Bmp.c File Reference

#include <stdlib.h>
#include <string.h>
#include <stdio.h>
#include "errors.h"

Include dependency graph for Bmp.c:

Go to the source code of this file.

Data Structures
struct	Bmp
	It stores an image in memory. More...

Macros
#define	RGB_COLOR_LENGTH   3
#define	FILE_HEADER_LENGTH   14
#define	INFO_HEADER_LENGTH   40
#define	PAD_LENGTH   3

Functions
struct Bmp *	Bmp_destruct (struct Bmp *this)
	It destructs a managing object for one image.
unsigned int	Bmp_getWidth (struct Bmp *this)
unsigned int	Bmp_getHeight (struct Bmp *this)
	It supplies the height of an image.
unsigned long	Bmp_getLength (struct Bmp *this)
	It supplies the number of pixels.
void	Bmp_getPixelOfRaster (struct Bmp *this, int horizontal, int vertical, unsigned char *red, unsigned char *green, unsigned char *blue, int *error)
	It supplies three colors of a pixel when the horizontal and vertical positions of a raster are provided by the caller.
void	Bmp_getPixelOfLine (struct Bmp *this, int index, unsigned char *red, unsigned char *green, unsigned char *blue, int *error)
	It supplies three colors of a pixel when the horizontal and vertical positions of a raster are provided by the caller.
struct Bmp *	Bmp_readFile (const char *filename, int *error)
	It loads an image file with the bmp format into memory.
void	Bmp_writeFile (struct Bmp *this, const char *filename, int *error)
	It writes an image in a file in bmp format.

Macro Definition Documentation

FILE_HEADER_LENGTH

#define FILE_HEADER_LENGTH   14

Definition at line 8 of file Bmp.c.

INFO_HEADER_LENGTH

#define INFO_HEADER_LENGTH   40

Definition at line 9 of file Bmp.c.

PAD_LENGTH

#define PAD_LENGTH   3

Definition at line 10 of file Bmp.c.

RGB_COLOR_LENGTH

#define RGB_COLOR_LENGTH   3

Definition at line 7 of file Bmp.c.

Function Documentation

Bmp_destruct()

struct Bmp * Bmp_destruct

(

struct Bmp *

this

)

It destructs a managing object for one image.

Parameters

this	a managing object for one image

Definition at line 22 of file Bmp.c.

Bmp_getHeight()

unsigned int Bmp_getHeight

(

struct Bmp *

this

)

It supplies the height of an image.

Parameters

this	a managing object for one image

Definition at line 39 of file Bmp.c.

Bmp_getLength()

unsigned long Bmp_getLength

(

struct Bmp *

this

)

It supplies the number of pixels.

It is used to extract individual pixels in a loop.

Returns

the number of pixels in the image.

Parameters

this	a managing object for one image

Definition at line 44 of file Bmp.c.

Bmp_getPixelOfLine()

void Bmp_getPixelOfLine	(	struct Bmp *	this,
		int	index,
		unsigned char *	red,
		unsigned char *	green,
		unsigned char *	blue,
		int *	error
	)

It supplies three colors of a pixel when the horizontal and vertical positions of a raster are provided by the caller.

Parameters

this	a managing object for one image
index	the pixel position in a line (0 is top left), it cannot be equal or exceed the length of an image
red	red value (from 0 to 255)
green	green value (from 0 to 255)
blue	blue value (from 0 to 255)
error	error tracking (0 means no error)

Definition at line 58 of file Bmp.c.

Bmp_getPixelOfRaster()

void Bmp_getPixelOfRaster	(	struct Bmp *	this,
		int	horizontal,
		int	vertical,
		unsigned char *	red,
		unsigned char *	green,
		unsigned char *	blue,
		int *	error
	)

It supplies three colors of a pixel when the horizontal and vertical positions of a raster are provided by the caller.

Parameters

this	a managing object for one image
horizontal	the vertical pixel position starting from above (0 is top), it cannot be equal or exceed the image width
vertical	the horizontal position of a pixel counted from the left side of the screen from the point of view of the user (0 is left), it cannot be equal or exceed the image height
red	red value (from 0 to 255)
green	green value (from 0 to 255)
blue	blue value (from 0 to 255)
error	error tracking (0 means no error)

Definition at line 49 of file Bmp.c.

Bmp_getWidth()

unsigned int Bmp_getWidth

(

struct Bmp *

this

)

Parameters

this	a managing object for one image

Definition at line 34 of file Bmp.c.

Bmp_readFile()

struct Bmp * Bmp_readFile	(	const char *	filename,
		int *	error
	)

It loads an image file with the bmp format into memory.

The order is RGBRGBRGB from top left to bottom right, without any padding. The RGBA format with alpha channel for opacity is not supported.

One pixel image reserves 54 bytes for headers. Color space information must not be added to the headers.

> hexdump -C bmps/one_pixel_all_channels_different.bmp
00000000  42 4d 3a 00 00 00 00 00  00 00 36 00 00 00 28 00  |BM:.......6...(.|
00000010  00 00 01 00 00 00 01 00  00 00 01 00 18 00 00 00  |................|
00000020  00 00 04 00 00 00 23 2e  00 00 23 2e 00 00 00 00  |......#...#.....|
00000030  00 00 00 00 00 00 56 34  12 00                    |......V4..|
 
--------  -- -- -- -- -- -- 56 34  12 -- here: blue 56 + green 34 + red 12

Returns

a managing object for one image

Parameters

filename	a path to a file
error	error tracking (0 means no error)

Definition at line 65 of file Bmp.c.

Bmp_writeFile()

void Bmp_writeFile	(	struct Bmp *	this,
		const char *	filename,
		int *	error
	)

It writes an image in a file in bmp format.

Parameters

this	a managing object for one image
filename	a path to a file
error	error tracking (0 means no error)

Definition at line 242 of file Bmp.c.