编程技巧15法之三

1. 如何替换HBITMAP[/b]中的颜色值[/b]
#define COLORREF2RGB(Color) (Color & 0xff00) | ((Color >> 16) & 0xff) /
| ((Color << 16) & 0xff0000)

HBITMAP ReplaceColor (HBITMAP hBmp,COLORREF cOldColor,COLORREF cNewColor)
{
HBITMAP RetBmp=NULL;
if (hBmp)
{
HDC BufferDC=CreateCompatibleDC(NULL); // 源位图DC
if (BufferDC)
{
SelectObject(BufferDC,hBmp); 　 // 选入DC中

HDC DirectDC=CreateCompatibleDC(NULL); // 目标DC
if (DirectDC)
{
// 获取源位图大小
BITMAP bm;
GetObject(hBmp, sizeof(bm), &bm);

// 初始化BITMAPINFO信息，以便使用CreateDIBSection
BITMAPINFO RGB32BitsBITMAPINFO;
ZeroMemory(&RGB32BitsBITMAPINFO,sizeof(BITMAPINFO));
RGB32BitsBITMAPINFO.bmiHeader.biSize=sizeof(BITMAPINFOHEADER);
RGB32BitsBITMAPINFO.bmiHeader.biWidth=bm.bmWidth;
RGB32BitsBITMAPINFO.bmiHeader.biHeight=bm.bmHeight;
RGB32BitsBITMAPINFO.bmiHeader.biPlanes=1;
RGB32BitsBITMAPINFO.bmiHeader.biBitCount=32;
UINT * ptPixels;

HBITMAP DirectBitmap= CreateDIBSection(DirectDC,
(BITMAPINFO *)&RGB32BitsBITMAPINFO,
DIB_RGB_COLORS,(void **)&ptPixels, NULL, 0);
if (DirectBitmap)
{
HGDIOBJ PreviousObject=SelectObject(DirectDC, DirectBitmap);
BitBlt(DirectDC,0,0,bm.bmWidth,bm.bmHeight,BufferDC,0,0,SRCCOPY);

// 转换 COLORREF 为 RGB
cOldColor=COLORREF2RGB(cOldColor);
cNewColor=COLORREF2RGB(cNewColor);

// 替换颜色
for (int i=((bm.bmWidth*bm.bmHeight)-1);i>=0;i--)
{
if (ptPixels==cOldColor) ptPixels[i]=cNewColor;
}

// 修改位图 DirectBitmap
SelectObject(DirectDC,PreviousObject);

// 完成
RetBmp=DirectBitmap;
}
// 释放DC
DeleteDC(DirectDC);
}
// 释放DC
DeleteDC(BufferDC);
}
}
return RetBmp;
}

用法[/b]：
HBITMAP hBmp2 = LoadBitmap(g_hinstance,MAKEINTRESOURCE(IDB_SAMPLEBITMAP));
HBITMAP hBmp = ReplaceColor(hBmp2,0xff0000,0x00ff00); // 替换蓝色为绿色

......

DeleteObject(hBmp2);
DeleteObject(hBmp);

2. 如何转换并保存位图[/b]
//********************************************************************************
//* 名称：DDBToDIB
//* 作者：徐景周(jingzhou_xu@163.net)
//* 功能：设备相关转换为设备无关位图
//********************************************************************************
HANDLE CScreenSnapDlg::DDBToDIB( CBitmap& bitmap, DWORD dwCompression /* = BI_RGB */)
{
BITMAP bm;
BITMAPINFOHEADER bi;
LPBITMAPINFOHEADER lpbi;
DWORD dwLen;
HANDLE hDIB;
HANDLE handle;
HDC hDC;
HPALETTE hPal;

CWindowDC dc( this );
CPalette pal;
//如果支持调色板的话，则建立它
if( dc.GetDeviceCaps( RASTERCAPS ) & RC_PALETTE )
{
UINT nSize = sizeof(LOGPALETTE) + ( sizeof(PALETTEENTRY) * 256 );
LOGPALETTE* pLP = (LOGPALETTE*)new BYTE[nSize];
pLP->palVersion = 0x300;
pLP->palNumEntries = (unsigned short)GetSystemPaletteEntries( dc, 0, 255,
pLP->palPalEntry );

pal.CreatePalette( pLP );

//释放
delete[] pLP;
}

ASSERT( bitmap.GetSafeHandle() );

