# pcb-rnd - user manual

## 5.4. pcb-rnd GUI (common)

### 5.4.1. keyboard bindings

The same default menu file is used in all GUI HIDs. It comes with multi-stroke key bindings, plus only a very few, alternative keys that use modifiers (mostly ctrl). A multi-stroke key binding requires the user to type in a sequence of keys, e.g. pressing 't' and 'l' (written as {t l} in this document) will make pcb-rnd switch to the line tool. There are two major advanatges of using multi-stroke instead of modifiers:

- It is often easier to remember them, e.g. the above {t l} can be memorized as 'tool, line', and it is similar to {t a} for 'tool, arc' and {t, p} for 'tool, polygon'. The old menu file had these as F2, F3 and F6. They could be also ctrl+l, ctrl+a, ctrl+p, but then if another group of functionality required similar letters, like l for list or p for print, they would ned to use a different modifier, e.g. alt+l and alt+p. At the end there would be a random set of alt, ctrl, shift combinations that are real hard to remember - this is exactly how the old (pre-2.0.0) default menu file was.
- Since pcb-rnd is a graphical CAD, the mouse is an inportant user input device. Most users will have one hand constantly on the mouse. It is much faster to type a sequence of 2 or rarely 3 plain keys with one hand than doing the acrobatics for something like ctrl+t or even alt+shif+u.

Most multi-stroke keys, especially the commonly used ones, use two strokes. Some rarely used feature will require three. The system can be regarded as a tree: e.g. in a 3-key sequence, starting from the root (nothing is pressed) the first key select a chapter, the second key narrows it down to a subchapter and the third key (leaf) selects the actual action within the subchapter. The current key tree is accessible in a large svg drawing or in a script-digestable flat list.

### 5.4.2 Grid

The grid is an imaginary set of points over the drawing. The crosshair can snap to the grid, helping the user to keep coordinates of objects distributed evenly.

The only grid geometr pcb-rnd supports is a regular, rectangular grid, that is: grid points spaced evenly in x and y directions, aligned into horizontal and vertical rows. The grid also has an optional offset in x and y directions (which is usually set to 0;0).

The grid spacing (distance between grid points) is user configurable. There are two methods managing the grid.

### 5.4.3. Preset grid

The configuration system has a node called editor/grids, which is an ordered list of preset grid settings. This list should contain the grid settings preferred by the user, or preferred for the given design. Since this is a configuration item, the usual conf rules apply (e.g. local grid config can be saved in the project's config or even in the board file).

While drawing, the user can use the {g b} and {g f} hotkeys, or the shorter [ and ] keys to step the current grid, selecting the previous or next item from the list. The grid sizes menu will always have the currently selected item checked.

If the user changes grid properties directly, the new grid setup will most likely not match any of the presets and the check mark is gone from the menu. However, pcb-rnd remember the last used preset menu and upon the next stepping it will move from the last selected preset grid.

The format for the grid configuration is a simple text that lists an optional grid name, the mandatory grid size, the optional offset and optionally instructs pcb-rnd to also switch units when the grid is activated. The full syntax, optional parts written in [] is:

    [name:]size[@offs][!unit]

(The optional name has no functionality other than being displayed, helping the user to remember the purpose of the grid.)

Examples:

grid spec | description
--- | ---

    10 mil

anonymous 10 mil grid with no offset

    1.5 mm

anonymous 1.5 mm grid with no offset

    20 mil@1mil;-3mil

20 mil grid with a horizontal offset of +1 mil and vertical offset of -3 mil

    1.5 mm!mm

1.5 mm grid; when activated, switch untis to mm

    placing dips:100 mil

named grid

    leds:1mm@0.5mm;-0.1mm!mm

all the above features, combined

### 5.4.4. Custom grid

The current grid is stored as grid distance and x;y offset. Regardless of the configured presets, these properties of the current grid can be changed any time, using the SetValue() action or using the menu.