[WIP] Implement color themes - closes #28

[MCord]

This PR refactors all color related code and creates an style that can be modified to create different color themes for the program. it also provides serialization to and from a config file. changes in this PR

1. created Theme struct to represent different colors and some helper functions.
2. replaced all hard coded colors with references to the global THEME variable.
3. add serde and ron crates for serialization. and lazy_static for static init.
4. on start the program tries to load ~/.gitui/theme.ron to load the theme or creates one with default values if not found.

This PR alone at the current state is not enough to provide theming since many components don't specify any style and rely on defaults to draw elements. I have not yet looked into how to change these defaults.

[extrawurst]

Looking at the theme.ron I am worried that we went too far here. afterall in most cases we only use one of the colors and no modifier. maybe we can take another angle at it and only load colours and pass a color scheme down to any component that uses styling. this component then could generate the styles on the fly as before but based on the color schema.

this way me might end up with less content in the theme.ron and less todo for anyone getting their hands on it.

The big benefit for us is aswell that it is easier to reason about what colors we already use in the scheme.

What do you think?

[MCord]

@extrawurst can you provide an example theme.ron file so that I better understand the model you have in mind ?

[extrawurst]

pretty sure I missed some:

(
    selection_bg: Rgb(0,0,100), // also used for commands background
    selected_tab: Yellow,
    command_disabled: LightGrey,
    diff_line_add: Green,
    diff_line_delete: Red,
    diff_file_added: LightGreen,
    diff_file_removed: LightRed,
    diff_file_moved: LightMagenta,
    commit_hash: Magenta,
    commit_time: Blue,
    commit_author: Green,
    commit_tag: Yellow,
)

the trick is then to consider every new entry and reuse any color that is already in there (of course that will drive appropriate naming virtually impossible. But this way looking at gitui someone right aways know: "ok this yellow I see here is bad in my term color scheme, so I change yellow in the file and it is fixed in all places at once"

[MCord]

I think having specific names for colors like 'selected_tab' can be confusing once we have used this color in other places but I agree that we don't have enough cases to try to generalize now. I will implement specific case for the moment as you specified.

[MCord]

fixed

…

On Tue, May 19, 2020 at 12:35 PM Stephan Dilly ***@***.***> wrote: ***@***.**** commented on this pull request. ------------------------------ In src/app.rs <#65 (comment)>: > @@ -37,24 +39,32 @@ pub struct App { revlog: Revlog, status_tab: Status, queue: Queue, + pub theme: Theme, this can be private — You are receiving this because you authored the thread. Reply to this email directly, view it on GitHub <#65 (review)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AALZWZY4WKJXIWCXKM44YQTRSJOIJANCNFSM4NDLUMAA> .

[extrawurst]

some styles seem to be lost in translation:

before:

after:

[MCord]

strange, the difference is not visible on windows. I try to reproduce on Linux.

[MCord]

i have tried to reproduce it by looking at the diff. can you try again ? (feel free to fix if you know what's wrong)

[extrawurst]

looks good. I checked how the default looks on a light terminal:

that is not bad as a default actually.

my only remaining concern is that we now rely on an ENV variable to set when one wants to switch the theme.

what if we only put the dark theme in the binary and dont parse the ENV but document in the readme what to paste into the generated ron file?

[MCord]

The idea was to include two themes and a way to auto detect which to use given terminals background color but I failed to find a way to auto detect so there is not much value in keeping both unless we find a way to auto detect.

[extrawurst]

Yeah I reached out to the crossterm guys on discord, there is not good way for auto detecting. I would love to have that. but I think for now this is out of scope of this PR

[MCord]

gone !

[extrawurst]

It is in! Thank you so much for all the effort!🚀