将位图文件读入结构
我想将一个位图文件读入一个结构和manuplate它就像制作一个镜像效果等但我无法理解我应该创建哪种结构以便读入它。
谢谢您的帮助
»这是你如何手动加载bmp文件
位图文件格式：位图文件头位图信息头调色板数据位图达达
所以在代码部分，这是我们需要创建的结构来保存位图文件头
#pragma pack(push, 1) typedef struct tagBITMAPFILEHEADER { WORD bfType; //specifies the file type DWORD bfSize; //specifies the size in bytes of the bitmap file WORD bfReserved1; //reserved; must be 0 WORD bfReserved2; //reserved; must be 0 DWORD bfOffBits; //species the offset in bytes from the bitmapfileheader to the bitmap bits }BITMAPFILEHEADER; #pragma pack(pop) bftype字段检查你是否正在加载bmp文件，如果你是字段应该是0x4D42。
现在我们需要创建我们的bitmapinfoheader结构。 这包含有关我们位图的信息。
#pragma pack(push, 1) typedef struct tagBITMAPINFOHEADER { DWORD biSize; //specifies the number of bytes required by the struct LONG biWidth; //specifies width in pixels LONG biHeight; //species height in pixels WORD biPlanes; //specifies the number of color planes, must be 1 WORD biBitCount; //specifies the number of bit per pixel DWORD biCompression;//spcifies the type of compression DWORD biSizeImage; //size of image in bytes LONG biXPelsPerMeter; //number of pixels per meter in x axis LONG biYPelsPerMeter; //number of pixels per meter in y axis DWORD biClrUsed; //number of colors used by th ebitmap DWORD biClrImportant; //number of colors that are important }BITMAPINFOHEADER; #pragma pack(pop)
现在开始加载我们的Bitmap
unsigned char *LoadBitmapFile(char *filename, BITMAPINFOHEADER *bitmapInfoHeader) { FILE *filePtr; //our file pointer BITMAPFILEHEADER bitmapFileHeader; //our bitmap file header unsigned char *bitmapImage; //store image data int imageIdx=0; //image index counter unsigned char tempRGB; //our swap variable //open filename in read binary mode filePtr = fopen(filename,"rb"); if (filePtr == NULL) return NULL; //read the bitmap file header fread(&bitmapFileHeader, sizeof(BITMAPFILEHEADER),1,filePtr); //verify that this is a bmp file by check bitmap id if (bitmapFileHeader.bfType !=0x4D42) { fclose(filePtr); return NULL; } //read the bitmap info header fread(bitmapInfoHeader, sizeof(BITMAPINFOHEADER),1,filePtr); // small edit. forgot to add the closing bracket at sizeof //move file point to the begging of bitmap data fseek(filePtr, bitmapFileHeader.bfOffBits, SEEK_SET); //allocate enough memory for the bitmap image data bitmapImage = (unsigned char*)malloc(bitmapInfoHeader->biSizeImage); //verify memory allocation if (!bitmapImage) { free(bitmapImage); fclose(filePtr); return NULL; } //read in the bitmap image data fread(bitmapImage,bitmapInfoHeader->biSizeImage,filePtr); //make sure bitmap image data was read if (bitmapImage == NULL) { fclose(filePtr); return NULL; } //swap the r and b values to get RGB (bitmap is BGR) for (imageIdx = 0;imageIdx < bitmapInfoHeader->biSizeImage;imageIdx+=3) // fixed semicolon { tempRGB = bitmapImage[imageIdx]; bitmapImage[imageIdx] = bitmapImage[imageIdx + 2]; bitmapImage[imageIdx + 2] = tempRGB; } //close file and return bitmap iamge data fclose(filePtr); return bitmapImage; }
现在来利用所有这些：
BITMAPINFOHEADER bitmapInfoHeader; unsigned char *bitmapData; ... bitmapData = LoadBitmapFile("mypic.bmp",&bitmapInfoHeader); //now do what you want with it, later on i will show you how to display it in a normal window
生病了以后写一个到bmp以及如何加载targa文件以及如何显示它们。«
引自： http ：//www.vbforums.com/showthread.php？261522-CC-Loading-Bitmap-Files-％28Manually％29（User：BeholderOf）。 （做了一些小修改）
这是一个简短的工作示例。
它将一个wav文件转换为bmp（很久以前我就有这么好玩）。
码：
