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DOS下看真彩BMP位图的小程序（我给加了注释） [复制链接]

bierdaci

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发表于 2004-03-03 23:55 |只看该作者 |正序浏览

很久以前编的DOS看真彩BMP位图的小程序给贴上来了，有兴趣的就自己编译着玩玩，里边还有我写的一个画直线的算法，不过很笨拙。初学者可以试着看看源码挺简单的，看到有不少人看这个贴子我就给注释了，不过画直线的函数就不用看了，很乱我自己都懒得看所以就没有注释
另外几个函数的功能在后面的跟贴我简单的介绍了一下

A.c main文件

#include <stdio.h>;
#include <conio.h>;
#include "a.h"
/*extern void print();
*extern void init(int);
*extern void vinfo(int)
*extern void demo(int,int,int);
*extern void Pixel16HiC(int,int,int);
*extern void Pixel24TrC(unsigned long int,int,int);
*extern void Pixel256C(char,int,int);
*#define Hi15(R,G,B)
*#define HiColor(R,G,B) R*2048+G*32+B
*#define TrColor(R,G,B) R*65536+G*256+B
*#define Tr_HColor(R,G,B)
*#define H_TColor(RGB)
*#define T_HColor(RGB)
*/
main()
{
unsigned int i,j,x,y;
FILE *fp;
if((fp=fopen("d:\\BC4\\Ship\\24.bmp","rb"))==NULL)/*自己选择路径*/
printf("Can't open 256.bmp\n");
init(Tr800_600);/*初始化显示模式为24位真彩色，800*600分辨率*/
readpic(fp);/*主函数*/
fclose(fp);
/*for(i=0;i<=767;i++)
* line(i,i,1023,0,TrC(i,i*3,i/2));/*这里是画直线函数*/
*/
getch();
return;
}

复制代码

BMP.C 主文件，里边有画直线函数

#include<stdio.h>;
#include<alloc.h>;
#include<dos.h>;
#include"a.h"
unsigned far* readpic(FILE *fp)
{
struct bmp_head far* bhead;
int x,y;
unsigned long size,length,width;
void far * farmem;
unsigned char far *RGB;
char temp[30],over;
fread(temp,30L,1,fp); /*读BMP文件头信息*/
bhead=(char far*)temp;
over=bhead->;width%4;/*BMP格式每行多出的位，我也不清楚为什么要多出这几位，当时我这里让我很头痛费了好大劲才查出来*/
width=bhead->;width*3+over;/*位图宽*/
if((farmem=farmalloc(width*10+10))==NULL)/*分配缓冲区因为DOS最大可分配内存是一个段64K字节这里我分配了位图宽度*10 +10*/
printf("Not enough Memory\n");
fseek(fp,bhead->;offset,0);/*读指针跳到位图数据起点*/
fread(farmem,width,10,fp);/*读位图数据到缓冲区*/
RGB=farmem;/*RGB画像素用的指针，每像素3个字节*/
for(y=bhead->;hight;y>;=0;y--)/*bhead->;hight 位图高度*/
{
for(x=0;x<bhead->;width;x++)/*bhead->;width 位图宽度*/
{
Pixel24TrC(TrC(*(RGB+2),*(RGB+1),*RGB),x,y);/*画点*/
RGB=RGB+3;/*一个像素点3个字节*/
if(FP_OFF(RGB)==width*10+FP_OFF(farmem)||FP_OFF(RGB)==width*10+FP_OFF(farmem)+3)/*FP_OFF取远指针偏移，这个条件语句判断画完一个缓冲区*/
{
fread(farmem,width,10,fp);
RGB=farmem;
}/*把BMP位图分成缓冲区大小的段*/
}
RGB=RGB+over;/*每行最后多出over个字节*/
}
farfree(farmem);
return farmem;
}
/*画直线函数*/
void line(unsigned long left_x,unsigned long left_y,unsigned long right_x,unsigned long right_y,unsigned long color)
{
unsigned long x=left_x,y=left_y;
if(left_x>;right_x)
if(left_y>;right_y)
{
while(left_x-right_x>;left_x-x)
{
Pixel24TrC(color,x,y);
if((left_x-right_x)>;(left_y-right_y))
while((left_y-right_y)*(left_x-x)<(left_x-right_x)*(left_y-y))
{
x--;
Pixel24TrC(color,x,y);
}
x--;
if(y<=right_y)
continue;
if((left_y-right_y)>;(left_x-right_x))
while((left_y-right_y)*(left_x-x)>;(left_x-right_x)*(left_y-y))
{
y--;
Pixel24TrC(color,x,y);
}
y--;
};
while(y>;right_y)
{
Pixel24TrC(color,x,y);
y--;
};
}
else
{
while(x>;right_x)
{
Pixel24TrC(color,x,y);
if((left_x-right_x)>;(right_y-left_y))
while((right_y-left_y)*(left_x-x)<(left_x-right_x)*(y-left_y))
{
x--;
Pixel24TrC(color,x,y);
}
x--;
if(!(y<right_y))
continue;
if((right_y-left_y)>;(left_x-right_x))
while((right_y-left_y)*(left_x-x)>;(left_x-right_x)*(y-left_y))
{
y++;
Pixel24TrC(color,x,y);
}
y++;
};
while(y<=right_y)
{
Pixel24TrC(color,x,y);
y++;
};
}
else
if(left_y>;right_y)
{
while(x<right_x)
{
Pixel24TrC(color,x,y);
if((right_x-left_x)>;(left_y-right_y))
while((left_y-right_y)*(x-left_x)<(right_x-left_x)*(left_y-y))
{
x++;
Pixel24TrC(color,x,y);
}
x++;
if(left_y-y>;left_y-right_y)
continue;
if((left_y-right_y)>;(right_x-left_x))
while((left_y-right_y)*(x-left_x)>;(right_x-left_x)*(left_y-y))
{
y--;
Pixel24TrC(color,x,y);
}
y--;
};
while(left_y-y<=left_y-right_y)
{
Pixel24TrC(color,x,y);
y--;
};
}
else
{
while(x<right_x)
{
Pixel24TrC(color,x,y);
if((right_x-left_x)>;(right_y-left_y))
while((right_y-left_y)*(x-left_x)<(right_x-left_x)*(y-left_y))
{
x++;
Pixel24TrC(color,x,y);
}
x++;
if(y>;=right_y)
continue;
if((right_y-left_y)>;(right_x-left_x))
while((right_y-left_y)*(x-left_x)>;(right_x-left_x)*(y-left_y))
{
y++;
Pixel24TrC(color,x,y);
}
y++;
};
while(y<=right_y)
{
Pixel24TrC(color,x,y);
y++;
};
}
return 0;
}

