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首先 简单解释一下bmp文件格式
bmp 格式文件 分为四个部分
header 文件格式，大小
infoheader 图像的高，宽，位数
optional palette 可选调色板：使用索引来表示图像是的 索引与颜色的映射 并非一定包含
image data 图像像素信息的数据
其中24位bmp文件不使用索引 所以不需要optional palette 部分
所以在读取调色板是进行文件格式的判断，如24位，则不需要读取调色板，直接读取像素信息
FILE *fp=NULL;
int ret = fopen_s(&fp,"D:\\11.bmp","rb");
if(fp==0)
{
return ;
}
BITMAPFILEHEADER fileheader={0};
fread(&fileheader,sizeof(fileheader),1,fp);
if(fileheader.bfType!=0x4D42)
{
fclose(fp);
return ;
}
BITMAPINFOHEADER head;
fread(&head,sizeof(BITMAPINFOHEADER),1,fp);
long bmpWidth = head.biWidth;
long bmpHeight = head.biHeight;
WORD biBitCount = head.biBitCount;
if(biBitCount != 24)
{
::AfxMessageBox(_T("请选择24位位图！"));
fclose(fp);
return ;
}
int totalSize = (bmpWidth *biBitCount/8+3)/4*4*bmpHeight;
BYTE *pBmpBuf = new BYTE[totalSize];
size_t size = 0;
while(true)
{
int iret = fread(&pBmpBuf[size],1,1,fp);
if(iret == 0)
break;
size = size + iret;
}
fclose(fp);
int i,j;
CClientDC dc(this);
int pitch=bmpWidth%4;
for(i=0;i<bmpHeight;i++)
{
int realPitch=i*pitch;
for(j=0;j<bmpWidth;j++)
{
dc.SetPixel(j,i,RGB(
pBmpBuf[(i*bmpWidth+j)*3+2+realPitch],
pBmpBuf[(i*bmpWidth+j)*3+1+realPitch],
pBmpBuf[(i*bmpWidth+j)*3+realPitch]));
}
}
delete [] pBmpBuf; pBmpBuf = NULL;
return ;
完整读取代码，为了兼容Linux 和windows平台用fopen、fread、fseek、fclose替换掉了open、read、lseek、close系列函数。
#include <unistd.h>
#include <fcntl.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <stdlib.h>
#include <stdio.h>
//#include "window.h"
/*bmp file header*/
typedef struct FileHeader
{
unsigned short bfType;
unsigned int bfSize;
unsigned short bfReserved1;
unsigned short bfReserved2;
unsigned int bfOffBits;
}__attribute__((packed))FileHeader;
/*bmp info header*/
typedef struct InfoHeader
{
unsigned int biSize;
int biWidth;
int biHeight;
unsigned short biPlanes;
unsigned short biBitCount;
unsigned int biCompression;
unsigned int biSizeImage;
int biXPelsPerMeter;
int biYPelsPerMeter;
unsigned int biClrUsed;
unsigned int biClrImportant;
}__attribute__((packed))InfoHeader;
//we won't use it while BitCount=24
typedef struct tagRGBQUAD
{
unsigned char rgbBlue;
unsigned char rgbGreen;
unsigned char rgbRed;
unsigned char rgbReserved;
}RGBQUAD;
typedef struct
{
unsigned char b;
unsigned char g;
unsigned char r;
}RGB_data;
/*for test global variable*/
/*maybe can not use this in the project*/
unsigned char *pBmpBuf,*pBmpBufOne,*pBmpBufTwo,*pBmpBufThree;
RGBQUAD *pColorTable;
int bmpWidth,bmpWidthback,bmpWidthsky;
int bmpHeight,bmpHeightback,bmpHeightsky;
int biBitCount,biBitCountback,biBitCountsky;
char * readBmp(char *bmpName)
{
FILE *fp = fopen(bmpName, "rb");
//int fp; /*maybe fd should be more comfortably*/
//fp = open(bmpName, O_RDONLY);
if (NULL == fp)
{
printf("There is no fp!!!\n");
return 0;
}
fseek(fp, sizeof(FileHeader), SEEK_SET);
//lseek(fp, sizeof(FileHeader), SEEK_SET);
InfoHeader head;
fread(&head, sizeof(InfoHeader), 1, fp);
//read(fp, &head, sizeof(InfoHeader));
bmpWidth = head.biWidth;
bmpHeight = head.biHeight;
biBitCount = head.biBitCount;
int lineByte = (bmpWidth * biBitCount / 8 + 3) / 4 * 4;
if (biBitCount == 8)
{
//pColorTable=new RGBQUAD[256];
pColorTable = (RGBQUAD *)malloc(sizeof(RGBQUAD) * 1024);
fread(pColorTable, sizeof(RGBQUAD), 256, fp);
}
pBmpBuf = (unsigned char *)malloc(sizeof(unsigned char) * lineByte * bmpHeight);
fread(pBmpBuf, 1, lineByte * bmpHeight, fp);
