Utility function to save bitmaps

Macros
#define	BX_AVERAGE   0
#define	BX_DARKEN   1
#define	BX_LIGHTEN   2
#define	BX_MAXCONTRAST   4
#define	BX_NODITHER   8
#define	BX_GRAYSCALE   16
#define	BX_TXFILE   32
#define	BX_DOTRANSFER   256
#define	BX_NODRAW   512
#define	SV_NOREPLACE   1
#define	SV_MAKEPATH   2

Functions
int	el_bitmap_save_and_backdrop (EYEBITMAP *hbm, INT16 xs, INT16 ys, INT16 width, INT16 height, const char *fname, const char *path, INT16 sv_options, INT16 xd, INT16 yd, UINT16 xferoptions)
int	el_set_backdrop (const char *fname)
int	el_bitmap_to_backdrop (EYEBITMAP *hbm, INT16 xs, INT16 ys, INT16 width, INT16 height, INT16 xd, INT16 yd, UINT16 xferoptions)
int	el_bitmap_save (EYEBITMAP *hbm, INT16 xs, INT16 ys, INT16 width, INT16 height, char *fname, char *path, INT16 sv_options)
int	set_write_image_hook (int(*hookfn)(char *outfilename, int format, EYEBITMAP *bitmap), int options)

Detailed Description

Macro Definition Documentation

#define BX_AVERAGE   0

Average combined pixels

#define BX_DARKEN   1

Choose darkest (keep thin dark lines)

#define BX_DOTRANSFER   256

Send bitmap to host

#define BX_GRAYSCALE   16

Gray scale

#define BX_LIGHTEN   2

Choose darkest (keep thin white lines)

#define BX_MAXCONTRAST   4

Stretch contrast to black->white

#define BX_NODITHER   8

No dither, just quantize

#define BX_NODRAW   512

When set, it want draw after image transer

#define BX_TXFILE   32

Transfer and draw to host using tcp

#define SV_MAKEPATH   2

make destination path if does not already exists

#define SV_NOREPLACE   1

do not replace if the file already exists

Function Documentation

int el_bitmap_save	(	EYEBITMAP *	hbm,
		INT16	xs,
		INT16	ys,
		INT16	width,
		INT16	height,
		char *	fname,
		char *	path,
		INT16	sv_options
	)

This function saves the entire bitmap or selected part of a bitmap in an image file (with an extension of .png, .bmp, .jpg, or .tif). It creates the specified file if this file does not exist.

Parameters

hbm	Bitmap to save or transfer or both.
xs	X position.
ys	Y position.
width	Width.
height	Height.
fname	File name to save as. The extension decides the format of the file.
path	The directory to which the file will be written.
sv_options	If the file exists, it replaces the file unless SV_NOREPLACE is specified.

Remarks

This function relies on the writeImageHook set by call to set_write_image_hook() to write the images in different formats. By default, if eyelink_core_graphics library is used, gd library is used to write the images and if eyelink_gdi_graphics is used FreeImage library is used to write the images. If neither one of them is used, call to this function does not write the images unless, set_write_image_hook() is used to set the writeImageHook.

This function should not be called when timing is critical, as this might take very long to return.

int el_bitmap_save_and_backdrop	(	EYEBITMAP *	hbm,
		INT16	xs,
		INT16	ys,
		INT16	width,
		INT16	height,
		const char *	fname,
		const char *	path,
		INT16	sv_options,
		INT16	xd,
		INT16	yd,
		UINT16	xferoptions
	)

This function saves the entire bitmap as a .BMP, .JPG, .PNG, or .TIF file, and transfers the image to tracker as backdrop for gaze cursors.

Parameters

hbm	Bitmap to save or transfer or both.
xs	X position.
ys	Y position.
width	Width.
height	Height.
fname	File name to save as. The extension decides the format of the file.
path	The directory to which the file will be written.
sv_options	If the file exists, it replaces the file unless SV_NOREPLACE is specified.
xd	X position.
yd	Y position.
xferoptions	Transfer options set with bitwise OR of the following constants, determines how bitmap is processed: BX_AVERAGE Averaging combined pixels BX_DARKEN Choosing darkest and keep thin dark lines. BX_LIGHTEN Choosing darkest and keep thin white lines and control how bitmap size is reduced to fit tracker display. BX_MAXCONTRAST Maximizes contrast for clearest image. BX_NODITHER Disables the dithering of the image. BX_GREYSCALE Converts the image to grayscale (grayscale works best for EyeLink I, text, etc.).

See also

el_bitmap_to_backdrop(), el_bitmap_save(), sdl_bitmap_to_backdrop(), sdl_bitmap_save(),sdl_bitmap_save_and_backdrop, gdi_bitmap_to_backdrop(), gdi_bitmap_save(),gdi_bitmap_save_and_backdrop, bitmap_save(), and bitmap_to_backdrop() for more information.

Remarks

This function relies on the writeImageHook set by call to set_write_image_hook() to write the images in different formats. By default, if eyelink_core_graphics library is used, gd library is used to write the images and if eyelink_gdi_graphics is used FreeImage library is used to write the images. If neither one of them is used, call to this function does not write the images unless, set_write_image_hook() is used to set the writeImageHook.

This function should not be called when timing is critical, as this might take very long to return.

int el_bitmap_to_backdrop	(	EYEBITMAP *	hbm,
		INT16	xs,
		INT16	ys,
		INT16	width,
		INT16	height,
		INT16	xd,
		INT16	yd,
		UINT16	xferoptions
	)

This function transfers the bitmap to the tracker PC as backdrop for gaze cursors.

Parameters

hbm	Bitmap to save or transfer or both.
xs	X position.
ys	Y position.
width	Width.
height	Height.
xd	X position.
yd	Y position.
xferoptions	Transfer options set with bitwise OR of the following constants, determines how bitmap is processed: BX_AVERAGE Averaging combined pixels BX_DARKEN Choosing darkest and keep thin dark lines. BX_LIGHTEN Choosing darkest and keep thin white lines and control how bitmap size is reduced to fit tracker display. BX_MAXCONTRAST Maximizes contrast for clearest image. BX_NODITHER Disables the dithering of the image. BX_GREYSCALE Converts the image to grayscale (grayscale works best for EyeLink I, text, etc.).

See also

sdl_bitmap_to_backdrop(), el_bitmap_save_and_backdrop(), sdl_bitmap_save_and_backdrop(), gdi_bitmap_to_backdrop(), gdi_bitmap_save_and_backdrop(), and bitmap_to_backdrop() for more information.

Remarks

This function should not be called when timing is critical, as this might take very long to return.

int el_set_backdrop

(

const char *

fname

)

This function set the previously saved bitmap at the tracker. When a bitmap image is sent to tracker and saved with the function el_bitmap_save_and_backdrop with BX_TXFILE option. The bitmapped previously sent gets saved at the traker with the provided filename. The same file name should be used in this function to show that bitmap at the tracker.

Parameters

fname

File name that was previously sent to show it as backdrop at the tracker.

Remarks

This function should be called with the filename that was saved before.

int set_write_image_hook	(	int(*)(char *outfilename, int format, EYEBITMAP *bitmap)	hookfn,
		int	options
	)

Use this function to set function pointer, so that the call to el_bitmap_save and el_bitmap_save_and_backdrop will use the passed in function to write the image to disk.