Topic       : The ATARI Compendium
Author      : Scott Sanders / JAY Software
Version     : 1.25 (20/6/2003)
Subject     : Documentation
Nodes       : 1117
Index Size  : 32614
HCP-Version : 6
Compiled on : Atari
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View Ref-Fileobjc_draw()
Object Library
objc_offset()                                                           AES

Syntax

WORD objc_offset( tree, obj, ox, oy )
OBJECT *tree;
WORD obj;
WORD *ox, *oy;

Function       objc_offset() calculates the true screen coordinates of an
               object.

Opcode         44 (0x2C)

Availability   All AES versions.

Parameters     tree specifies the object tree containing obj. The WORDs
               pointed to by ox and oy will be filled in with the true X
               and Y screen position of object obj.

Binding        intin[0] = obj;

               addrin[0] = tree;

               crys_if(0x2C);

               *ox = intout[1];
               *oy = intout[2];

               return intout[0];

Return Value   objc_offset() returns 0 if an error occurred or non-zero
               otherwise.

Comments       The ob_x and ob_y structure members of objects give an
               offset from their parent as opposed to true screen
               location. This call is used to determine a true screen
               coordinate.
               The values returned by objc_offset() coupled with the
               ob_width and ob_height members do not take into account
               negative borders, shadowing, or sculpturing. When redrawing
               an object you are responsible for using these values to and
               the object's state to compensate for a correct clipping
               rectangle.

See Also       objc_draw()

Group          Object Library