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生成隨機碼檢驗圖片

Posted on 2006-08-22 03:00 大大毛閱讀(755) 評論(0) 編輯收藏所屬分類: ASP.NET

???網頁中需要用到這樣的功能，參照網上的介紹，做了一個放在這里備查。
???效果圖：
???為了方便調用，寫成了一個類(RandomCodeImage.cs)。

using ?System;

using ?System.Drawing;

/// ? <summary>

/// ?隨機檢驗碼圖像模糊度

/// ? </summary>

public ? enum ?RandomCodeImageMistily? {

????None? = ? 0 ,

????General,

????Deep

}

/// ? <summary>

/// ?生成隨機校驗碼圖象

/// ?ddm,2006-8-22

/// ? </summary>

public ? class ?RandomCodeImage? {

???? // 隨機數

????Random?random? = ? null ;

???? // 字體

???? private ? string ?fontName? = ? null ;

???? // 字體大小

???? private ? int ?fontSize? = ? 0 ;

???? // 校驗碼長度

???? private ? int ?codeLength? = ? 0 ;

???? // 間距

???? private ? int ?codeSpace? = ? 0 ;

???? // 校驗碼

???? private ? string ?code? = ? null ;

???? // 字體

???? private ?Font?font? = ? null ;

???? // 模糊度

???? private ?RandomCodeImageMistily?mistily? = ?RandomCodeImageMistily.General;

???? public ?RandomCodeImage()? {

???????? this .random? = ? new ?Random();

???????? this .fontName? = ? " Arial " ;

???????? this .fontSize? = ? 12 ;

???????? this .codeLength? = ? 4 ;

???????? this .codeSpace? = ? 0 ;

????}

???? /// ? <summary>

???? /// ?設置/獲取字體

???? /// ? </summary>

???? public ? string ?FontName? {

???????? get ? {

???????????? return ? this .fontName;

????????}

???????? set ? {

???????????? this .fontName? = ?value;

????????}

????}

???? /// ? <summary>

???? /// ?設置/獲取字體大小

???? /// ? </summary>

???? public ? int ?FontSize? {

???????? get ? {

???????????? return ? this .fontSize;

????????}

???????? set ? {

???????????? this .fontSize? = ?value;

????????}

????}

???? /// ? <summary>

???? /// ?設置/獲取校驗碼的長度

???? /// ? </summary>

???? public ? int ?CodeLength? {

???????? get ? {

???????????? return ? this .codeLength;

????????}

???????? set ? {

???????????? this .codeLength? = ?value;

????????}

????}

???? /// ? <summary>

???? /// ?設置/獲取檢驗碼的間距

???? /// ? </summary>

???? public ? int ?CodeSpace? {

???????? get ? {

???????????? return ? this .codeSpace;

????????}

???????? set ? {

???????????? this .codeSpace? = ?value;

????????}

????}

???? /// ? <summary>

???? /// ?設置/獲取檢驗碼

???? /// ? </summary>

???? public ? string ?Code? {

???????? get ? {

???????????? if ?( this .code? == ? null )? {

???????????????? // 生成檢驗碼

???????????????? this .code? = ? this .createRandomCode();

????????????}

???????????? return ? this .code;

????????}

???????? set ? {

???????????? this .code? = ?value;

????????}

????}

???? public ?RandomCodeImageMistily?Mistily? {

???????? set ? {

???????????? this .mistily? = ?value;

????????}

????}

???? /// ? <summary>

???? /// ?獲取檢驗碼生成的圖像

???? /// ? </summary>

???? public ?System.Drawing.Bitmap?getCodeImage()? {

???????? if ?( this .code? == ? null )? {

???????????? // 生成檢驗碼

???????????? this .code? = ? this .createRandomCode();

????????}

???????? return ? this .createCodeImage();

????}

???? /// ? <summary>

???? /// ?獲取檢驗碼生成的圖像

???? /// ? </summary>

???? /// ? <param?name="mistily"> 輸出圖像的模糊度 </param>

???? public ?System.Drawing.Bitmap?getCodeImage(RandomCodeImageMistily?mistily)? {

???????? this .mistily? = ?mistily;

???????? return ? this .getCodeImage();

????}

???? /// ? <summary>

???? /// ?創建隨機檢驗碼

???? /// ? </summary>

???? protected ? string ?createRandomCode()? {

????????System.Text.StringBuilder?codeBuilder? = ? new ?System.Text.StringBuilder();

