fix(xbacklight): Lower inc/dec value to 5 and fix flooring

include/modules/xbacklight.hpp

@@ -56,7 +56,7 @@ namespace modules {
     progressbar_t m_progressbar;
 
     bool m_scroll{true};
-    int m_percentage{0};
+    std::atomic<int> m_percentage{0};
   };
 }
 

include/utils/math.hpp

@@ -69,6 +69,16 @@ namespace math_util {
     else
       return cap<ReturnType>(percentage * (max_value - min_value) / 100.0f, 0.0f, max_value - min_value) + min_value;
   }
+
+  template <typename ReturnType = int>
+  ReturnType nearest_10(double value) {
+    return static_cast<ReturnType>(static_cast<int>(value / 10.0 + 0.5) * 10.0);
+  }
+
+  template <typename ReturnType = int>
+  ReturnType nearest_5(double value) {
+    return static_cast<ReturnType>(static_cast<int>(value / 5.0 + 0.5) * 5.0);
+  }
 }
 
 POLYBAR_NS_END

include/x11/extensions/randr.hpp

@@ -22,18 +22,18 @@ namespace evt {
 }
 
 struct backlight_values {
-  uint32_t atom = 0;
-  uint32_t min = 0;
-  uint32_t max = 0;
-  uint32_t val = 0;
+  uint32_t atom{0};
+  double min{0.0};
+  double max{0.0};
+  double val{0.0};
 };
 
 struct randr_output {
   string name;
-  uint16_t w = 0;
-  uint16_t h = 0;
-  int16_t x = 0;
-  int16_t y = 0;
+  uint16_t w{0U};
+  uint16_t h{0U};
+  int16_t x{0};
+  int16_t y{0};
   xcb_randr_output_t output;
   backlight_values backlight;
 

src/modules/xbacklight.cpp

@@ -92,10 +92,16 @@ namespace modules {
    * Query the RandR extension for the new values
    */
   void xbacklight_module::update() {
+    if (!m_updatelock.try_lock()) {
+      return;
+    }
+
+    std::lock_guard<mutex> guard(m_updatelock, std::adopt_lock);
+
     // Query for the new backlight value
     auto& bl = m_output->backlight;
     randr_util::get_backlight_value(m_connection, m_output, bl);
-    m_percentage = math_util::percentage(bl.val, bl.min, bl.max);
+    m_percentage = math_util::nearest_5(math_util::percentage<double>(bl.val, bl.min, bl.max));
 
     // Update label tokens
     if (m_label) {
@@ -116,16 +122,14 @@ namespace modules {
     // the format prefix/suffix also gets wrapped
     // with the cmd handlers
     string output{module::get_output()};
-    bool scroll_up{m_scroll && m_percentage < 100};
-    bool scroll_down{m_scroll && m_percentage > 0};
 
-    m_builder->cmd(mousebtn::SCROLL_UP, string{EVENT_SCROLLUP}, scroll_up);
-    m_builder->cmd(mousebtn::SCROLL_DOWN, string{EVENT_SCROLLDOWN}, scroll_down);
+    m_builder->cmd(mousebtn::SCROLL_UP, EVENT_SCROLLUP);
+    m_builder->cmd(mousebtn::SCROLL_DOWN, EVENT_SCROLLDOWN);
 
     m_builder->append(output);
 
-    m_builder->cmd_close(scroll_down);
-    m_builder->cmd_close(scroll_up);
+    m_builder->cmd_close();
+    m_builder->cmd_close();
 
     return m_builder->flush();
   }
@@ -150,22 +154,21 @@ namespace modules {
    * Process scroll events by changing backlight value
    */
   bool xbacklight_module::input(string&& cmd) {
-    int value_mod = 0;
+    double value_mod{0.0};
 
     if (cmd == EVENT_SCROLLUP) {
-      value_mod = 10;
+      value_mod = 5.0;
       m_log.info("%s: Increasing value by %i%", name(), value_mod);
     } else if (cmd == EVENT_SCROLLDOWN) {
-      value_mod = -10;
+      value_mod = -5.0;
       m_log.info("%s: Decreasing value by %i%", name(), -value_mod);
     } else {
       return false;
     }
 
     try {
-      const int new_perc = math_util::cap(m_percentage + value_mod, 0, 100);
-      const int new_value = math_util::percentage_to_value<int>(new_perc, m_output->backlight.max);
-      const int values[1]{new_value};
+      int rounded = math_util::cap<double>(m_percentage + value_mod, 0.0, 100.0) + 0.5;
+      const int values[1]{math_util::percentage_to_value<int>(rounded, m_output->backlight.max)};
 
       m_connection.change_output_property_checked(
           m_output->output, m_output->backlight.atom, XCB_ATOM_INTEGER, 32, XCB_PROP_MODE_REPLACE, 1, values);

src/x11/extensions/randr.cpp

@@ -159,7 +159,7 @@ namespace randr_util {
     auto reply = conn.get_output_property(mon->output, dst.atom, XCB_ATOM_NONE, 0, 4, 0, 0);
 
     if (reply->num_items == 1 && reply->format == 32 && reply->type == XCB_ATOM_INTEGER) {
-      dst.val = *reinterpret_cast<uint32_t*>(xcb_randr_get_output_property_data(reply.get().get()));
+      dst.val = *xcb_randr_get_output_property_data(reply.get().get());
     }
   }
 }

tests/unit_tests/utils/math.cpp

@@ -58,4 +58,20 @@ int main() {
     expect(math_util::percentage_to_value(50, 200, 300) == 250);
     expect(math_util::percentage_to_value(50, 1, 5) == 3);
   };
+
+  "round_to_nearest_10"_test = [] {
+    expect(math_util::nearest_10(52) == 50);
+    expect(math_util::nearest_10(9.1) == 10);
+    expect(math_util::nearest_10(95.0) == 100);
+    expect(math_util::nearest_10(94.9) == 90);
+  };
+
+  "round_to_nearest_5"_test = [] {
+    expect(math_util::nearest_5(52) == 55);
+    expect(math_util::nearest_5(9.1) == 5);
+    expect(math_util::nearest_5(95.0) == 95);
+    expect(math_util::nearest_5(94.9) == 95);
+    expect(math_util::nearest_5(1) == 0);
+    expect(math_util::nearest_5(99.99) == 100);
+  };
 }