各位大虾:如何将IMAGE1的图片旋转90度放到IMAGE2中?(100分)

以下是C语言解答，Delphi版答案正在准备之中。
摘录自吕凤军著《数字图象处理编程入门》一书
//////////////////////////////////////////////////////////////
//Name:geotrans.c
//Purpose: To perform geometric transform
//Author: phoenix, CS, TshingHua, Beijing, P.R.C.
//Email: bjlufengjun@www.163.net or lufengjun@hotmail.com
//Date:April 3, 1998

//header file
#include "bmp.h"
#include "memory.h"
#include "math.h"

//macro definition
#define WIDTHBYTES(i) ((i+31)/32*4)
#define PI 3.1415926535
#define RADIAN(angle) ((angle)*PI/180.0) //convert angle to radian

//function declaration
int PASCAL WinMain (HANDLE, HANDLE, LPSTR, int);
LRESULT CALLBACK MainWndProc(HWND , UINT,WPARAM, LPARAM);
BOOL LoadBmpFile (HWND hWnd,char *BmpFileName);
BOOL CALLBACK InputBox( HWND hDlg, UINT message,WPARAM wParam, LPARAM lParam );
BOOL Translation(HWND hWnd);
BOOL Rotation(HWND hWnd);
BOOL Mirror(HWND hWnd,BOOL XDirection);
BOOL Transpose(HWND hWnd);
BOOL Zoom(HWND hWnd);

//global variable declaration
BITMAPFILEHEADER bf;
BITMAPINFOHEADER bi;
HPALETTE hPalette=NULL;
HBITMAP hBitmap=NULL;
HGLOBAL hImgData=NULL;
DWORD NumColors;
DWORD LineBytes;
HWND hWnd;
HINSTANCE ghInst;
int xOffset=0,yOffset=0;
float RotateAngle=0.0f;
float ZoomRatio=0.25f;
DWORD ImgWidth=0 , ImgHeight=0;
///////////////////////////////////////////////////////////
int PASCAL WinMain (HANDLE hInstance, HANDLE hPrevInstance,
LPSTR lpszCmdLine, int nCmdShow)
{
MSG msg;
WNDCLASS wndclass;

ghInst=hInstance;
if ( ! hPrevInstance ){
wndclass.style = CS_HREDRAW | CS_VREDRAW;
wndclass.lpfnWndProc = MainWndProc;
wndclass.cbClsExtra = 0;
wndclass.cbWndExtra = 0;
wndclass.hInstance = hInstance;
wndclass.hIcon = LoadIcon (NULL, IDI_APPLICATION);
wndclass.hCursor = LoadCursor (NULL, IDC_ARROW);
wndclass.hbrBackground = GetStockObject (WHITE_BRUSH);
wndclass.lpszMenuName = "BMPMENU";
wndclass.lpszClassName = "phoenix ip system";
}

if ( ! RegisterClass (&wndclass) )
return FALSE;

hWnd = CreateWindow ("phoenix ip system","geometric transform",
WS_OVERLAPPEDWINDOW,CW_USEDEFAULT,CW_USEDEFAULT,
CW_USEDEFAULT, CW_USEDEFAULT, NULL,NULL,
hInstance, NULL);
if (!hWnd)
return FALSE;
ShowWindow (hWnd, SW_SHOWMAXIMIZED);
UpdateWindow (hWnd);

while ( GetMessage (&msg, NULL, 0, 0) ){
TranslateMessage (&msg);
DispatchMessage (&msg);
}
return msg.wParam;
}

////////////////////////////////////////////////////////////////
LRESULT CALLBACK MainWndProc(HWND hWnd, UINT message,WPARAM wParam, LPARAM lParam)
{
static HDC hDC,hMemDC;
PAINTSTRUCT ps;

switch (message){
case WM_PAINT:
{
hDC = BeginPaint(hWnd, &ps);
if (hBitmap)
{
hMemDC = CreateCompatibleDC(hDC);
if (hPalette)
{
SelectPalette (hDC, hPalette, FALSE);
SelectPalette (hMemDC, hPalette, FALSE);
RealizePalette (hDC);
}
SelectObject(hMemDC, hBitmap);
BitBlt(hDC, 0, 0, ImgWidth,ImgHeight, hMemDC, 0, 0, SRCCOPY);
DeleteDC(hMemDC);
}
EndPaint(hWnd, &ps);
break;
}
case WM_DESTROY: //注意释放内存和位图，调色板句柄
if(hBitmap!=NULL)
DeleteObject(hBitmap);

if(hPalette!=NULL)
DeleteObject(hPalette);

