English
dib2jpeg.txt
资源名称：dib2jpeg.zip [点击查看]
上传用户：jinjie988
上传日期：2007-01-03
资源大小：4k
文件大小：12k
源码类别：
图片显示
开发平台：
Visual C++
- ///////////////////////////////////////////////////////////////Example of use:
- /////////////////////////////////////////////////////////////void MakeJpeg(){
- CBitmap cBitmap; BITMAP bm; CString csMsg = "";
- cBitmap.LoadBitmap(IDB_TEST); cBitmap.GetBitmap(&bm);
- HANDLE hDib = DDBToDIB((HBITMAP)cBitmap,
- BI_RGB,
- NULL); //Use default palette
- //Turn DIB into JPEG file if (hDib != NULL) {
- if (!JpegFromDib(hDib, 100, //Quality setting
- "test.jpg", &csMsg)) {
- AfxMessageBox(csMsg); } else
- AfxMessageBox("test.jpg created"); ::GlobalFree(hDib); }
- else AfxMessageBox("Failed to load IDB_TEST");}
- ////////////////////////////////////////////////////////////
- //////////////////////////////////////////////////////////////Header file code
- ////////////////////////////////////////////////////////////
- ////////////////////////////////////////////////////////////
- //In the relevant header file (up near the top):#include "jpeglib.h"
- BOOL JpegFromDib(HANDLE hDib, //Handle to DIB
- int nQuality, //JPEG quality (0-100)
- CString csJpeg, //Pathname to target jpeg file
- CString* pcsMsg); //Error msg to return
- BOOL BuildSamps(HANDLE hDib,
- int nSampsPerRow,
- struct jpeg_compress_struct cinfo,
- JSAMPARRAY jsmpArray,
- CString* pcsMsg);
- RGBQUAD QuadFromWord(WORD b16);
- ////////////////////////////////////////////////////////////
- //////////////////////////////////////////////////////////////Source file code
- ////////////////////////////////////////////////////////////
- ////////////////////////////////////////////////////////////extern "C"{
- #include "jpeglib.h"} #include struct ima_error_mgr{
- struct jpeg_error_mgr pub; //"public" fields
- jmp_buf setjmp_buffer; //for return to caller};
- ////////////////////////////////////////////////////////////////////////////
- //This function takes the contents of a DIB//and turns it into a JPEG file.//
- //The DIB may be monochrome, 16-color, 256-color, or 24-bit color.//
- //Any functions or data items beginning with "jpeg_" belong to jpeg.lib,
- //and are not included here.//
- //The function assumes 3 color components per pixel.
- /////////////////////////////////////////////////////////////////////////////
- BOOL JpegFromDib(HANDLE hDib, //Handle to DIB
- int nQuality, //JPEG quality (0-100)
- CString csJpeg, //Pathname to jpeg file
- CString* pcsMsg) //Error msg to return{
- //Basic sanity checks... if (nQuality < 0 || nQuality > 100 ||
- hDib == NULL || pcsMsg == NULL || csJpeg == "") {
- if (pcsMsg != NULL) *pcsMsg = "Invalid input data";
- return FALSE; } *pcsMsg = "";
- LPBITMAPINFOHEADER lpbi = (LPBITMAPINFOHEADER)hDib; byte *buf2 = 0;
- //Use libjpeg functions to write scanlines to disk in JPEG format
- struct jpeg_compress_struct cinfo; struct jpeg_error_mgr jerr;
- FILE* pOutFile; //Target file
- int nSampsPerRow; //Physical row width in image buffer
- JSAMPARRAY jsmpArray; //Pixel RGB buffer for JPEG file
- cinfo.err = jpeg_std_error(&jerr); //Use default error handling (ugly!)
