Raster Library - Quantization rules. More...

#include <stdlib.h>
#include <grass/gis.h>
#include <grass/raster.h>

Include dependency graph for quant.c:

Macros
#define	USE_LOOKUP 1

#define	MAX_LOOKUP_TABLE_SIZE 2048

#define	NO_DATA (Rast_set_c_null_value(&tmp, 1), (CELL)tmp)

#define	NO_LEFT_INFINITE_RULE (!q->infiniteLeftSet)

#define	NO_RIGHT_INFINITE_RULE (!q->infiniteRightSet)

#define	NO_FINITE_RULE (q->nofRules <= 0)

#define	NO_EXPLICIT_RULE (NO_FINITE_RULE && NO_LEFT_INFINITE_RULE && NO_RIGHT_INFINITE_RULE)

Functions
void	Rast_quant_clear (struct Quant *q)
	Resets the number of defined rules and number of infinite rules to 0. More...

void	Rast_quant_free (struct Quant *q)
	Resets and frees allocated memory. More...

int	Rast__quant_organize_fp_lookup (struct Quant *q)
	Organized fp_lookup table. More...

void	Rast_quant_init (struct Quant *quant)
	Initialize the structure. More...

int	Rast_quant_is_truncate (const struct Quant *quant)
	Returns whether or not quant rules are set to truncate map. More...

int	Rast_quant_is_round (const struct Quant *quant)
	Returns whether or not quant rules are set to round map. More...

void	Rast_quant_truncate (struct Quant *quant)
	Sets the quant rules to perform simple truncation on floats. More...

void	Rast_quant_round (struct Quant *quant)
	Sets the quant rules to perform simple rounding on floats. More...

int	Rast_quant_get_limits (const struct Quant q, DCELL dMin, DCELL dMax, CELL cMin, CELL *cMax)
	Returns the minimum and maximum cell and dcell values of all the ranges defined. More...

int	Rast_quant_nof_rules (const struct Quant *q)
	Returns the number of quantization rules defined. More...

void	Rast_quant_get_ith_rule (const struct Quant q, int i, DCELL dLow, DCELL dHigh, CELL cLow, CELL *cHigh)
	Returns the i'th quantization rule. More...

void	Rast_quant_set_neg_infinite_rule (struct Quant *q, DCELL dLeft, CELL c)
	Defines a rule for values "dLeft" and smaller. More...

int	Rast_quant_get_neg_infinite_rule (const struct Quant q, DCELL dLeft, CELL *c)
	Returns in "dLeft" and "c" the rule values. More...

void	Rast_quant_set_pos_infinite_rule (struct Quant *q, DCELL dRight, CELL c)
	Defines a rule for values "dRight" and larger. More...

int	Rast_quant_get_pos_infinite_rule (const struct Quant q, DCELL dRight, CELL *c)
	Returns in "dRight" and "c" the rule values. More...

void	Rast_quant_add_rule (struct Quant *q, DCELL dLow, DCELL dHigh, CELL cLow, CELL cHigh)
	Adds a new rule to the set of quantization rules. More...

void	Rast_quant_reverse_rule_order (struct Quant *q)
	Rreverses the order in which the qunatization rules are stored. More...

CELL	Rast_quant_get_cell_value (struct Quant *q, DCELL dcellVal)
	Returns a CELL category for the floating-point value based on the quantization rules in q. The first rule found that applies is used. The rules are searched in the reverse order they are added to q. If no rule is found, the value is first tested against the negative infinite rule, and finally against the positive infinite rule. If none of these rules apply, the NULL-value is returned. More...

void	Rast_quant_perform_d (struct Quant q, const DCELL dcell, CELL *cell, int n)
	Returns in "cell" the quantized CELL values. More...

void	Rast_quant_perform_f (struct Quant q, const FCELL fcell, CELL *cell, int n)
	Same as Rast_quant_perform_d(), except the type. More...

struct Quant_table *	Rast__quant_get_rule_for_d_raster_val (const struct Quant *q, DCELL val)
	Returns quant rule which will be applied. More...

