Image Read/Write

Functions provided by the LIBICV image processing library for reading and writing of images. More...

Collaboration diagram for Image Read/Write:

Files
file	io.h

Functions
icv_image_t *	icv_create (size_t width, size_t height, ICV_COLOR_SPACE color_space)
icv_image_t *	icv_zero (icv_image_t *bif)
int	icv_destroy (icv_image_t *bif)
int	icv_image_size (const char *label, size_t dpi, size_t data_size, bu_mime_image_t type, size_t *widthp, size_t *heightp)
icv_image_t *	icv_read (const char *filename, bu_mime_image_t format, size_t width, size_t height)
int	icv_write (icv_image_t *bif, const char *filename, bu_mime_image_t format)
int	icv_writeline (icv_image_t *bif, size_t y, void *data, ICV_DATA type)
int	icv_writepixel (icv_image_t *bif, size_t x, size_t y, double *data)
unsigned char *	icv_data2uchar (const icv_image_t *bif)
double *	icv_uchar2double (unsigned char *data, size_t size)

Detailed Description

Functions provided by the LIBICV image processing library for reading and writing of images.

Function Documentation

icv_create()

icv_image_t * icv_create	(	size_t	width,
		size_t	height,
		ICV_COLOR_SPACE	color_space
	)

This function allocates memory for an image and returns the resultant image.

Parameters

width	Width of the image to be created
height	Height of the image to be created
color_space	Color space of the image (RGB, grayscale)

Returns

Image structure with allocated space and zeroed data array

icv_zero()

icv_image_t * icv_zero

(

icv_image_t *

bif

)

This function zeroes all the data entries of an image

Parameters

bif	Image Structure

icv_destroy()

int icv_destroy

(

icv_image_t *

bif

)

This function frees the allocated memory for a ICV Structure and data.

icv_image_size()

int icv_image_size	(	const char *	label,
		size_t	dpi,
		size_t	data_size,
		bu_mime_image_t	type,
		size_t *	widthp,
		size_t *	heightp
	)

Function to calculate (or make an educated guess) about the dimensions of an image, when the image doesn't supply such information.

Standard image sizes may be hinted using the label parameter. Many standard print and display sizes (e.g., "A4" and "SVGA") are recognized and used in concert with the dpi and data_size parameters.

Parameters

[in]	label	String hinting at a size (pass NULL if not using)
[in]	dpi	Dots per inch of image (pass 0 if not using)
[in]	data_size	Number of uncompressed image bytes (necessary if deducing an unspecified image size)
[in]	type	Image type (necessary if deducing an unspecified image size)
[out]	widthp	Pointer to variable that will hold image width
[out]	heightp	Pointer to variable that will hold image height

Returns

Returns 1 if an image size was identified, zero otherwise.

icv_read()

icv_image_t * icv_read	(	const char *	filename,
		bu_mime_image_t	format,
		size_t	width,
		size_t	height
	)

Load a file into an ICV struct. For most formats, this will be called with format=ICV_IMAGE_AUTO.

The data is packed in icv_image struct in double format with varied channels as per the specification of image to be loaded.

To read stream from stdin pass NULL pointer for filename.

In case of bw and pix image if size is unknown pass 0 for width and height. This will read the image till EOF is reached. The image size of the output image will be : height = 1; width = size; where size = total bytes read

Parameters

filename	File to read
format	Probable format of the file, typically ICV_IMAGE_AUTO
width	Width when passed as parameter from calling program.
height	Height when passed as parameter from calling program.

Returns

A newly allocated struct holding the loaded image info.

icv_write()

int icv_write	(	icv_image_t *	bif,
		const char *	filename,
		bu_mime_image_t	format
	)

Saves Image to a file or streams to stdout in respective format

To stream it to stdout pass NULL pointer for filename.

Parameters

bif	Image structure of file.
filename	Filename of the file to be written.
format	Specific format of the file to be written.

Returns

on success 0, on failure -1 with log messages.

icv_writeline()

int icv_writeline	(	icv_image_t *	bif,
		size_t	y,
		void *	data,
		ICV_DATA	type
	)

Write an image line to the data of ICV struct. Can handle unsigned char buffers.

Note : This function requires memory allocation for ICV_UCHAR_DATA, which in turn acquires BU_SEM_SYSCALL semaphore.

Parameters

bif	ICV struct where data is to be written
y	Index of the line at which data is to be written. 0 for the first line
data	Line Data to be written
type	Type of data, e.g., uint8 data specify ICV_DATA_UCHAR or 1

Returns

on success 0, on failure -1

icv_writepixel()

int icv_writepixel	(	icv_image_t *	bif,
		size_t	x,
		size_t	y,
		double *	data
	)

Writes a pixel to the specified coordinates in the data of ICV struct.

Parameters

bif	ICV struct where data is to be written
x	x-dir coordinate of the pixel
y	y-dir coordinate of the pixel. (0,0) coordinate is taken as bottom left
data	Data to be written

Returns

on success 0, on failure -1

icv_data2uchar()

unsigned char * icv_data2uchar

(

const icv_image_t *

bif

)

Converts double data of icv_image to unsigned char data. This function also does gamma correction using the gamma_corr parameter of the image structure.

Gamma correction prevents bad color aliasing.

Parameters

bif	ICV struct where data is to be read from

Returns

array of unsigned char converted data, or NULL on failure

icv_uchar2double()

double * icv_uchar2double	(	unsigned char *	data,
		size_t	size
	)

Converts unsigned char array to double array. This function returns array of double data.

Used to convert data from pix, bw, ppm type images for icv_image struct.

This does not free the char data.

Parameters

data	pointer to the array to be converted.
size	Size of the array.

Returns

double array.