读取多波段的tif(利用GDAL)

bmp的格式是RGBRGB.....排列下来的每个像素的三个分量靠在一起描述完一个像素接着描述下一个像素。tif的格式更多样。通常的格式也是BGRBGR.....(次序与bmp相反)排列下来的但偶尔有一些tif文件采用RRRRRR.......GGGGG.........BBBBB.....的安排。还有的tif文件内容是压缩过的。。。。这里我们只考虑三个颜色分量靠在一起的情况。下面的例子是一个tif文件宽896,高608,三个分量。这里直接用gdal读取tif再写入bmp。与前面《一个tif转bmp的示例》不同使用gdal不需要手动交换B-R的位置。具体项目见我的资源中的gdalTif.rar_GDAL批量处理TIF到BMP资源-CSDN下载#include gdal_priv.h #include algorithm #include iostream #include fstream #pragma comment(lib, gdal_i.lib) bool bReadImageMultiBand(unsigned char * pImgData, int iWidth, int iHeight, int iChannel, char * strPath); bool bWriteImageData(char *, unsigned char *, int, int, int, int); void vFindImageTypeGDAL(char *, char *); int main(void) { GDALAllRegister(); int iWidth, iHeight, iChannel; unsigned char * pImgData; if(bReadImageMultiBand(pImgData, iWidth, iHeight, iChannel, earthRGBRGB.tif)) { bWriteImageData(earth.bmp, pImgData, iWidth, iHeight, iChannel, iChannel); delete [] pImgData; } return 0; } bool bReadImageMultiBand(unsigned char * pImgData, int iWidth, int iHeight, int iChannel, char * strPath) { GDALDataset * pDataSet nullptr; pDataSet (GDALDataset *)GDALOpen(strPath, GA_ReadOnly); if(pDataSet nullptr) { GDALClose(pDataSet); return false; } GDALDataType dt pDataSet-GetRasterBand(1)-GetRasterDataType(); iWidth pDataSet-GetRasterXSize(); iHeight pDataSet-GetRasterYSize(); iChannel std::min(pDataSet-GetRasterCount(), 3); int arrBandMap[] {1,2,3}; pImgData new unsigned char[iWidth * iHeight * iChannel]; pDataSet-RasterIO(GF_Read, 0,0, iWidth, iHeight, pImgData, iWidth, iHeight, dt, iChannel, arrBandMap, 0,0,0); GDALClose(pDataSet); return true; } bool bWriteImageData(char * strDestPath, unsigned char * pData, int iWidth, int iHeight, int iSrcChannel, int iDestChannel) { char arrType[1024] {0}; vFindImageTypeGDAL(strDestPath, arrType); if(arrType) { std::fstream file; file.open(strDestPath, std::ios_base::out); file.close(); GDALDriver * pMemDriver GetGDALDriverManager()-GetDriverByName(MEM); if(pMemDriver nullptr) return false; GDALDataset * pMemDataSet pMemDriver-Create(,iWidth,iHeight,iDestChannel,GDT_Byte,NULL); GDALRasterBand *pBand NULL; int arrBandMap[3] { 1, 2, 3 }; pMemDataSet-RasterIO(GF_Write, 0, 0, iWidth, iHeight, pData, iWidth, iHeight, GDT_Byte, iDestChannel, arrBandMap, 0,0,0); GDALDriver *pDstDriver NULL; pDstDriver (GDALDriver *)GDALGetDriverByName(arrType); if (pDstDriver NULL) { GDALClose(pMemDataSet); return false; } GDALDataset * pDataSet pDstDriver-CreateCopy(strDestPath,pMemDataSet,FALSE, NULL, NULL, NULL); if (pDataSet NULL) { GDALClose(pMemDataSet); return false; } GDALClose(pDataSet); GDALClose(pMemDataSet); return true; } else { return false; } } void vFindImageTypeGDAL(char * pDstImgFileName, char * pDst) { char * dstExtension strlwr(strrchr(pDstImgFileName, .) 1); if (0 strcmp(dstExtension, bmp)) sprintf(pDst, %s, BMP); else if (0 strcmp(dstExtension, jpg)) sprintf(pDst, %s, JPEG); else if (0 strcmp(dstExtension, png)) sprintf(pDst, %s, PNG); else if (0 strcmp(dstExtension, tif)) sprintf(pDst, %s, GTiff); else if (0 strcmp(dstExtension, gif)) sprintf(pDst, %s, GIF); }