if(hImgData!=NULL){
GlobalUnlock(hImgData);
GlobalFree(hImgData);
}
PostQuitMessage (0);
return 0;
case WM_COMMAND:
switch (wParam){
case IDM_LOADBMP:
//注意重新分配内存和调色板，位图句柄时，先释放原来的
if(hBitmap!=NULL){
DeleteObject(hBitmap);
hBitmap=NULL;
}
if(hPalette!=NULL){
DeleteObject(hPalette);
hPalette=NULL;
}
if(hImgData!=NULL){
GlobalUnlock(hImgData);
GlobalFree(hImgData);
hImgData=NULL;
}
if(LoadBmpFile(hWnd,"c://test.bmp")) //成功，则重画窗口
InvalidateRect(hWnd,NULL,TRUE);
break;
case IDM_TRANSLATION:
if(hImgData!=NULL){
if(Translation(hWnd))
InvalidateRect(hWnd,NULL,TRUE);
}
else
MessageBox(hWnd,"File not loaded yet!","Error Message",MB_OK|MB_ICONEXCLAMATION);
break;
case IDM_ROTATION:
if(hImgData!=NULL){
if(Rotation(hWnd))
InvalidateRect(hWnd,NULL,TRUE);
}
else
MessageBox(hWnd,"File not loaded yet!","Error Message",MB_OK|MB_ICONEXCLAMATION);
break;
case IDM_MIRRORX:
if(hImgData!=NULL){
if(Mirror(hWnd,TRUE))
InvalidateRect(hWnd,NULL,TRUE);
}
else
MessageBox(hWnd,"File not loaded yet!","Error Message",MB_OK|MB_ICONEXCLAMATION);
break;
case IDM_MIRRORY:
if(hImgData!=NULL){
if(Mirror(hWnd,FALSE))
InvalidateRect(hWnd,NULL,TRUE);
}
else
MessageBox(hWnd,"File not loaded yet!","Error Message",MB_OK|MB_ICONEXCLAMATION);
break;
case IDM_TRANSPOSE:
if(hImgData!=NULL){
if(Transpose(hWnd))
InvalidateRect(hWnd,NULL,TRUE);
}
else
MessageBox(hWnd,"File not loaded yet!","Error Message",MB_OK|MB_ICONEXCLAMATION);
break;
case IDM_ZOOM:
if(hImgData!=NULL){
if(Zoom(hWnd))
InvalidateRect(hWnd,NULL,TRUE);
}
else
MessageBox(hWnd,"File not loaded yet!","Error Message",MB_OK|MB_ICONEXCLAMATION);
break;
case IDM_EXIT:
SendMessage(hWnd,WM_DESTROY,0,0L);
break;
}
break;
}
return DefWindowProc (hWnd, message, wParam, lParam);
}

////////////////////////////////////////////////////////////////
BOOL LoadBmpFile (HWND hWnd,char *BmpFileName)
{
HFILE hf;
LPBITMAPINFOHEADER lpImgData;
LOGPALETTE *pPal;
LPRGBQUAD lpRGB;
HPALETTE hPrevPalette;
HDC hDc;
HLOCAL hPal;
DWORD ImgSize;
DWORD i;

if((hf=_lopen(BmpFileName,OF_READ))==HFILE_ERROR){
MessageBox(hWnd,"File c://test.bmp not found!","Error Message",MB_OK|MB_ICONEXCLAMATION);
return FALSE;
}
_lread(hf,(LPSTR)&bf,sizeof(BITMAPFILEHEADER));
_lread(hf,(LPSTR)&bi,sizeof(BITMAPINFOHEADER));
ImgWidth=bi.biWidth;
ImgHeight=bi.biHeight;
LineBytes=(DWORD)WIDTHBYTES(bi.biWidth*bi.biBitCount);
ImgSize=(DWORD)LineBytes*bi.biHeight;
if(bi.biClrUsed!=0)
NumColors=(DWORD)bi.biClrUsed;
else
switch(bi.biBitCount){
case 1:
NumColors=2;
break;
case 4:
NumColors=16;
break;
case 8:
NumColors=256;
break;
case 24:
NumColors=0;
break;
default:
MessageBox(hWnd,"Invalid color numbers!","Error Message",MB_OK|MB_ICONEXCLAMATION);
_lclose(hf);
return FALSE;
}
if(bf.bfOffBits!=(DWORD)(NumColors*sizeof(RGBQUAD)+sizeof(BITMAPFILEHEADER)
+sizeof(BITMAPINFOHEADER)))
{
MessageBox(hWnd,"Invalid color numbers!","Error Message" ,MB_OK|
MB_ICONEXCLAMATION);
_lclose(hf);
return FALSE;
}
bf.bfSize=sizeof(BITMAPFILEHEADER)+sizeof(BITMAPINFOHEADER)+NumColors*sizeof(RGBQUAD)+ImgSize;
if((hImgData=GlobalAlloc(GHND,(DWORD)(sizeof(BITMAPINFOHEADER)+
NumColors*sizeof(RGBQUAD)+ImgSize)))==NULL)
{
MessageBox(hWnd,"Error alloc memory!","ErrorMessage",MB_OK|
MB_ICONEXCLAMATION);
_lclose(hf);
return FALSE;
}

