本文介绍了麻烦正确读取.BMP头文件的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！
问题描述
我想参加一个.bmp文件，并最终编辑像素一个接一个，但我想出的宽度和高度的问题在INFOHEADER结构退还给我。返回的宽度是13107200，高度为65536然而，每当我通过程序总共只有60003总像素计数运行。我不知道这是为什么。任何帮助将大大AP preciated。
的#include＆LT;＆stdio.h中GT;
＃包括LT＆;＆stdlib.h中GT;INT主（INT ARGC，CHAR *的argv []）{
//定义结构
typedef结构
{无符号短整型; / *魔法标识符* /
unsigned int类型的大小; / *文件的字节大小* /
无符号短整型保留1，RESERVED2;
unsigned int类型胶印机;偏移到数据（B）/ * * /
}报头; / * - 14字节 - * / typedef结构
{unsigned int类型的大小; / *头字节大小* /
INT宽度，高度; / *宽/图像高度* /
无符号短整型平面; / *颜色平面数* /
无符号短整数位; / *每个像素位* /
unsigned int类型的COM pression; / *的COM pression型* /
无符号整型IMAGESIZE; / *图像大小以字节为单位* /
INT xResolution，yResolution; / *每米*像素/
unsigned int类型的颜色; / *色数* /
unsigned int类型ImportantColors; / *重要的颜色* /
} INFOHEADER; / * - 40字节 - * / typedef结构
{unsigned char型红，绿，蓝;
}像素; //使所有三个结构的一个实例
标题数据;
INFOHEADER DATA2;
PIXEL像素; //声明文件中读出指针
FILE *文件; //声明FILEOUT读指针
// FILE * FILEOUT; //声明文件打印文件指针 参数计数器//打开文件1，并返回0 APON错误
如果（！（文件= FOPEN（CU.bmp，RB）））返回0;
//读取头数据到数据
的fread（安培;数据的sizeof（HEADER），1，文件）;
//读IB + NFOHEADER数据到数据2
的fread（安培;数据2，的sizeof（INFOHEADER），1，文件）;
//打印像素数据 //为分配空间pixelarray
PIXEL ** pixelarray;
INT R = 0，C = 0，行= data2.Height，collumns = data2.Width;
pixelarray =的malloc（行*的sizeof（PIXEL *））;
为（R = 0;为r行; R ++）{
pixelarray [R] =的malloc（collumns *的sizeof（PIXEL））;
} //填充像素结构像素阵列
使r = 0 C = 0;
INT pixelnum = 1;
而（的fread（安培;像素的sizeof（PIXEL），1，文件））{
如果（C == collumns）{
C = 0;
- [R ++;
}
pixelarray [R] [C] =像素;
的printf（\\ nPixel％10D：％02X％02X％02X，pixelnum，pixelarray [R] [C] .Red，pixelarray [R] [C]。蓝色，pixelarray [R] [C]。绿色）;
fflush（标准输出）;
C ++; pixelnum ++; } 免费（pixelarray）; FCLOSE（文件）; //之前关闭文件退出
解决方案
我猜你的问题是结构比。你可以参考这里 。要消除它使用的#pragma 指令。所以，你的结构声明将是这样的：
的#pragma包（推）//推动当前对齐堆栈
的#pragma包（1）//设置对齐1字节边界
typedef结构
{
无符号短整型; / *魔法标识符* /
unsigned int类型的大小; / *文件的字节大小* /
无符号短整型保留1;
无符号短整型RESERVED2;
unsigned int类型胶印机;偏移到数据（B）/ * * /
}报头; / * - 14字节 - * /typedef结构
{
unsigned int类型的大小; / *头字节大小* /
INT宽度;
INT高度; / *宽/图像高度* /
无符号短整型平面; / *颜色平面数* /
无符号短整数位; / *每个像素位* /
unsigned int类型的COM pression; / *的COM pression型* /
无符号整型IMAGESIZE; / *图像大小以字节为单位* /
INT xResolution;
INT yResolution; / *每米像素* /
unsigned int类型的颜色; / *色数* /
unsigned int类型ImportantColors; / *重要的颜色* /
} INFOHEADER; / * - 40字节 - * /typedef结构
{
unsigned char型红;
unsigned char型绿色;
unsigned char型蓝色;
}像素;
的#pragma包（POP）//恢复从堆栈原定线
这正确读取BMP图像的宽度和高度。而且在读取图像数据，直接做到这一点：
为（R = 0;为r行; R ++）
{
为（C = 0;℃下collumns; C ++）//读取图像的像素数据
{
的fread（安培; pixelarray [R] [C]，1，sizeof的（PIXEL），文件）;
pixelnum ++;
}
}
I am trying to take in a .bmp file and eventually edit the pixels one by one but I am coming up with a problem with the width and height returned to me in the INFOHEADER struct. The width returned is 13107200 and the height is 65536. However, whenever I run through the program a total of only 60003 total pixels are counted. I have no idea why this is. Any help would be greatly appreciated.
