feat(backlight): Add enable-scroll (#1957)

* backlight: enable changing via scroll

* squash! feedback

* Update src/modules/backlight.cpp

Co-Authored-By: Jérôme BOULMIER <jerome.boulmier@outlook.fr>

Co-authored-by: Jérôme BOULMIER <jerome.boulmier@outlook.fr>

include/modules/backlight.hpp

@@ -1,13 +1,14 @@
 #pragma once
 
 #include "components/config.hpp"
-#include "settings.hpp"
 #include "modules/meta/inotify_module.hpp"
+#include "modules/meta/input_handler.hpp"
+#include "settings.hpp"
 
 POLYBAR_NS
 
 namespace modules {
-  class backlight_module : public inotify_module<backlight_module> {
+  class backlight_module : public inotify_module<backlight_module>, public input_handler {
    public:
     struct brightness_handle {
       void filepath(const string& path);
@@ -17,6 +18,8 @@ namespace modules {
       string m_path;
     };
 
+    string get_output();
+
    public:
     explicit backlight_module(const bar_settings&, string);
 
@@ -24,20 +27,29 @@ namespace modules {
     bool on_event(inotify_event* event);
     bool build(builder* builder, const string& tag) const;
 
+   protected:
+    bool input(string&& cmd);
+
    private:
     static constexpr auto TAG_LABEL = "<label>";
     static constexpr auto TAG_BAR = "<bar>";
     static constexpr auto TAG_RAMP = "<ramp>";
 
+    static constexpr const char* EVENT_SCROLLUP{"backlight+"};
+    static constexpr const char* EVENT_SCROLLDOWN{"backlight-"};
+
     ramp_t m_ramp;
     label_t m_label;
     progressbar_t m_progressbar;
+    string m_path_backlight;
+    float m_max_brightness;
+    bool m_scroll{false};
 
     brightness_handle m_val;
     brightness_handle m_max;
 
     int m_percentage = 0;
   };
-}
+}  // namespace modules
 
 POLYBAR_NS_END

include/utils/file.hpp

@@ -104,6 +104,7 @@ namespace file_util {
   bool exists(const string& filename);
   string pick(const vector<string>& filenames);
   string contents(const string& filename);
+  void write_contents(const string& filename, const string& contents);
   bool is_fifo(const string& filename);
   vector<string> glob(string pattern);
   const string expand(const string& path);
@@ -112,6 +113,6 @@ namespace file_util {
   decltype(auto) make_file_descriptor(Args&&... args) {
     return factory_util::unique<file_descriptor>(forward<Args>(args)...);
   }
-}
+}  // namespace file_util
 
 POLYBAR_NS_END

src/modules/backlight.cpp

@@ -3,9 +3,9 @@
 #include "drawtypes/label.hpp"
 #include "drawtypes/progressbar.hpp"
 #include "drawtypes/ramp.hpp"
-#include "utils/file.hpp"
-
 #include "modules/meta/base.inl"
+#include "utils/file.hpp"
+#include "utils/math.hpp"
 
 POLYBAR_NS
 
@@ -27,6 +27,9 @@ namespace modules {
       : inotify_module<backlight_module>(bar, move(name_)) {
     auto card = m_conf.get(name(), "card");
 
+    // Get flag to check if we should add scroll handlers for changing value
+    m_scroll = m_conf.get(name(), "enable-scroll", m_scroll);
+
     // Add formats and elements
     m_formatter->add(DEFAULT_FORMAT, TAG_LABEL, {TAG_LABEL, TAG_BAR, TAG_RAMP});
 
@@ -41,17 +44,17 @@ namespace modules {
     }
 
     // Build path to the sysfs folder the current/maximum brightness values are located
-    auto path_backlight = string_util::replace(PATH_BACKLIGHT, "%card%", card);
+    m_path_backlight = string_util::replace(PATH_BACKLIGHT, "%card%", card);
 
