C#實現返回驗證碼圖片的類庫源碼

驗證碼字符個數、生成圖片寬度、高度自定均可由構造方法自定，無參構造生成默認字符個數和默認大小的Image,方法 GetImgWithValidateCode()返回生成的驗證碼圖片，方法 IsRight(string inputValCode) 判斷用戶輸入的驗證碼 inputValCode與圖片顯示的字符是否一致，不區分大小寫

using System;
using System.IO;
using System.Data;
using System.Configuration;
using System.Collections;
using System.Drawing;
using System.Drawing.Imaging;
using System.Drawing.Drawing2D;
namespace DrawValidateImageLib
{
public class DrawValImg
{
/// <summary>
/// 無參構造
/// </summary>
public DrawValImg() { }
/// <summary>
/// 帶有生成字符個數的構造
/// </summary>
/// <param name="charNum">驗證碼中包含隨機字符的個數</param>
public DrawValImg(int charNum)
{
this.CharNum = charNum;
}
/// <summary>
/// 帶有驗證碼圖片寬度和高度的構造
/// </summary>
/// <param name="width">驗證碼圖片寬度</param>
/// <param name="height">驗證碼圖片高度</param>
public DrawValImg(int width,int height)
{
this.width = width;
this.height = height;
}
/// <summary>
/// 帶有生成字符個數，驗證碼圖片寬度和高度的構造
/// </summary>
/// <param name="charNum">驗證碼中包含隨機字符的個數</param>
/// <param name="width">驗證碼圖片寬度</param>
/// <param name="height">驗證碼圖片高度</param>
public DrawValImg(int charNum,int width,int height)
{
this.CharNum = charNum;
this.width = width;
this.height = height;
}
/// <summary>
/// 驗證碼中字符個數
/// </summary>
int charNum = 5; //默認字符個數為5
public int CharNum
{
get { return charNum; }
set { charNum = value; }
}
/// <summary>
/// 字號
/// </summary>
int fontSize = 20;
public int FontSize
{
get { return fontSize; }
}
/// <summary>
/// 圖片寬度
/// </summary>
int width=200;
public int Width
{
get { return width; }
}
/// <summary>
/// 圖片高度
/// </summary>
int height=45;
public int Height
{
get { return height; }
set { height = value; }
}
/// <summary>
/// 隨機生成的字符串
/// </summary>
string validStr="";
public string ValidStr
{
get { return validStr; }
set { validStr = value; }
}
/// <summary>
/// 產生指定個數的隨機字符串，默認字符個數為5
/// </summary>
void GetValidateCode()
{
Random rd = new Random(); //創建隨機數對象
//產生由 charNum 個字母或數字組成的一個字符串
string str = "abcdefghijkmnpqrstuvwyzABCDEFGHJKLMNPQRSTUVWYZ23456789田國興";//共57個字符，除 l,o,x,I,O,X,1,0 的所有數字和大寫字母
for (int i = 0; i < charNum; i++)
{
validStr = validStr + str.Substring(rd.Next(57), 1);//返回0到56共57個
}
}
/// <summary>
/// 由隨機字符串，隨即顏色背景，和隨機線條產生的Image
/// </summary>
/// <returns>Image</returns>
public Image GetImgWithValidateCode()//返回 Image
{
//產生隨機字符串
GetValidateCode();
//聲明一個位圖對象
Bitmap bitMap = null;
//聲明一個繪圖畫面
Graphics gph = null;
//創建內存流
MemoryStream memStream = new MemoryStream();
Random random = new Random();
//由給定的需要生成字符串中字符個數 CharNum， 圖片寬度 Width 和高度 Height 確定字號 FontSize，
//確保不因字號過大而不能全部顯示在圖片上
int fontWidth=(int)Math.Round(width/(charNum+2)/1.3);
int fontHeight=(int)Math.Round(height/1.5);
//字號取二者中小者，以確保所有字符能夠顯示，並且字符的下半部分也能顯示
fontSize = fontWidth <= fontHeight ? fontWidth : fontHeight;
//創建位圖對象
bitMap = new Bitmap(width+FontSize,height);
//根據上面創建的位圖對象創建繪圖圖面
gph = Graphics.FromImage(bitMap);
//設定驗證碼圖片背景色
gph.Clear(GetControllableColor(200));
//產生隨機干擾線條
for (int i = 0; i < 10; i++)
{
Pen backPen = new Pen(GetControllableColor(100), 2);
//線條起點
int x = random.Next(width);
int y = random.Next(height);
//線條終點
int x2 = random.Next(width);