lpImgData=(LPBITMAPINFOHEADER)GlobalLock(hImgData);
_llseek(hf,sizeof(BITMAPFILEHEADER),SEEK_SET);
_hread(hf,(char *)lpImgData,(long)sizeof(BITMAPINFOHEADER)
+(long)NumColors*sizeof(RGBQUAD)+ImgSize);
_lclose(hf);
if(NumColors!=0)
{
hPal=LocalAlloc(LHND,sizeof(LOGPALETTE) + NumColors* sizeof(PALETTEENTRY));
pPal =(LOGPALETTE *)LocalLock(hPal);
pPal->palNumEntries =(WORD) NumColors;
pPal->palVersion = 0x300;
lpRGB = (LPRGBQUAD)((LPSTR)lpImgData + (DWORD)sizeof(BITMAPINFOHEADER));
for (i = 0; i < NumColors; i++) {
pPal->palPalEntry.peRed=lpRGB->rgbRed;
pPal->palPalEntry.peGreen=lpRGB->rgbGreen;
pPal->palPalEntry.peBlue=lpRGB->rgbBlue;
pPal->palPalEntry.peFlags=(BYTE)0;
lpRGB++;
}
hPalette=CreatePalette(pPal);
LocalUnlock(hPal);
LocalFree(hPal);
}
hDc=GetDC(hWnd);
if(hPalette){
hPrevPalette=SelectPalette(hDc,hPalette,FALSE);
RealizePalette(hDc);
}
hBitmap=CreateDIBitmap(hDc, (LPBITMAPINFOHEADER)lpImgData, (LONG)CBM_INIT,
(LPSTR)lpImgData+sizeof(BITMAPINFOHEADER) +NumColors*sizeof(RGBQUAD),
(LPBITMAPINFO)lpImgData, DIB_RGB_COLORS);
if(hPalette &amp;&amp; hPrevPalette){
SelectPalette(hDc,hPrevPalette,FALSE);
RealizePalette(hDc);
}

ReleaseDC(hWnd,hDc);
GlobalUnlock(hImgData);
return TRUE;
}
////////////////////////////////////////////////////////////////
BOOL CALLBACK InputBox( HWND hDlg, UINT message,WPARAM wParam, LPARAM lParam )
{
char str[80];

switch ( message ){
case WM_INITDIALOG:
SetDlgItemText(hDlg,ID_XOFFSET,"0");
SetDlgItemText(hDlg,ID_YOFFSET,"0");
SetDlgItemText(hDlg,ID_ANGLE,"0");
SetDlgItemText(hDlg,ID_ZOOMRATIO,"0.25");
return TRUE;
case WM_COMMAND:
if ( wParam == IDOK || wParam == IDCANCEL )
{
GetDlgItemText(hDlg,ID_XOFFSET,str,80);
xOffset=atoi(str);
GetDlgItemText(hDlg,ID_YOFFSET,str,80);
yOffset=atoi(str);
GetDlgItemText(hDlg,ID_ANGLE,str,80);
RotateAngle=(float)atof(str);
GetDlgItemText(hDlg,ID_ZOOMRATIO,str,80);
ZoomRatio=(float)atof(str);
EndDialog ( hDlg, TRUE );
return TRUE;
}
break;
}
return FALSE;
}
////////////////////////////////////////////////////////////////
BOOL Translation(HWND hWnd)
{
DLGPROC dlgInputBox = NULL;
DWORD OffBits,BufSize;
LPBITMAPINFOHEADER lpImgData;
LPSTR lpPtr;
HLOCAL hTempImgData;
LPBITMAPINFOHEADER lpTempImgData;
LPSTR lpTempPtr;
int SrcX0,SrcY0,SrcX1,SrcY1,DstX0,DstY0,DstX1,DstY1;
int RectWidth,RectHeight;
BOOL xVisible,yVisible;
HDC hDc;
HFILE hf;
int i;

dlgInputBox = (DLGPROC) MakeProcInstance ( (FARPROC)InputBox, ghInst );
DialogBox (ghInst, "INPUTBOX", hWnd, dlgInputBox);
FreeProcInstance ( (FARPROC) dlgInputBox );