     /*
      * amdgpu drivers set the actual_brightness in a different scale than [0, max_brightness]
      * The only sensible way is to use the 'brightness' file instead
      * Ref: https://github.com/Alexays/Waybar/issues/335
      */
-    auto path_backlight_val = path_backlight + "/" + (card == "amdgpu_bl0"? "brightness" : "actual_brightness");
+    auto path_backlight_val = m_path_backlight + "/" + (card == "amdgpu_bl0" ? "brightness" : "actual_brightness");
 
     m_val.filepath(path_backlight_val);
-    m_max.filepath(path_backlight + "/max_brightness");
+    m_max.filepath(m_path_backlight + "/max_brightness");
 
     // Add inotify watch
     watch(path_backlight_val);
@@ -66,7 +69,8 @@ namespace modules {
       m_log.trace("%s: %s", name(), event->filename);
     }
 
-    m_percentage = static_cast<int>(m_val.read() / m_max.read() * 100.0f + 0.5f);
+    m_max_brightness = m_max.read();
+    m_percentage = static_cast<int>(m_val.read() / m_max_brightness * 100.0f + 0.5f);
 
     if (m_label) {
       m_label->reset_tokens();
@@ -76,6 +80,25 @@ namespace modules {
     return true;
   }
 
+  string backlight_module::get_output() {
+    // Get the module output early so that
+    // the format prefix/suffix also gets wrapped
+    // with the cmd handlers
+    string output{module::get_output()};
+
+    if (m_scroll) {
+      m_builder->cmd(mousebtn::SCROLL_UP, EVENT_SCROLLUP);
+      m_builder->cmd(mousebtn::SCROLL_DOWN, EVENT_SCROLLDOWN);
+    }
+
+    m_builder->append(std::move(output));
+
+    m_builder->cmd_close();
+    m_builder->cmd_close();
+
+    return m_builder->flush();
+  }
+
   bool backlight_module::build(builder* builder, const string& tag) const {
     if (tag == TAG_BAR) {
       builder->node(m_progressbar->output(m_percentage));
@@ -88,6 +111,33 @@ namespace modules {
     }
     return true;
   }
+
+  bool backlight_module::input(string&& cmd) {
+    double value_mod{0.0};
+
+    if (cmd == EVENT_SCROLLUP) {
+      value_mod = 5.0;
+    } else if (cmd == EVENT_SCROLLDOWN) {
+      value_mod = -5.0;
+    } else {
+      return false;
     }
 
+    m_log.info("%s: Changing value by %f%", name(), value_mod);
+
+    try {
+      int rounded = math_util::cap<double>(m_percentage + value_mod, 0.0, 100.0) + 0.5;
+      int value = math_util::percentage_to_value<int>(rounded, m_max_brightness);
+      file_util::write_contents(m_path_backlight + "/brightness", to_string(value));
+    } catch (const exception& err) {
+      m_log.err(
+          "%s: Unable to change backlight value. Your system may require additional "
+          "configuration. Please read the module documentation.\n(reason: %s)",
+          name(), err.what());
+    }
+
+    return true;
+  }
+}  // namespace modules
+
 POLYBAR_NS_END

src/utils/file.cpp

@@ -1,6 +1,9 @@
+#include "utils/file.hpp"
+
 #include <fcntl.h>
 #include <glob.h>
 #include <sys/stat.h>
+
 #include <cstdio>
 #include <cstdlib>
 #include <fstream>
@@ -8,7 +11,6 @@
 
 #include "errors.hpp"
 #include "utils/env.hpp"
-#include "utils/file.hpp"
 #include "utils/string.hpp"
 
 POLYBAR_NS
@@ -202,6 +204,16 @@ namespace file_util {
     }
   }
 
+  /**
+   * Writes the contents of the given file
+   */
+  void write_contents(const string& filename, const string& contents) {
+    std::ofstream out(filename, std::ofstream::out);
+    if (!(out << contents)) {
+      throw std::system_error(errno, std::system_category(), "failed to write to " + filename);
+    }
+  }
+
   /**
    * Checks if the given file is a named pipe
    */
@@ -262,6 +274,6 @@ namespace file_util {
     }
     return ret;
   }
-}
+}  // namespace file_util
 
 POLYBAR_NS_END