using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Drawing.Imaging;
using System.Linq;
using System.Text;
using System.Windows.Forms;
namespace WindowsFormsApplication1
{
unsafe public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
this.Paint += new PaintEventHandler(Form1_Paint);
this.comboBox1.SelectedIndexChanged += new System.EventHandle (this.comboBox1_SelectedIndexChanged);
(this.pictureBox1_Paint);
}
Bitmap myBitmap = null;
private void button1_Click(object sender, EventArgs e) ////載入圖檔
{
this.openFileDialog1.Filter = "所有檔案|*.*|BMP File| *.bmp|JPEG File|*.jpg| GIF File|*.gif";
if (openFileDialog1.ShowDialog() == DialogResult.OK) ////由對話框選取圖檔
{
myBitmap = new Bitmap(openFileDialog1.FileName);
pictureBox1.Image = myBitmap;
}
SwitchChannel(0);
comboBox1.Text = "Y";
}
private void comboBox1_SelectedIndexChanged(object sender, EventArgs e)
{
SwitchChannel(comboBox1.SelectedIndex);
}
public void SwitchChannel(int channel)
{
int[, ,] ImgData = GetImgData(myBitmap);
long[] Values= new long[256];
ChannelProcess(ImgData, channel);
Bitmap processedBitmap = CreateBitmap(ImgData);
Values = GetHistogram(ImgData, channel);
DrawHistogram(Values);
lblHistogram.ForeColor= myColor;
pictureBox2.Image = processedBitmap;
}
private int[, ,] GetImgData(Bitmap myBitmap)
{
int[,,] ImgData = new int[myBitmap.Width, myBitmap.Height, 3];
BitmapData byteArray = myBitmap.LockBits(new Rectangle(0, 0, myBitmap.Width, myBitmap.Height), ImageLockMode.ReadWrite, PixelFormat.Format24bppRgb);
int ByteOfSkip = byteArray.Stride - byteArray.Width * 3;
byte* imgPtr = (byte*)(byteArray.Scan0);
for (int y = 0; y < byteArray.Height; y++)
{
for (int x = 0; x < byteArray.Width; x++)
{
ImgData[x, y, 2] = (int) *(imgPtr);
ImgData[x, y, 1] = (int) *(imgPtr + 1);
ImgData[x, y, 0] = (int) *(imgPtr + 2);
imgPtr += 3;
}
imgPtr += ByteOfSkip;
}
myBitmap.UnlockBits(byteArray);
return ImgData;
}
public static Bitmap CreateBitmap(int[, ,] ImgData)
{
int Width = ImgData.GetLength(0);
int Height = ImgData.GetLength(1);
Bitmap myBitmap = new Bitmap(Width, Height, PixelFormat.Format24bppRgb);
BitmapData byteArray = myBitmap.LockBits(new Rectangle(0, 0, Width, Height),
ImageLockMode.WriteOnly,
PixelFormat.Format24bppRgb);
//Padding bytes的長度
int ByteOfSkip = byteArray.Stride - myBitmap.Width * 3;
byte* imgPtr = (byte*) byteArray.Scan0;
for (int y = 0; y < Height; y++)
{
for (int x = 0; x < Width; x++)
{
*imgPtr = (byte)ImgData[x, y, 2]; //B
*(imgPtr+1) = (byte)ImgData[x, y, 1]; //G
*(imgPtr+2) = (byte)ImgData[x, y, 0]; //R
imgPtr += 3;
}
imgPtr += ByteOfSkip; // 跳過Padding bytes
}
myBitmap.UnlockBits(byteArray);
return myBitmap;
}
long myMaxValue;
private long[] myValues;
private bool myIsDrawing;
private float myYUnit; //this gives the vertical unit used to scale our values
private float myXUnit; //this gives the horizontal unit used to scale our values
private int myOffset = 20; //the offset, in pixels, from the control margins.