OffBits=bf.bfOffBits-sizeof(BITMAPFILEHEADER);
BufSize=bf.bfSize-sizeof(BITMAPFILEHEADER);

if((hTempImgData=LocalAlloc(LHND,BufSize))==NULL)
{
MessageBox(hWnd,"Error alloc memory!","Error Message",MB_OK|MB_ICONEXCLAMATION);
return FALSE;
}

lpImgData=(LPBITMAPINFOHEADER)GlobalLock(hImgData);
lpTempImgData=(LPBITMAPINFOHEADER)LocalLock(hTempImgData);

lpPtr=(char *)lpImgData;
lpTempPtr=(char *)lpTempImgData;

memset(lpTempPtr,(BYTE)255,BufSize);
memcpy(lpTempPtr,lpPtr,OffBits);

xVisible=TRUE;
if( xOffset<= -bi.biWidth )
xVisible=FALSE;
else if( xOffset<=0){
DstX0=0;
DstX1=bi.biWidth+xOffset;
}
else if ( xOffset<bi.biWidth){
DstX0=xOffset;
DstX1=bi.biWidth;
}
else
xVisible=FALSE;
SrcX0=DstX0-xOffset;
SrcX1=DstX1-xOffset;
RectWidth=DstX1-DstX0;

yVisible=TRUE;
if( yOffset<= -bi.biHeight )
yVisible=FALSE;
else if( yOffset<=0){
DstY0=0;
DstY1=bi.biHeight+yOffset;
}
else if ( yOffset<bi.biHeight){
DstY0=yOffset;
DstY1=bi.biHeight;
}
else
yVisible=FALSE;
SrcY0=DstY0-yOffset;
SrcY1=DstY1-yOffset;
RectHeight=DstY1-DstY0;

if( xVisible &amp;&amp; yVisible){
for(i=0;i<RectHeight;i++){
lpPtr=(char *)lpImgData+(BufSize-LineBytes-(i+SrcY0)*LineBytes)+SrcX0;
lpTempPtr=(char *)lpTempImgData+(BufSize-LineBytes-(i+DstY0)*LineBytes)+DstX0;
memcpy(lpTempPtr,lpPtr,RectWidth);
}
}

hDc=GetDC(hWnd);
if(hBitmap!=NULL)
DeleteObject(hBitmap);

hBitmap=CreateDIBitmap(hDc, (LPBITMAPINFOHEADER)lpTempImgData, (LONG)CBM_INIT,
(LPSTR)lpTempImgData+sizeof(BITMAPINFOHEADER) +NumColors*sizeof(RGBQUAD),
(LPBITMAPINFO)lpTempImgData, DIB_RGB_COLORS);

hf=_lcreat("c://translation.bmp",0);
_lwrite(hf,(LPSTR)&amp;bf,sizeof(BITMAPFILEHEADER));
_lwrite(hf,(LPSTR)lpTempImgData,BufSize);
_lclose(hf);

ReleaseDC(hWnd,hDc);
LocalUnlock(hTempImgData);
LocalFree(hTempImgData);
GlobalUnlock(hImgData);
return TRUE;
}
////////////////////////////////////////////////////////////////
BOOL Rotation(HWND hWnd)
{
DLGPROC dlgInputBox = NULL;
DWORD OffBits,SrcBufSize,DstBufSize,DstLineBytes;
LPBITMAPINFOHEADER lpImgData;
LPSTR lpPtr;
HLOCAL hTempImgData;
LPBITMAPINFOHEADER lpTempImgData;
LPSTR lpTempPtr;
float SrcX1,SrcY1,SrcX2,SrcY2,SrcX3,SrcY3,SrcX4,SrcY4;
float DstX1,DstY1,DstX2,DstY2,DstX3,DstY3,DstX4,DstY4;
DWORD Wold,Hold,Wnew,Hnew;
HDC hDc;
HFILE hf;
DWORD x0,y0,x1,y1;
float cosa,sina; //cos(a),sin(a)
float num1,num2;
BITMAPFILEHEADER DstBf;
BITMAPINFOHEADER DstBi;

dlgInputBox = (DLGPROC) MakeProcInstance ( (FARPROC)InputBox, ghInst );
DialogBox (ghInst, "INPUTBOX", hWnd, dlgInputBox);
FreeProcInstance ( (FARPROC) dlgInputBox );

