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3. Resource file format

A resource file has the name extension .grc. That is not required, but it will make for an easier recognition of the file's purpose. Also, cl65 recognizes those files. grc65's parser is very weak at the moment; so, read the comments carefully, and write resources exactly as they are written here. Look out for CAPS and small letters. Everything after a ';' until the end of the line is considered as a comment and ignored. See the included commented example .grc file for a better view of the situation.

3.1 Menu definition

MENU menuName leftx,topy <ORIENTATION> {
    "item name 1" <MENU_TYPE> pointer
    "item name x" <MENU_TYPE> pointer
The definition starts with the keyword MENU, then comes the menu's name, which will be represented in C as const void. Then are the co-ordinates of the top left corner of the menu box. The position of the bottom right corner is estimated, based on the length of item names and the menu's orientation. It means that the menu box always will be as large as it should be. Then, there's the orientation keyword; it can be either HORIZONTAL or VERTICAL. Between { and }, there's the menu's content. It consists of item definitions. First is an item name -- it has to be in quotes. Next is a menu-type bit. It can be MENU_ACTION or SUB_MENU; either of them can be combined with the DYN_SUB_MENU bit (see the GEOSLib documentation for descriptions of them). You can use C logical operators in expressions, but you have to do it without spaces. So a dynamically created submenu will be something like:
"dynamic" SUB_MENU|DYN_SUB_MENU create_dynamic
The last part of the item definition is a pointer which can be any name that is present in the C source code that includes the generated header. It can point to a function or to another menu definition.

If you are doing sub(sub)menu definitions, remember to place the lowest level definition first, and the top-level menu as the last one. That way the C compiler won't complain about unknown names.

3.2 Header definition

HEADER <GEOS_TYPE> "dosname" "classname" "version" {
    author    "Joe Schmoe"
    info      "This is my killer-app!"
    date      yy mm dd hh ss
    dostype   SEQ
    mode      any
    structure SEQ
    icon      "sprite.raw"
The header definition describes the GEOS header sector which is unique to each file. The definition starts with the keyword HEADER, then goes the GEOS file-type. You can use only APPLICATION here at the moment. Then, there are (each one in quotes) the DOS file-name (up to 16 characters), the GEOS Class name (up to 12 characters), and the version info (up to 4 characters). The version should be written as "Vx.y", where x is the major, and y is the minor, version number. Those fields, along with both braces, are required. The lines between braces are optional, and will be replaced by default and current values. The keyword author and its value in quotes name the programmer, and can be up to 63 bytes long. info (in the same format) can have up to 95 characters. If the date field is omitted, then the time of that compilation will be placed into the header. Note that, if you do specify the date, you have to write all 5 numbers. The dostype can be SEQ, PRG, or USR. USR is used by default; GEOS usually doesn't care. The mode can be any, 40only, 80only, or c64only; and, it describes system requirements. any will work on both 64-GEOS and 128-GEOS, in 40- and 80-column modes. 40only will work on 128-GEOS in 40-column mode only. 80only will work on only 128-GEOS in 80-column mode, and c64only will work on only 64-GEOS. The default value for structure is SEQ (sequential). You can put VLIR there, too; but then, you also have to put in a third type of resource -- a memory definition. The value of icon is a quoted file-name. The first 63 bytes of this file are expected to represent a standard monochrome VIC sprite. The file gets accessed when the generated assembly source is being processed by ca65. Examples for programs generating such files are Sprite Painter, SpritePad and the sp65 sprite and bitmap utility. The default icon is an empty frame internally represented in the generated assembly file.

3.3 Memory definition

    stacksize   0x0800
    overlaysize 0x2000
    overlaynums 0 1 2 4 5
The memory definition is unique to each file and describes several attributes related to the memory layout. It consists of the keyword MEMORY followed by braces which contain optional lines. The value of stacksize can be either decimal (e.g. 4096) or hexadecimal with a 0x prefix (e.g. 0x1000). The default value of 0x400 comes from the linker configuration file. The value of backbuffer can be either yes or no. The further means that the application uses the system-supplied background screen buffer while the latter means that the program uses the memory of the background screen buffer for own purposes. The default value of yes comes from the linker configuration file. If the structure in the header definition is set to the value VLIR then it is possible and necessary to provide here the attributes of the VLIR overlays. overlaysize defines the maximal size for all VLIR records but number 0. It can be either decimal (e.g. 4096) or hexadecimal with a 0x prefix (e.g. 0x1000). overlaynums defines the VLIR record numbers used by the application. Skipped numbers denote empty records. In the example, record number 3 is missing. Read this description for details.

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