【原創】C語言讀取BMP格式圖片
BMP是英文Bitmap（位圖）的簡寫，它是Windows操作系統中的標准圖像文件格式，能夠被多種Windows應用程序所支持。隨着Windows操作系統的流行與豐富的Windows應用程序的開發，BMP位圖格式理所當然地被廣泛應用。這種格式的特點是包含的圖像信息較豐富，幾乎不進行壓縮，但由此導致了它與生俱生來的缺點--占用磁盤空間過大。所以，目前BMP在單機上比較流行。
BMP文件格式分析
簡介
BMP(Bitmap-File)圖形文件是Windows采用的圖形文件格式，在Windows環境下運行的所有圖象處理軟件都支持BMP圖象文件格式。Windows系統內部各圖像繪制操作都是以BMP為基礎的。Windows 3.0以前的BMP圖文件格式與顯示設備有關，因此把這種BMP圖象文件格式稱為設備相關位圖DDB(device-dependent bitmap)文件格式。Windows 3.0以后的BMP圖象文件與顯示設備無關，因此把這種BMP圖象文件格式稱為設備無關位圖DIB(device-independent bitmap)格式（注：Windows 3.0以后，在系統中仍然存在DDB位圖，象BitBlt()這種函數就是基於DDB位圖的，只不過如果你想將圖像以BMP格式保存到磁盤文件中時，微軟極力推薦你以DIB格式保存），目的是為了讓Windows能夠在任何類型的顯示設備上顯示所存儲的圖象。BMP位圖文件默認的文件擴展名是BMP或者bmp（有時它也會以.DIB或.RLE作擴展名）。
位圖文件結構表
位圖文件 位圖文件頭 14 字節
位圖信息頭 40 字節
彩色表（調色板） 4N 字節
位圖數據 x 字節
構件詳解：
位圖文件頭
位圖文件頭包含文件類型、文件大小、存放位置等信息。結構定義如下：
typedef struct tagBITMAPFILEHEADER
{
UNIT bfType;
DWORD bfSize;
UINT bfReserved1;
UINT bfReserved2;
DWORD bfOffBits;
}BITMAPFILEHEADER;
其中：
bfType 說明文件類型，在windows系統中為BM。
bfSize 說明文件大小。
bfReserved1 bfReserved2 保留，設置為０。
bfOffBits 說明實際圖形數據的偏移量。
位圖信息頭
位圖信息頭包含位圖的大小、壓縮類型、和顏色格式，結構定義如下：
typedef struct tagBITMAPINFOHEADER
{
DWORD biSize;
LONG biWidth;
LONG biHeight;
WORD biPlanes;
WORD biBitCount;
DWORD biCompression;
DWORD biSizeImage;
LONG biXPelsPerMerer;
LONG biYPelsPerMerer;
DWORD biClrUsed;
DWORD biClrImportant;
}BITMAPINFOHEADER;
其中：
biSize 說明BITMAPINFOHEADER結構所需字節數，在windows系統中為28h
biWidth 說明圖像寬度
biHeight 說明圖像高度
biPlanes 為目標設備說明位面數，其值設為１
biBitCount每個像素的位數，單色位圖為１，２５６色為８，２４bit為２４。
biCompression壓縮說明，BI_RGB：無壓縮，BI_RLE8：８位RLE壓縮，BI_RLE4：４位RLE壓縮
biSizeImage說明圖像大小，如無壓縮，可設為０
biXPelsPerMeter水平分辨率
biYPelsPerMeter垂直分辨率
biClrUsed 位圖使用的顏色數
biImportant重要顏色數目
彩色表
彩色表包含的元素與位圖所具有的顏色數目相同，像素顏色用結構RGBQUAD來表示：
typedef struct tagRGBQUAD
{
BYTE rgbBlue;
BYTE rgbGreen;
BYTE rgbRed;
BYTE rgbReserved;
}RGBQUAD;
其中：
rgbBlue 指定藍色強度
rgbGreen 指定綠色強度
rgbRed 指定紅色強度
rgbReserved保留，設為０
位圖數據
緊跟在彩色表后的是圖像數據陣列，圖像每一掃描行由連續的字節組成，掃描行由底向上存儲，陣列中第一字節為左下角像素，最后一字節為右上角像素。
源代碼1
/* File name: bmpTest.c
Description: Show all Info a bmp file has. including
FileHeader Info, InfoHeader Info and Data Part.
