From 68035e57fe9dd320eca4f9548297284ef0b8d6ab Mon Sep 17 00:00:00 2001
From: Ilya M <mail@ilya-m.com>
Date: Sat, 1 Jul 2023 17:34:43 +0200
Subject: [PATCH] Support custom header buttons layouts (#30)
MIME-Version: 1.0
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* Support custom header buttons layouts

* Support custom header buttons layouts: review tweaks

* Safe unwrap layout config function

Co-authored-by: Bartłomiej Maryńczak <marynczak.bartlomiej@gmail.com>

---------

Co-authored-by: Ilya Malyavin <ilya-m64@protonmail.com>
Co-authored-by: Bartłomiej Maryńczak <marynczak.bartlomiej@gmail.com>
---
 src/buttons.rs | 208 +++++++++++++++++++++++++++++++++++++------------
 src/config.rs  |  32 ++++++++
 src/lib.rs     | 115 +++++++++++++++------------
 3 files changed, 257 insertions(+), 98 deletions(-)

diff --git a/src/buttons.rs b/src/buttons.rs
index d124ba8..3e024c2 100644
--- a/src/buttons.rs
+++ b/src/buttons.rs
@@ -1,3 +1,4 @@
+use log::warn;
 use tiny_skia::{FillRule, PathBuilder, PixmapMut, Rect, Stroke, Transform};
 
 use smithay_client_toolkit::shell::xdg::window::{WindowManagerCapabilities, WindowState};
@@ -11,42 +12,59 @@ const BUTTON_SPACING: f32 = 13.;
 
 #[derive(Debug)]
 pub(crate) struct Buttons {
-    pub close: Button,
-    pub maximize: Option<Button>,
-    pub minimize: Option<Button>,
+    // Sorted by order vec of buttons for the left and right sides
+    buttons_left: Vec<Button>,
+    buttons_right: Vec<Button>,
+    layout_config: Option<(String, String)>,
 }
 
+type ButtonLayout = (Vec<Button>, Vec<Button>);
+
 impl Default for Buttons {
     fn default() -> Self {
+        let (buttons_left, buttons_right) = Buttons::get_default_buttons_layout();
+
         Self {
-            close: Button::new(ButtonKind::Close),
-            maximize: Some(Button::new(ButtonKind::Maximize)),
-            minimize: Some(Button::new(ButtonKind::Minimize)),
+            buttons_left,
+            buttons_right,
+            layout_config: None,
         }
     }
 }
 
 impl Buttons {
+    pub fn new(layout_config: Option<(String, String)>) -> Self {
+        match Buttons::parse_button_layout(layout_config.clone()) {
+            Some((buttons_left, buttons_right)) => Self {
+                buttons_left,
+                buttons_right,
+                layout_config,
+            },
+            _ => Self::default(),
+        }
+    }
+
     /// Rearrange the buttons with the new width.
-    pub fn arrange(&mut self, width: u32) {
-        let mut x = width as f32 - BUTTON_MARGIN;
-
-        for button in [
-            Some(&mut self.close),
-            self.maximize.as_mut(),
-            self.minimize.as_mut(),
-        ]
-        .into_iter()
-        .flatten()
-        {
+    pub fn arrange(&mut self, width: u32, margin_h: f32) {
+        let mut left_x = BUTTON_MARGIN + margin_h;
+        let mut right_x = width as f32 - BUTTON_MARGIN;
+
+        for button in &mut self.buttons_left {
+            button.offset = left_x;
+
+            // Add the button size plus spacing
+            left_x += BUTTON_SIZE + BUTTON_SPACING;
+        }
+
+        for button in &mut self.buttons_right {
             // Subtract the button size.
-            x -= BUTTON_SIZE;
+            right_x -= BUTTON_SIZE;
 
-            // Update it's
-            button.offset = x;
+            // Update it
+            button.offset = right_x;
 
             // Subtract spacing for the next button.
-            x -= BUTTON_SPACING;
+            right_x -= BUTTON_SPACING;
         }
     }
 
