NJB_Get_EAX_Type(3)

Usage

#include <libnjb.h>

extern int njb_error

void NJB_Reset_Get_EAX_Type(njb_t *njb)

njb_eax_t *NJB_Get_EAX_Type(njb_t *njb)

void NJB_Destroy_EAX_Type(njb_eax_t *eax)

Library

libnjb

Overview

NJB_Get_EAX_Type is used to fetch the available EAX control types and min/max values for the current device. Different devices present different number and types of controls, and e.g. GUI:s must therefore be built dynamically by using these types as prototypes.

NJB_Reset_Get_EAX_Type should be called first to initialize the fetch operation.

Any retrieved and used types must be destroyed using NJB_Destroy_EAX_Type afterwards.

The values can thereafter be modified using the NJB_Adjust_EAX(3) function.

When the last EAX type has been fetched, NJB_Get_EAX_Type returns a NULL pointer.

Return values

A njb_eax_t object is returned from a successful query. If no more tags remain, or an error is encountered, a NULL pointer is returned.

Eax type structure

The EAX type struct has the following form:

typedef struct {
u_int16_t number;
char *name;
u_int8_t exclusive;
u_int8_t group;
u_int8_t selectable;
u_int16_t current_selectionvalue;
u_int16_t min_selectionvalue;
u_int16_t max_selectionvalue;
char **selection_names;
u_int8_t scaleable;
int16_t current_scalevalue;
int16_t min_scalevalue;
int16_t max_scalevalue; } njb_eax_t;

number: The unique ID number of this EAX type, which shall be used in all calls to NJB_Adjust_EAX(3).

name: The name of this EAX type, as a zero-terminated string.

exclusive: The "exclusive" attribute signifies if this effect can be used in parallell with other EAX effects, GUI:s shall make sure all other exclusive effects are reset to default values when one exclusive effect is chosen. A value of 0 signifies that the effect is not exclusive, any other value means it is exclusive.

group: The visual group for this effect - effects appearing after each other are grouped if their group numbers are identical. This is used e.g. when grouping controls in a GUI.

selectable: If this value is different from 0 it means that this effect has several selectable patches.

current_selectionvalue: If the effect has selectable patches, this is the current patch index selected.

min_selectionvalue: If the effect has selectable patches, this is the minimum value for selecting a patch with NJB_Adjust_EAX(3).

max_selectionvalue: If the effect has selectable patches, this is the maximum value for selecting a patch with NJB_Adjust_EAX(3).

selection_names: If the effect has selectable patches, this is an array of names for the individual patches, indexed from 0 and upwards. The expression max_selectionvalue - min_selectionvalue + 1 gives the number of available patches. (The zero:th value is thus included.)

scaleable: If this value is different from 0 the effect can be slided on a scale. (It is in theory possible for an effect to be both selectable and scaleable though this phenomenon has not occured in the wild.) A scaleable effect can take both negative and positive values.

current_scalevalue: If the effect can be slided on a scale, this indicates the current value of the value on that scale. Observe that this number can be negative!

min_scalevalue: If the effect can be slided on a scale, this indicates the minimum value the value can take on that scale. Observe that this number can be negative!

max_scalevalue: If the effect can be slided on a scale, this indicates the maximum value the value can take on that scale. This number is typically not negative, though there is no guarantee that it will never be.

Referred to by