應用裝飾模式於影像處理函式－天天向上

下圖(A)、(B)、(C)是一般影像處理常見的處理手法，如何撰寫ImgProc blockset讓影像資料，可以像是串流般一直往下進行，本篇將撰寫一個應用範例:將各個獨立影像模組(module)如同積木般堆疊、依照所需要的順序串接，且不限制積木的個數；過程中還能隨時觀看處理前後的結果，甚至恢復上一步(Undo)。

裝飾模式(Decorator)[1]: 動態地給一個物件加入一些額外的職責，就增加功能來說，裝飾模式比產生子類別更為靈活。

   1: class ImgProc   2:     {   3:         private Mat m_srcImg;   4:         private Mat m_dstImg;   5:         private ImageBox m_srcImageBox;   6:         private ImageBox m_dstImageBox;   7:         public Mat SourceImage   8:         {   9:             get { return m_srcImg; }  10:             set { m_srcImg = value; }  11:         }  12:         public Mat TargetImage  13:         {  14:             get { return m_dstImg; }  15:             set { m_dstImg = value; }  16:         }  17:    18:         public void LoadImage(string filename)  19:         {  20:             m_srcImg = CvInvoke.Imread(filename, LoadImageType.Unchanged);  21:             m_dstImg = m_srcImg.Clone();  22:         }  23:         public virtual void SetSrcImageBox(ImageBox imageBox)  24:         {  25:             m_srcImageBox = imageBox;  26:         }  27:         public virtual void SetDstImageBox(ImageBox imageBox)  28:         {  29:             m_dstImageBox = imageBox;  30:         }  31:           32:         public virtual void ShowSrcImage()  33:         {  34:             m_srcImageBox.Image = m_srcImg;  35:         }  36:         public virtual void ShowDstImage()  37:         {  38:             m_dstImageBox.Image = m_dstImg;  39:         }  40:         public virtual void ImageProc()  41:         {  42:    43:         }  44:         public virtual void Undo()  45:         {  46:             this.m_dstImg = this.m_srcImg.Clone();  47:         }  48:     }

   1: // Decorator:   2:     class ImgProcDecorator : ImgProc   3:     {   4:         protected ImgProc m_ip;   5:            6:         // 打扮   7:         public void Decorate(ImgProc ip)   8:         {   9:             this.m_ip = ip;  10:             this.m_ip.SourceImage = ip.TargetImage.Clone();  11:             this.ImageProc();  12:            13:         }  14:    15:         public override void  ShowDstImage()  16:         {  17:             if (m_ip != null)  18:                 m_ip.ShowDstImage();  19:         }  20:         public override void ShowSrcImage()  21:         {  22:             if (m_ip != null)  23:                 m_ip.ShowSrcImage();  24:         }  25:    26:        27:         public override void ImageProc()  28:         {  29:             if (m_ip != null)  30:                 m_ip.ImageProc();  31:         }  32:     }

   1: //ConcreteDecorator   2:    class RGB2Gray : ImgProcDecorator   3:    {   4:        public override void ImageProc()   5:        {   6:            if (m_ip.SourceImage.NumberOfChannels == 3)   7:                CvInvoke.CvtColor(m_ip.SourceImage, m_ip.TargetImage, ColorConversion.Rgb2Gray);   8:            else   9:                throw new Exception("請確認為彩色照片");  10:        }  11:    }  12:    class Gray2BW : ImgProcDecorator  13:    {  14:        byte m_thresh;  15:        public Gray2BW(byte thresh)  16:        {  17:            m_thresh = thresh;  18:        }  19:        public override void ImageProc()  20:        {  21:            CvInvoke.Threshold(m_ip.SourceImage, m_ip.TargetImage, m_thresh, 255, ThresholdType.Binary);      22:        }  23:    }  24:    class PyrDown : ImgProcDecorator  25:    {  26:        public override void ImageProc()  27:        {  28:            CvInvoke.PyrDown(m_ip.SourceImage, m_ip.TargetImage);  29:        }  30:    }  31:    class PyrUp : ImgProcDecorator  32:    {  33:        public override void ImageProc()  34:        {  35:            CvInvoke.PyrUp(m_ip.SourceImage, m_ip.TargetImage);  36:        }  37:    }

客戶端程式

   1: ImgProc ip = new ImgProc();

   1: private void 載入ToolStripMenuItem_Click(object sender, EventArgs e)   2:         {   3:             using (OpenFileDialog ofd = new OpenFileDialog())   4:             {   5:                 if (ofd.ShowDialog() == System.Windows.Forms.DialogResult.OK)   6:                 {   7:                     ip.LoadImage(ofd.FileName);   8:                     ip.SetSrcImageBox(imageBox1);   9:                     ip.SetDstImageBox(imageBox2);  10:                     ip.ShowSrcImage();  11:                     ip.ShowDstImage();  12:                 }  13:             }  14:         }

RGB->Gray

   1: private void rGBGrayToolStripMenuItem_Click(object sender, EventArgs e)   2:         {   3:             RGB2Gray rgb2gray = new RGB2Gray();   4:             try   5:             {   6:                 rgb2gray.Decorate(ip);   7:             }   8:             catch (Exception ex)   9:             {  10:                 MessageBox.Show(ex.Message.ToString());  11:             }  12:             ip.ShowSrcImage();  13:             ip.ShowDstImage();  14:         }

Gray->BW

   1: private void grayBWToolStripMenuItem_Click(object sender, EventArgs e)   2: {   3:     Gray2BW gray2bw = new Gray2BW(100);   4:     gray2bw.Decorate(ip);   5:     ip.ShowSrcImage();   6:     ip.ShowDstImage();   7: }

PyrDown

   1: private void pyrDownToolStripMenuItem_Click(object sender, EventArgs e)   2: {   3:     PyrDown prydown = new PyrDown();   4:     prydown.Decorate(ip);   5:     ip.ShowSrcImage();   6:     ip.ShowDstImage();   7: }

PyrUp

   1: private void pyrUpToolStripMenuItem_Click(object sender, EventArgs e)   2: {   3:     PyrUp pyrup = new PyrUp();   4:     pyrup.Decorate(ip);   5:     ip.ShowSrcImage();   6:     ip.ShowDstImage();   7: }