???????? int ?ascii? = ? 0 ;

???????? for ?( int ?i? = ? 0 ;?i? < ? this .codeLength;?i ++ )? {

???????????? // 0-9,A-Z一共36個

????????????ascii? = ? this .random.Next()? % ? 36 ;

???????????? if ?(ascii? < ? 10 )? {

???????????????? // 數字

????????????????ascii? += ? 48 ;

????????????} ? else ? {

???????????????? // 大寫字母

????????????????ascii? += ? 55 ;

????????????}

????????????codeBuilder.Append(( char )ascii);

????????}

???????? return ?codeBuilder.ToString();

????}

???? /// ? <summary>

???? /// ?創建代碼圖像

???? /// ? </summary>

???? private ?System.Drawing.Bitmap?createCodeImage()? {

????????Bitmap?tmpImage? = ? null ,?resultImage? = ? null ;

????????Graphics?tmpG? = ? null ,?resultG? = ? null ;

???????? float ?charWidth? = ?0f,?charHeight? = ?0f;

???????? int ?imageWidth? = ? 0 ,?imageHeight? = ? 0 ;

????????SizeF?size? = ?SizeF.Empty;

???????? // 噪音

???????? int ?noiseNum? = ? 0 ;

???????? // 生成字體

???????? this .font? = ? new ?Font( this .fontName,? this .fontSize,?(FontStyle.Bold? | ?FontStyle.Italic),?GraphicsUnit.Point);

???????? using ?(tmpImage? = ? new ?Bitmap( 1 ,? 1 ))? {

???????????? using ?(tmpG? = ?Graphics.FromImage(tmpImage))? {

???????????????? // 獲得code的輸出寬度

???????????????? for ?( int ?i? = ? 0 ;?i? < ? this .code.Length;?i ++ )? {

????????????????????size? = ?tmpG.MeasureString(code.Substring(i,? 1 ),?font);

????????????????????charWidth? += ?size.Width;

????????????????????charHeight? = ?Math.Max(charHeight,?size.Height);

????????????????}

????????????}

????????}

???????? // 輸出字符的大小

????????imageWidth? = ?( int )Math.Ceiling(charWidth);

????????imageHeight? = ?( int )Math.Ceiling(charHeight);

???????? // 加入間距

????????imageWidth? = ?imageWidth? + ? this .code.Length? * ? this .codeSpace? + ? this .codeSpace;

????????imageHeight? = ?imageHeight? + ? 2 ? * ? this .codeSpace;

???????? // 生成輸出圖像

????????resultImage? = ? new ?Bitmap(imageWidth,?imageHeight);

???????? // 畫刷,線性顏色漸變畫刷,渲染區域是整個圖片,從Blue漸變到Pruple,從X軸方面1.2弧度,漸變受角度影響

????????Brush?brush? = ? new ?System.Drawing.Drawing2D.LinearGradientBrush( new ?Rectangle( 0 ,? 0 ,?resultImage.Width,?resultImage.Height),?Color.Blue,?Color.Purple,? 1.2f ,? true );

???????? using ?(resultG? = ?Graphics.FromImage(resultImage))? {

???????????? // 填充背景色

????????????resultG.Clear(Color.White);

???????????? // resultG.TextRenderingHint?=?System.Drawing.Text.TextRenderingHint.ClearTypeGridFit;

???????????? switch ?( this .mistily)? {

???????????????? case ?RandomCodeImageMistily.Deep:

????????????????????noiseNum? = ?resultImage.Width? * ?resultImage.Height? / ? 30 ;

???????????????????? break ;

???????????????? case ?RandomCodeImageMistily.General:

????????????????????noiseNum? = ?resultImage.Width? * ?resultImage.Height? / ? 50 ;

???????????????????? break ;

???????????????? default :

????????????????????noiseNum? = ? 0 ;

???????????????????? break ;

????????????}

???????????? // 畫背景噪音線

???????????? for ?( int ?i? = ? 0 ;?i? < ?noiseNum;?i ++ )? {

???????????????? // 隨機坐標

???????????????? int ?x1? = ?random.Next(resultImage.Width);

???????????????? int ?x2? = ?random.Next(resultImage.Width);

