《学习OpenCV》练习题第四章第七题abc

题外话：一直是打算把这本书的全部课后编程题写完的，中间断了几个月，一直忙于其他事。现在开始补上。

这道题我不清楚我理解的题意是不是正确的，这道题可以练习用OpenCV实现透视变换（可以用于矫正在3维环境下的图像失真），b&c部分则是实现图像放大缩小插值，旋转图像。所有的功能都和键盘事件处理联系起来，纯OpenCV实现，和OS无关。不过，在处理SHIFT键时，我取得是其在键盘上对应字符的ASCII码，好像OpenCV对键盘事件的支持不如对鼠标事件的支持。所以SHIFT键+小键盘上的数字键是不行的。

代码：

 #include <opencv/highgui.h>
 #include <opencv/cv.h>
 #include <opencv_libs.h>

 /*
  *《学习OpenCV》第四章第七题
  * 完成时间：0:23 10/4 星期五 2013
  */    

 #define   WARPSTEPSIZE     0.01      // 透视变换矩阵每次的变化率

 #define   RESIZESTEPSIZE   0.1       // 放大、缩小每次的变化率

 #define   ROTATESTEPSIZE   10        // 旋转图像时每次旋转的角度（逆时针）

 // 透视变换目标变换矩阵
 CvPoint2D32f g_dstQuad[];

 // image width & height
 int g_width = ;
 int g_height = ;

 // rotate degree
 int g_RotateDegree = ;  

 /*
  * function: Zoom in or zoom out an image.
  * param: inorout -- indicate in or out(0 means zoom in; 1 means zoom out)
  * param: the destination size.
  */
 CvSize getZoomDstSize(int inorout)
 {
     if(inorout !=  && inorout != )
     {
         return cvSize(-, -);
     }
     if(g_height ==  || g_width == )
     {
         return cvSize(-, -);
     }

     // Zoom in
     if(inorout == )
     {
         g_width += g_width * RESIZESTEPSIZE;
         g_height += g_height * RESIZESTEPSIZE;
     }
     else if(inorout == )
     {
         g_width -= g_width * RESIZESTEPSIZE;
         g_height -= g_height * RESIZESTEPSIZE;

         if(g_height < )
         {
             g_height = ;
         }
         else if(g_width < )
         {
             g_width = ;
         }
     }

     return cvSize(g_width, g_height);
 }

 void rotateImage(IplImage* img, IplImage *img_rotate,float degree)
 {
     // 旋转中心
     CvPoint2D32f center;
     center.x=float (img->width/2.0+0.5);
     center.y=float (img->height/2.0+0.5);
     // 计算二维旋转的仿射变换矩阵
     float m[];
     CvMat M = cvMat( , , CV_32F, m );
     cv2DRotationMatrix( center, degree,, &M);
     // 变换图像，并用黑色填充其余值
     cvWarpAffine(img,img_rotate, &M,CV_INTER_LINEAR+CV_WARP_FILL_OUTLIERS,cvScalarAll() );
 } 

 /*
  * function: change the g_dstQuad(minus or plus one of the element)
  * param: index -- which element(0 -- 4)
  * param: xory -- indicate x or y to change(0 means x; 1 means y)
  * param: operation -- indicate which operation(0 means plus; 1 means minus)
  * return: 0 means success.  -1 means failed.
  */
 int changeg_dstQuad(int index, int xory, int operation)
 {
     // param check
     if( index >  || index <  ||
         (xory !=  && xory != ) ||
         (operation !=  && operation != ) ||
         g_width ==  || g_height == )
     {
         return -;
     }

     // plus
     if(operation == )
     {
         if(xory == )    // x
         {
             g_dstQuad[index].x += WARPSTEPSIZE * g_width;
             if(g_dstQuad[index].x > g_width - )
             {
                 g_dstQuad[index].x = g_width - ;
             }
         }
         else if(xory == )   // y
         {
             g_dstQuad[index].y += WARPSTEPSIZE * g_height;
             if(g_dstQuad[index].y > g_height - )
             {
                 g_dstQuad[index].y = g_height -;
             }
         }
     }

     // minus
     else if (operation == )
     {
         if(xory == )        // x
         {
             g_dstQuad[index].x -= WARPSTEPSIZE * g_width;
             if(g_dstQuad[index].x < )
             {
                 g_dstQuad[index].x = ;
             }
         }
         else if(xory ==  )   // y
         {
             g_dstQuad[index].y -= WARPSTEPSIZE * g_height;
             if(g_dstQuad[index].y < )
             {
                 g_dstQuad[index].y = ;
             }
         }
     }

     return ;
 }

 int main()
 {
     const char * FILEPATH = "lena.bmp";
     IplImage * src = cvLoadImage(FILEPATH, CV_LOAD_IMAGE_UNCHANGED);

     if(!src)
     {
         printf("load image error.\texit\n");
         return -;
     }

     CvPoint2D32f srcQuad[];
     CvMat* warp_matrix = cvCreateMat(, , CV_32FC1);
     IplImage *dst;

     cvNamedWindow("Source_Image", );
     cvNamedWindow("Perspective_Warp", );

     dst = cvCloneImage(src);
     dst->origin = dst->origin;
     cvZero(dst);