Reference: BMP圖像數據的C語言讀取源碼
*/
#include "stdafx.h"
//#include <stdio.h>
#include <stdlib.h>
#define BITMAPFILEHEADERLENGTH 14 // The bmp FileHeader length is 14
#define BM 19778 // The ASCII code for BM
/* Test the file is bmp file or not */
void bmpFileTest(FILE* fpbmp);
/* To get the OffSet of header to data part */
void bmpHeaderPartLength(FILE* fpbmp);
/* To get the width and height of the bmp file */
void BmpWidthHeight(FILE* fpbmp);
/* Show bmp file tagBITMAPFILEHEADER info */
void bmpFileHeader(FILE* fpbmp);
/* Show bmp file tagBITMAPINFOHEADER info */
void bmpInfoHeader(FILE* fpbmp);
/* Show the Data Part of bmp file */
void bmpDataPart(FILE* fpbmp);
unsigned int OffSet = 0; // OffSet from Header part to Data Part
long BmpWidth = 0L; // The Width of the Data Part
long BmpHeight = 0L; // The Height of the Data Part
int main(int argc, char* argv[])
{
/* Open bmp file */
// FILE *fpbmp = fopen("lena.bmp", "r+");
FILE *fpbmp = fopen("picture.bmp", "r+");
if (fpbmp == NULL)
{
fprintf(stderr, "Open lena.bmp failed!!!\n");
return 1;
}
bmpFileTest(fpbmp); //Test the file is bmp file or not
bmpHeaderPartLength(fpbmp); //Get the length of Header Part
BmpWidthHeight(fpbmp); //Get the width and width of the Data Part
bmpFileHeader(fpbmp); //Show the FileHeader Information
bmpInfoHeader(fpbmp); //Show the InfoHeader Information
bmpDataPart(fpbmp); //Reserve the data to file
fclose(fpbmp);
return 0;
}
/* Test the file is bmp file or not */
void bmpFileTest(FILE* fpbmp)
{
unsigned short bfType = 0;
fseek(fpbmp, 0L, SEEK_SET);
fread(&bfType, sizeof(char), 2, fpbmp);
if (BM != bfType)
{
fprintf(stderr, "This file is not bmp file.!!!\n");
exit(1);
}
}
/* To get the OffSet of header to data part */
void bmpHeaderPartLength(FILE* fpbmp)
{
fseek(fpbmp, 10L, SEEK_SET);
fread(&OffSet, sizeof(char), 4, fpbmp);
//printf("The Header Part is of length %d.\n", OffSet);
}
/* To get the width and height of the bmp file */
void BmpWidthHeight(FILE* fpbmp)
{
fseek(fpbmp, 18L, SEEK_SET);
fread(&BmpWidth, sizeof(char), 4, fpbmp);
fread(&BmpHeight, sizeof(char), 4, fpbmp);
//printf("The Width of the bmp file is %ld.\n", BmpWidth);
//printf("The Height of the bmp file is %ld.\n", BmpHeight);
}
/* Show bmp file tagBITMAPFILEHEADER info */
void bmpFileHeader(FILE* fpbmp)
{
unsigned short bfType; //UNIT bfType;
unsigned int bfSize; //DWORD bfSize;
unsigned short bfReserved1; //UINT bfReserved1;
unsigned short bfReserved2; //UINT bfReserved2;
unsigned int bfOffBits; //DWORD bfOffBits;
fseek(fpbmp, 0L, SEEK_SET);
fread(&bfType, sizeof(char), 2, fpbmp);
fread(&bfSize, sizeof(char), 4, fpbmp);
fread(&bfReserved1, sizeof(char), 2, fpbmp);
fread(&bfReserved2, sizeof(char), 2, fpbmp);
fread(&bfOffBits, sizeof(char), 4, fpbmp);
printf("************************************************\n");
printf("*************tagBITMAPFILEHEADER info***********\n");
printf("************************************************\n");
printf("bfType is %d.\n", bfType);
printf("bfSize is %d.\n", bfSize);
printf("bfReserved1 is %d.\n", bfReserved1);
printf("bfReserved2 is %d.\n", bfReserved2);
printf("bfOffBits is %d.\n", bfOffBits);
}
