how to create a new bitmap with rotated image?

[cocacola]

[stranger]

// GetRotatedBitmap - Create a new bitmap with rotated image
// Returns - Returns new bitmap with rotated image
// hBitmap - Bitmap to rotate
// radians - Angle of rotation in radians
// clrBack - Color of pixels in the resulting bitmap that do
// not get covered by source pixels
// Note - If the bitmap uses colors not in the system palette
// then the result is unexpected. You can fix this by
// adding an argument for the logical palette.
HBITMAP GetRotatedBitmap( HBITMAP hBitmap, float radians, COLORREF clrBack )
{
// Create a memory DC compatible with the display
CDC sourceDC, destDC;
sourceDC.CreateCompatibleDC( NULL );
destDC.CreateCompatibleDC( NULL );

// Get logical coordinates
BITMAP bm;
::GetObject( hBitmap, sizeof( bm ), &bm );

float cosine = (float)cos(radians);
float sine = (float)sin(radians);

// Compute dimensions of the resulting bitmap
// First get the coordinates of the 3 corners other than origin
int x1 = (int)(-bm.bmHeight * sine);
int y1 = (int)(bm.bmHeight * cosine);
int x2 = (int)(bm.bmWidth * cosine - bm.bmHeight * sine);
int y2 = (int)(bm.bmHeight * cosine + bm.bmWidth * sine);
int x3 = (int)(bm.bmWidth * cosine);
int y3 = (int)(bm.bmWidth * sine);

int minx = min(0,min(x1, min(x2,x3)));
int miny = min(0,min(y1, min(y2,y3)));
int maxx = max(x1, max(x2,x3));
int maxy = max(y1, max(y2,y3));

int w = maxx - minx;
int h = maxy - miny;


// Create a bitmap to hold the result
HBITMAP hbmResult = ::CreateCompatibleBitmap(CClientDC(NULL), w, h);

HBITMAP hbmOldSource = (HBITMAP)::SelectObject( sourceDC.m_hDC, hBitmap );
HBITMAP hbmOldDest = (HBITMAP)::SelectObject( destDC.m_hDC, hbmResult );

// Draw the background color before we change mapping mode
HBRUSH hbrBack = CreateSolidBrush( clrBack );
HBRUSH hbrOld = (HBRUSH)::SelectObject( destDC.m_hDC, hbrBack );
destDC.PatBlt( 0, 0, w, h, PATCOPY );
::DeleteObject( ::SelectObject( destDC.m_hDC, hbrOld ) );

// Set mapping mode so that +ve y axis is upwords
sourceDC.SetMapMode(MM_ISOTROPIC);
sourceDC.SetWindowExt(1,1);
sourceDC.SetViewportExt(1,-1);
sourceDC.SetViewportOrg(0, bm.bmHeight-1);

destDC.SetMapMode(MM_ISOTROPIC);
destDC.SetWindowExt(1,1);
destDC.SetViewportExt(1,-1);
destDC.SetWindowOrg(minx, maxy);

// Now do the actual rotating - a pixel at a time
// Computing the destination point for each source point
// will leave a few pixels that do not get covered
// So we use a reverse transform - e.i. compute the source point
// for each destination point

for( int y = miny; y < maxy; y++ )
{
for( int x = minx; x < maxx; x++ )
{
int sourcex = (int)(x*cosine + y*sine);
int sourcey = (int)(y*cosine - x*sine);
if( sourcex >= 0 && sourcex < bm.bmWidth && sourcey >= 0
&& sourcey < bm.bmHeight )
destDC.SetPixel(x,y,sourceDC.GetPixel(sourcex,sourcey));
}
}

// Restore DCs
::SelectObject( sourceDC.m_hDC, hbmOldSource );
::SelectObject( destDC.m_hDC, hbmOldDest );

return hbmResult;
}

// GetRotatedBitmap - Create a new bitmap with rotated image
// Returns - Returns new bitmap with rotated image
// hDIB - Device-independent bitmap to rotate
// radians - Angle of rotation in radians
// clrBack - Color of pixels in the resulting bitmap that do
// not get covered by source pixels
HANDLE GetRotatedBitmap( HANDLE hDIB, float radians, COLORREF clrBack )
{
// Get source bitmap info
BITMAPINFO &bmInfo = *(LPBITMAPINFO)hDIB ;
int bpp = bmInfo.bmiHeader.biBitCount; // Bits per pixel

int nColors = bmInfo.bmiHeader.biClrUsed ? bmInfo.bmiHeader.biClrUsed :
1 << bpp;
int nWidth = bmInfo.bmiHeader.biWidth;
int nHeight = bmInfo.bmiHeader.biHeight;
int nRowBytes = ((((nWidth * bpp) + 31) & ~31) / 8);

// Make sure height is positive and biCompression is BI_RGB or BI_BITFIELDS
DWORD &compression = bmInfo.bmiHeader.biCompression;
if( nHeight < 0 || (compression!=BI_RGB && compression!=BI_BITFIELDS))
return NULL;

