feat: backlight slider

include/modules/backlight_slider.hpp

@@ -0,0 +1,24 @@
+#pragma once
+
+#include <chrono>
+
+#include "ASlider.hpp"
+#include "util/backlight_backend.hpp"
+
+namespace waybar::modules {
+
+class BacklightSlider : public ASlider {
+ public:
+  BacklightSlider(const std::string&, const Json::Value&);
+  virtual ~BacklightSlider() = default;
+
+  void update() override;
+  void onValueChanged() override;
+
+ private:
+  std::chrono::milliseconds interval_;
+  std::string preferred_device_;
+  util::BacklightBackend backend;
+};
+
+}  // namespace waybar::modules

include/util/backlight_backend.hpp

@@ -56,9 +56,11 @@ class BacklightBackend {
 
   void set_previous_best_device(const BacklightDevice *device);
 
-  void set_brightness(std::string preferred_device, int brightness);
   void set_brightness(std::string preferred_device, ChangeType change_type, double step);
 
+  void set_scaled_brightness(std::string preferred_device, int brightness);
+  int get_scaled_brightness(std::string preferred_device);
+
   template <class ForwardIt, class Inserter>
   static void upsert_device(ForwardIt first, ForwardIt last, Inserter inserter, udev_device *dev);
 

man/waybar-backlight-slider.5.scd

@@ -0,0 +1,88 @@
+waybar-backlight-slider(5)
+
+# NAME
+
+waybar - backlight slider module
+
+# DESCRIPTION
+
+The *backlight slider* module displays and controls the current brightness of the default or preferred device.
+
+The brightness can be controlled by dragging the slider accross the bar, or clicking on a specific position.
+
+# CONFIGURATION
+
+*min*: ++
+    typeof: int ++
+    default: 0 ++
+    The minimum volume value the slider should display and set.
+
+*max*: ++
+    typeof: int ++
+    default: 100 ++
+    The maximum volume value the slider should display and set.
+
+*orientation*: ++
+    typeof: string ++
+    default: horizontal ++
+    The orientation of the slider. Can be either `horizontal` or `vertical`.
+
+*device*: ++
+    typeof: string ++
+    The name of the preferred device to control. If left empty, a device will be chosen automatically.
+
+# EXAMPLES
+
+```
+"modules-right": [
+    "backlight-slider",
+],
+"backlight/slider": {
+    "min": 0,
+    "max": 100,
+    "orientation": "horizontal",
+    "device": "intel_backlight"
+}
+```
+
+# STYLE
+
+The slider is a component with multiple CSS Nodes, of which the following are exposed:
+
+*#backlight-slider*: ++
+    Controls the style of the box *around* the slider and bar.
+
+*#backlight-slider slider*: ++
+    Controls the style of the slider handle.
+
+*#backlight-slider trough*: ++
+    Controls the style of the part of the bar that has not been filled.
+
+*#backlight-slider highlight*: ++
+    Controls the style of the part of the bar that has been filled.
+
+## STYLE EXAMPLE
+
+```
+#backlight-slider slider {
+    min-height: 0px;
+    min-width: 0px;
+    opacity: 0;
+    background-image: none;
+    border: none;
+    box-shadow: none;
+}
+
+#backlight-slider trough {
+    min-height: 80px;
+    min-width: 10px;
+    border-radius: 5px;
+    background-color: black;
+}
+
+#backlight-slider highlight {
+    min-width: 10px;
+    border-radius: 5px;
+    background-color: red;
+}
+```

meson.build

@@ -301,6 +301,7 @@ endif
 if libudev.found() and (is_linux or libepoll.found())
     add_project_arguments('-DHAVE_LIBUDEV', language: 'cpp')
     src_files += 'src/modules/backlight.cpp'
+    src_files += 'src/modules/backlight_slider.cpp'
     src_files += 'src/util/backlight_backend.cpp'
 endif
 
@@ -429,6 +430,7 @@ if scdoc.found()
     man_files = [
         main_manpage_path,
         'waybar-backlight.5.scd',
+        'waybar-backlight-slider.5.scd',
         'waybar-battery.5.scd',
         'waybar-cava.5.scd',
         'waybar-clock.5.scd',

src/factory.cpp

@@ -4,6 +4,10 @@
 #include "modules/pulseaudio_slider.hpp"
 #endif
 
+#ifdef HAVE_LIBUDEV
+#include "modules/backlight_slider.hpp"
+#endif
+
 waybar::Factory::Factory(const Bar& bar, const Json::Value& config) : bar_(bar), config_(config) {}
 
 waybar::AModule* waybar::Factory::makeModule(const std::string& name) const {
@@ -130,6 +134,9 @@ waybar::AModule* waybar::Factory::makeModule(const std::string& name) const {
     if (ref == "backlight") {
       return new waybar::modules::Backlight(id, config_[name]);
     }
+    if (ref == "backlight/slider") {
+      return new waybar::modules::BacklightSlider(id, config_[name]);
+    }
 #endif
 #ifdef HAVE_LIBEVDEV
     if (ref == "keyboard-state") {

src/modules/backlight_slider.cpp

@@ -0,0 +1,23 @@
+#include "modules/backlight_slider.hpp"
+
+#include "ASlider.hpp"
+
+namespace waybar::modules {
+
+BacklightSlider::BacklightSlider(const std::string& id, const Json::Value& config)
+    : ASlider(config, "backlight-slider", id),
+      interval_(config_["interval"].isUInt() ? config_["interval"].asUInt() : 1000),
+      preferred_device_(config["device"].isString() ? config["device"].asString() : ""),
+      backend(interval_, [this] { this->dp.emit(); }) {}
+
+void BacklightSlider::update() {
+  uint16_t brightness = backend.get_scaled_brightness(preferred_device_);
+  scale_.set_value(brightness);
+}
+
+void BacklightSlider::onValueChanged() {
+  auto brightness = scale_.get_value();
+  backend.set_scaled_brightness(preferred_device_, brightness);
+}
+
+}  // namespace waybar::modules

src/util/backlight_backend.cpp

@@ -188,11 +188,13 @@ void BacklightBackend::set_previous_best_device(const BacklightDevice *device) {
   }
 }
 
-void BacklightBackend::set_brightness(std::string preferred_device, int brightness) {
+void BacklightBackend::set_scaled_brightness(std::string preferred_device, int brightness) {
   GET_BEST_DEVICE(best, (*this), preferred_device);
 
   if (best != nullptr) {
-    set_brightness_internal(best->name(), brightness, best->get_max());
+    const auto max = best->get_max();
+    const auto abs_val = static_cast<int>(round(brightness * max / 100.0f));
+    set_brightness_internal(best->name(), abs_val, best->get_max());
   }
 }
 
@@ -221,6 +223,16 @@ void BacklightBackend::set_brightness_internal(std::string device_name, int brig
   login_proxy_->call_sync("SetBrightness", call_args);
 }
 
+int BacklightBackend::get_scaled_brightness(std::string preferred_device) {
+  GET_BEST_DEVICE(best, (*this), preferred_device);
+
+  if (best != nullptr) {
+    return best->get_actual() * 100 / best->get_max();
+  }
+
+  return 0;
+}
+
 template <class ForwardIt, class Inserter>
 void BacklightBackend::upsert_device(ForwardIt first, ForwardIt last, Inserter inserter,
                                      udev_device *dev) {