private Color myColor = Color.Black;
private Font myFont = new Font("Tahoma", 10);
public long[] GetHistogram(int[, ,] ImgData, int channel)
{
long[] myHistogram = new long[256];
int Width = ImgData.GetLength(0);
int Height = ImgData.GetLength(1);
for (int y = 0; y < Height; y++)
for (int x = 0; x < Width; x++)
{
switch (channel)
{
case 0: //Gray
int gray = ImgData[x, y, 1] ;
myHistogram[gray]++;
myColor = Color.Black;
break;
case 1: //Red
int Red = ImgData[x, y, 0];
myHistogram[Red]++;
myColor = Color.Red;
break;
case 2: //Green
int Green = ImgData[x, y, 1];
myHistogram[Green]++;
myColor = Color.Green;
break;
case 3: //Blue
int Blue = ImgData[x, y, 2];
myHistogram[Blue]++;
myColor = Color.Blue;
break;
}
}
return myHistogram;
}
private void ChannelProcess(int[, ,] ImgData, int channel)
{
int Width = ImgData.GetLength(0);
int Height = ImgData.GetLength(1);
for (int y = 0; y < Height; y++)
{
for (int x = 0; x < Width; x++)
{
switch(channel){
case 0: //Gray
int gray = (int) ((double) ImgData[x, y, 0] * 0.299 + (double) ImgData[x, y, 1] * 0.587 + (double) ImgData[x, y, 2] * 0.114);
ImgData[x, y, 0] = gray;
ImgData[x, y, 1] = gray;
ImgData[x, y, 2] = gray;
break;
case 1: //Red
ImgData[x, y, 1] = 0;
ImgData[x, y, 2] = 0;
break;
case 2: //Green
ImgData[x, y, 0] = 0;
ImgData[x, y, 2] = 0;
break;
case 3: //Blue
ImgData[x, y, 0] = 0;
ImgData[x, y, 1] = 0;
break;
}
}
}
}
public void DrawHistogram(long[] Values)
{
myValues = new long[Values.Length];
Values.CopyTo(myValues, 0);
myIsDrawing = true;
myMaxValue = getMaxim(myValues);
myMaxValue = getMaxim(Values);
ComputeXYUnitValues();
// this.pictureBox3.Invalidate();
this.Refresh();
}
private void ComputeXYUnitValues()
{
myYUnit = (float)(this.pictureBox3.Height - (2 * myOffset)) / myMaxValue;
myXUnit = (float)(this.pictureBox3.Width - (2 * myOffset)) / (myValues.Length - 1);
}
private long getMaxim(long[] Vals)
{
if (myIsDrawing)
{
long max = 0;
for (int i = 0; i < Vals.Length; i++)
{
if (Vals[i] > max)
max = Vals[i];
}
return max;
}
return 1;
}
private void Form1_Paint(object sender, PaintEventArgs e)
{
if (myIsDrawing)
{
Graphics g = this.pictureBox3.CreateGraphics();
Pen myPen = new Pen(myColor, 2);
int xPos, yPos;
for (int i = 0; i < myValues.Length; i++)
{
xPos = myOffset + (int)(i * myXUnit);
yPos = this.pictureBox3.Height - myOffset;
g.DrawLine(myPen,
new PointF(xPos, yPos),
new PointF(xPos, yPos - (int)(myValues[i] * myYUnit)));
}
g.DrawString("0", myFont, new SolidBrush(myColor), new PointF(myOffset, this.pictureBox3.Height - myFont.Height), System.Drawing.StringFormat.GenericDefault);
g.DrawString((myValues.Length - 1).ToString(), myFont,
new SolidBrush(myColor),
new PointF(myOffset + (myValues.Length * myXUnit) - g.MeasureString((myValues.Length - 1).ToString(), myFont).Width,
this.pictureBox3.Height - myFont.Height),
System.Drawing.StringFormat.GenericDefault);
//Histogram周圍畫一個方型
g.DrawRectangle(new System.Drawing.Pen(new SolidBrush(myColor), 2), myOffset, myOffset, this.pictureBox3.Width - myOffset * 2, this.pictureBox3.Height - myOffset * 2);
}
}
}
}
參考文章:
A simple histogram displaying control.
文章定位：