LPVOID lpDIBBits;
if( bmInfo.bmiHeader.biBitCount > 8 )
lpDIBBits = (LPVOID)((LPDWORD)(bmInfo.bmiColors +
bmInfo.bmiHeader.biClrUsed) +
((compression == BI_BITFIELDS) ? 3 : 0));
else
lpDIBBits = (LPVOID)(bmInfo.bmiColors + nColors);


// Compute the cosine and sine only once
float cosine = (float)cos(radians);
float sine = (float)sin(radians);

// Compute dimensions of the resulting bitmap
// First get the coordinates of the 3 corners other than origin
int x1 = (int)(-nHeight * sine);
int y1 = (int)(nHeight * cosine);
int x2 = (int)(nWidth * cosine - nHeight * sine);
int y2 = (int)(nHeight * cosine + nWidth * sine);
int x3 = (int)(nWidth * cosine);
int y3 = (int)(nWidth * sine);

int minx = min(0,min(x1, min(x2,x3)));
int miny = min(0,min(y1, min(y2,y3)));
int maxx = max(x1, max(x2,x3));
int maxy = max(y1, max(y2,y3));

int w = maxx - minx;
int h = maxy - miny;


// Create a DIB to hold the result
int nResultRowBytes = ((((w * bpp) + 31) & ~31) / 8);
long len = nResultRowBytes * h;
int nHeaderSize = ((LPBYTE)lpDIBBits-(LPBYTE)hDIB) ;
HANDLE hDIBResult = GlobalAlloc(GMEM_FIXED,len+nHeaderSize);
// Initialize the header information
memcpy( (void*)hDIBResult, (void*)hDIB, nHeaderSize);
BITMAPINFO &bmInfoResult = *(LPBITMAPINFO)hDIBResult ;
bmInfoResult.bmiHeader.biWidth = w;
bmInfoResult.bmiHeader.biHeight = h;
bmInfoResult.bmiHeader.biSizeImage = len;

LPVOID lpDIBBitsResult = (LPVOID)((LPBYTE)hDIBResult + nHeaderSize);

// Get the back color value (index)
ZeroMemory( lpDIBBitsResult, len );
DWORD dwBackColor;
switch(bpp)
{
case 1: //Monochrome
if( clrBack == RGB(255,255,255) )
memset( lpDIBBitsResult, 0xff, len );
break;
case 4:
case 8: //Search the color table
int i;
for(i = 0; i < nColors; i++ )
{
if( bmInfo.bmiColors[i].rgbBlue == GetBValue(clrBack)
&& bmInfo.bmiColors[i].rgbGreen == GetGValue(clrBack)
&& bmInfo.bmiColors[i].rgbRed == GetRValue(clrBack) )
{
if(bpp==4) i = i | i<<4;
memset( lpDIBBitsResult, i, len );
break;
}
}
// If not match found the color remains black
break;
case 16:
// Windows95 supports 5 bits each for all colors or 5 bits for red & blue
// and 6 bits for green - Check the color mask for RGB555 or RGB565
if( *((DWORD*)bmInfo.bmiColors) == 0x7c00 )
{
// Bitmap is RGB555
dwBackColor = ((GetRValue(clrBack)>>3) << 10) +
((GetRValue(clrBack)>>3) << 5) +
(GetBValue(clrBack)>>3) ;
}
else
{
// Bitmap is RGB565
dwBackColor = ((GetRValue(clrBack)>>3) << 11) +
((GetRValue(clrBack)>>2) << 5) +
(GetBValue(clrBack)>>3) ;
}
break;
case 24:
case 32:
dwBackColor = (((DWORD)GetRValue(clrBack)) << 16) |
(((DWORD)GetGValue(clrBack)) << 8) |
(((DWORD)GetBValue(clrBack)));
break;
}


// Now do the actual rotating - a pixel at a time
// Computing the destination point for each source point
// will leave a few pixels that do not get covered
// So we use a reverse transform - e.i. compute the source point
// for each destination point

