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ForeverZer0/bitmap.c

Created August 13, 2018 23:51
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Cross-platform C sources to read device-independent bitmap files
Raw
bitmap.c
/*
* Windows BMP file functions for OpenGL.
*
* Written by Michael Sweet.
*/
#include "bitmap.h"
#include <stdio.h>
#include <stdlib.h>
#include <errno.h>
#ifdef WIN32
/*
* 'LoadDIBitmap()' - Load a DIB/BMP file from disk.
*
* Returns a pointer to the bitmap if successful, NULL otherwise...
*/
GLubyte * /* O - Bitmap data */
LoadDIBitmap(const char *filename, /* I - File to load */
BITMAPINFO **info) /* O - Bitmap information */
{
FILE *fp; /* Open file pointer */
GLubyte *bits; /* Bitmap pixel bits */
int bitsize; /* Size of bitmap */
int infosize; /* Size of header information */
BITMAPFILEHEADER header; /* File header */
/* Try opening the file; use "rb" mode to read this *binary* file. */
if ((fp = fopen(filename, "rb")) == NULL)
return (NULL);
/* Read the file header and any following bitmap information... */
if (fread(&header, sizeof(BITMAPFILEHEADER), 1, fp) < 1)
{
/* Couldn't read the file header - return NULL... */
fclose(fp);
return (NULL);
}
if (header.bfType != 'MB') /* Check for BM reversed... */
{
/* Not a bitmap file - return NULL... */
fclose(fp);
return (NULL);
}
infosize = header.bfOffBits - sizeof(BITMAPFILEHEADER);
if ((*info = (BITMAPINFO *)malloc(infosize)) == NULL)
{
/* Couldn't allocate memory for bitmap info - return NULL... */
fclose(fp);
return (NULL);
}
if (fread(*info, 1, infosize, fp) < infosize)
{
/* Couldn't read the bitmap header - return NULL... */
free(*info);
fclose(fp);
return (NULL);
}
/* Now that we have all the header info read in, allocate memory for *
* the bitmap and read *it* in... */
if ((bitsize = (*info)->bmiHeader.biSizeImage) == 0)
bitsize = ((*info)->bmiHeader.biWidth *
(*info)->bmiHeader.biBitCount + 7) / 8 *
abs((*info)->bmiHeader.biHeight);
if ((bits = malloc(bitsize)) == NULL)
{
/* Couldn't allocate memory - return NULL! */
free(*info);
fclose(fp);
return (NULL);
}
if (fread(bits, 1, bitsize, fp) < bitsize)
{
/* Couldn't read bitmap - free memory and return NULL! */
free(*info);
free(bits);
fclose(fp);
return (NULL);
}
/* OK, everything went fine - return the allocated bitmap... */
fclose(fp);
return (bits);
}
/*
* 'SaveDIBitmap()' - Save a DIB/BMP file to disk.
*
* Returns 0 on success or -1 on failure...
*/
int /* O - 0 = success, -1 = failure */
SaveDIBitmap(const char *filename, /* I - File to load */
BITMAPINFO *info, /* I - Bitmap information */
GLubyte *bits) /* I - Bitmap data */
{
FILE *fp; /* Open file pointer */
int size, /* Size of file */
infosize, /* Size of bitmap info */
bitsize; /* Size of bitmap pixels */
BITMAPFILEHEADER header; /* File header */
/* Try opening the file; use "wb" mode to write this *binary* file. */
if ((fp = fopen(filename, "wb")) == NULL)
return (-1);
/* Figure out the bitmap size */
if (info->bmiHeader.biSizeImage == 0)
bitsize = (info->bmiHeader.biWidth *
info->bmiHeader.biBitCount + 7) / 8 *
abs(info->bmiHeader.biHeight);
else
bitsize = info->bmiHeader.biSizeImage;
/* Figure out the header size */
infosize = sizeof(BITMAPINFOHEADER);
switch (info->bmiHeader.biCompression)
{
case BI_BITFIELDS :
infosize += 12; /* Add 3 RGB doubleword masks */
if (info->bmiHeader.biClrUsed == 0)
break;
case BI_RGB :
if (info->bmiHeader.biBitCount > 8 &&
info->bmiHeader.biClrUsed == 0)
break;
case BI_RLE8 :
case BI_RLE4 :
if (info->bmiHeader.biClrUsed == 0)
infosize += (1 << info->bmiHeader.biBitCount) * 4;
else
infosize += info->bmiHeader.biClrUsed * 4;
break;
}
size = sizeof(BITMAPFILEHEADER) + infosize + bitsize;
/* Write the file header, bitmap information, and bitmap pixel data... */
header.bfType = 'MB'; /* Non-portable... sigh */
header.bfSize = size;
header.bfReserved1 = 0;
header.bfReserved2 = 0;
header.bfOffBits = sizeof(BITMAPFILEHEADER) + infosize;
if (fwrite(&header, 1, sizeof(BITMAPFILEHEADER), fp) < sizeof(BITMAPFILEHEADER))
{
/* Couldn't write the file header - return... */
fclose(fp);
return (-1);
}
if (fwrite(info, 1, infosize, fp) < infosize)
{
/* Couldn't write the bitmap header - return... */
fclose(fp);
return (-1);
}
if (fwrite(bits, 1, bitsize, fp) < bitsize)
{
/* Couldn't write the bitmap - return... */
fclose(fp);
return (-1);
}
/* OK, everything went fine - return... */
fclose(fp);
return (0);
}
#else /* !WIN32 */
/*
* Functions for reading and writing 16- and 32-bit little-endian integers.
