# Advanced OCP Art Studio internal data structures

This document describes some of the internal structures used by OCP Advanced Art Studio. Description of OCP Art Studio's resource data format: buttons, menu items etc are defined in this way:

These data structures are collected into a list:

Offset | Length | Description
--- | --- | ---
0 | 2 | x position in pixels (0-639) (note 2)
1 | 1 | Y position in lines (0-199)
2 | 2 | width of element
4 | 1 | height of element
5 | 2 | ??
7 | 2 | address of function to call when clicked
9 | 1 | ?? if 0x02c draws horizontal lines in button
10 | 1 | bit 7,6: if 0, no border is shown, if !=0 border is shown bit 5,4: ?? bit 3,2: foreground colour (border & text) bit 1,0: background colour (note 3)
11 | 1 | ??
12 | 1 | bit 7,6: button type (bit 7=1, bit 6=1: toggle button) bit 2: button state 0x0c4 = toggle button 0x0a0 = tick/cross aligned to right side
13 | x | 0x0ff or ascii characters. Last char has bit 7 set. codes>0x07f codes<0 0x0c0 control code? control code 0x02: text with position 2 bytes x position, 1 byte y position text last char of last string has bit 7 set.

1. Horizontal coordinates are in the range 0-639. These define a "resolution" equivalent to CPC's mode 2. The vertical coordinates are in the range 0-199.
2. If this value is -1, then this indicates the end of the list.
3. If foreground and background are the same, then no button is displayed