Reading-Writing PGM(Portable Graphics Media) Image Files With C#(C Sharp)
source：http://mennan.kagitkalem.com/ReadingWritingPGMPortableGraphicsMediaImageFilesWithCCSharp.aspx
备注：程序可能有点小问题，代码可以从下面下载。
I demonstrate a simple example in order to show how to read-write PGM files.
Yo can download source from here（或者https://files.cnblogs.com/lihongsheng0217/PGM.zip）
Output is below:
Type = P2
ColorSize = 255
Comment = Created by ..
Length = 512
Width = 512
Program.cs:
using System;
namespace PGM
{
class Program
{
static void Main(string[] args)
{
string InputFileName = "lenna.pgm"; //args[0]
//read PGM
PGM Picture = new PGM(InputFileName);
//Print info
Picture.PrintPGMInfo();
//Set image data
//Picture.Data
//Save PGM
Picture.Save("new_"+InputFileName);
Console.ReadLine();
}
}
}
PGM.cs:
using System;
using System.IO;
namespace PGM
{
public class PGM
{
private int mWidth;
private int mLength; private int mColor;
private string mType;
private byte[] mData; private string mComments;
public string Comment
{
get { return this.mComments; }
}
public int Width
{
get { return this.mWidth; }
}
public int Length
{
get { return this.mLength; }
}
public int ColorSize
{
get { return this.mColor; }
}
public string Type
{
get
{
return this.mType;
}
}
public string Header
{
get
{
return this.Type + Convert.ToChar(10) +
'#' + this.Comment + Convert.ToChar(10) +
this.mWidth.ToString() + " " + this.mLength.ToString() + Convert.ToChar(10) +
this.mColor.ToString() + Convert.ToChar(10);
}
}
public byte[] Data
{
get { return this.mData; }
set { this.mData = value; }
}
public PGM(string _filePath)
{
ReadPGM(_filePath);
}
public void Save(string _filePath) { WritePGM(_filePath); } private void ReadPGM(string _filePath)
{
FileStream InputStream = File.OpenRead(_filePath);
BinaryReader PGMReader = new BinaryReader(InputStream);
char[] Seperators = { ' ', '\n' };
byte NewLineAsciiCode = 10;
byte DiezAsciiCode = 35;
byte SpaceAsciiCode = 32;
byte[] TempArray = new byte[1000];
int i = 0;
string TempS;
byte TempByte;
/* Sample PGM :
*
*
* P2
* # Created by ...
* 512 512
* 255
* [data]
*/
//read PGM Type P2, P5
TempArray[0] = PGMReader.ReadByte();
TempArray[1] = PGMReader.ReadByte();
this.mType = System.Text.ASCIIEncoding.Default.GetString(TempArray, 0, 2);
//read until new line
while (PGMReader.ReadByte() != NewLineAsciiCode) { ;}
//read comments if exists. Only one comment line supported!!
i = 0;
TempArray[i] = PGMReader.ReadByte();
if (TempArray[i] == DiezAsciiCode)
{
TempByte = PGMReader.ReadByte();
while (TempByte != NewLineAsciiCode)
{
TempArray[i++] = TempByte;
TempByte = PGMReader.ReadByte();
}
}
this.mComments = System.Text.ASCIIEncoding.Default.GetString(TempArray, 0, i);
//read width
i = 0;
TempByte = PGMReader.ReadByte();
while (TempByte != SpaceAsciiCode)
{
TempArray[i++] = TempByte;
TempByte = PGMReader.ReadByte();
}
TempS = System.Text.ASCIIEncoding.Default.GetString(TempArray, 0, i);
this.mWidth = Convert.ToInt32(TempS);
//read length
i = 0;
TempByte = PGMReader.ReadByte();
while (TempByte != NewLineAsciiCode)
{
TempArray[i++] = TempByte;
TempByte = PGMReader.ReadByte();
}
TempS = System.Text.ASCIIEncoding.Default.GetString(TempArray, 0, i);
this.mLength = Convert.ToInt32(TempS);
//read color
i = 0;
TempByte = PGMReader.ReadByte();
while (TempByte != NewLineAsciiCode)
{
TempArray[i++] = TempByte;
TempByte = PGMReader.ReadByte();
}
TempS = System.Text.ASCIIEncoding.Default.GetString(TempArray, 0, i);
this.mColor = Convert.ToInt32(TempS);
//read image data
byte[] PGMDataBuffer = new byte[this.mWidth * this.mLength];
int k = 0;
if (this.mType == "P5")
{
//If file is binary, read every byte
byte[] ReadedByte = PGMReader.ReadBytes(PGMDataBuffer.Length);
Array.Copy(ReadedByte, PGMDataBuffer, ReadedByte.Length);
}
else if (this.mType == "P2")
{
//If file is text based every pixel is distinguished by "space" and it has up to 3 chars(255)
try
{
TempByte = PGMReader.ReadByte();
while (TempByte != -1)
{
i = 0;
while (TempByte != NewLineAsciiCode && TempByte != SpaceAsciiCode)
{
TempArray[i++] = TempByte;
TempByte = PGMReader.ReadByte();
}
TempS = System.Text.ASCIIEncoding.Default.GetString(TempArray, 0, i);
i = 0;
//TempS contains, string representation of every pixel
PGMDataBuffer[k++] = Convert.ToByte(TempS);
TempByte = PGMReader.ReadByte();
if (TempByte == NewLineAsciiCode || TempByte == SpaceAsciiCode)
{
TempByte = PGMReader.ReadByte();
}
}
}
catch (Exception e)
{
//Console.WriteLine(e.InnerException);
;
}
}
this.mData = PGMDataBuffer;
PGMReader.Close();
InputStream.Close();
}
private void WritePGM(string _filePath)
{
FileStream OutputStream = File.Create(_filePath);
BinaryWriter PGMWriter = new BinaryWriter(OutputStream);
string PGMInfo = this.Header;
byte[] PGMInfoBuffer = System.Text.ASCIIEncoding.Default.GetBytes(PGMInfo);
PGMWriter.Write(PGMInfoBuffer);
if (this.mType == "P5")
{
//File is binary, write complete data
PGMWriter.Write(this.mData);
}
else if (this.mType == "P2")
{
byte NewLineAsciiCode = 10;
byte SpaceAsciiCode = 32;
int Temp;
for (int i = 0; i < this.Length * this.Width; i++)
{
//File is text based, convert every byte to text representation followed by "space"
Temp = this.mData[i];
byte[] TempByteArray = System.Text.ASCIIEncoding.Default.GetBytes(Temp.ToString());
PGMWriter.Write(TempByteArray);
PGMWriter.Write(SpaceAsciiCode);
if (i % this.Width == 0)
{
PGMWriter.Write(NewLineAsciiCode);
}
}
}
PGMWriter.Close();
}
public void PrintPGMInfo()
{
Console.WriteLine("Type = " + this.Type.ToString());
Console.WriteLine("ColorSize = " + this.ColorSize.ToString() );
Console.WriteLine("Comment = " + this.Comment);
Console.WriteLine("Length = " + this.Length.ToString());
Console.WriteLine("Width = " + this.Width.ToString());
}
}
}
