NAME

glGetMinmax - get minimum and maximum pixel values

C SPECIFICATION

void ggllGGeettMMiinnmmaaxx( GLenum _t_a_r_g_e_t,
                  GLboolean _r_e_s_e_t,
                  GLenum _f_o_r_m_a_t,
                  GLenum _t_y_p_e_s,
                  GLvoid _*_v_a_l_u_e_s )

PARAMETERS

_t_a_r_g_e_t
Must be GGLL__MMIINNMMAAXX.
_r_e_s_e_t
If GGLL__TTRRUUEE, all entries in the minmax table that are actually returned are reset to their initial values. (Other entries are unaltered.) If GGLL__FFAALLSSEE, the minmax table is unaltered.
_f_o_r_m_a_t
The of the data to be returned in _v_a_l_u_e_s. Must be one of GGLL__RREEDD, GGLL__GGRREEEENN, GGLL__BBLLUUEE, GGLL__AALLPPHHAA, GGLL__RRGGBB, GGLL__BBGGRR, GGLL__RRGGBBAA, GGLL__BBGGRRAA, GGLL__LLUUMMIINNAANNCCEE, or GGLL__LLUUMMIINNAANNCCEE__AALLPPHHAA.
_t_y_p_e_s
The type of the data to be returned in _v_a_l_u_e_s. Symbolic constants GGLL__UUNNSSIIGGNNEEDD__BBYYTTEE, GGLL__BBYYTTEE, GGLL__BBIITTMMAAPP, GGLL__UUNNSSIIGGNNEEDD__SSHHOORRTT, GGLL__SSHHOORRTT, GGLL__UUNNSSIIGGNNEEDD__IINNTT, GGLL__IINNTT, GGLL__FFLLOOAATT, GGLL__UUNNSSIIGGNNEEDD__BBYYTTEE__33__33__22, GGLL__UUNNSSIIGGNNEEDD__BBYYTTEE__22__33__33__RREEVV, GGLL__UUNNSSIIGGNNEEDD__SSHHOORRTT__55__66__55, GGLL__UUNNSSIIGGNNEEDD__SSHHOORRTT__55__66__55__RREEVV, GGLL__UUNNSSIIGGNNEEDD__SSHHOORRTT__44__44__44__44, GGLL__UUNNSSIIGGNNEEDD__SSHHOORRTT__44__44__44__44__RREEVV, GGLL__UUNNSSIIGGNNEEDD__SSHHOORRTT__55__55__55__11, GGLL__UUNNSSIIGGNNEEDD__SSHHOORRTT__11__55__55__55__RREEVV, GGLL__UUNNSSIIGGNNEEDD__IINNTT__88__88__88__88, GGLL__UUNNSSIIGGNNEEDD__IINNTT__88__88__88__88__RREEVV, GGLL__UUNNSSIIGGNNEEDD__IINNTT__1100__1100__1100__22, and GGLL__UUNNSSIIGGNNEEDD__IINNTT__22__1100__1100__1100__RREEVV are accepted.
_v_a_l_u_e_s
A pointer to storage for the returned values.

DESCRIPTION

ggllGGeettMMiinnmmaaxx returns the accumulated minimum and maximum pixel values (computed on a per-component basis) in a one-dimensional image of width 2. The first set of return values are the minima, and the second set of return values are the maxima. The of the return values is determined by _f_o_r_m_a_t, and their type is determined by _t_y_p_e_s.

No pixel transfer operations are performed on the return values, but pixel storage modes that are applicable to 1-dimensional images are performed. Color components that are requested in the specified _f_o_r_m_a_t, but that are not included in the internal of the minmax table, are returned as zero. The assignment of internal color components to the components requested by _f_o_r_m_a_t are as follows:

center;
lb lb
l l.
_
Internal ComponentResulting Component
_
Red               Red
Green             Green
Blue              Blue
Alpha             Alpha
Luminance         Red
_

If _r_e_s_e_t is GGLL__TTRRUUEE, the minmax table entries corresponding to the return values are reset to their initial values. Minimum and maximum values that are not returned are not modified, even if _r_e_s_e_t is GGLL__TTRRUUEE.

NOTES

ggllGGeettMMiinnmmaaxx is present only if GGLL__AARRBB__iimmaaggiinngg is returned when ggllGGeettSSttrriinngg is called with an argument of GGLL__EEXXTTEENNSSIIOONNSS.

ERRORS

GGLL__IINNVVAALLIIDD__EENNUUMM is generated if _t_a_r_g_e_t is not GGLL__MMIINNMMAAXX.

GGLL__IINNVVAALLIIDD__EENNUUMM is generated if _f_o_r_m_a_t is not one of the allowable values.

GGLL__IINNVVAALLIIDD__EENNUUMM is generated if _t_y_p_e_s is not one of the allowable values.

GGLL__IINNVVAALLIIDD__OOPPEERRAATTIIOONN is generated if ggllGGeettMMiinnmmaaxx is executed between the execution of ggllBBeeggiinn and the corresponding execution of ggllEEnndd.

GGLL__IINNVVAALLIIDD__OOPPEERRAATTIIOONN is generated if _t_y_p_e_s is one of GGLL__UUNNSSIIGGNNEEDD__BBYYTTEE__33__33__22, GGLL__UUNNSSIIGGNNEEDD__BBYYTTEE__22__33__33__RREEVV, GGLL__UUNNSSIIGGNNEEDD__SSHHOORRTT__55__66__55, or GGLL__UUNNSSIIGGNNEEDD__SSHHOORRTT__55__66__55__RREEVV and _f_o_r_m_a_t is not GGLL__RRGGBB.

GGLL__IINNVVAALLIIDD__OOPPEERRAATTIIOONN is generated if _t_y_p_e_s is one of GGLL__UUNNSSIIGGNNEEDD__SSHHOORRTT__44__44__44__44, GGLL__UUNNSSIIGGNNEEDD__SSHHOORRTT__44__44__44__44__RREEVV, GGLL__UUNNSSIIGGNNEEDD__SSHHOORRTT__55__55__55__11, GGLL__UUNNSSIIGGNNEEDD__SSHHOORRTT__11__55__55__55__RREEVV, GGLL__UUNNSSIIGGNNEEDD__IINNTT__88__88__88__88, GGLL__UUNNSSIIGGNNEEDD__IINNTT__88__88__88__88__RREEVV, GGLL__UUNNSSIIGGNNEEDD__IINNTT__1100__1100__1100__22, or GGLL__UUNNSSIIGGNNEEDD__IINNTT__22__1100__1100__1100__RREEVV and _f_o_r_m_a_t is neither GGLL__RRGGBBAA nor GGLL__BBGGRRAA.

SEE ALSO

ggllMMiinnmmaaxx((33GG)), ggllRReesseettMMiinnmmaaxx((33GG)), ggllGGeettMMiinnmmaaxxPPaarraammeetteerr((33GG))