复制代码

a.h 头文件

#define LINE 640
#define C256(R,G,B) (unsigned char)R*0x20%0x100+(unsigned char)G*0x4%0x20+B
#define Hi15(R,G,B) (unsigned)R*0x400%0x8000+(unsigned)G*0x20%0x400+(char)B%0x20
#define HiC(R,G,B) (unsigned)R*0x800%0x10000+(unsigned)G*32%0x800+(char)B%0x20
#define TrC(R,G,B) (unsigned long)R*0x10000%0x1000000+(unsigned long)G*0x100%0x10000+(unsigned)B%0x100
#define Hi-TrC(RGB) (unsigned long)RGB%0x10000/2048*65536+(unsigned long)RGB%2048/32*256+(unsigned char)RGB%32
#define Tr-HiC(RGB) (unsigned long)RGB%0x1000000/65536%32*2048+(unsigned long)RGB%65536/64*32+(unsigned char)(RGB%32)
#define C256_640_400 0x100
#define C256_640_480 0x101
#define C16_800_600 0x102
#define C256_800_600 0x103
#define C16_1024_768 0x104
#define C256_1024_768 0x105
#define Hi15_640_480 0x110
#define Hi640_480 0x111
#define Tr640_480 0x112
#define Hi15_800_600 0x113
#define Hi800_600 0x114
#define Tr800_600 0x115
#define Hi15_1024_768 0x116
#define Hi1024_768 0x117
#define Tr1024_768 0x118
extern void Demo(unsigned long,int,int);
extern void init(int);
extern void Pixel16HiC(int,int,int);
extern void Pixel24TrC(unsigned long,int,int);
extern void Pixel256C(char,int,int);
extern void line(unsigned long x1,unsigned long y1,unsigned long x2,unsigned long y2,unsigned long color);
/*seepic*/
extern unsigned far* readpic(FILE *fp);
extern void mouse(void);
struct bmp_head
{
int other1;
unsigned long length;
char other2[4];
unsigned int offset;
char other3[6];
unsigned int width;
char other4[2];
unsigned int hight;
char other5[4];
unsigned char color;
};