@@ -54,43 +72,125 @@ impl Buttons {
     pub fn find_button(&self, x: f64, y: f64) -> Location {
         let x = x as f32;
         let y = y as f32;
-        if self.close.contains(x, y) {
-            Location::Button(ButtonKind::Close)
-        } else if self.maximize.as_ref().map(|b| b.contains(x, y)) == Some(true) {
-            Location::Button(ButtonKind::Maximize)
-        } else if self.minimize.as_ref().map(|b| b.contains(x, y)) == Some(true) {
-            Location::Button(ButtonKind::Minimize)
-        } else {
-            Location::Head
+        let buttons = self.buttons_left.iter().chain(self.buttons_right.iter());
+
+        for button in buttons {
+            if button.contains(x, y) {
+                return Location::Button(button.kind);
+            }
         }
+
+        Location::Head
+    }
+
+    pub fn update_wm_capabilities(&mut self, wm_capabilites: WindowManagerCapabilities) {
+        let supports_maximize = wm_capabilites.contains(WindowManagerCapabilities::MAXIMIZE);
+        let supports_minimize = wm_capabilites.contains(WindowManagerCapabilities::MINIMIZE);
+
+        self.update_buttons(supports_maximize, supports_minimize);
+    }
+
+    pub fn update_buttons(&mut self, supports_maximize: bool, supports_minimize: bool) {
+        let is_supported = |button: &Button| match button.kind {
+            ButtonKind::Close => true,
+            ButtonKind::Maximize => supports_maximize,
+            ButtonKind::Minimize => supports_minimize,
+        };
+
+        let (buttons_left, buttons_right) =
+            Buttons::parse_button_layout(self.layout_config.clone())
+                .unwrap_or_else(Buttons::get_default_buttons_layout);
+
+        self.buttons_left = buttons_left.into_iter().filter(is_supported).collect();
+        self.buttons_right = buttons_right.into_iter().filter(is_supported).collect();
     }
 
-    pub fn update(&mut self, wm_capabilites: WindowManagerCapabilities) {
-        self.maximize = wm_capabilites
-            .contains(WindowManagerCapabilities::MAXIMIZE)
-            .then_some(Button::new(ButtonKind::Maximize));
-        self.minimize = wm_capabilites
-            .contains(WindowManagerCapabilities::MINIMIZE)
-            .then_some(Button::new(ButtonKind::Minimize));
+    pub fn right_buttons_start_x(&self) -> Option<f32> {
+        self.buttons_right.last().map(|button| button.x())
     }
 
-    pub fn left_most(&self) -> &Button {
-        if let Some(minimize) = self.minimize.as_ref() {
-            minimize
-        } else if let Some(maximize) = self.maximize.as_ref() {
-            maximize
+    pub fn left_buttons_end_x(&self) -> Option<f32> {
+        self.buttons_left.last().map(|button| button.end_x())
+    }
+
+    pub fn draw(
+        &self,
+        start_x: f32,
+        end_x: f32,
+        scale: f32,
+        colors: &ColorMap,
+        mouse_location: Location,
+        pixmap: &mut PixmapMut,
+        resizable: bool,
+        state: &WindowState,
+    ) {
+        let left_buttons_right_limit =
+            self.right_buttons_start_x().unwrap_or(end_x).min(end_x) - BUTTON_SPACING;
+        let buttons_left = self.buttons_left.iter().map(|x| (x, Side::Left));
+        let buttons_right = self.buttons_right.iter().map(|x| (x, Side::Right));
+
+        for (button, side) in buttons_left.chain(buttons_right) {
+            let is_visible = button.x() > start_x && button.end_x() < end_x
+                // If we have buttons from both sides and they overlap, prefer the right side
+                && (side == Side::Right || button.end_x() < left_buttons_right_limit);
+
+            if is_visible {
+                button.draw(scale, colors, mouse_location, pixmap, resizable, state);
+            }
+        }
+    }
+
+    fn parse_button_layout(sides: Option<(String, String)>) -> Option<ButtonLayout> {
+        let Some((left_side, right_side)) = sides else {
+            return None;
+        };
+
+        let buttons_left = Buttons::parse_button_layout_side(left_side, Side::Left);
+        let buttons_right = Buttons::parse_button_layout_side(right_side, Side::Right);
+
+        if buttons_left.is_empty() && buttons_right.is_empty() {
+            warn!("No valid buttons found in configuration");
+            return None;
+        }
+
+        Some((buttons_left, buttons_right))
+    }
+
+    fn parse_button_layout_side(config: String, side: Side) -> Vec<Button> {
+        let mut buttons: Vec<Button> = vec![];
+
+        for button in config.split(',').take(3) {
+            let button_kind = match button {
+                "close" => Some(ButtonKind::Close),
+                "maximize" => Some(ButtonKind::Maximize),
+                "minimize" => Some(ButtonKind::Minimize),
+                _ => None,
+            };
+
+            let Some(kind) = button_kind else {
+                warn!("Found unknown button type, ignoring");
+                continue;
+            };
+            buttons.push(Button::new(kind));
+        }
+
+        // For the right side, we need to revert the order
+        if side == Side::Right {
+            buttons.into_iter().rev().collect()
         } else {
-            &self.close
+            buttons
         }
     }
 