#include #include #include #include #include #define RATE 44100 typedef struct { unsigned short type; /* Magic identifier */ unsigned int size; /* File size in bytes */ unsigned int reserved; unsigned int offset; /* Offset to image data, bytes */ } HEADER; typedef struct { unsigned int size; /* Header size in bytes */ int width,height; /* Width and height of image */ unsigned short planes; /* Number of colour planes */ unsigned short bits; /* Bits per pixel */ unsigned int compression; /* Compression type */ unsigned int imagesize; /* Image size in bytes */ int xresolution,yresolution; /* Pixels per meter */ unsigned int ncolours; /* Number of colours */ unsigned int importantcolours; /* Important colours */ } INFOHEADER; typedef struct { unsigned char r,g,b,junk; } COLOURINDEX; int main(int argc, char *argv[]){ int i,j,rd; int gotindex = 0; unsigned char grey,r,g,b; double ampl; short _2byte[2]; HEADER header; INFOHEADER infoheader; COLOURINDEX colourindex[256]; FILE *fptr; SNDFILE* sndfile = NULL; SF_INFO sfinfo; long rate = RATE; void (*bmpread)(); void _eightbit(){ if(fread(&grey, sizeof(unsigned char), 1, fptr) != 1){ fprintf(stderr,"Image read failed\n"); exit(-1); } if (gotindex){ ampl = colourindex[grey].r * 64. + colourindex[grey].g * 128.+ colourindex[grey].b * 64.; } else { ampl = grey * 256. - 32768.; } // printf("%.2f\n", ampl); } void _twentyfourbit(){ do{ if((rd = fread(&b, sizeof(unsigned char), 1, fptr)) != 1) break; if((rd = fread(&g, sizeof(unsigned char), 1, fptr)) != 1) break; if((rd = fread(&r, sizeof(unsigned char), 1, fptr)) != 1) break; }while(0); if(rd != 1){ fprintf(stderr,"Image read failed\n"); exit(-1); } ampl = r * 64. + g * 128. + b * 64. - 32768.; // printf("%.2f\n", ampl); } if (argc < 3){ printf("Usage: %s [samplerate]\n", argv[0]); printf("For example:\n\t%s pict.bmp sample.wav 44100 2\n", argv[0]); exit(0); } printf("Input file: %s\n", argv[1]); printf("Output file: %s\n", argv[2]); if(argc > 3) rate = atoi(argv[3]); if(rate < 4000) rate = 4000; //if(argc > 4) channels = atoi(argv[4]); sfinfo.samplerate = rate; sfinfo.channels = 2; sfinfo.format = SF_FORMAT_WAV|SF_FORMAT_PCM_16; if((fptr = fopen(argv[1],"r")) == NULL) { fprintf(stderr,"Unable to open BMP file \"%s\"\n",argv[1]); exit(-1); } /* Read and check BMP header */ if(fread(&header.type, 2, 1, fptr) != 1){ fprintf(stderr, "Failed to read BMP header\n"); exit(-1); } if(header.type != 'M'*256+'B'){ fprintf(stderr, "File is not bmp type\n"); exit(-1); } do{ if((rd = fread(&header.size, 4, 1, fptr)) != 1) break; printf("File size: %d bytes\n", header.size); if((rd = fread(&header.reserved, 4, 1, fptr)) != 1) break; if((rd = fread(&header.offset, 4, 1, fptr)) != 1) break; printf("Offset to image data is %d bytes\n", header.offset); }while(0); if(rd =! 1){ fprintf(stderr, "Error reading file\n"); exit(-1); } /* Read and check the information header */ if (fread(&infoheader, sizeof(INFOHEADER), 1, fptr) != 1) { fprintf(stderr,"Failed to read BMP info header\n"); exit(-1); } printf("Image size = %dx %d\n", infoheader.width, infoheader.height); printf("Number of colour planes is %d\n", infoheader.planes); printf("Bits per pixel is %d\n", infoheader.bits); printf("Compression type is %d\n", infoheader.compression); printf("Number of colours is %d\n", infoheader.ncolours); printf("Number of required colours is %d\n", infoheader.importantcolours); /* Read the lookup table if there is one */ for (i=0; i<255; i++){ colourindex[i].r = rand() % 256; colourindex[i].g = rand() % 256; colourindex[i].b = rand() % 256; colourindex[i].junk = rand() % 256; } if (infoheader.ncolours > 0) { for (i=0; i