*/
static unsigned short read_word(FILE *fp);
static unsigned int read_dword(FILE *fp);
static int read_long(FILE *fp);
static int write_word(FILE *fp, unsigned short w);
static int write_dword(FILE *fp, unsigned int dw);
static int write_long(FILE *fp, int l);
/*
* 'LoadDIBitmap()' - Load a DIB/BMP file from disk.
*
* Returns a pointer to the bitmap if successful, NULL otherwise...
*/
GLubyte * /* O - Bitmap data */
LoadDIBitmap(const char *filename, /* I - File to load */
BITMAPINFO **info) /* O - Bitmap information */
{
FILE *fp; /* Open file pointer */
GLubyte *bits; /* Bitmap pixel bits */
GLubyte *ptr; /* Pointer into bitmap */
GLubyte temp; /* Temporary variable to swap red and blue */
int x, y; /* X and Y position in image */
int length; /* Line length */
int bitsize; /* Size of bitmap */
int infosize; /* Size of header information */
BITMAPFILEHEADER header; /* File header */
/* Try opening the file; use "rb" mode to read this *binary* file. */
if ((fp = fopen(filename, "rb")) == NULL)
return (NULL);
/* Read the file header and any following bitmap information... */
header.bfType = read_word(fp);
header.bfSize = read_dword(fp);
header.bfReserved1 = read_word(fp);
header.bfReserved2 = read_word(fp);
header.bfOffBits = read_dword(fp);
if (header.bfType != BF_TYPE) /* Check for BM reversed... */
{
/* Not a bitmap file - return NULL... */
fclose(fp);
return (NULL);
}
infosize = header.bfOffBits - 18;
if ((*info = (BITMAPINFO *)malloc(sizeof(BITMAPINFO))) == NULL)
{
/* Couldn't allocate memory for bitmap info - return NULL... */
fclose(fp);
return (NULL);
}
(*info)->bmiHeader.biSize = read_dword(fp);
(*info)->bmiHeader.biWidth = read_long(fp);
(*info)->bmiHeader.biHeight = read_long(fp);
(*info)->bmiHeader.biPlanes = read_word(fp);
(*info)->bmiHeader.biBitCount = read_word(fp);
(*info)->bmiHeader.biCompression = read_dword(fp);
(*info)->bmiHeader.biSizeImage = read_dword(fp);
(*info)->bmiHeader.biXPelsPerMeter = read_long(fp);
(*info)->bmiHeader.biYPelsPerMeter = read_long(fp);
(*info)->bmiHeader.biClrUsed = read_dword(fp);
(*info)->bmiHeader.biClrImportant = read_dword(fp);
if (infosize > 40)
if (fread((*info)->bmiColors, infosize - 40, 1, fp) < 1)
{
/* Couldn't read the bitmap header - return NULL... */
free(*info);
fclose(fp);
return (NULL);
}
/* Now that we have all the header info read in, allocate memory for *
* the bitmap and read *it* in... */
if ((bitsize = (*info)->bmiHeader.biSizeImage) == 0)
bitsize = ((*info)->bmiHeader.biWidth *
(*info)->bmiHeader.biBitCount + 7) / 8 *
abs((*info)->bmiHeader.biHeight);
if ((bits = malloc(bitsize)) == NULL)
{
/* Couldn't allocate memory - return NULL! */
free(*info);
fclose(fp);
return (NULL);
}
if (fread(bits, 1, bitsize, fp) < bitsize)
{
/* Couldn't read bitmap - free memory and return NULL! */
free(*info);
free(bits);
fclose(fp);
return (NULL);
}
/* Swap red and blue */
length = ((*info)->bmiHeader.biWidth * 3 + 3) & ~3;
for (y = 0; y < (*info)->bmiHeader.biHeight; y ++)
for (ptr = bits + y * length, x = (*info)->bmiHeader.biWidth;
x > 0;
x --, ptr += 3)
{
temp = ptr[0];
ptr[0] = ptr[2];
ptr[2] = temp;
}
/* OK, everything went fine - return the allocated bitmap... */
fclose(fp);
return (bits);
}
/*
* 'SaveDIBitmap()' - Save a DIB/BMP file to disk.
