!Draw: save rectangular grid options

I am looking at adding a new feature to !Draw in time for RISC OS 5.30. It was raised in ticket #295.

One can ask for a rectangular grid by y-only options in the menu. However, this information is not saved in a draw file, so when you reload you’ll go back to a square grid.

The grid items that are saved (See PRM 4-471):

• Show
• Lock
• Auto adjust
• Inch vs cm
• Spacing
• Subdivision
• Rectangular vs isometric

These are saved in an ‘Options’ object (type 11) alongside paper size etc.

The items not saved are:

• Colour
• Inch vs cm (y-only)
• Spacing (y-only)
• Subdivision (y-only)

Note that Choices for !Draw does save colour (0-15), but doesn’t save the y-only settings. This work will not affect Choices.

I propose a new Draw object type.

Options for rectangular grid (object type 16)
---------------------------------------------

Header - bounding box reserved, set to all zero.
Data
Size
8    - grid y-spacing (floating point)
4    - grid y-subdivision
4    - grid y-units (zero inches, non-zero centimetres)
4    - grid colour (0 - 15, otherwise &BBGGRR00)

At this stage 24-bit grid colours wouldn’t be supported by Draw (e.g. it could treat it as the default blue), but it seemed sensible to have in the object definition in case we want this in the future.

The first object of type 16 in a file will be used and all later ones ignored.

Might I suggest you first take a look at DrawPlus to see if this hasn’t already been done?

http://www.keelhaul.me.uk/acorn/oss/

I am surprised someone hasn’t had go at a Linux version of the Draw+ family.

Thanks for pointing that out. DrawPlus saves its settings in an object of type 101. Looking quickly through the source I didn’t see that it saves a rectangular grid.