     // image width & height
     g_width = src->width;
     g_height = src->height;

     srcQuad[].x = ;               // src Top left
     srcQuad[].y = ;
     srcQuad[].x = g_width - ;   // src Top right
     srcQuad[].y = ;
     srcQuad[].x = ;                // src Bottom left
     srcQuad[].y = g_height - ;
     srcQuad[].x = g_width - ;     // src Bottom right
     srcQuad[].y = g_height - ;

     g_dstQuad[].x = ;           // dst Top left
     g_dstQuad[].y = ;
     g_dstQuad[].x = g_width - ;   // dst Top right
     g_dstQuad[].y = ;
     g_dstQuad[].x = ;           // dst Bottom left
     g_dstQuad[].y = g_height - ;
     g_dstQuad[].x = g_width - ;   // dst Bottom right
     g_dstQuad[].y = g_height - ;

     while()
     {
         cvShowImage("Source_Image", src);
         char c = cvWaitKey();

         int ret = ;
         switch(c)
         {
         // ESC
         case :
             goto end;
             break;
         // 0 -- 放大图像
         case :
             {
                 cvNamedWindow("Resize", );
                 CvSize dstSize = getZoomDstSize();
                 if(dstSize.height == - || dstSize.width == -)
                 {
                     goto end;
                 }

                 IplImage* imageresize = cvCreateImage(dstSize, src->depth, src->nChannels);
                 if(!imageresize)
                 {
                     goto end;
                 }
                 cvResize(src, imageresize, CV_INTER_LINEAR);
                 cvShowImage("Resize", imageresize);
                 cvReleaseImage(&imageresize);
             }
             break;
         // SHIFT + 0 ')' -- 缩小图像
         case :
             {
                 cvNamedWindow("Resize", );
                 CvSize dstSize = getZoomDstSize();
                 if(dstSize.height == - || dstSize.width == -)
                 {
                     goto end;
                 }

                 IplImage* imageresize = cvCreateImage(dstSize, src->depth, src->nChannels);
                 if(!imageresize)
                 {
                     goto end;
                 }
                 cvResize(src, imageresize, CV_INTER_LINEAR);
                 cvShowImage("Resize", imageresize);
                 cvReleaseImage(&imageresize);
             }
             break;
         // 9 -- 旋转图像（逆时针）
         case :
             {
                 cvNamedWindow("Rotate", );

                 IplImage* imagerotate = cvCreateImage(cvGetSize(src), src->depth, src->nChannels);
                 if(!imagerotate)
                 {
                     goto end;
                 }
                 g_RotateDegree += ROTATESTEPSIZE;
                 rotateImage(src, imagerotate, g_RotateDegree);
                 cvShowImage("Rotate", imagerotate);
                 cvReleaseImage(&imagerotate);
             }
             break;
         // SHIFT + 9 '(' -- 旋转图像（顺时针）
         case :
             {
                 cvNamedWindow("Rotate", );

                 IplImage* imagerotate = cvCreateImage(cvGetSize(src), src->depth, src->nChannels);
                 if(!imagerotate)
                 {
                     goto end;
                 }
                 g_RotateDegree -= ROTATESTEPSIZE;
                 rotateImage(src, imagerotate, g_RotateDegree);
                 cvShowImage("Rotate", imagerotate);
                 cvReleaseImage(&imagerotate);
             }
             break;
         //
         case :
             ret = changeg_dstQuad(, , );
             break;
         //
         case :
             ret = changeg_dstQuad(, , );
             break;
         //
         case :
             ret = changeg_dstQuad(, , );
             break;
         //
         case :
             ret = changeg_dstQuad(, , );
             break;
         //
         case :
             ret = changeg_dstQuad(, , );
             break;
         //
         case :
             ret = changeg_dstQuad(, , );
             break;
         //
         case :
             ret = changeg_dstQuad(, , );
             break;
         //
         case :
             ret = changeg_dstQuad(, , );
             break;
         // SHIFT + 1  '!'
         case :
             ret = changeg_dstQuad(, , );
             break;
         // SHIFT + 2  '@'
         case :
             ret = changeg_dstQuad(, , );
             break;
         // SHIFT + 3 '#'
         case :
             ret = changeg_dstQuad(, , );
             break;
         // SHIFT + 4 '$'
         case :
             ret = changeg_dstQuad(, , );
             break;
         // SHIFT + 5 '%'
         case :
             ret = changeg_dstQuad(, , );
             break;
         // SHIFT + 6 '^'
         case :
             ret = changeg_dstQuad(, , );
             break;
         // SHIFT + 7 '&'
         case :
             ret = changeg_dstQuad(, , );
             break;
         // SHIFT + 8 '*'
         case :
             ret = changeg_dstQuad(, , );
             break;

         default:
             break;
         }

         // Error
         if(ret != )
         {
             goto end;
         }
         cvGetPerspectiveTransform(srcQuad, g_dstQuad, warp_matrix);
         cvWarpPerspective( src, dst, warp_matrix,
                            CV_INTER_LINEAR + CV_WARP_FILL_OUTLIERS, cvScalarAll());

         cvShowImage("Source_Image", src);
         cvShowImage("Perspective_Warp", dst);
     }

 end:
     cvReleaseImage(&src);
     cvReleaseImage(&dst);
     cvReleaseMat(&warp_matrix);
     cvDestroyAllWindows();

     return ;
 }

程序运行截图：

首先是透视变换：

图像放大缩小（b部分）：

图像旋转（c部分）：