*
* Returns 0 on success or -1 on failure...
*/
int /* O - 0 = success, -1 = failure */
SaveDIBitmap(const char *filename, /* I - File to load */
BITMAPINFO *info, /* I - Bitmap information */
GLubyte *bits) /* I - Bitmap data */
{
FILE *fp; /* Open file pointer */
int size, /* Size of file */
infosize, /* Size of bitmap info */
bitsize; /* Size of bitmap pixels */
/* Try opening the file; use "wb" mode to write this *binary* file. */
if ((fp = fopen(filename, "wb")) == NULL)
return (-1);
/* Figure out the bitmap size */
if (info->bmiHeader.biSizeImage == 0)
bitsize = (info->bmiHeader.biWidth *
info->bmiHeader.biBitCount + 7) / 8 *
abs(info->bmiHeader.biHeight);
else
bitsize = info->bmiHeader.biSizeImage;
/* Figure out the header size */
infosize = sizeof(BITMAPINFOHEADER);
switch (info->bmiHeader.biCompression)
{
case BI_BITFIELDS :
infosize += 12; /* Add 3 RGB doubleword masks */
if (info->bmiHeader.biClrUsed == 0)
break;
case BI_RGB :
if (info->bmiHeader.biBitCount > 8 &&
info->bmiHeader.biClrUsed == 0)
break;
case BI_RLE8 :
case BI_RLE4 :
if (info->bmiHeader.biClrUsed == 0)
infosize += (1 << info->bmiHeader.biBitCount) * 4;
else
infosize += info->bmiHeader.biClrUsed * 4;
break;
}
size = sizeof(BITMAPFILEHEADER) + infosize + bitsize;
/* Write the file header, bitmap information, and bitmap pixel data... */
write_word(fp, BF_TYPE); /* bfType */
write_dword(fp, size); /* bfSize */
write_word(fp, 0); /* bfReserved1 */
write_word(fp, 0); /* bfReserved2 */
write_dword(fp, 18 + infosize); /* bfOffBits */
write_dword(fp, info->bmiHeader.biSize);
write_long(fp, info->bmiHeader.biWidth);
write_long(fp, info->bmiHeader.biHeight);
write_word(fp, info->bmiHeader.biPlanes);
write_word(fp, info->bmiHeader.biBitCount);
write_dword(fp, info->bmiHeader.biCompression);
write_dword(fp, info->bmiHeader.biSizeImage);
write_long(fp, info->bmiHeader.biXPelsPerMeter);
write_long(fp, info->bmiHeader.biYPelsPerMeter);
write_dword(fp, info->bmiHeader.biClrUsed);
write_dword(fp, info->bmiHeader.biClrImportant);
if (infosize > 40)
if (fwrite(info->bmiColors, infosize - 40, 1, fp) < 1)
{
/* Couldn't write the bitmap header - return... */
fclose(fp);
return (-1);
}
if (fwrite(bits, 1, bitsize, fp) < bitsize)
{
/* Couldn't write the bitmap - return... */
fclose(fp);
return (-1);
}
/* OK, everything went fine - return... */
fclose(fp);
return (0);
}
/*
* 'read_word()' - Read a 16-bit unsigned integer.
*/
static unsigned short /* O - 16-bit unsigned integer */
read_word(FILE *fp) /* I - File to read from */
{
unsigned char b0, b1; /* Bytes from file */
b0 = getc(fp);
b1 = getc(fp);
return ((b1 << 8) | b0);
}
/*
* 'read_dword()' - Read a 32-bit unsigned integer.
*/
static unsigned int /* O - 32-bit unsigned integer */
read_dword(FILE *fp) /* I - File to read from */
{
unsigned char b0, b1, b2, b3; /* Bytes from file */
b0 = getc(fp);
b1 = getc(fp);
b2 = getc(fp);
b3 = getc(fp);
return ((((((b3 << 8) | b2) << 8) | b1) << 8) | b0);
}
/*
* 'read_long()' - Read a 32-bit signed integer.