Detailed Description

Raster Library - Quantization rules.

The quantization table is stored as a linear array. Rules are added starting from index 0. Redundant rules are not eliminated. Rules are tested from the highest index downto 0. There are two "infinite" rules. Support is provided to reverse the order of the rules.

This program is free software under the GNU General Public License (>=v2). Read the file COPYING that comes with GRASS for details.

Author: USACERL and many others

Definition in file quant.c.

Macro Definition Documentation

◆ MAX_LOOKUP_TABLE_SIZE

#define MAX_LOOKUP_TABLE_SIZE 2048

Definition at line 27 of file quant.c.

◆ NO_DATA

#define NO_DATA (Rast_set_c_null_value(&tmp, 1), (CELL)tmp)

Definition at line 28 of file quant.c.

◆ NO_EXPLICIT_RULE

#define NO_EXPLICIT_RULE (NO_FINITE_RULE && NO_LEFT_INFINITE_RULE && NO_RIGHT_INFINITE_RULE)

Definition at line 33 of file quant.c.

◆ NO_FINITE_RULE

#define NO_FINITE_RULE (q->nofRules <= 0)

Definition at line 32 of file quant.c.

◆ NO_LEFT_INFINITE_RULE

#define NO_LEFT_INFINITE_RULE (!q->infiniteLeftSet)

Definition at line 30 of file quant.c.

◆ NO_RIGHT_INFINITE_RULE

#define NO_RIGHT_INFINITE_RULE (!q->infiniteRightSet)

Definition at line 31 of file quant.c.

◆ USE_LOOKUP

#define USE_LOOKUP 1

Definition at line 26 of file quant.c.

Function Documentation

◆ Rast__quant_get_rule_for_d_raster_val()

struct Quant_table* Rast__quant_get_rule_for_d_raster_val	(	const struct Quant *	q,
		DCELL	val
	)

Returns quant rule which will be applied.

Returns quant rule which will be applied when looking up the integer quant value for val (used when organizing fp_lookup).

Parameters

q	pointer to Quant structure which holds quant rules info
val	fp cell value

Returns: pointer to the Quant_table (color rule); NULL otherwise

Definition at line 774 of file quant.c.

References Quant_table::dHigh, Quant_table::dLow, Quant::nofRules, NULL, and Quant::table.

◆ Rast__quant_organize_fp_lookup()

int Rast__quant_organize_fp_lookup ( struct Quant * q )

Organized fp_lookup table.

Organizes fp_lookup table for faster (logarithmic) lookup time G_quant_organize_fp_lookup() creates a list of min and max for each quant rule, sorts this list, and stores the pointer to quant rule that should be used in between any 2 numbers in this list. Also it stores extreme points for 2 infinite rules, if exist. After the call to G_quant_organize_fp_lookup() instead of linearly searching through list of rules to find a rule to apply, quant lookup will perform a binary search to find an interval containing floating point value, and then use the rule associated with this interval. when the value doesn't fall within any interval, check for the infinite rules.

Parameters

q	pointer to Quant structure which holds quant rules info

Returns: 1 on success

Definition at line 90 of file quant.c.

◆ Rast_quant_add_rule()

void Rast_quant_add_rule	(	struct Quant *	q,
		DCELL	dLow,
		DCELL	dHigh,
		CELL	cLow,
		CELL	cHigh
	)

Adds a new rule to the set of quantization rules.

If dLow < dHigh the rule will be stored with the low and high values interchanged.

Note: currently no cleanup of rules is performed, i.e. redundant rules are not removed. This can't be changed because Categories structure HEAVILY depends of quant rules stored in exactly the same order they are entered. So if the cleanup or rearrangement is done in the future make a flag for add_rule whether or not to do it, then quant will not set this flag.

Parameters

q	pointer to Quant structure which holds quant rules info
dLow	minimum fp value
dHigh	maximum fp value
cLow	minimum value
cHigh	maximum value

Definition at line 469 of file quant.c.