RotateAngle=(float)RADIAN(RotateAngle);
cosa=(float)cos((double)RotateAngle);
sina=(float)sin((double)RotateAngle);

Wold=bi.biWidth;
Hold=bi.biHeight;
SrcX1=(float)(-0.5*Wold);
SrcY1=(float)(0.5*Hold);
SrcX2=(float)(0.5*Wold);
SrcY2=(float)(0.5*Hold);
SrcX3=(float)(-0.5*Wold);
SrcY3=(float)(-0.5*Hold);
SrcX4=(float)(0.5*Wold);
SrcY4=(float)(-0.5*Hold);

DstX1=cosa*SrcX1+sina*SrcY1;
DstY1=-sina*SrcX1+cosa*SrcY1;
DstX2=cosa*SrcX2+sina*SrcY2;
DstY2=-sina*SrcX2+cosa*SrcY2;
DstX3=cosa*SrcX3+sina*SrcY3;
DstY3=-sina*SrcX3+cosa*SrcY3;
DstX4=cosa*SrcX4+sina*SrcY4;
DstY4=-sina*SrcX4+cosa*SrcY4;

Wnew = (DWORD)(max(fabs(DstX4-DstX1), fabs(DstX3-DstX2))+0.5);
Hnew = (DWORD)(max(fabs(DstY4-DstY1), fabs(DstY3-DstY2))+0.5);
num1=(float)( -0.5*Wnew*cosa-0.5*Hnew*sina+0.5*Wold);
num2=(float)(0.5*Wnew*sina-0.5*Hnew*cosa+0.5*Hold);

OffBits=bf.bfOffBits-sizeof(BITMAPFILEHEADER);
SrcBufSize=bf.bfSize-sizeof(BITMAPFILEHEADER);

ImgWidth=Wnew;
ImgHeight=Hnew;

DstLineBytes=(DWORD)WIDTHBYTES(Wnew*bi.biBitCount);
DstBufSize=(DWORD)(sizeof(BITMAPINFOHEADER)+NumColors*sizeof(RGBQUAD)+(DWORD)DstLineBytes*Hnew);

if((hTempImgData=LocalAlloc(LHND,DstBufSize))==NULL)
{
MessageBox(hWnd,"Error alloc memory!","Error Message",MB_OK|MB_ICONEXCLAMATION);
return FALSE;
}

lpImgData=(LPBITMAPINFOHEADER)GlobalLock(hImgData);
lpTempImgData=(LPBITMAPINFOHEADER)LocalLock(hTempImgData);

lpPtr=(char *)lpImgData;
lpTempPtr=(char *)lpTempImgData;

memset(lpTempPtr,(BYTE)255,DstBufSize);
memcpy(lpTempPtr,lpPtr,OffBits);

//get new bitmapfileheader and bitmapinfoheader
memcpy((char *)&amp;DstBf,(char *)&amp;bf,sizeof(BITMAPFILEHEADER));
memcpy((char *)&amp;DstBi,(char *)&amp;bi,sizeof(BITMAPINFOHEADER));
DstBf.bfSize=DstBufSize+sizeof(BITMAPFILEHEADER);
DstBi.biWidth=Wnew;
DstBi.biHeight=Hnew;

//overwrite bitmapinfoheader with the new one
memcpy(lpTempPtr,(char *)&amp;DstBi,sizeof(BITMAPINFOHEADER));

for(y1=0;y1<Hnew;y1++)
for(x1=0;x1<Wnew;x1++){
x0= (DWORD)(x1*cosa+y1*sina+num1);
y0= (DWORD)(-1.0f*x1*sina+y1*cosa+num2);
if( (x0>=0) &amp;&amp; (x0<Wold) &amp;&amp; (y0>=0) &amp;&amp; (y0<Hold))
{
lpPtr=(char *)lpImgData+(SrcBufSize-LineBytes-y0*LineBytes)+x0;
lpTempPtr=(char *)lpTempImgData+(DstBufSize-DstLineBytes-y1*DstLineBytes)+x1;
*lpTempPtr=*lpPtr;
}
}

hDc=GetDC(hWnd);
if(hBitmap!=NULL)
DeleteObject(hBitmap);

hBitmap=CreateDIBitmap(hDc, (LPBITMAPINFOHEADER)lpTempImgData, (LONG)CBM_INIT,
(LPSTR)lpTempImgData+sizeof(BITMAPINFOHEADER) +NumColors*sizeof(RGBQUAD),
(LPBITMAPINFO)lpTempImgData, DIB_RGB_COLORS);

hf=_lcreat("c://rotation.bmp",0);
_lwrite(hf,(LPSTR)&amp;DstBf,sizeof(BITMAPFILEHEADER));
_lwrite(hf,(LPSTR)lpTempImgData,DstBufSize);
_lclose(hf);

