c语言easyx旋转函数rotateimage的问题

Question

转着转着就变成这样了（，各位有什么办法可以解决嘛，有没有自己写的旋转函数源代码啊

Answer 1

仅供参考：

#include <math.h>
#include <string.h>
#include <stdio.h>
#include <windows.h>
#include <gdiplus.h>
#pragma comment(lib, "gdiplus.lib")
using namespace Gdiplus;
wchar_t formats[5][11]={
    L"image/bmp",
    L"image/jpeg",
    L"image/gif",
    L"image/tiff",
    L"image/png",
};
wchar_t exts[5][5]={
    L".bmp",
    L".jpg",
    L".gif",
    L".tif",
    L".png",
};
int GetEncoderClsid(const WCHAR* format, CLSID* pClsid) {
   UINT  num = 0;          // number of image encoders
   UINT  size = 0;         // size of the image encoder array in bytes
   ImageCodecInfo* pImageCodecInfo = NULL;
   GetImageEncodersSize(&num, &size);
   if(size == 0) return -1;  // Failure
   pImageCodecInfo = (ImageCodecInfo*)(malloc(size));
   if(pImageCodecInfo == NULL) return -1;  // Failure
   GetImageEncoders(num, size, pImageCodecInfo);
   for (UINT j = 0; j < num; ++j) {
      if ( wcscmp(pImageCodecInfo[j].MimeType, format) == 0 ) {
         *pClsid = pImageCodecInfo[j].Clsid;
         free(pImageCodecInfo);
         return j;  // Success
      }
   }
   free(pImageCodecInfo);
   return -1;  // Failure
}
int wmain(int argc,wchar_t *argv[]) {
    int r=1;
    if (argc<4) {
    USAGE:
        wprintf(L"%s srcimg.{bmp|jpg|gif|tif|png|wmf|emf|ico}  desimg.{bmp|jpg|gif|tif|png}  angle\n",argv[0]);
        return r;
    }
    int i;
    for (i=0;i<5;i++) {
        if (0==_wcsicmp(argv[1]+wcslen(argv[1])-4,exts[i])) break;
    }
    if (i>=5) goto USAGE;
    for (i=0;i<5;i++) {
        if (0==_wcsicmp(argv[2]+wcslen(argv[2])-4,exts[i])) break;
    }
    if (i>=5) goto USAGE;
    GdiplusStartupInput gdiplusstartupinput;
    ULONG_PTR gdiplustoken;
    GdiplusStartup(&gdiplustoken, &gdiplusstartupinput, NULL);
    {
        Image img(argv[1]);
        if (Ok==img.GetLastStatus()) {
            UINT height = img.GetHeight();
            UINT width  = img.GetWidth();
            REAL angle;
            if (1==swscanf_s(argv[3],L"%f",&angle)) {
                REAL size;
                size=(REAL)sqrt(1.0*width*width+1.0*height*height);
                Matrix mat;
                mat.Translate(size / -2.0f, size / -2.0f);
                mat.Rotate(-angle, MatrixOrderAppend);
                mat.Translate(size / 2.0f, size / 2.0f, MatrixOrderAppend);
                PointF pfTL((size-width)/2.0f      ,(size-height)/2.0f       );
                PointF pfTR((size-width)/2.0f+width,(size-height)/2.0f       );
                PointF pfBL((size-width)/2.0f      ,(size-height)/2.0f+height);
                PointF pfBR((size-width)/2.0f+width,(size-height)/2.0f+height);
                Graphics tgp(&img);
                Bitmap bmp((UINT)size,(UINT)size,&tgp);//Let bmp Resolution equal to img Resolution
                Graphics gp(&bmp);
                gp.SetTransform(&mat);
                gp.DrawImage(&img,pfTL);
                REAL xmin,ymin,xmax,ymax,x,y,rw,rh;
                mat.TransformPoints(&pfTL);
                xmin=xmax=pfTL.X;
                ymin=ymax=pfTL.Y;
                mat.TransformPoints(&pfTR);
                if (xmin>pfTR.X) xmin=pfTR.X;
                if (xmax<pfTR.X) xmax=pfTR.X;
                if (ymin>pfTR.Y) ymin=pfTR.Y;
                if (ymax<pfTR.Y) ymax=pfTR.Y;
                mat.TransformPoints(&pfBL);
                if (xmin>pfBL.X) xmin=pfBL.X;
                if (xmax<pfBL.X) xmax=pfBL.X;
                if (ymin>pfBL.Y) ymin=pfBL.Y;
                if (ymax<pfBL.Y) ymax=pfBL.Y;
                mat.TransformPoints(&pfBR);
                if (xmin>pfBR.X) xmin=pfBR.X;
                if (xmax<pfBR.X) xmax=pfBR.X;
                if (ymin>pfBR.Y) ymin=pfBR.Y;
                if (ymax<pfBR.Y) ymax=pfBR.Y;
                x=xmin;
                y=ymin;
                rw=xmax-x;
                rh=ymax-y;
                Bitmap* clone;
                clone = bmp.Clone(x,y,rw,rh,PixelFormat24bppRGB);//bmp.GetPixelFormat()
                CLSID encoderClsid;
                if (0<=GetEncoderClsid(formats[i],&encoderClsid)) {
                    if (Ok==clone->Save(argv[2],&encoderClsid)) {
                        wprintf(L"OK to %s  %s  %s  %s\n",argv[0],argv[1],argv[2],argv[3]);
                        r=0;
                    } else {
                        wprintf(L"Error to save %s\n",argv[2]);
                        r=4;
                    }
                } else {
                    wprintf(L"Error to GetEncoderClsid(%s,...)\n",formats[i]);
                    r=3;
                }
                delete clone;
            } else {
                wprintf(L"Error to get angle %s\n",argv[3]);
                r=2;
            }
        } else {
            wprintf(L"Error to load %s\n",argv[1]);
            r=5;
        }
    }
    GdiplusShutdown(gdiplustoken);
    return r;
}