/* Show bmp file tagBITMAPINFOHEADER info */
void bmpInfoHeader(FILE* fpbmp)
{
unsigned int biSize; // DWORD biSize;
long biWidth; // LONG biWidth;
long biHeight; // LONG biHeight;
unsigned int biPlanes; // WORD biPlanes;
unsigned int biBitCount; // WORD biBitCount;
unsigned int biCompression; // DWORD biCompression;
unsigned int biSizeImage; // DWORD biSizeImage;
long biXPelsPerMerer; // LONG biXPelsPerMerer;
long biYPelsPerMerer; // LONG biYPelsPerMerer;
unsigned int biClrUsed; // DWORD biClrUsed;
unsigned int biClrImportant; // DWORD biClrImportant;
fseek(fpbmp, 14L, SEEK_SET);
fread(&biSize, sizeof(char), 4, fpbmp);
fread(&biWidth, sizeof(char), 4, fpbmp);
fread(&biHeight, sizeof(char), 4, fpbmp);
fread(&biPlanes, sizeof(char), 4, fpbmp);
fread(&biBitCount, sizeof(char), 4, fpbmp);
fread(&biCompression, sizeof(char), 4, fpbmp);
fread(&biSizeImage, sizeof(char), 4, fpbmp);
fread(&biXPelsPerMerer, sizeof(char), 4, fpbmp);
fread(&biYPelsPerMerer, sizeof(char), 4, fpbmp);
fread(&biClrUsed, sizeof(char), 4, fpbmp);
fread(&biClrImportant, sizeof(char), 4, fpbmp);
printf("************************************************\n");
printf("*************tagBITMAPINFOHEADER info***********\n");
printf("************************************************\n");
printf("biSize is %d. \n", biSize);
printf("biWidth is %ld.\n", biWidth);
printf("biHeight is %ld.\n", biHeight);
printf("biPlanes is %d. \n", biPlanes);
printf("biBitCount is %d. \n", biBitCount);
printf("biCompression is %d. \n", biCompression);
printf("biSizeImage is %d. \n", biSizeImage);
printf("biXPelsPerMerer is %ld.\n", biXPelsPerMerer);
printf("biYPelsPerMerer is %ld.\n", biYPelsPerMerer);
printf("biClrUsed is %d. \n", biClrUsed);
printf("biClrImportant is %d. \n", biClrImportant);
}
/* Show the Data Part of bmp file */
void bmpDataPart(FILE* fpbmp)
{
int i, j;
// unsigned char bmpPixel[BmpWidth][BmpHeight];
unsigned char bmpPixel[1000][1000];
//因為暫時還未找到好的方法，暫且長和寬都設為1000，如果圖像的尺寸大於1000，則要重新設置
unsigned char* bmpPixelTmp = NULL;
FILE* fpDataBmp;
/* New a file to save the data matrix */
if((fpDataBmp=fopen("bmpData.dat","w+")) == NULL)
{
fprintf(stderr, "Failed to construct file bmpData.dat.!!!");
exit(1);
}
fseek(fpbmp, OffSet, SEEK_SET);
if ((bmpPixelTmp=(unsigned char*)malloc(sizeof(char)*BmpWidth*BmpHeight))==NULL)
{
fprintf(stderr, "Data allocation failed.!!!\n");
exit(1);
}
fread(bmpPixelTmp, sizeof(char), BmpWidth*BmpHeight, fpbmp);
/* Read the data to Matrix and save it in file bmpData.dat */
for(i =0; i < BmpHeight; i++)
{
fprintf(fpDataBmp, "The data in line %-3d:\n", i+1);
for(j = 0; j < BmpWidth; j++)
{
bmpPixel[i][j] = bmpPixelTmp[BmpWidth*(BmpHeight-1-i)+j];
//fwrite(&chartmp, sizeof(char), 1, fpDataBmp);
fprintf(fpDataBmp, "%-3d ", bmpPixel[i][j]);
if ((j+1)%32 == 0)
{
fprintf(fpDataBmp, "\n");
}
}
}
/* Used to test the data read is true or false
You can open the file using Matlab to compare the data */
//printf("bmpPixel[2][3] is %d.\n", bmpPixel[2][3]);
//printf("bmpPixel[20][30] is %d.\n", bmpPixel[20][30]);
free(bmpPixelTmp);
fclose(fpDataBmp);
}
源代碼2
// 讀取圖像2.cpp : Defines the entry point for the console application.