- jpeg_create_compress(&cinfo);
- if ((pOutFile = fopen(csJpeg, "wb")) == NULL) {
- *pcsMsg = "Cannot open "; *pcsMsg += csJpeg;
- jpeg_destroy_compress(&cinfo); return FALSE; }
- jpeg_stdio_dest(&cinfo, pOutFile);
- cinfo.image_width = lpbi->biWidth; //Image width and height, in pixels
- cinfo.image_height = lpbi->biHeight;
- cinfo.input_components = 3; //Color components per pixel
- //(RGB_PIXELSIZE - see jmorecfg.h)
- cinfo.in_color_space = JCS_RGB; //Colorspace of input image
- jpeg_set_defaults(&cinfo); jpeg_set_quality(&cinfo,
- nQuality, //Quality: 0-100 scale
- TRUE); //Limit to baseline-JPEG values
- jpeg_start_compress(&cinfo, TRUE); //JSAMPLEs per row in output buffer
- nSampsPerRow = cinfo.image_width * cinfo.input_components;
- //Allocate array of pixel RGB values
- jsmpArray = (*cinfo.mem->alloc_sarray)
- ((j_common_ptr) &cinfo, JPOOL_IMAGE,
- nSampsPerRow, cinfo.image_height);
- if (DibToSamps(hDib, nSampsPerRow,
- cinfo, jsmpArray,
- pcsMsg)) {
- //Write the array of scan lines to the JPEG file
- (void)jpeg_write_scanlines(&cinfo,
- jsmpArray,
- cinfo.image_height); }
- jpeg_finish_compress(&cinfo); //Always finish fclose(pOutFile);
- jpeg_destroy_compress(&cinfo); //Free resources if (*pcsMsg != "")
- return FALSE; else return TRUE;}
- ////////////////////////////////////////////////////////////////
- //This function fills a jsmpArray with the RGB values//for the CBitmap.//
- //It has been improved to handle all legal bitmap formats.//
- //A jsmpArray is a big array of RGB values, 3 bytes per value.//
- //Note that rows of pixels are processed bottom to top:
- //The data in the jsamp array must be arranged top to bottom.
- ////////////////////////////////////////////////////////////////
- BOOL DibToSamps(HANDLE hDib,
- int nSampsPerRow,
- struct jpeg_compress_struct cinfo,
- JSAMPARRAY jsmpPixels,
- CString* pcsMsg){ //Sanity...
- if (hDib == NULL || nSampsPerRow <= 0 || pcsMsg == NULL) {
- if (pcsMsg !=NULL) *pcsMsg="Invalid input data";
- return FALSE; } int r=0, p=0, q=0, b=0, n=0,
- nUnused=0, nBytesWide=0, nUsed=0, nLastBits=0, nLastNibs=0, nCTEntries=0,
- nRow=0, nByte=0, nPixel=0; BYTE bytCTEnt=0;
- LPBITMAPINFOHEADER pbBmHdr= (LPBITMAPINFOHEADER)hDib; //The bit count tells you the format of the bitmap: //Decide how many entries will be in the color table (if any)
- switch (pbBmHdr->biBitCount) { case 1:
- nCTEntries = 2; //Monochrome break; case 4:
- nCTEntries = 16; //16-color break; case 8:
- nCTEntries = 256; //256-color break; case 16:
- case 24: case 32: nCTEntries = 0; //No color table needed
- break; default: *pcsMsg = "Invalid bitmap bit count";
- return FALSE; //Unsupported format }
- //Point to the color table and pixels
- DWORD dwCTab = (DWORD)pbBmHdr + pbBmHdr->biSize;
- LPRGBQUAD pCTab = (LPRGBQUAD)(dwCTab); LPSTR lpBits = (LPSTR)pbBmHdr +
- (WORD)pbBmHdr->biSize +
- (WORD)(nCTEntries * sizeof(RGBQUAD));
- //Different formats for the image bits
- LPBYTE lpPixels = (LPBYTE) lpBits; RGBQUAD* pRgbQs = (RGBQUAD*)lpBits;
- WORD* wPixels = (WORD*) lpBits;
- //Set up the jsamps according to the bitmap's format.