-    pub fn iter(&self) -> std::array::IntoIter<Option<Button>, 3> {
-        [
-            Some(self.close.clone()),
-            self.maximize.clone(),
-            self.minimize.clone(),
-        ]
-        .into_iter()
+    fn get_default_buttons_layout() -> ButtonLayout {
+        (
+            vec![],
+            vec![
+                Button::new(ButtonKind::Close),
+                Button::new(ButtonKind::Maximize),
+                Button::new(ButtonKind::Minimize),
+            ],
+        )
     }
 }
 
@@ -123,6 +223,10 @@ impl Button {
         BUTTON_MARGIN + self.radius()
     }
 
+    pub fn end_x(&self) -> f32 {
+        self.offset + BUTTON_SIZE
+    }
+
     fn contains(&self, x: f32, y: f32) -> bool {
         x > self.offset
             && x < self.offset + BUTTON_SIZE
@@ -265,3 +369,9 @@ pub enum ButtonKind {
     Maximize,
     Minimize,
 }
+
+#[derive(Debug, Copy, Clone, PartialEq)]
+pub enum Side {
+    Left,
+    Right,
+}
diff --git a/src/config.rs b/src/config.rs
index 39322ee..3299790 100644
--- a/src/config.rs
+++ b/src/config.rs
@@ -22,3 +22,35 @@ pub(crate) fn prefer_dark() -> bool {
 
     matches!(stdout, Some(s) if s.trim().ends_with("uint32 1"))
 }
+
+/// Query system configuration for buttons layout.
+/// Should be updated to use standard xdg-desktop-portal specs once available
+/// https://github.com/flatpak/xdg-desktop-portal/pull/996
+pub(crate) fn get_button_layout_config() -> Option<(String, String)> {
+    let config_string = Command::new("dbus-send")
+        .arg("--reply-timeout=100")
+        .arg("--print-reply=literal")
+        .arg("--dest=org.freedesktop.portal.Desktop")
+        .arg("/org/freedesktop/portal/desktop")
+        .arg("org.freedesktop.portal.Settings.Read")
+        .arg("string:org.gnome.desktop.wm.preferences")
+        .arg("string:button-layout")
+        .output()
+        .ok()
+        .and_then(|out| String::from_utf8(out.stdout).ok())?;
+
+    let sides_split: Vec<_> = config_string
+        // Taking last word
+        .rsplit(' ')
+        .next()?
+        // Split by left/right side
+        .split(':')
+        // Only two sides
+        .take(2)
+        .collect();
+
+    match sides_split.as_slice() {
+        [left, right] => Some((left.to_string(), right.to_string())),
+        _ => None,
+    }
+}
diff --git a/src/lib.rs b/src/lib.rs
index 267e576..9899043 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -32,6 +32,7 @@ use crate::theme::{
 };
 
 use buttons::Buttons;
+use config::get_button_layout_config;
 use parts::DecorationParts;
 use pointer::{Location, MouseState};
 use title::TitleText;
@@ -104,7 +105,7 @@ where
             title: None,
             title_text: TitleText::new(theme.active.font_color),
             theme,
-            buttons: Default::default(),
+            buttons: Buttons::new(get_button_layout_config()),
             mouse: Default::default(),
             state: WindowState::empty(),
             wm_capabilities: WindowManagerCapabilities::all(),
@@ -310,7 +311,7 @@ where
     fn update_wm_capabilities(&mut self, wm_capabilities: WindowManagerCapabilities) {
         self.dirty |= self.wm_capabilities != wm_capabilities;
         self.wm_capabilities = wm_capabilities;
-        self.buttons.update(wm_capabilities);
+        self.buttons.update_wm_capabilities(wm_capabilities);
     }
 
     fn set_hidden(&mut self, hidden: bool) {
@@ -340,7 +341,8 @@ where
             .expect("trying to resize the hidden frame.");
 
         decorations.resize(width.get(), height.get());
-        self.buttons.arrange(width.get());
+        self.buttons
+            .arrange(width.get(), get_margin_h_lp(&self.state));
         self.dirty = true;
     }
 
@@ -489,68 +491,74 @@ fn draw_headerbar(
     let _ = draw_headerbar_bg(pixmap, scale, colors, state);
 