//
#include "stdafx.h"
//#include <stdio.h>
#include <stdlib.h>
#define BITMAPFILEHEADERLENGTH 14 // The bmp FileHeader length is 14
#define BM 19778 // The ASCII code for BM
/* Test the file is bmp file or not */
void bmpFileTest(FILE* fpbmp);
/* To get the OffSet of header to data part */
void bmpHeaderPartLength(FILE* fpbmp);
/* To get the width and height of the bmp file */
void BmpWidthHeight(FILE* fpbmp);
//get r,g,b data
void bmpDataPart(FILE* fpbmp);
// output data to corresponding txt file
void bmpoutput(FILE *fpout);
unsigned int OffSet = 0; // OffSet from Header part to Data Part
long width ; // The Width of the Data Part
long height ; // The Height of the Data Part
unsigned char r[2000][2000],output_r[2000][2000];
unsigned char g[2000][2000],output_g[2000][2000];
unsigned char b[2000][2000],output_b[2000][2000];
int main(int argc, char* argv[])
{
/* Open bmp file */
unsigned char *fp_temp;
FILE *fpbmp;
FILE *fpout;
fpbmp= fopen("lena.bmp", "rb");
if (fpbmp == NULL)
{
printf("Open bmp failed!!!\n");
return 1;
}
fpout= fopen("out.bmp", "wb+");
if (fpout == NULL)
{
printf("Open out.bmp failed!!!\n");
return 1;
}
bmpFileTest(fpbmp); //Test the file is bmp file or not
bmpHeaderPartLength(fpbmp); //Get the length of Header Part
BmpWidthHeight(fpbmp); //Get the width and width of the Data Part
//
fseek(fpbmp, 0L, SEEK_SET);
fseek(fpout, 0L, SEEK_SET);
fp_temp=(unsigned char *)malloc(OffSet);
fread(fp_temp, 1, OffSet, fpbmp);
fwrite(fp_temp,1,OffSet,fpout);
bmpDataPart(fpbmp); //Reserve the data to file
/*
如果您想對圖片進行處理，請您再這里插入處理函數!!!!!!!!!!!!!!!!!!
*/
bmpoutput(fpout);
fclose(fpbmp);
fclose(fpout);
return 0;
}
void bmpoutput(FILE* fpout)
{
int i, j=0;
int stride;
unsigned char* pixout=NULL;
stride=(24*width+31)/8;
stride=stride/4*4;
pixout=(unsigned char *)malloc(stride);
fseek(fpout, OffSet, SEEK_SET);
for(j=0;j<height;j++)
{
for(i=0;i<width;i++)
{
pixout[i*3+2]=output_r[height-1-j][i];
pixout[i*3+1]=output_g[height-1-j][i];
pixout[i*3] =output_b[height-1-j][i];
}
fwrite(pixout, 1, stride, fpout);
}
}
void bmpDataPart(FILE* fpbmp)
{
int i, j=0;
int stride;
unsigned char* pix=NULL;
FILE* fpr;
FILE* fpg;
FILE* fpb;
if((fpr=fopen("bmpr.txt","w+")) == NULL)
{
printf("Failed to construct file bmpr.txt.!!!");
exit(1);
}
if((fpg=fopen("bmpg.txt","w+")) == NULL)
{
printf("Failed to construct file bmpg.txt.!!!");
exit(1);
}
if((fpb=fopen("bmpb.txt","w+")) == NULL)
{
printf("Failed to construct file bmpb.txt.!!!");
exit(1);
}
fseek(fpbmp, OffSet, SEEK_SET);
stride=(24*width+31)/8;
stride=stride/4*4;
pix=(unsigned char *)malloc(stride);
for(j=0;j<height;j++)
{
fread(pix, 1, stride, fpbmp);
for(i=0;i<width;i++)
{
r[height-1-j][i] = pix[i*3+2];
g[height-1-j][i] = pix[i*3+1];
b[height-1-j][i] = pix[i*3];
output_r[height-1-j][i] = pix[i*3+2];
output_g[height-1-j][i] = pix[i*3+1];
output_b[height-1-j][i] = pix[i*3];
}
}
for(i =0; i < height; i++)
{
for(j = 0; j < width-1; j++)
{
fprintf(fpb,"%4d",b[i][j]);
fprintf(fpg,"%4d",g[i][j]);
fprintf(fpr,"%4d",r[i][j]);
}
fprintf(fpb,"%4d\n",b[i][j]);
fprintf(fpg,"%4d\n",g[i][j]);
fprintf(fpr,"%4d\n",r[i][j]);
}
fclose(fpr);
fclose(fpg);
fclose(fpb);
}
void bmpFileTest(FILE* fpbmp)
{
unsigned short bfType = 0;
fseek(fpbmp, 0L, SEEK_SET);//seek_set 起始位置
fread(&bfType, sizeof(char), 2, fpbmp);
if (BM != bfType)
{
printf("This file is not bmp file.!!!\n");
exit(1);
}
}
/* To get the OffSet of header to data part */
void bmpHeaderPartLength(FILE* fpbmp)
{
fseek(fpbmp, 10L, SEEK_SET);
fread(&OffSet, sizeof(char), 4, fpbmp);
printf("The Header Part is of length %d.\n", OffSet);
}
/* To get the width and height of the bmp file */
void BmpWidthHeight(FILE* fpbmp)
{
fseek(fpbmp, 18L, SEEK_SET);
fread(&width, sizeof(char), 4, fpbmp);
fseek(fpbmp, 22L, SEEK_SET);
fread(&height, sizeof(char), 4, fpbmp);
printf("The Width of the bmp file is %ld.\n", width);
printf("The Height of the bmp file is %ld.\n", height);
}