- //Note that rows are processed bottom to top, because
- //that's how bitmaps are created. switch (pbBmHdr->biBitCount) {
- case 1: nUsed = (pbBmHdr->biWidth + 7) / 8;
- nUnused = (((nUsed + 3) / 4) * 4) - nUsed;
- nBytesWide = nUsed + nUnused;
- nLastBits = 8 - ((nUsed * 8) - pbBmHdr->biWidth);
- for (r=0; r < pbBmHdr->biHeight; r++) {
- for (p=0,q=0; p < nUsed; p++) {
- nRow=(pbBmHdr->biHeight-r-1) * nBytesWide;
- nByte = nRow + p;
- int nBUsed = (p <(nUsed 1)) ? 8 : nLastBits; for(b=0; b < nBUsed;b++)
- { bytCTEnt = lpPixels[nByte] << b;
- bytCTEnt = bytCTEnt >> 7;
- jsmpPixels[r][q+0] = pCTab[bytCTEnt].rgbRed;
- jsmpPixels[r][q+1] = pCTab[bytCTEnt].rgbGreen;
- jsmpPixels[r][q+2] = pCTab[bytCTEnt].rgbBlue;
- q += 3; } } } break;
- case 4: nUsed = (pbBmHdr->biWidth + 1) / 2;
- nUnused = (((nUsed + 3) / 4) * 4) - nUsed;
- nBytesWide = nUsed + nUnused;
- nLastNibs = 2 - ((nUsed * 2) - pbBmHdr->biWidth);
- for (r=0; r < pbBmHdr->biHeight;r++) {
- for (p=0,q=0; p < nUsed;p++) {
- nRow=(pbBmHdr->biHeight-r-1) * nBytesWide;
- nByte = nRow + p; int nNibbles = (p > (4-(n*4));
- jsmpPixels[r][q+0] = pCTab[bytCTEnt].rgbRed;
- jsmpPixels[r][q+1] = pCTab[bytCTEnt].rgbGreen;
- jsmpPixels[r][q+2] = pCTab[bytCTEnt].rgbBlue;
- q += 3; } } } break;
- default: case 8: //Each byte is a pointer to a pixel color
- nUnused = (((pbBmHdr->biWidth + 3) / 4) * 4) -
- pbBmHdr->biWidth;
- for (r=0;r < pbBmHdr->biHeight; r++) {
- for (p=0,q=0; p < pbBmHdr->biWidth; p++,q+=3) {
- nRow = (pbBmHdr->biHeight-r-1) * (pbBmHdr->biWidth + nUnused);
- nPixel = nRow + p;
- jsmpPixels[r][q+0] = pCTab[lpPixels[nPixel]].rgbRed;
- jsmpPixels[r][q+1] = pCTab[lpPixels[nPixel]].rgbGreen;
- jsmpPixels[r][q+2] = pCTab[lpPixels[nPixel]].rgbBlue;
- } } break;
- case 16: //Hi-color (16 bits per pixel)
- for (r=0;r < pbBmHdr->biHeight; r++) {
- for (p=0,q=0; p < pbBmHdr->biWidth; p++,q+=3) {
- nRow = (pbBmHdr->biHeight-r-1) * pbBmHdr->biWidth;
- nPixel = nRow + p;
- RGBQUAD quad = QuadFromWord(wPixels[nPixel]);
- jsmpPixels[r][q+0] = quad.rgbRed;
- jsmpPixels[r][q+1] = quad.rgbGreen;
- jsmpPixels[r][q+2] = quad.rgbBlue; } }
- break; case 24: nBytesWide = (pbBmHdr->biWidth*3);
- nUnused = (((nBytesWide + 3) / 4) * 4) -
- nBytesWide; nBytesWide += nUnused;
- for (r=0;r biHeight;r++) {
- for (p=0,q=0;p < (nBytesWide-nUnused); p+=3,q+=3) {
- nRow = (pbBmHdr->biHeight-r-1) * nBytesWide;
- nPixel = nRow + p;
- jsmpPixels[r][q+0] = lpPixels[nPixel+2]; //Red
- jsmpPixels[r][q+1] = lpPixels[nPixel+1]; //Green
- jsmpPixels[r][q+2] = lpPixels[nPixel+0]; //Blue }
- } break; case 32:
- for (r=0; r < pbBmHdr->biHeight; r++) {
- for (p=0,q=0; p < pbBmHdr->biWidth; p++,q+=3) {
- nRow = (pbBmHdr->biHeight-r-1) *
- pbBmHdr->biWidth; nPixel = nRow + p;
- jsmpPixels[r][q+0] = pRgbQs[nPixel].rgbRed;
- jsmpPixels[r][q+1] = pRgbQs[nPixel].rgbGreen;
- jsmpPixels[r][q+2] = pRgbQs[nPixel].rgbBlue; }
- } break; } //end switchreturn TRUE;}
- //////////////////////////////////////////This function turns a 16-bit pixel
- //into an RGBQUAD value.////////////////////////////////////////
- RGBQUAD QuadFromWord(WORD b16){ BYTE bytVals[] = {
- 0, 16, 24, 32, 40, 48, 56, 64, 72, 80, 88, 96, 104,112,120,128,
- 136,144,152,160,168,176,184,192, 200,208,216,224,232,240,248,255 };
- WORD wR = b16; WORD wG = b16; WORD wB = b16; wR <<= 1; wR >>= 11;
- wG <<= 6; wG >>= 11; wB <<= 11; wB >>= 11; RGBQUAD rgb;
- rgb.rgbReserved = 0; rgb.rgbBlue = bytVals[wB];
- rgb.rgbGreen = bytVals[wG]; rgb.rgbRed = bytVals[wR]; return rgb;
- }
