Blades of Exile Documentation			{#mainpage}
=============================

This is the documentation for parts of the Blades of Exile source code.
Currently it covers only the dialog engine.

Defining a Dialog
=================

Creating a new dialog consists of two basic steps: first, you have to
create the XML dialog definition, and then you need to write the code to
set it up and implement all the required callbacks.

The format of the XML dialog files is defined by the schema in
_rsrc/schemas/dialog.xsd_, but this document will cover what you need to
know in a more readable manner. A dialog definition consists of a
`<dialog>` tag containing any number of tags representing various dialog
controls. Each tag will be documented in some detail below.

Common Attributes
-----------------

The following attributes are allowed on all or most elements:

* `top`, `left`, `width`, `height` - Specifies the location and bounding
rect of the control within the dialog. All non-container controls
support these attributes, and in fact the `top` and `left` attributes
are required. Some controls may ignore the `width` and `height`
attributes.
* `def-key`, `key-mod` - Specifies the default keyboard shortcut for the
control. See **Keyboard Shortcuts** below for more information on the
format of these attributes.
* `font`, `size`, `color`, `colour` - Specifies text attributes of the
control. See **Text Formatting** below for details on accepted values.
* `name` - Give the control a unique identifier which you can use to
refer to it from the code. If omitted, the code will generate a random
identifier. All controls support this attribute.
* `fromlist` - Currently unused, but the intended use is to look up the
control's text value in a string list (in _rsrc/strings_)

The `<dialog>` tag
------------------

The `<dialog>` tag accepts the following attributes:

* `skin` - Specify the dialog's background pattern. Currently only
accepts `dark` or `light`. If omitted, a default is used which depends
on whether the dialog is used in the game or the scenario editor. As
such, this attribute should be omitted for most dialogs.
* `debug` - This attribute is completely ignored by the game, but if set
to `true`, the XSL stylesheet will draw the bounding rects of LEDs and
other debug information.
* `fore` - The default text colour. Generally this shouldn't be needed.
* `defbtn` - The ID (`name` attribute) of the default button. This is an
IDREF, so it must exist in the dialog.

The `<text>` tag
----------------

The `<text>` tag can be used either for a non-editable text message or
for a frame to group elements. Within a `<text>` tag, you can use a
`<br>` tag to insert a line break. See **Whitespace** for an explanation
of the intended whitespace collapsing behaviour.

The `<text>` tag accepts the following attributes:

* `framed` - Specifies whether a frame is drawn around the text. Can be
either `true` or `false`; defaults to `false`.
* `clickable` - Specifies that the text is clickable. This attribute is
useless, as clickability is determined solely by having a click handler
set in the code.
* `fromlist`, `font`, `size`, `color`, `colour`, `def-key`, `key-mod` -
See **Common Attributes** above.

The `<button>` tag
------------------

The `<button>` tag decribes a non-LED button. It can contain label text
as well as an optional empty `<key>` element. It does not support the
`<br>` tag. The `<key>` element was intended as a way of inserting a
readable form of the button's keyboard shortcut, but at present this is
unimplemented.

The `<button>` tag accepts the following attributes:

* `name` - This attribute is required on the `<button>` tag. See
**Common Attributes** above.
* `type` - Specifies the type of button. This attribute is required.
* `wrap` - Specifies whether to wrap the text on the button. Can be
either `true` or `false`; defaults to `false`.
* `fromlist`, `def-key`, `key-mod` - See **Common Attributes** above.

The possible values for the `type` attribute are:

* `small` - A small 23x23 button.
* `regular` - A normal-sized 63x23 button.
* `large` - A large 102x23 button.
* `help` - A small 16x13 help button - a white bubble with a ? mark.
* `left` - A normal-sized 63x23 button with a left-pointing arrow.
* `right` - A normal-sized 63x23 button with a right-pointing arrow.
* `up` - A normal-sized 63x23 button with an up-pointing arrow.
* `down` - A normal-sized 63x23 button with a down-pointing arrow.
* `tiny` - A tiny 14x10 button, same size as an LED.
* `done` - A normal-sized 63x23 button with "Done" on it.
* `tall` - A tall 63x40 button.
* `trait` - A tall 63x40 button with "Race Good/Bad Traits" on it.
* `push` - A round red 30x30 push button.

(Naturally, they correspond perfectly with the values of the eBtnType
enumeration.)

The `<led>` tag
---------------

The `<led>` tag descripts an LED button. It can contain label text,
which is drawn to the right of the button graphic. This differs from
normal practice in the original Blades of Exile dialog engine, where LED
labels were typically left-aligned to the _left_ of their associated
LED. I've chosen to make this change because I feel it is easier to see
which LED a label is associated to, and because the behaviour is more
similar to the checkboxes and radio buttons found in normal GUIs.

The `<led>` tag accepts the following attributes:

* `name` - This attribute is required on the `<led>` tag. See **Common
Attributes** above.
* `state` - Specifies the starting state of the LED. Can be one of
`red`, `green`, or `off`; defaults to `off`.
* `font`, `size`, `color`, `colour` - See **Common Attributes** above.

The `<group>` tag
-----------------

The `<group>` tag defines an LED group, a collection of LEDs that behave
like radio buttons rather than checkboxes. The tag can contain any
number of `<led>` elements.