???????????????? int ?y1? = ?random.Next(resultImage.Height);

???????????????? int ?y2? = ?random.Next(resultImage.Height);

???????????????? // 畫噪音線

????????????????resultG.DrawLine( new ?Pen(Color.Silver),?x1,?y1,?x2,?y2);

????????????}

???????????? // 畫背景噪音點

???????????? for ?( int ?i? = ? 0 ;?i? < ?noiseNum? * ? 20 ;?i ++ )? {

???????????????? // 隨機坐標

???????????????? int ?x? = ?random.Next(resultImage.Width);

???????????????? int ?y? = ?random.Next(resultImage.Height);

???????????????? // 畫噪音點

????????????????resultG.DrawEllipse( new ?Pen(Color.FromArgb(random.Next())),?x,?y,? 1 ,? 1 );

????????????}

???????????? // 輸出字符

????????????charWidth? = ?charHeight? = ? this .codeSpace;

???????????? for ?( int ?i? = ? 0 ;?i? < ? this .code.Length;?i ++ )? {

????????????????resultG.DrawString( this .code.Substring(i,? 1 ),?font,?brush,?charWidth,?charHeight);

???????????????? // 起始X坐標

????????????????charWidth? = ?charWidth? + ?resultG.MeasureString( this .code.Substring(i,? 1 ),?font).Width? + ? this .codeSpace;

????????????}

???????????? // 畫圖片邊框

????????????resultG.DrawRectangle( new ?Pen(Color.SaddleBrown),? 0 ,? 0 ,?resultImage.Width? - ? 1 ,?resultImage.Height? - ? 1 );

????????}

???????? return ?resultImage;

????}

}

???該類實現功能：
??????能夠返回一個隨機碼檢驗圖片(Image對象)，這樣可以進行第2次處理。
??????屬性：
??????FontName，字體；
??????FontSize，字體大小(point)；
??????CodeLength，隨機生成的檢驗碼長度；
??????CodeSpace，字間距；
??????Code，校驗碼，如果通過setter設置了該屬性，則類不會隨機生成新的檢驗碼；
??????Mistily，模糊度，效果不是很好。

???在ASP頁面中(例ShowCodeImage.aspx)調用類：

????protected?void?Page_Load(object?sender,?EventArgs?e)
????{
????????//初始化類
????????RandomCodeImage?r?=?new?RandomCodeImage();
????????//設置字體大小
????????r.FontSize?=?10;
????????//r.FontName?=?"Times?Now?Roman";
????????//設置字間距
????????r.CodeSpace?=?2;
????????//獲取圖像
????????System.Drawing.Image?image?=?r.getCodeImage();
????????//輸出圖像
????????System.IO.MemoryStream?ms?=?new?System.IO.MemoryStream();
????????image.Save(ms,?System.Drawing.Imaging.ImageFormat.Png);
????????image.Dispose();
????????Response.ContentType?=?"image/Png";
????????Response.BinaryWrite(ms.ToArray());

????????//將code放入Session或Cokie用于提交檢驗
????????Session.Add("ddm",?r.Code);
????}

???最后在最終需要顯示的ASP頁面中加以引用：

<img?src="ShowCodeImage.aspx"?alt="驗證圖片"/>

???后記：
??????在計算字符輸出寬度時遇到了麻煩，輸出時經常不對頭，直到逐步的拆解代碼才找到原因。MS在輸出字符時，由于各個字符是不等寬的(比如 I 就比較窄)，因此在輸出時必須先用 Graphics.MeasureString() 方法來計算寬度，但是實際上采用不同的輸出方式得到的結果是不同的。如:1.在輸出時采用一次性輸出整個字符串;2.逐個字符的輸出。可以發現各字符的輸出寬度之和要遠大于整個字符串的輸出寬度，如果沒有考慮到這點就容易產生輸出無法定位的情況。

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哪怕沒有辦法一定有說法, 就算沒有鴿子一定有烏鴉, 固執無罪 夢想有價, 讓他們驚訝.

生成隨機碼檢驗圖片

日歷

公告

隨筆分類(4)

文章分類(59)

積分與排名

最新評論

i am ddm

大大毛的筆記
DDM's Note

大大毛的筆記

哪怕沒有辦法一定有說法,
就算沒有鴿子一定有烏鴉,
固執無罪夢想有價,
讓他們驚訝.