Referenced by Rast_quantize_fp_map_range(), Rast_set_d_cat(), and Rast_set_quant_rules().

◆ Rast_quant_clear()

void Rast_quant_clear ( struct Quant * q )

Resets the number of defined rules and number of infinite rules to 0.

Parameters

q	pointer to Quant structure to be reset

Definition at line 41 of file quant.c.

References Quant::infiniteLeftSet, Quant::infiniteRightSet, and Quant::nofRules.

Referenced by Rast_quant_free(), and Rast_quant_init().

◆ Rast_quant_free()

void Rast_quant_free ( struct Quant * q )

Resets and frees allocated memory.

Resets the number of defined rules to 0 and free's space allocated for rules. Calls Rast_quant_clear().

Parameters

q	pointer to Quant structure to be reset

Definition at line 55 of file quant.c.

References Quant::active, Quant::fp_lookup, G_free(), Quant::maxNofRules, Quant::nalloc, Rast_quant_clear(), Quant::rules, Quant::table, and Quant::vals.

Referenced by Rast__quant_import(), and Rast_free_cats().

◆ Rast_quant_get_cell_value()

CELL Rast_quant_get_cell_value	(	struct Quant *	q,
		DCELL	dcellVal
	)

Returns a CELL category for the floating-point value based on the quantization rules in q. The first rule found that applies is used. The rules are searched in the reverse order they are added to q. If no rule is found, the value is first tested against the negative infinite rule, and finally against the positive infinite rule. If none of these rules apply, the NULL-value is returned.

Note: See G_quant_organize_fp_lookup() for details on how the values are looked up from fp_lookup table when it is active. Right now fp_lookup is automatically organized during the first call to Rast_quant_get_cell_value().

Parameters

q	pointer to Quant structure which holds quant rules info
dcellValue	fp cell value

Returns: cell value (integer)

Definition at line 592 of file quant.c.

Referenced by Rast_quant_perform_d(), and Rast_quant_perform_f().

◆ Rast_quant_get_ith_rule()

void Rast_quant_get_ith_rule	(	const struct Quant *	q,
		int	i,
		DCELL *	dLow,
		DCELL *	dHigh,
		CELL *	cLow,
		CELL *	cHigh
	)

Returns the i'th quantization rule.

For 0 <= i < Rast_quant_nof_rules(). A larger value for i means that the rule has been added later.

Parameters

	q	pointer to Quant structure which holds quant rules info
	i	index
[out]	dLow	minimum fp value
[out]	dHigh	maximum fp value
[out]	cLow	minimum value
[out]	cHigh	maximum value

Definition at line 327 of file quant.c.

References Quant_table::cHigh, Quant_table::cLow, Quant_table::dHigh, Quant_table::dLow, and Quant::table.

Referenced by Rast_get_ith_d_cat().

◆ Rast_quant_get_limits()

int Rast_quant_get_limits	(	const struct Quant *	q,
		DCELL *	dMin,
		DCELL *	dMax,
		CELL *	cMin,
		CELL *	cMax
	)

Returns the minimum and maximum cell and dcell values of all the ranges defined.

Extracts the minimum and maximum floating-point and integer values from all the rules (except the "infinite" rules) in q into dmin, dmax, cmin, and cmax.

Parameters

	quant	pointer to Quant structure which holds quant rules info
[out]	dmin	minimum fp value
[out]	dmax	maximum fp value
[out]	cmin	minimum value
[out]	cmax	maximum value

Returns: -1 if q->truncate or q->round are true or after Rast_quant_init (), or any call to Rast_quant_clear () or Rast_quant_free() no explicit rules have been added. In this case the returned minimum and maximum CELL and DCELL values are null.; 1 if there are any explicit rules; 0 if there are no explicit rules (this includes cases when q is set to truncate or round map), and sets dmin, dmax, cmin, and cmax to NULL.