ReleaseDC(hWnd,hDc);
LocalUnlock(hTempImgData);
LocalFree(hTempImgData);
GlobalUnlock(hImgData);
return TRUE;
}
////////////////////////////////////////////////////////////////
BOOL Mirror(HWND hWnd,BOOL XDirection)
{
DWORD OffBits,BufSize;
LPBITMAPINFOHEADER lpImgData;
LPSTR lpPtr;
HLOCAL hTempImgData;
LPBITMAPINFOHEADER lpTempImgData;
LPSTR lpTempPtr;
HDC hDc;
HFILE hf;
LONG x0,y0,x1,y1;

OffBits=bf.bfOffBits-sizeof(BITMAPFILEHEADER);
BufSize=bf.bfSize-sizeof(BITMAPFILEHEADER);

if((hTempImgData=LocalAlloc(LHND,BufSize))==NULL)
{
MessageBox(hWnd,"Error alloc memory!","Error Message",MB_OK|MB_ICONEXCLAMATION);
return FALSE;
}

lpImgData=(LPBITMAPINFOHEADER)GlobalLock(hImgData);
lpTempImgData=(LPBITMAPINFOHEADER)LocalLock(hTempImgData);

lpPtr=(char *)lpImgData;
lpTempPtr=(char *)lpTempImgData;

memset(lpTempPtr,(BYTE)255,BufSize);
memcpy(lpTempPtr,lpPtr,OffBits);

if( XDirection){
for(y1=0;y1<bi.biHeight;y1++)
for(x1=0;x1<bi.biWidth;x1++){
x0=bi.biWidth-1-x1;
y0=y1;
lpPtr=(char *)lpImgData+(BufSize-LineBytes-y0*LineBytes)+x0;
lpTempPtr=(char *)lpTempImgData+(BufSize-LineBytes-y1*LineBytes)+x1;
*lpTempPtr=*lpPtr;
}
}
else{
for(y1=0;y1<bi.biHeight;y1++)
for(x1=0;x1<bi.biWidth;x1++){
x0=x1;
y0=bi.biHeight-1-y1;
lpPtr=(char *)lpImgData+(BufSize-LineBytes-y0*LineBytes)+x0;
lpTempPtr=(char *)lpTempImgData+(BufSize-LineBytes-y1*LineBytes)+x1;
*lpTempPtr=*lpPtr;
}
}

hDc=GetDC(hWnd);
if(hBitmap!=NULL)
DeleteObject(hBitmap);

hBitmap=CreateDIBitmap(hDc, (LPBITMAPINFOHEADER)lpTempImgData, (LONG)CBM_INIT,
(LPSTR)lpTempImgData+sizeof(BITMAPINFOHEADER) +NumColors*sizeof(RGBQUAD),
(LPBITMAPINFO)lpTempImgData, DIB_RGB_COLORS);
if( XDirection)
hf=_lcreat("c://mirrorx.bmp",0);
else
hf=_lcreat("c://mirrory.bmp",0);

_lwrite(hf,(LPSTR)&amp;bf,sizeof(BITMAPFILEHEADER));
_lwrite(hf,(LPSTR)lpTempImgData,BufSize);
_lclose(hf);

ReleaseDC(hWnd,hDc);
LocalUnlock(hTempImgData);
LocalFree(hTempImgData);
GlobalUnlock(hImgData);
return TRUE;
}
////////////////////////////////////////////////////////////////
BOOL Transpose(HWND hWnd)
{
DWORD OffBits,SrcBufSize,DstBufSize,DstLineBytes;
LPBITMAPINFOHEADER lpImgData;
LPSTR lpPtr;
HLOCAL hTempImgData;
LPBITMAPINFOHEADER lpTempImgData;
LPSTR lpTempPtr;
DWORD Wnew,Hnew;
HDC hDc;
HFILE hf;
DWORD x0,y0,x1,y1;
BITMAPFILEHEADER DstBf;
BITMAPINFOHEADER DstBi;

Wnew = (DWORD)bi.biHeight;
Hnew = (DWORD)bi.biWidth;

OffBits=bf.bfOffBits-sizeof(BITMAPFILEHEADER);
SrcBufSize=bf.bfSize-sizeof(BITMAPFILEHEADER);

ImgWidth=Wnew;
ImgHeight=Hnew;