int y2 = random.Next(height);
//劃線
gph.DrawLine(backPen, x, y, x2, y2);
}
//定義一個含10種字體的數組
String[] fontFamily ={ "Arial", "Verdana", "Comic Sans MS", "Impact", "Haettenschweiler",
"Lucida Sans Unicode", "Garamond", "Courier New", "Book Antiqua", "Arial Narrow" };
　　
SolidBrush sb = new SolidBrush(GetControllableColor(0));
//通過循環,繪制每個字符,
for (int i = 0; i < validStr.Length; i++)
{
Font textFont = new Font(fontFamily[random.Next(10)], fontSize, FontStyle.Bold);//字體隨機,字號大小30,加粗
//每次循環繪制一個字符,設置字體格式,畫筆顏色,字符相對畫布的X坐標,字符相對畫布的Y坐標
int space = (int)Math.Round((double)((width - fontSize * (CharNum + 2)) / CharNum));
//縱坐標
int y = (int)Math.Round((double)((height - fontSize)/3));
gph.DrawString(validStr.Substring(i, 1), textFont, sb, fontSize + i * (fontSize + space), y);
}
//扭曲圖片
bitMap=TwistImage(bitMap, true, random.Next(3,5),random.Next(3));
try
{
bitMap.Save(memStream, ImageFormat.Gif);
}
catch (Exception ex)
{
System.Windows.Forms.MessageBox.Show(ex.Message);
}
//gph.Dispose();
bitMap.Dispose();
Image img = Image.FromStream(memStream);
gph.DrawImage(img, 50, 20, width, 10);
return img;
}
/// <summary>
/// 產生一種 R,G,B 均大於 colorBase 隨機顏色，以確保顏色不會過深
/// </summary>
/// <returns>背景色</returns>
Color GetControllableColor(int colorBase)
{
Color color=Color.Black;
if (colorBase > 200)
{
System.Windows.Forms.MessageBox.Show("可控制顏色參數大於200，顏色默認位黑色");
}
Random random = new Random();
//確保 R,G,B 均大於 colorBase，這樣才能保證背景色較淺
color= Color.FromArgb(random.Next(56) + colorBase, random.Next(56) + colorBase, random.Next(56) + colorBase);
return color;
}
/// <summary>
/// 扭曲圖片
/// </summary>
/// <param name="srcBmp"></param>
/// <param name="bXDir"></param>
/// <param name="dMultValue"></param>
/// <param name="dPhase"></param>
/// <returns></returns>
Bitmap TwistImage(Bitmap srcBmp, bool bXDir, double dMultValue, double dPhase)
{
int leftMargin = 0;
int rightMargin = 0;
int topMargin = 0;
int bottomMargin = 0;
//float PI = 3.14159265358979f;
float PI2 = 6.28318530717959f;
Bitmap destBmp = new Bitmap(srcBmp.Width, srcBmp.Height);
double dBaseAxisLen = bXDir ? Convert.ToDouble(destBmp.Height) : Convert.ToDouble(destBmp.Width);
for (int i = 0; i < destBmp.Width; i++)
{
for (int j = 0; j < destBmp.Height; j++)
{
double dx = 0;
dx = bXDir ? PI2 * Convert.ToDouble(j) / dBaseAxisLen : PI2 * Convert.ToDouble(i) / dBaseAxisLen;
dx += dPhase;
double dy = Math.Sin(dx);
//取得當前點的顏色
int nOldX = 0;
int nOldY = 0;
nOldX = bXDir ? i + Convert.ToInt32(dy * dMultValue) : i;
nOldY = bXDir ? j : j + Convert.ToInt32(dy * dMultValue);
System.Drawing.Color color = srcBmp.GetPixel(i, j);
if (nOldX >= leftMargin && nOldX < destBmp.Width - rightMargin && nOldY >= bottomMargin && nOldY < destBmp.Height - topMargin)
{
destBmp.SetPixel(nOldX, nOldY, color);
}
}
}
return destBmp;
}
/// <summary>
/// 判斷驗證碼是否正確
/// </summary>
/// <param name="inputValCode">待判斷的驗證碼</param>
/// <returns>正確返回 true,錯誤返回 false</returns>
public bool IsRight(string inputValCode)
{
if (validStr.ToUpper().Equals(inputValCode.ToUpper()))//無論輸入大小寫都轉換為大些判斷
{
return true;
}
else
{
return false;
}
}
}
}