#include <stdio.h>
#include <stdlib.h>
int main( int argc, char *argv[] ){
//define structures
typedef struct
{ unsigned short int Type; /* Magic identifier */
unsigned int Size; /* File size in bytes */
unsigned short int Reserved1, Reserved2;
unsigned int Offset; /* Offset to data (in B)*/
}HEADER; /* -- 14 Bytes -- */
typedef struct
{ unsigned int Size; /* Header size in bytes */
int Width, Height; /* Width / Height of image */
unsigned short int Planes; /* Number of colour planes */
unsigned short int Bits; /* Bits per pixel */
unsigned int Compression; /* Compression type */
unsigned int ImageSize; /* Image size in bytes */
int xResolution, yResolution;/* Pixels per meter */
unsigned int Colors; /* Number of colors */
unsigned int ImportantColors;/* Important colors */
}INFOHEADER; /* -- 40 Bytes -- */
typedef struct
{ unsigned char Red, Green, Blue;
}PIXEL;
//make instance of all three structures
HEADER data;
INFOHEADER data2;
PIXEL pixel;
//declare file read pointer
FILE *file;
//declare fileout read pointer
//FILE *fileout; //declare file printed file pointer
// open file 1 of argument counter and return 0 apon error
if( !(file = fopen( "CU.bmp","rb")))return 0;
//read HEADER data into data
fread(&data,sizeof(HEADER),1,file);
//read IB+NFOHEADER data into data2
fread(&data2,sizeof(INFOHEADER),1,file);
//Print PIXEL data
//Allocate space for pixelarray
PIXEL **pixelarray;
int r=0,c=0,rows=data2.Height,collumns=data2.Width;
pixelarray= malloc(rows*sizeof(PIXEL *));
for(r=0; r<rows; r++){
pixelarray[r]=malloc(collumns*sizeof(PIXEL));
}
//fill pixel array with pixel structs
r=0;c=0;
int pixelnum=1;
while( fread(&pixel,sizeof(PIXEL),1,file) ){
if(c == collumns){
c=0;
r++;
}
pixelarray[r][c] = pixel;
printf("\nPixel %10d: %02X%02X%02X",pixelnum,pixelarray[r][c].Red,pixelarray[r][c].Blue,pixelarray[r][c].Green);
fflush(stdout);
c++;pixelnum++;
}
free(pixelarray);
fclose(file); //close the files prior to exiting
解决方案
I guess your problem is structure alignment. You can refer to it here and here. To eliminate it use the #pragma directive. So your structure declaration would be something like this:
#pragma pack(push) // push current alignment to stack
#pragma pack(1) // set alignment to 1 byte boundary
typedef struct
{
unsigned short int Type; /* Magic identifier */
unsigned int Size; /* File size in bytes */
unsigned short int Reserved1;
unsigned short int Reserved2;
unsigned int Offset; /* Offset to data (in B)*/
}HEADER; /* -- 14 Bytes -- */
typedef struct
{
unsigned int Size; /* Header size in bytes */
int Width;
int Height; /* Width / Height of image */
unsigned short int Planes; /* Number of colour planes */
unsigned short int Bits; /* Bits per pixel */
unsigned int Compression; /* Compression type */
unsigned int ImageSize; /* Image size in bytes */
int xResolution;
int yResolution;/* Pixels per meter */
unsigned int Colors; /* Number of colors */
unsigned int ImportantColors;/* Important colors */
}INFOHEADER; /* -- 40 Bytes -- */
typedef struct
{
unsigned char Red;
unsigned char Green;
unsigned char Blue;
}PIXEL;
#pragma pack(pop) // restore original alignment from stack
This correctly reads the width and height of BMP image. Further while reading image data, do it directly:
for( r=0; r<rows; r++ )
{
for( c=0; c<collumns; c++ ) // read pixel data from image
{
fread(&pixelarray[r][c] , 1, sizeof(PIXEL), file);
pixelnum++;
}
}
这篇关于麻烦正确读取.BMP头文件的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！