Brightness slider works with mouse wheel.

power_console.fluid

@@ -7,14 +7,14 @@ declblock {\#if 1} {
 extern void saverChosen();
 extern void perfChosen();} open public map 1 after {\#endif}
 } {
-  decl {\#include "power_console_common.h"} {selected public global
+  decl {\#include "power_console_common.h"} {public global
   }
 }
 
 Function {make_window()} {open
 } {
   Fl_Window {} {open
-    xywh {506 191 177 183} type Double box GLEAM_UP_BOX visible
+    xywh {506 1271 177 183} type Double box GLEAM_UP_BOX visible
   } {
     Fl_Light_Button conserveButton {
       label {Conserve Battery}
@@ -52,6 +52,7 @@ Function {make_window()} {open
       label Brightness
       callback adjustBrightness
       xywh {129 81 20 52} labelsize 12
+      class MouseWheelSlider
     }
   }
 }

power_console_common.h

@@ -1,5 +1,49 @@
 #pragma once
 
+#include <Fl/Fl.H>
+#include <Fl/Fl_Window.H>
+#include <Fl/Fl_Value_Slider.H>
+
+
 void saverChosen();
 void perfChosen();
 void balChosen();
+
+class MouseWheelSlider : public Fl_Value_Slider
+{
+	public:
+		explicit
+		MouseWheelSlider( const int x, const int y, const int w, const int h,
+				const char *const l= 0 )
+			: Fl_Value_Slider( x, y, w, h, l )
+		{
+
+			step( 1 );
+		}
+
+		int
+		handle( const int event ) override
+		{
+			switch( event )
+			{
+				case FL_MOUSEWHEEL:
+				{
+					// Negative, because I use this for the Brightness control.
+					const int dy= -Fl::event_dy();
+
+					value( value() - dy * step() );
+
+					do_callback();
+
+					return 1;
+				}
+				break;
+
+				default:
+				{
+					return this->Fl_Value_Slider::handle( event );
+				}
+				break;
+			}
+		}
+};

power_console_main.cc

@@ -6,6 +6,7 @@
 #include <map>
 #include <fstream>
 #include <thread>
+#include <algorithm>
 #include <sstream>
 #include <string>
 
@@ -88,7 +89,7 @@ scheduledUpdate( void * )
 	int in;
 	inf >> in;
 
-	brightness->value( 101 - 100 * in / max );
+	brightness->value( 100 * in / max );
 }
 
 // Since this requires launching bg processes, we only do it at startup and then every 30s.
@@ -115,9 +116,9 @@ main( const int argcnt, char **argvec )
 	level->value( 0 );
 	level->label( battLevelString.c_str() );
 
-	brightness->minimum( 1 );
-	brightness->maximum( 100 );
-	brightness->step( 1 );
+	brightness->maximum( 1 );
+	brightness->minimum( 100 );
+	brightness->step( -1 );
 
 
 	w->hotspot( w );
@@ -203,9 +204,9 @@ namespace
 }
 
 void
-adjustBrightness( Fl_Slider *, void * )
+adjustBrightness( MouseWheelSlider *, void * )
 {
-	const int amount= 101 - brightness->value();
+	const int amount= brightness->value();
 	std::cerr << "Adjusting brightness by " << amount << std::endl;
-	changeBrightness( amount );
+	changeBrightness( std::clamp( amount, 1, 100 ) );
 }