Definition at line 281 of file quant.c.

References Quant::cMax, Quant::cMin, Quant::dMax, Quant::dMin, NO_EXPLICIT_RULE, Rast_set_c_null_value(), and Rast_set_d_null_value().

Referenced by Rast_read_range(), and Rast_write_quant().

◆ Rast_quant_get_neg_infinite_rule()

int Rast_quant_get_neg_infinite_rule	(	const struct Quant *	q,
		DCELL *	dLeft,
		CELL *	c
	)

Returns in "dLeft" and "c" the rule values.

For the negative infinite interval (see Rast_quant_set_neg_infinite_rule()).

Parameters

	q	pointer to Quant structure which holds quant rules info
[out]	dLeft	fp value
[out]	c	value

Returns: 0 if this rule is not defined; 1 otherwise

Definition at line 390 of file quant.c.

Referenced by Rast_set_quant_rules().

◆ Rast_quant_get_pos_infinite_rule()

int Rast_quant_get_pos_infinite_rule	(	const struct Quant *	q,
		DCELL *	dRight,
		CELL *	c
	)

Returns in "dRight" and "c" the rule values.

For the positive infinite interval (see Rast_quant_set_pos_infinite_rule()).

Parameters

	q	pointer to Quant structure which holds quant rules info
[out]	dRight	fp value
[out]	c	value

Returns: 0 if this rule is not defined; 1 otherwise

Definition at line 438 of file quant.c.

Referenced by Rast_set_quant_rules().

◆ Rast_quant_init()

void Rast_quant_init ( struct Quant * quant )

Initialize the structure.

Initializes the q struct.

Parameters

quant pointer to Quant structure to be initialized

Definition at line 175 of file quant.c.

References Quant::active, Quant::fp_lookup, Quant::maxNofRules, Rast_quant_clear(), Quant::round_only, and Quant::truncate_only.

Referenced by Rast_init_cats(), Rast_quantize_fp_map_range(), Rast_read_quant(), Rast_round_fp_map(), Rast_set_quant_rules(), and Rast_truncate_fp_map().

◆ Rast_quant_is_round()

int Rast_quant_is_round ( const struct Quant * quant )

Returns whether or not quant rules are set to round map.

Parameters

quant pointer to Quant structure which holds quant rules info

Returns: 1 is round; 0 not round

Definition at line 204 of file quant.c.

References Quant::round_only.

Referenced by Rast_read_range().

◆ Rast_quant_is_truncate()

int Rast_quant_is_truncate ( const struct Quant * quant )

Returns whether or not quant rules are set to truncate map.

Parameters

quant pointer to Quant structure which holds quant rules info

Returns: 1 if truncate is enable; 0 if not truncated

Definition at line 192 of file quant.c.

References Quant::truncate_only.

Referenced by Rast_read_range().

◆ Rast_quant_nof_rules()

int Rast_quant_nof_rules ( const struct Quant * q )

Returns the number of quantization rules defined.

This number does not include the 2 infinite intervals.

Parameters

q	pointer to Quant structure which holds quant rules info

Returns: number of quantization rules

Definition at line 309 of file quant.c.

References Quant::nofRules.

Referenced by Rast3d_write_cats(), and Rast_get_next_marked_d_cat().

◆ Rast_quant_perform_d()

void Rast_quant_perform_d	(	struct Quant *	q,
		const DCELL *	dcell,
		CELL *	cell,
		int	n
	)

Returns in "cell" the quantized CELL values.

Returns in "cell" the quantized CELL values corresponding to the DCELL values stored in "dcell". the number of elements quantized is n. quantization is performed by repeated application of Rast_quant_get_cell_value().

Parameters

	q	pointer to Quant structure which holds quant rules info
	dcell	pointer to fp cell values array
[out]	cell	pointer cell values array
	n	number of cells

Definition at line 715 of file quant.c.

References Rast_is_d_null_value, Rast_quant_get_cell_value(), and Rast_set_c_null_value().