for( int y = 0; y < h; y++ )
{
for( int x = 0; x < w; x++ )
{
int sourcex = (int)((x+minx)*cosine + (y+miny)*sine);
int sourcey = (int)((y+miny)*cosine - (x+minx)*sine);
if( sourcex >= 0 && sourcex < nWidth && sourcey >= 0
&& sourcey < nHeight )
{
// Set the destination pixel
switch(bpp)
{
BYTE mask;
case 1: //Monochrome
mask = *((LPBYTE)lpDIBBits + nRowBytes*sourcey +
sourcex/8) & (0x80 >> sourcex%8);
//Adjust mask for destination bitmap
mask = mask ? (0x80 >> x%8) : 0;
*((LPBYTE)lpDIBBitsResult + nResultRowBytes*(y) +
(x/8)) &= ~(0x80 >> x%8);
*((LPBYTE)lpDIBBitsResult + nResultRowBytes*(y) +
(x/8)) |= mask;
break;
case 4:
mask = *((LPBYTE)lpDIBBits + nRowBytes*sourcey +
sourcex/2) & ((sourcex&1) ? 0x0f : 0xf0);
//Adjust mask for destination bitmap
if( (sourcex&1) != (x&1) )
mask = (mask&0xf0) ? (mask>>4) : (mask<<4);
*((LPBYTE)lpDIBBitsResult + nResultRowBytes*(y) +
(x/2)) &= ~((x&1) ? 0x0f : 0xf0);
*((LPBYTE)lpDIBBitsResult + nResultRowBytes*(y) +
(x/2)) |= mask;
break;
case 8:
BYTE pixel ;
pixel = *((LPBYTE)lpDIBBits + nRowBytes*sourcey +
sourcex);
*((LPBYTE)lpDIBBitsResult + nResultRowBytes*(y) +
(x)) = pixel;
break;
case 16:
DWORD dwPixel;
dwPixel = *((LPWORD)((LPBYTE)lpDIBBits +
nRowBytes*sourcey + sourcex*2));
*((LPWORD)((LPBYTE)lpDIBBitsResult +
nResultRowBytes*y + x*2)) = (WORD)dwPixel;
break;
case 24:
dwPixel = *((LPDWORD)((LPBYTE)lpDIBBits +
nRowBytes*sourcey + sourcex*3)) & 0xffffff;
*((LPDWORD)((LPBYTE)lpDIBBitsResult +
nResultRowBytes*y + x*3)) |= dwPixel;
break;
case 32:
dwPixel = *((LPDWORD)((LPBYTE)lpDIBBits +
nRowBytes*sourcey + sourcex*4));
*((LPDWORD)((LPBYTE)lpDIBBitsResult +
nResultRowBytes*y + x*4)) = dwPixel;
}
}
else
{
// Draw the background color. The background color
// has already been drawn for 8 bits per pixel and less
switch(bpp)
{
case 16:
*((LPWORD)((LPBYTE)lpDIBBitsResult +
nResultRowBytes*y + x*2)) =
(WORD)dwBackColor;
break;
case 24:
*((LPDWORD)((LPBYTE)lpDIBBitsResult +
nResultRowBytes*y + x*3)) |= dwBackColor;
break;
case 32:
*((LPDWORD)((LPBYTE)lpDIBBitsResult +
nResultRowBytes*y + x*4)) = dwBackColor;
break;
}
}
}
}

return hDIBResult;
}

[cocacola]

#define BMPWIDTH(w) ((w*3+3)/4*4);
STDMETHODIMP CFunctions::GetRotatedBitmap(long hbmp, long rad, LPDISPATCH *ppobj)
{
*ppobj = NULL;
if (hbmp == NULL)
return S_OK;
BITMAP bm;
::GetObject((HGDIOBJ)hbmp,sizeof(bm),&bm);
HDC sdc = ::CreateCompatibleDC(NULL);
BITMAPINFO bminfo;
ZeroMemory(&bminfo,sizeof(bminfo));
BITMAPINFOHEADER& bmhdr = bminfo.bmiHeader;
bmhdr.biSize = sizeof(BITMAPINFOHEADER);
bmhdr.biWidth = bm.bmWidth;
bmhdr.biHeight = bm.bmHeight;
bmhdr.biPlanes = 1;
bmhdr.biBitCount = 24;
bmhdr.biCompression = DIB_RGB_COLORS;
int wb = BMPWIDTH(bm.bmWidth);
BYTE* src = new BYTE[wb * bm.bmHeight + 0x10000];
int r = ::GetDIBits(sdc,(HBITMAP)hbmp,0,bm.bmHeight,src,&bminfo,DIB_RGB_COLORS);
HGDIOBJ o1 = ::SelectObject(sdc,(HGDIOBJ)hbmp);
if (rad == 90 || rad == 270)
{
bmhdr.biWidth = bm.bmHeight;
bmhdr.biHeight = bm.bmWidth;
}
HBITMAP hbmp1 = ::CreateCompatibleBitmap(sdc,bmhdr.biWidth,bmhdr.biHeight);
::SelectObject(sdc,o1);
int wb1 = BMPWIDTH(bmhdr.biWidth);
BYTE* dst = new BYTE[wb1 * bmhdr.biHeight + 0x10000];
for(int x = 0;x < bm.bmWidth;x++)
{
for (int y=0;y<bm.bmHeight;y++)
{
int x1,y1;
switch(rad)
{
case 90:
x1 = y;
y1 = (bm.bmWidth-x);
break;
case 180:
x1 = (bm.bmWidth-x);
y1 = (bm.bmHeight-y);
break;
case 270:
x1 = (bm.bmHeight-y);
y1 = x;
break;
default:
x1 = x;
y1 = y;
break;
}
CopyMemory(dst + wb1 * y1 + x1 * 3,src + wb * y + x * 3,3);
}
}
r = ::SetDIBits(sdc,hbmp1,0,bmhdr.biHeight,dst,&bminfo,DIB_RGB_COLORS);
::DeleteDC(sdc);
delete [] src;
delete [] dst;
PICTDESC pic;
pic.cbSizeofstruct = sizeof(pic);
pic.picType = PICTYPE_BITMAP;
pic.bmp.hbitmap = hbmp1;
pic.bmp.hpal = NULL;
HRESULT hr = ::OleCreatePictureIndirect(&pic,IID_IDispatch,TRUE,(LPVOID*)ppobj);
return hr;
}