//不支持BI_BITFIELDS类型
if( dwCompression == BI_BITFIELDS )
return NULL;

//如果调色板为空，则用默认调色板
hPal = (HPALETTE) pal.GetSafeHandle();
if (hPal==NULL)
hPal = (HPALETTE) GetStockObject(DEFAULT_PALETTE);

//获取位图信息
bitmap.GetObject(sizeof(bm),(LPSTR)&bm);

//初始化位图信息头
bi.biSize = sizeof(BITMAPINFOHEADER);
bi.biWidth = bm.bmWidth;
bi.biHeight = bm.bmHeight;
bi.biPlanes = 1;
bi.biBitCount = (unsigned short)(bm.bmPlanes * bm.bmBitsPixel) ;
bi.biCompression = dwCompression;
bi.biSizeImage = 0;
bi.biXPelsPerMeter = 0;
bi.biYPelsPerMeter = 0;
bi.biClrUsed = 0;
bi.biClrImportant = 0;

//计算信息头及颜色表大小
int nColors = 0;
if(bi.biBitCount <= 8)
{
nColors = (1 << bi.biBitCount);
}
dwLen = bi.biSize + nColors * sizeof(RGBQUAD);

hDC = ::GetDC(NULL);
hPal = SelectPalette(hDC,hPal,FALSE);
RealizePalette(hDC);

//为信息头及颜色表分配内存
hDIB = GlobalAlloc(GMEM_FIXED,dwLen);

if (!hDIB){
SelectPalette(hDC,hPal,FALSE);
::ReleaseDC(NULL,hDC);
return NULL;
}

lpbi = (LPBITMAPINFOHEADER)GlobalLock(hDIB);

*lpbi = bi;

//调用 GetDIBits 计算图像大小
GetDIBits(hDC, (HBITMAP)bitmap.GetSafeHandle(), 0L, (DWORD)bi.biHeight,
(LPBYTE)NULL, (LPBITMAPINFO)lpbi, (DWORD)DIB_RGB_COLORS);

bi = *lpbi;

//图像的每一行都对齐(32bit)边界
if (bi.biSizeImage == 0){
bi.biSizeImage = ((((bi.biWidth * bi.biBitCount) + 31) & ~31) / 8)
* bi.biHeight;

if (dwCompression != BI_RGB)
bi.biSizeImage = (bi.biSizeImage * 3) / 2;
}

//重新分配内存大小，以便放下所有数据
dwLen += bi.biSizeImage;
handle = GlobalReAlloc(hDIB, dwLen, GMEM_MOVEABLE) ;
if (handle != NULL)
hDIB = handle;
else
{
GlobalFree(hDIB);

//重选原始调色板
SelectPalette(hDC,hPal,FALSE);
::ReleaseDC(NULL,hDC);
return NULL;
}

//获取位图数据
lpbi = (LPBITMAPINFOHEADER)hDIB;

//最终获得的DIB
BOOL bGotBits = GetDIBits( hDC, (HBITMAP)bitmap.GetSafeHandle(),
0L, //扫描行起始处
(DWORD)bi.biHeight, //扫描行数
(LPBYTE)lpbi //位图数据地址
+ (bi.biSize + nColors * sizeof(RGBQUAD)),
(LPBITMAPINFO)lpbi, //位图信息地址
(DWORD)DIB_RGB_COLORS); //颜色板使用RGB

if( !bGotBits )
{
GlobalFree(hDIB);

SelectPalette(hDC,hPal,FALSE);
::ReleaseDC(NULL,hDC);
return NULL;
}

SelectPalette(hDC,hPal,FALSE);
::ReleaseDC(NULL,hDC);
return hDIB;
}

//********************************************************************************
//* 名称：SaveBitmapToFile
//* 修改：徐景周(jingzhou_xu@163.net)
//* 功能：保存为位图文件
//********************************************************************************
BOOL CScreenSnapDlg::SaveBitmapToFile(HBITMAP hBitmap , CString lpFileName)
{
HDC hDC; //设备描述表
int iBits; //当前显示分辨率下每个像素所占字节数
WORD wBitCount; //位图中每个像素所占字节数
DWORD dwPaletteSize=0, //定义调色板大小， 位图中像素字节大小 ，位图文件大小 ， 写入文件字节数
dwBmBitsSize,
dwDIBSize, dwWritten;
BITMAP Bitmap;
BITMAPFILEHEADER bmfHdr; //位图属性结构
BITMAPINFOHEADER bi; //位图文件头结构
LPBITMAPINFOHEADER lpbi; //位图信息头结构
HANDLE fh, hDib, hPal,hOldPal=NULL; //指向位图信息头结构,定义文件，分配内存句柄，调色板句柄