fclose(fp);
return pBmpBuf;
}
int saveBmp(char *bmpName, unsigned char *imgBuf, int width, int height, int biBitCount, RGBQUAD *pColorTable)
{
if(imgBuf == NULL)
{
printf("imgBuf is NULL!!\n");
return -1;
}
int colorTablesize = 0;
if (biBitCount == 8)
{
colorTablesize=1024;
}
int lineByte = (width * biBitCount / 8 + 3) / 4 * 4;
FILE *fp = fopen(bmpName, "wb");
if (fp == NULL)
{
printf("fopen error...\n");
return -1;
}
FileHeader fileHead;
fileHead.bfType=0x4D42;
fileHead.bfSize = sizeof(FileHeader) + sizeof(InfoHeader) + colorTablesize + lineByte * height;
fileHead.bfReserved1 = 0;
fileHead.bfReserved2 = 0;
fileHead.bfOffBits = 54 + colorTablesize;
fwrite(&fileHead, sizeof(FileHeader), 1, fp);
InfoHeader infoHead;
infoHead.biBitCount = biBitCount;
infoHead.biClrImportant = 0;
infoHead.biClrUsed = 0;
infoHead.biCompression = 0;
infoHead.biHeight = height;
infoHead.biPlanes = 1;
infoHead.biSize = 40;
infoHead.biSizeImage = lineByte * height;
infoHead.biWidth = width;
infoHead.biXPelsPerMeter = 0;
infoHead.biYPelsPerMeter = 0;
fwrite(&infoHead, sizeof(InfoHeader), 1, fp);
if (biBitCount == 8)
{
fwrite(pColorTable,sizeof(RGBQUAD),256,fp);
}
fwrite(imgBuf, height * lineByte, 1, fp);
fclose(fp);
return 0;
}
/* main function test program*/
#if 1
int main(int argc, char *argv[])
{
char readPath[] = "logo256.bmp";
readBmp(readPath);
printf("width = %d, height = %d, biBitCount = %d \n", bmpWidth, bmpHeight, biBitCount);
char writePath[] = "logo256copy.bmp";
saveBmp(writePath, pBmpBuf, bmpWidth, bmpHeight, biBitCount, pColorTable);
free(pBmpBuf);
if (biBitCount == 8)
{
free(pColorTable);
}
return 0;
}
#endif
#if 0
extern int a1,b1,n;
extern int a[50],b[50];
//int reviseBitMap(void)
int main(int argc,char *argv[])
{
int i,j;
int x,y;
int k;
char readPathOne[] = "back.bmp";
pBmpBufOne = readBmp(readPathOne);
printf("width = %d, height = %d, biBitCount = %d \n", bmpWidth, bmpHeight, biBitCount);
bmpWidthback = bmpWidth;
bmpHeightback = bmpHeight;
biBitCountback = biBitCount;
int lineByteback = (bmpWidthback * biBitCountback / 8 + 3) / 4 * 4;
char readPathThree[] = "sky.bmp";
pBmpBufThree = readBmp(readPathThree);
printf("width = %d, height = %d, biBitCount = %d \n", bmpWidth, bmpHeight, biBitCount);
bmpWidthsky = bmpWidth;
bmpHeightsky = bmpHeight;
biBitCountsky = biBitCount;
int lineBytesky = (bmpWidthsky * biBitCountsky / 8 + 3) / 4 * 4;
char readPathTwo[] = "plane.bmp";
pBmpBufTwo = readBmp(readPathTwo);
printf("wdith = %d, height = %d, biBitCount = %d \n", bmpWidth, bmpHeight, biBitCount);
int lineByteplane = (bmpWidth * biBitCount / 8 + 3) / 4 * 4;
if (biBitCount == 8)
{
for (i = 0; i < bmpHeight / 2; i++)
{
for (j = 0; j < bmpWidth / 2; j++)
{
*(pBmpBuf + i * lineByteplane + j) = 0;
}
}
}
else if (biBitCount == 24)
{
x = a[a1];
y = b[b1];
for (i = 0; i < bmpHeight; i++)
{
for(j=0;j<bmpWidth;j++)
{
for(k=0;k<3;k++)
{
*(pBmpBufOne+(x+i)*lineByteback+(y+j)*3+k) &= (*(pBmpBufThree+i*lineBytesky+j*3+k));
*(pBmpBufOne+(x+i)*lineByteback+(y+j)*3+k) |= (*(pBmpBufTwo+i*lineByteplane+j*3+k));
if (lineBytesky != lineByteplane)
{
printf("............................\n");
}
}
}
}
char writePath[]="hncuduplicate.bmp";
saveBmp(writePath,pBmpBufOne,bmpWidthback,bmpHeightback,biBitCountback,pColorTable);
}
free(pBmpBufOne);
free(pBmpBufTwo);
free(pBmpBufThree);
if (biBitCount == 8)
{
free(pColorTable);
}
return 0;
}
#endif
正文完
