 'e' ); x++; cc.area += y; break;
case 1: cracks.Append( 's' ); y++; c1v[y-1,x] = cc_no; break;
case 2: cracks.Append( 'w' ); x--; cc.area -= y; break;
case 3: cracks.Append( 'n' ); y--; c1v[y ,x] = cc_no; break;
}
} while ( x != start.X || y != start.Y ); //end of do
switch ( direction ) //draw the final crack
{ case 0: g.DrawLine( redpen, (x-1)*dx, y*dy, x*dx, y*dy ); break;
case 2: g.DrawLine( redpen, (x+1)*dx, y*dy, x*dx, y*dy ); break;
}
cc.cracks = cracks.ToString();
cc.perimeter = cc.cracks.Length;
all_chaincodes.Add( cc );
}// end of for
}
private Boolean start_crack_search()
{ Byte left;
for ( y=start.Y; y < ySize; y++ )
for ( x=0; x < xSize; x++ )
{ if ( x > 0 ) left = i0[y,x-1]; else left = 0;
if ( left < threshold && i0[y,x] >= threshold && c1v[y,x] == 0 )
{ start.X = x; start.Y = y; c1v[y,x] = 1; return true; }
}
return false;
}
}
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