tcell/CHANGESv2.adoc

== Breaking Changes in _Tcell_ v2

A number of changes were made to _Tcell_ for version two, and some of these
are breaking.

=== Import Path
The import path for tcell has changed to `github.com/gdamore/tcell/v2` to reflect a new major version.

=== Style Is Not Numeric
The type `Style` has changed to a structure, to allow us to add additional data such as flags for color setting, more attribute bits, and so forth.
Applications that relied on being a number will need to be updated to use the accessor methods.

=== Mouse Event Changes
The middle mouse button was reported as button 2 on Linux, but as button 3 on Windows,
and the right mouse button was reported the reverse way.
_Tcell_ now always reports the right mouse button as button 2, and the middle button as button 3.
To help make this clearer, new symbols `ButtonPrimary`, `ButtonSecondary`, and
`ButtonMiddle` are provided.
(Note that which button is right vs. left may be impacted by user preferences.
Usually the left button will be considered the Primary, and the right will be the Secondary.)
Applications may need to adjust their handling of mouse buttons 2 and 3 accordingly.

=== Terminals Removed
A number of terminals have been removed.
These are mostly ancient definitions unlikey to be used by anyone, such as `adm3a`.

=== High Number Function Keys

Historically terminfo reported function keys with modifiers set as a different
function key altogether.  For example, Shift-F1 was reported as F13 on xterm.
_Tcell_ now prefers to report these using the base key (such as F1) with modifiers added.
This works on xterm and VTE based emulators, but some emulators may not support this.
The new behavior more closely aligns with behavior on Windows platforms.

== New Features in _Tcell_ v2

These features are not breaking, but are introduced in version 2.

=== Improved Modifier Support

For terminals that appear to behave like the venerable XTerm, _tcell_
automatically adds modifier reporting for ALT, CTRL, SHIFT, and META keys
when the terminal reports them.

=== Better Support for Palettes (Themes)

When using a color by its name or palette entry, _Tcell_ now tries to
use that palette entry as is; this should avoid some inconsistency and undesirable
overriding of colors where colors would override settings made in the terminal.

When true fidelity to RGB values is needed, the new `TrueColor()` API can be used
to create a color that is precisely the direct color, which bypasses the palette
altogether.

=== Automatic TrueColor Detection

For some terminals, if the `Tc` or `RGB` properties are present in terminfo,
_Tcell_ will automatically assume the terminal supports 24-bit color.

=== ColorReset

A new color value, `ColorReset` can be used on the foreground or the background
to reset the color the default used by the terminal.

=== tmux Support

_Tcell_ now has improved support for tmux, when the `$TERM` variable is set to "tmux".

=== Strikethrough Support

_Tcell_ has support for strikethrough when the terminal supports it, using the new `StrikeThrough()` API.