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lib: Document assembling functions

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This commit is contained in:
Vasily Khoruzhick
2018-12-02 11:02:12 -08:00
committed by Bastien Nocera
parent c9733d27df
commit 2088a6177f
2 changed files with 112 additions and 16 deletions
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58
libfprint/fpi-assembling.h
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@@ -22,12 +22,36 @@
#include <fprint.h>
/**
* fpi_frame:
* @delta_x: X offset of the frame
* @delta_y: Y offset of the frame
* @data: bitmap
*
* #fpi_frame is used to store frames for swipe sensors. Drivers should
* populate delta_x and delta_y if the device supports hardware movement
* estimation.
*/
struct fpi_frame {
int delta_x;
int delta_y;
unsigned char data[0];
};
/**
* fpi_frame_asmbl_ctx:
* @frame_width: width of the frame
* @frame_height: height of the frame
* @image_width: resulting image width
* @get_pixel: pixel accessor, returns pixel brightness at x,y of frame
*
* #fpi_frame_asmbl_ctx is a structure holding the context for frame
* assembling routines.
*
* Drivers should define their own #fpi_frame_asmbl_ctx depending on
* hardware parameters of scanner. @image_width is usually 25% wider than
* @frame_width to take horizontal movement into account.
*/
struct fpi_frame_asmbl_ctx {
unsigned int frame_width;
unsigned int frame_height;
@@ -39,11 +63,39 @@ struct fpi_frame_asmbl_ctx {
};
void fpi_do_movement_estimation(struct fpi_frame_asmbl_ctx *ctx,
GSList *stripes, size_t stripes_len);
GSList *stripes, size_t num_stripes);
struct fp_img *fpi_assemble_frames(struct fpi_frame_asmbl_ctx *ctx,
GSList *stripes, size_t stripes_len);
GSList *stripes, size_t num_stripes);
/**
* fpi_line_asmbl_ctx:
* @line_width: width of line
* @max_height: maximal height of assembled image
* @resolution: scale factor used for line assembling routines.
* @median_filter_size: size of median filter for movement estimation
* @max_search_offset: the number of lines to search for the next line
* @get_deviation: pointer to a function that returns the numerical difference
* between two lines
* @get_pixel: pixel accessor, returns pixel brightness at x of line
*
* #fpi_line_asmbl_ctx is a structure holding the context for line assembling
* routines.
*
* Drivers should define their own #fpi_line_asmbl_ctx depending on
* the hardware parameters of the scanner. Swipe scanners of this type usually
* return two lines, the second line is often narrower than first and is used
* for movement estimation.
*
* The @max_search_offset value indicates how many lines forward the assembling
* routines should look while searching for next line. This value depends on
* how fast the hardware sends frames.
*
* The function pointed to by @get_deviation should return the numerical difference
* between two lines. Higher values means lines are more different. If the reader
* returns two lines at a time, this function should be used to estimate the
* difference between pairs of lines.
*/
struct fpi_line_asmbl_ctx {
unsigned int line_width;
unsigned int max_height;
@@ -58,6 +110,6 @@ struct fpi_line_asmbl_ctx {
};
struct fp_img *fpi_assemble_lines(struct fpi_line_asmbl_ctx *ctx,
GSList *lines, size_t lines_len);
GSList *lines, size_t num_lines);
#endif