DstLineBytes=(DWORD)WIDTHBYTES(Wnew*bi.biBitCount);
DstBufSize=(DWORD)(sizeof(BITMAPINFOHEADER)+NumColors*sizeof(RGBQUAD)+(DWORD)DstLineBytes*Hnew);

if((hTempImgData=LocalAlloc(LHND,DstBufSize))==NULL)
{
MessageBox(hWnd,"Error alloc memory!","Error Message",MB_OK|MB_ICONEXCLAMATION);
return FALSE;
}

lpImgData=(LPBITMAPINFOHEADER)GlobalLock(hImgData);
lpTempImgData=(LPBITMAPINFOHEADER)LocalLock(hTempImgData);

lpPtr=(char *)lpImgData;
lpTempPtr=(char *)lpTempImgData;

memset(lpTempPtr,(BYTE)255,DstBufSize);
memcpy(lpTempPtr,lpPtr,OffBits);

//get new bitmapfileheader and bitmapinfoheader
memcpy((char *)&amp;DstBf,(char *)&amp;bf,sizeof(BITMAPFILEHEADER));
memcpy((char *)&amp;DstBi,(char *)&amp;bi,sizeof(BITMAPINFOHEADER));
DstBf.bfSize=DstBufSize+sizeof(BITMAPFILEHEADER);
DstBi.biWidth=Wnew;
DstBi.biHeight=Hnew;

//overwrite bitmapinfoheader with the new one
memcpy(lpTempPtr,(char *)&amp;DstBi,sizeof(BITMAPINFOHEADER));

for(y1=0;y1<Hnew;y1++)
for(x1=0;x1<Wnew;x1++){
x0= y1;
y0= x1;
lpPtr=(char *)lpImgData+(SrcBufSize-LineBytes-y0*LineBytes)+x0;
lpTempPtr=(char *)lpTempImgData+(DstBufSize-DstLineBytes-y1*DstLineBytes)+x1;
*lpTempPtr=*lpPtr;
}

hDc=GetDC(hWnd);
if(hBitmap!=NULL)
DeleteObject(hBitmap);

hBitmap=CreateDIBitmap(hDc, (LPBITMAPINFOHEADER)lpTempImgData, (LONG)CBM_INIT,
(LPSTR)lpTempImgData+sizeof(BITMAPINFOHEADER) +NumColors*sizeof(RGBQUAD),
(LPBITMAPINFO)lpTempImgData, DIB_RGB_COLORS);

hf=_lcreat("c://transpose.bmp",0);
_lwrite(hf,(LPSTR)&amp;DstBf,sizeof(BITMAPFILEHEADER));
_lwrite(hf,(LPSTR)lpTempImgData,DstBufSize);
_lclose(hf);

ReleaseDC(hWnd,hDc);
LocalUnlock(hTempImgData);
LocalFree(hTempImgData);
GlobalUnlock(hImgData);
return TRUE;
}
////////////////////////////////////////////////////////////////
BOOL Zoom(HWND hWnd)
{
DLGPROC dlgInputBox = NULL;
DWORD OffBits,SrcBufSize,DstBufSize,DstLineBytes;
LPBITMAPINFOHEADER lpImgData;
LPSTR lpPtr;
HLOCAL hTempImgData;
LPBITMAPINFOHEADER lpTempImgData;
LPSTR lpTempPtr;
DWORD Wold,Hold,Wnew,Hnew;
HDC hDc;
HFILE hf;
DWORD x0,y0,x1,y1;
float num1;
BITMAPFILEHEADER DstBf;
BITMAPINFOHEADER DstBi;

dlgInputBox = (DLGPROC) MakeProcInstance ( (FARPROC)InputBox, ghInst );
DialogBox (ghInst, "INPUTBOX", hWnd, dlgInputBox);
FreeProcInstance ( (FARPROC) dlgInputBox );

num1=(float)(1.0/ZoomRatio);
Wold=bi.biWidth;
Hold=bi.biHeight;
Wnew = (DWORD)(Wold*ZoomRatio+0.5);
Hnew = (DWORD)(Hold*ZoomRatio+0.5);

OffBits=bf.bfOffBits-sizeof(BITMAPFILEHEADER);
SrcBufSize=bf.bfSize-sizeof(BITMAPFILEHEADER);

ImgWidth=Wnew;
ImgHeight=Hnew;