//计算位图文件每个像素所占字节数
hDC = CreateDC("DISPLAY",NULL,NULL,NULL);
iBits = GetDeviceCaps(hDC, BITSPIXEL) *
GetDeviceCaps(hDC, PLANES);
DeleteDC(hDC);
if (iBits <= 1)
wBitCount = 1;
else if (iBits <= 4)
wBitCount = 4;
else if (iBits <= 8)
wBitCount = 8;
else if (iBits <= 24)
wBitCount = 24;
//计算调色板大小
if (wBitCount <= 8)
dwPaletteSize = (1 << wBitCount) *sizeof(RGBQUAD);

//设置位图信息头结构
GetObject(hBitmap, sizeof(BITMAP), (LPSTR)&Bitmap);
bi.biSize = sizeof(BITMAPINFOHEADER);
bi.biWidth = Bitmap.bmWidth;
bi.biHeight = Bitmap.bmHeight;
bi.biPlanes = 1;
bi.biBitCount = wBitCount;
bi.biCompression = BI_RGB;
bi.biSizeImage = 0;
bi.biXPelsPerMeter = 0;
bi.biYPelsPerMeter = 0;
bi.biClrUsed = 0;
bi.biClrImportant = 0;

dwBmBitsSize = ((Bitmap.bmWidth *
wBitCount+31)/32)* 4
*Bitmap.bmHeight ;

//为位图内容分配内存
hDib = GlobalAlloc(GHND,dwBmBitsSize+
dwPaletteSize+sizeof(BITMAPINFOHEADER));
lpbi = (LPBITMAPINFOHEADER)GlobalLock(hDib);
*lpbi = bi;

// 处理调色板
hPal = GetStockObject(DEFAULT_PALETTE);
if (hPal)
{
hDC = ::GetDC(NULL);
hOldPal = SelectPalette(hDC, (HPALETTE)hPal, FALSE);
RealizePalette(hDC);
}

// 获取该调色板下新的像素值
GetDIBits(hDC, hBitmap, 0, (UINT) Bitmap.bmHeight,
(LPSTR)lpbi + sizeof(BITMAPINFOHEADER)+dwPaletteSize,
(LPBITMAPINFO)lpbi, DIB_RGB_COLORS);

//恢复调色板
if (hOldPal)
{
SelectPalette(hDC, (HPALETTE)hOldPal, TRUE);
RealizePalette(hDC);
::ReleaseDC(NULL, hDC);
}

//创建位图文件
fh = CreateFile(lpFileName, GENERIC_WRITE,
0, NULL, CREATE_ALWAYS,
FILE_ATTRIBUTE_NORMAL | FILE_FLAG_SEQUENTIAL_SCAN, NULL);

if (fh == INVALID_HANDLE_VALUE)
return FALSE;

// 设置位图文件头
bmfHdr.bfType = 0x4D42; // "BM"
dwDIBSize = sizeof(BITMAPFILEHEADER) + sizeof(BITMAPINFOHEADER) + dwPaletteSize + dwBmBitsSize;
bmfHdr.bfSize = dwDIBSize;
bmfHdr.bfReserved1 = 0;
bmfHdr.bfReserved2 = 0;
bmfHdr.bfOffBits = (DWORD)sizeof(BITMAPFILEHEADER)
+ (DWORD)sizeof(BITMAPINFOHEADER)
+ dwPaletteSize;

// 写入位图文件头
WriteFile(fh, (LPSTR)&bmfHdr, sizeof
(BITMAPFILEHEADER), &dwWritten, NULL);
// 写入位图文件其余内容
WriteFile(fh, (LPSTR)lpbi, dwDIBSize,
&dwWritten, NULL);

//消除内存分配
GlobalUnlock(hDib);
GlobalFree(hDib);
CloseHandle(fh);

return TRUE;
}

联系方式：[/b]
地址：陕西省西安市劳动路2号院六单元
邮编：710082
作者EMAIL：jingzhou_xu@163.net
未来工作室(Future Studio)