*/
static int /* O - 32-bit signed integer */
read_long(FILE *fp) /* I - File to read from */
{
unsigned char b0, b1, b2, b3; /* Bytes from file */
b0 = getc(fp);
b1 = getc(fp);
b2 = getc(fp);
b3 = getc(fp);
return ((int)(((((b3 << 8) | b2) << 8) | b1) << 8) | b0);
}
/*
* 'write_word()' - Write a 16-bit unsigned integer.
*/
static int /* O - 0 on success, -1 on error */
write_word(FILE *fp, /* I - File to write to */
unsigned short w) /* I - Integer to write */
{
putc(w, fp);
return (putc(w >> 8, fp));
}
/*
* 'write_dword()' - Write a 32-bit unsigned integer.
*/
static int /* O - 0 on success, -1 on error */
write_dword(FILE *fp, /* I - File to write to */
unsigned int dw) /* I - Integer to write */
{
putc(dw, fp);
putc(dw >> 8, fp);
putc(dw >> 16, fp);
return (putc(dw >> 24, fp));
}
/*
* 'write_long()' - Write a 32-bit signed integer.
*/
static int /* O - 0 on success, -1 on error */
write_long(FILE *fp, /* I - File to write to */
int l) /* I - Integer to write */
{
putc(l, fp);
putc(l >> 8, fp);
putc(l >> 16, fp);
return (putc(l >> 24, fp));
}
#endif /* WIN32 */
Raw
bitmap.h
/*
* Windows BMP file definitions for OpenGL.
*
* Written by Michael Sweet.
*/
#ifndef _BITMAP_H_
# define _BITMAP_H_
/*
* Include necessary headers.
*/
# include <GL/glut.h>
# ifdef WIN32
# include <windows.h>
# include <wingdi.h>
# endif /* WIN32 */
/*
* Make this header file work with C and C++ source code...
*/
# ifdef __cplusplus
extern "C" {
# endif /* __cplusplus */
/*
* Bitmap file data structures (these are defined in <wingdi.h> under
* Windows...)
*
* Note that most Windows compilers will pack the following structures, so
* when reading them under MacOS or UNIX we need to read individual fields
* to avoid differences in alignment...
*/
# ifndef WIN32
typedef struct /**** BMP file header structure ****/
{
unsigned short bfType; /* Magic number for file */
unsigned int bfSize; /* Size of file */
unsigned short bfReserved1; /* Reserved */
unsigned short bfReserved2; /* ... */
unsigned int bfOffBits; /* Offset to bitmap data */
} BITMAPFILEHEADER;
# define BF_TYPE 0x4D42 /* "MB" */
typedef struct /**** BMP file info structure ****/
{
unsigned int biSize; /* Size of info header */
int biWidth; /* Width of image */
int biHeight; /* Height of image */
unsigned short biPlanes; /* Number of color planes */
unsigned short biBitCount; /* Number of bits per pixel */
unsigned int biCompression; /* Type of compression to use */
unsigned int biSizeImage; /* Size of image data */
int biXPelsPerMeter; /* X pixels per meter */
int biYPelsPerMeter; /* Y pixels per meter */
unsigned int biClrUsed; /* Number of colors used */
unsigned int biClrImportant; /* Number of important colors */
} BITMAPINFOHEADER;
/*
* Constants for the biCompression field...
*/
# define BI_RGB 0 /* No compression - straight BGR data */
# define BI_RLE8 1 /* 8-bit run-length compression */
# define BI_RLE4 2 /* 4-bit run-length compression */
# define BI_BITFIELDS 3 /* RGB bitmap with RGB masks */
typedef struct /**** Colormap entry structure ****/
{
unsigned char rgbBlue; /* Blue value */
unsigned char rgbGreen; /* Green value */
unsigned char rgbRed; /* Red value */
unsigned char rgbReserved; /* Reserved */
} RGBQUAD;
typedef struct /**** Bitmap information structure ****/
{
BITMAPINFOHEADER bmiHeader; /* Image header */
RGBQUAD bmiColors[256]; /* Image colormap */
} BITMAPINFO;
# endif /* !WIN32 */
/*
* Prototypes...
*/
extern GLubyte *LoadDIBitmap(const char *filename, BITMAPINFO **info);
extern int SaveDIBitmap(const char *filename, BITMAPINFO *info,
GLubyte *bits);
# ifdef __cplusplus
}
# endif /* __cplusplus */
#endif /* !_BITMAP_H_ */
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