The `<group>` tag accepts the following attributes:

* `fromlist` - See **Common Attributes** above. I don't remember exactly
how this would have applied to an LED group though; perhaps it would use
the string list to assign labels to its component LEDs in order of
declaration?

The `<pict>` tag
----------------

The `<pict>` tag defines a dialog picture. This covers a wide range of
things, from large pictures to small icons.

The `<pict>` tag accepts the following attributes:

* `type` - Specifies the type of graphic. This attribute is required.
* `num` - Specifies the graphic number. This attribute is required.
* `clickable` - Specifies that the picture is clickable. This attribute
is useless, as clickability is determined solely by having a click
handler set in the code.
* `custom` - Specifies whether the picture is custom or preset. Can be
either `true` or `false`; defaults to `false`.
* `framed` - Specifies whether a frame is drawn around the picture. Can
be either `true` or `false`; defaults to `true`.
* `size` - For certain types of graphics, this provides an additional
hint. Can be one of `small`, `wide`, `tall`, or `large`.
* `def-key`, `key-mod` - See **Common Attributes** above.

The possible values for the `type` attribute are:

* `blank` - Draw no graphic, just fill the bounding rect with black.
* `ter` - A terrain graphic.
* `teranim` - An animated terrain graphic.
* `monst` - A monster graphic. The `size` attribute can be set to any of
its four accepted values to indicate the size of the monster.
* `dlog` - A dialog graphic. The `size` attribute can be `small` (the
default) or `large`.
* `talk` - A conversation graphic.
* `scen` - A scenario icon. The `size` attribute can be `small` (the
default) or `large`.
* `item` - An item graphic.
* `pc` - A PC graphic.
* `field` - A field graphic.
* `boom` - A boom graphic.
* `missile` - A missile graphic.
* `map` - A map graphic.
* `status` - A status icon.
* `full` - A full sheet. With this value and with `custom` left at
`false`, the `num` parameter must be one of the following:
	* 1100 - The inventory help frame.
	* 1200 - The stats area help frame.
	* 1300 - The action points help fram.
	* 1400 - The outdoor toolbar help frame.
	* 1401 - The combat toolbar help frame.
	* 1402 - The town toolbar help frame.
	* 1500 - The stat icons help frame.

The `<field>` tag
-----------------

The `<field>` tag defines an editable text field. It can contain default
text as its contents, but does not support the `<br>` tag.

The `<field>` tag accepts the following attributes:

* `type` - Specifies the input type of the field. Can be one of `text`,
`int`, `uint`, or `real`; defaults to `text`.
* `tab-order` - Specifies the tab order of the field. This must be an
integer that is unique in the dialog.

The `<stack>` tag
-----------------

The `<stack>` tag is currently unimplemented. Trying to load a dialog
that contains it will crash the game.

Keyboard Shortcuts
------------------

Keyboard shortcuts are specified with a pair of attributes.

The `def-key` attribute specifies the main key that triggers the
control. It can take any of the following values:

* A single digit
* A lowercase letter
* One of the following special characters:

		` - = [ ] \ ; ' , . /
* `left` - The left arrow key
* `right` - The right arrow key
* `up` - The up arrow key
* `down` - The down arrow key
* `esc` - The escape key
* `enter` - The enter key.
* `return` - The enter key. (Note: Theoretically, `enter` should be
numpad enter while this is normal enter; I don't think this distinction
is implemented though.)
* `tab` - The tab key.
* `help` - The help key (on keyboards that have one) or the F1 key.
* `space` - The space key.
* `none` - No key shortcut (the default).

The `key-mod` attribute contains a space-separated list of any of the
following values:

* `ctrl` - The primary accelerator key (either control or command).
* `shift` - The shift key
* `alt` - The alt or option key

Text Formatting
---------------

Text formatting options in dialogs are actually quite limited. There are
only three possible attributes, with a very limited number of possible
values.

* `font` - This attribute can take one of the following values: `plain`,
`bold`, `dungeon`, `maidenword`. It defaults to `bold`. The latter two
options are fantasy-style scripts such as that used for the conversation
screen.
* `size` - Although the dialog engine supports any font size, the XML
specification simplifies it to three keywords: `small`, `large`, and
`title`, representing 10pt, 12pt, and 18pt font, respectively.
* `color` or `colour` - This is the only truly unrestricted attribute,
accepting any HTML colour code. It understands three-digit hex codes (eg
`#333`, which is equivalent to `#333333`), six-digit hex codes, and the
sixteen standard HTML colour names. Both the British and American
spelling are supported for the attribute name.

Whitespace
----------

Whitespace collapse rules within Dialog XML elements are a little weird.
All tabs are stripped out, and then runs of newlines are replaced with a
single space, but runs of spaces are left as-is.

Note: Currently, the runs of newlines are simply removed rather than
replaced with a space. This needs to be fixed.

Implementing a Dialog
=====================

Once the dialog is defined, it needs to be implemented! This consists of
a few steps - construct the dialog, attach handlers, possibly populate
the dialog's fields and other dynamic elements according to whatever the
dialog is supposed to display, and then run the dialog.

Use of `std::bind` for attaching the handlers is encouraged, and can be
used in conjunction with `std::ref` to provide state for the dialog.
Lambda expressions may also be useful for some of the simpler handlers.
Use of `dynamic_cast` will be required when dealing with LEDs or icons.