DstLineBytes=(DWORD)WIDTHBYTES(Wnew*bi.biBitCount);
DstBufSize=(DWORD)(sizeof(BITMAPINFOHEADER)+NumColors*sizeof(RGBQUAD)+(DWORD)DstLineBytes*Hnew);

if((hTempImgData=LocalAlloc(LHND,DstBufSize))==NULL)
{
MessageBox(hWnd,"Error alloc memory!","Error Message",MB_OK|MB_ICONEXCLAMATION);
return FALSE;
}

lpImgData=(LPBITMAPINFOHEADER)GlobalLock(hImgData);
lpTempImgData=(LPBITMAPINFOHEADER)LocalLock(hTempImgData);

lpPtr=(char *)lpImgData;
lpTempPtr=(char *)lpTempImgData;

memset(lpTempPtr,(BYTE)255,DstBufSize);
memcpy(lpTempPtr,lpPtr,OffBits);

//get new bitmapfileheader and bitmapinfoheader
memcpy((char *)&amp;DstBf,(char *)&amp;bf,sizeof(BITMAPFILEHEADER));
memcpy((char *)&amp;DstBi,(char *)&amp;bi,sizeof(BITMAPINFOHEADER));
DstBf.bfSize=DstBufSize+sizeof(BITMAPFILEHEADER);
DstBi.biWidth=Wnew;
DstBi.biHeight=Hnew;

//overwrite bitmapinfoheader with the new one
memcpy(lpTempPtr,(char *)&amp;DstBi,sizeof(BITMAPINFOHEADER));

for(y1=0;y1<Hnew;y1++)
for(x1=0;x1<Wnew;x1++){
x0= (DWORD)(x1*num1);
y0= (DWORD)(y1*num1);
if( (x0>=0) &amp;&amp; (x0<Wold) &amp;&amp; (y0>=0) &amp;&amp; (y0<Hold))
{
lpPtr=(char *)lpImgData+(SrcBufSize-LineBytes-y0*LineBytes)+x0;
lpTempPtr=(char *)lpTempImgData+(DstBufSize-DstLineBytes-y1*DstLineBytes)+x1;
*lpTempPtr=*lpPtr;
}
}

hDc=GetDC(hWnd);
if(hBitmap!=NULL)
DeleteObject(hBitmap);

hBitmap=CreateDIBitmap(hDc, (LPBITMAPINFOHEADER)lpTempImgData, (LONG)CBM_INIT,
(LPSTR)lpTempImgData+sizeof(BITMAPINFOHEADER) +NumColors*sizeof(RGBQUAD),
(LPBITMAPINFO)lpTempImgData, DIB_RGB_COLORS);

hf=_lcreat("c://zoom.bmp",0);
_lwrite(hf,(LPSTR)&amp;DstBf,sizeof(BITMAPFILEHEADER));
_lwrite(hf,(LPSTR)lpTempImgData,DstBufSize);
_lclose(hf);

ReleaseDC(hWnd,hDc);
LocalUnlock(hTempImgData);
LocalFree(hTempImgData);
GlobalUnlock(hImgData);
return TRUE;
}

原理：
以Image1的中心为坐标原点，逐点取出各点像素坐标，计算出旋转90度以后的
新坐标值，在Image2的相应坐标处画出该像素，具体实现需要较好的几何知识。

要是是90'是很简单的
var i,j:integer;
begin
for i:= 0 to image1.width do
for j:=0 to image1.Height do
image2.canvas.Pixels[j,i]:=image1.Canvas.Pixels[i,j];
end;
就ok了
不过这样只能做90,180,270的变换，要是是其他角度，那还要向jm 学习

withdraw的方法太慢了。

用scanline可以
C++ Builder的算法
Byte *ptr,*newscanline;

bitmap2->Height = bitmap1->Width;
bitmap2->Width = bitmap1->Height;

for (int y = 0; y < bitmap1->Width; y++){
newscanline = static_cast<Byte*>(bitmap2->ScanLine[y]);
for (int x = 0; x < bitmap1->Height; x++){
ptr = static_cast<Byte*>(bitmap1->ScanLine[x]);
newscanline[x] = ptr[y];
};
};

Image2->Canvas->Draw(0,0,bitmap2);

如何将Image控件上的Jpeg图象旋转90度？
http://www.gislab.ecnu.edu.cn/delphibbs/DispQ.asp?LID=213062

想听对xWolf问题的回答。
缺省的Jpeg没有Bitmap，好象也没有Canvas，我以前怎么也弄不出来。

TJPEG有个成员类型是TBitmap,TImage显示一幅jpg图象时,先把jpeg转换到
TBitmap中,然后显示TBitmap中的内容

在电脑报99年合定本下册中有一段delphi的原程序，
文章的题目叫《在delphi中实现水面倒影》

多人接受答案了。