     // Horizontal margin.
-    let margin_h = if state.intersects(WindowState::MAXIMIZED | WindowState::TILED) {
-        0.
-    } else {
-        VISIBLE_BORDER_SIZE as f32 * scale
-    };
+    let margin_h = get_margin_h_lp(state) * 2.0;
+
+    let canvas_w = pixmap.width() as f32;
+    let canvas_h = pixmap.height() as f32;
+
+    let header_w = canvas_w - margin_h * 2.0;
+    let header_h = canvas_h;
 
     if let Some(text_pixmap) = text_pixmap {
         const TEXT_OFFSET: f32 = 10.;
-
-        let closest_button_x = buttons.left_most().x() * scale;
         let offset_x = TEXT_OFFSET * scale;
 
-        let canvas_w = pixmap.width() as f32;
-        let canvas_h = pixmap.height() as f32;
-
-        let header_w = canvas_w - margin_h * 2.0;
-        let header_h = canvas_h;
-
         let text_w = text_pixmap.width() as f32;
         let text_h = text_pixmap.height() as f32;
 
         let x = margin_h + header_w / 2. - text_w / 2.;
         let y = header_h / 2. - text_h / 2.;
 
-        let (x, y) = if x + text_w < closest_button_x - offset_x {
-            (x, y)
-        } else {
-            let x = closest_button_x - text_w - offset_x;
-            let y = header_h / 2. - text_h / 2.;
-            (x, y)
-        };
+        let left_buttons_end_x = buttons.left_buttons_end_x().unwrap_or(0.0) * scale;
+        let right_buttons_start_x =
+            buttons.right_buttons_start_x().unwrap_or(header_w / scale) * scale;
 
-        // Ensure that text start within the bounds.
-        let x = x.max(margin_h + offset_x);
-
-        if let Some(clip) = Rect::from_xywh(0., 0., closest_button_x - offset_x, canvas_h) {
-            let mut mask = ClipMask::new();
-            mask.set_path(
-                canvas_w as u32,
-                canvas_h as u32,
-                &PathBuilder::from_rect(clip),
-                FillRule::Winding,
-                false,
-            );
-            pixmap.draw_pixmap(
-                x as i32,
-                y as i32,
-                text_pixmap.as_ref(),
-                &PixmapPaint::default(),
-                Transform::identity(),
-                Some(&mask),
-            );
+        {
+            // We have enough space to center text
+            let (x, y, text_canvas_start_x) = if (x + text_w < right_buttons_start_x - offset_x)
+                && (x > left_buttons_end_x + offset_x)
+            {
+                let text_canvas_start_x = x;
+
+                (x, y, text_canvas_start_x)
+            } else {
+                let x = left_buttons_end_x + offset_x;
+                let text_canvas_start_x = left_buttons_end_x + offset_x;
+
+                (x, y, text_canvas_start_x)
+            };
+
+            let text_canvas_end_x = right_buttons_start_x - x - offset_x;
+            // Ensure that text start within the bounds.
+            let x = x.max(margin_h + offset_x);
+
+            if let Some(clip) =
+                Rect::from_xywh(text_canvas_start_x, 0., text_canvas_end_x, canvas_h)
+            {
+                let mut mask = ClipMask::new();
+                mask.set_path(
+                    canvas_w as u32,
+                    canvas_h as u32,
+                    &PathBuilder::from_rect(clip),
+                    FillRule::Winding,
+                    false,
+                );
+                pixmap.draw_pixmap(
+                    x as i32,
+                    y as i32,
+                    text_pixmap.as_ref(),
+                    &PixmapPaint::default(),
+                    Transform::identity(),
+                    Some(&mask),
+                );
+            }
         }
     }
 
     // Draw the buttons.
-    for button in buttons.iter().flatten() {
-        // Ensure that it'll be visible.
-        if button.x() > margin_h {
-            button.draw(scale, colors, mouse, pixmap, resizable, state);
-        }
-    }
+    buttons.draw(
+        margin_h, header_w, scale, colors, mouse, pixmap, resizable, state,
+    );
 }
 
 #[must_use]
@@ -656,3 +664,12 @@ fn rounded_headerbar_shape(x: f32, y: f32, width: f32, height: f32, radius: f32)
 
     pb.finish()
 }
+
+// returns horizontal margin, logical points
+fn get_margin_h_lp(state: &WindowState) -> f32 {
+    if state.intersects(WindowState::MAXIMIZED | WindowState::TILED) {
+        0.
+    } else {
+        VISIBLE_BORDER_SIZE as f32
+    }
+}