◆ Rast_quant_perform_f()

void Rast_quant_perform_f	(	struct Quant *	q,
		const FCELL *	fcell,
		CELL *	cell,
		int	n
	)

Same as Rast_quant_perform_d(), except the type.

Parameters

	q	pointer to Quant structure which holds quant rules info
	fcell	pointer to fp cell values array
[out]	cell	pointer cell values array
	n	number of cells

Definition at line 735 of file quant.c.

References Rast_is_f_null_value, Rast_quant_get_cell_value(), and Rast_set_c_null_value().

◆ Rast_quant_reverse_rule_order()

void Rast_quant_reverse_rule_order ( struct Quant * q )

Rreverses the order in which the qunatization rules are stored.

Parameters

q	pointer to Quant rules which holds quant rules info

Definition at line 513 of file quant.c.

◆ Rast_quant_round()

void Rast_quant_round ( struct Quant * quant )

Sets the quant rules to perform simple rounding on floats.

Sets the quant for q rules to perform simple rounding on floats.

Parameters

quant pointer to Quant structure which holds quant rules info

Definition at line 230 of file quant.c.

References Quant::round_only.

Referenced by Rast_round_fp_map().

◆ Rast_quant_set_neg_infinite_rule()

void Rast_quant_set_neg_infinite_rule	(	struct Quant *	q,
		DCELL	dLeft,
		CELL	c
	)

Defines a rule for values "dLeft" and smaller.

Values in this range are mapped to "c" if none of the "finite" quantization rules applies.

Parameters

q	pointer to Quant structure which holds quant rules info
dLeft	fp value
c	value

Definition at line 364 of file quant.c.

Referenced by Rast_set_quant_rules().

◆ Rast_quant_set_pos_infinite_rule()

void Rast_quant_set_pos_infinite_rule	(	struct Quant *	q,
		DCELL	dRight,
		CELL	c
	)

Defines a rule for values "dRight" and larger.

Values in this range are mapped to "c" if none of the "finite" quantization rules or the negative infinite rule applies.

Parameters

q	pointer to Quant structure which holds quant rules info
dRight	fp value
c	value

Definition at line 412 of file quant.c.

Referenced by Rast_set_quant_rules().

◆ Rast_quant_truncate()

void Rast_quant_truncate ( struct Quant * quant )

Sets the quant rules to perform simple truncation on floats.

Sets the quant for q rules to perform simple truncation on floats.

Parameters

quant pointer to Quant structure which holds quant rules info

Definition at line 217 of file quant.c.

References Quant::truncate_only.

Referenced by Rast_set_quant_rules(), and Rast_truncate_fp_map().

Macros

Functions

Detailed Description

Macro Definition Documentation

◆ MAX_LOOKUP_TABLE_SIZE

◆ NO_DATA

◆ NO_EXPLICIT_RULE

◆ NO_FINITE_RULE

◆ NO_LEFT_INFINITE_RULE

◆ NO_RIGHT_INFINITE_RULE

◆ USE_LOOKUP

Function Documentation

◆ Rast__quant_get_rule_for_d_raster_val()

◆ Rast__quant_organize_fp_lookup()

◆ Rast_quant_add_rule()

◆ Rast_quant_clear()

◆ Rast_quant_free()

◆ Rast_quant_get_cell_value()

◆ Rast_quant_get_ith_rule()

◆ Rast_quant_get_limits()

◆ Rast_quant_get_neg_infinite_rule()

◆ Rast_quant_get_pos_infinite_rule()

◆ Rast_quant_init()

◆ Rast_quant_is_round()

◆ Rast_quant_is_truncate()

◆ Rast_quant_nof_rules()

◆ Rast_quant_perform_d()

◆ Rast_quant_perform_f()

◆ Rast_quant_reverse_rule_order()

◆ Rast_quant_round()

◆ Rast_quant_set_neg_infinite_rule()

◆ Rast_quant_set_pos_infinite_rule()

◆ Rast_quant_truncate()