Single-Operator Functions

Single-operator functions provide a C language interface to the individual operators of the PostScript language. The specification for a single-operator function is identical to that of the PostScript operator it represents. The PostScript Language Reference Manual, Second Edition, by Adobe Systems Incorporated, provides the specifications of all standard PostScript operators. Also refer to the Display PostScript System, Client Library Reference Manual, by Adobe Systems Incorporated. Listed below are single-operator functions that correspond to operators found in OpenStep but not in the standard implementation of the PostScript language.

These functions have either a PS or a DPS prefix. For every single-operator function with a PS prefix, there's a corresponding single-operator function with a DPS prefix. The PS and DPS functions are identical except that DPS functions take an additional (first) argument that represents the PostScript execution context.

Besides using standard C language types, some single-operator functions use userobjectan int that refers to the value returned by DPSDefineUserObject().

In the function descriptions below, x and y refer to the origin of source rectangles, and w and h refer to the width and height of the source rectangles. gstateNum refers to the graphics state (gstate) of the source rectangle. dx and dy refer to the origin of the destination for the compositing or dissolving operation. op refers to the specific compositing operation. a or alpha refers to the coverage component used for compositing operations.

PS Prefix Functions

void PScomposite(float x, float y, float w, float h, int gstateNum, float dx, float dy, int op)

void PScompositerect(float x, float y, float w, float h, int op)

void PScurrentalpha(float *alpha)

void PSdissolve(float x, float y, float w, float h, int gstateNum, float dx, float dy, float delta)

void PSsetalpha(float a)

DPS Prefix Functions

void DPScomposite(DPSContext ctxt, float x, float y, float w, float h, int gstateNum, float dx, float dy, int op)

void DPScompositerect(DPSContext ctxt, float dx, float dy, float w, float h, int op)

void DPScurrentalpha(DPSContext ctxt, float *pcoverage)

void DPSdissolve(DPSContext ctxt, float x, float y, float w, float h, int gstateNum, float dx, float dy, float delta)

void DPSsetalpha(DPSContext ctxt, float a)