editor documentation

Dependencies

• [2] N2NUGNN4 include a brief reference enabling many useful apps

Change contents

• edit in reference.md at line 184
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  +

  + ### text editor primitives
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  + The text-editor widget includes extremely thorough automated tests to give you

  + early warning if you break something.

  +

  + * `state = edit.initialize_state(top, left, right, font_height, line_height)` --

  + returns an object that can be used to render an interactive editor widgets

  + for text and line drawings starting at `y=top` on the app window, between

  + `x=left` and `x=right`. Wraps long lines at word boundaries where possible,

  + or in the middle of words (no hyphenation yet) when it must.

  +

  + * `edit.quit()` -- calling this ensures any final edits are flushed to disk

  + before the app exits.

  +

  + * `edit.draw(state)` -- Call this from `App.draw` to display the current

  + editor state on the app window as requested in the call to

  + `edit.initialize_state` that created `state`.

  +

  + * `edit.update(state, dt)` -- call this from `App.update` to periodically auto

  + saves editor contents to disk.

  +

  + * `edit.mouse_press(state, x,y, mouse_button)` and `edit.mouse_release(x,y,

  + mouse_button)` -- call these to position the cursor or select some text.

  +

  + * `edit.mouse_wheel_move(state, dx,dy)` -- call this to scroll the editor in

  + response to a mouse wheel.

  +

  + * `edit.keychord_press(state, chord, key)` and `edit.key_release(state, key)`

  + -- call these to perform some standard shortcuts: insert new lines,

  + backspace/delete, zoom in/out font size, cut/copy/paste to and from the

  + clipboard, undo/redo.

  +

  + * `edit.text_input(state, t)` -- call this to insert keystrokes into the

  + buffer.

  +

  + * `Text.redraw_all(state)` -- call this to clear and recompute any cached

  + state as the cursor moves and the buffer scrolls.

  +

  + If you need more precise control, look at the comment at the top of

  + `edit.initialize_state` in edit.lua. In brief, the widget contains an array of

  + `lines`. Positions in the buffer are described in _schema-1_ locations

  + consisting of a `line` index and a code-point `pos`. We may also convert them

  + at times to _schema-2_ locations consisting of a `line`, `screen_line` and

  + `pos` that better indicates how long lines wrap. Schema-2 locations are never

  + persisted, just generated as needed from schema-1. Important schema-1

  + locations in the widget are `cursor1` describing where text is inserted or

  + deleted and `screen_top1` which specifies how far down the lines is currently

  + visible on screen.

  +