Use distance/angle for pan points instead of X/Y.

Panner.C

@@ -24,16 +24,6 @@
 
 /* 2D Panner widget. Supports various multichannel configurations. */
 
-enum {
-    NONE = -1,
-    R    = 90,
-    L    = 270,
-    C   = 0,
-    FL   = 315,
-    FR   = 45,
-    RL   = 225,
-    RR   = 135,
-};
 
 /* multichannel layouts, in degrees */
 int Panner::_configs[][12] =
@@ -97,36 +87,41 @@ Panner::event_point ( void )
     {
         Point *p = &_points[ i ];
 
-        if ( Fl::event_inside( X + ((p->x * (W / 2)) + (W / 2)),
-                               Y + ((p->y * (H / 2)) + (H / 2)), pw(), ph() ) )
+        float px, py;
+
+        p->axes( &px, &py );
+
+        if ( Fl::event_inside( X + ((px * (W / 2)) + (W / 2)),
+                               Y + ((py * (H / 2)) + (H / 2)), pw(), ph() ) )
             return p;
+
     }
 
     return NULL;
 }
 
 /* translate angle /a/ into x/y coords and place the result in /X/ and /Y/ */
-Panner::Point
-Panner::angle_to_axes ( float a )
-{
-    Point p;
+/* Panner::Point */
+/* Panner::angle_to_axes ( float a ) */
+/* { */
+/*     Point p; */
 
-    a -= 90;
-    a = 360 - a;
+/*     a -= 90; */
+/*     a = 360 - a; */
 
-    double A;
+/*     double A; */
 
-    A = a * ( M_PI / 180 );
+/*     A = a * ( M_PI / 180 ); */
 
-    // const float r = tw / 2;
+/*     // const float r = tw / 2; */
 
-    const double  r = 1.0f;
+/*     const double  r = 1.0f; */
 
-    p.x = r * cos( A );
-    p.y = -r * sin( A );
+/*     p.x = r * cos( A ); */
+/*     p.y = -r * sin( A ); */
 
-    return p;
-}
+/*     return p; */
+/* } */
 
 void
 Panner::draw ( void )
@@ -166,8 +161,8 @@ Panner::draw ( void )
 /*             fl_arc( tx, ty, tw, th, a - 20, a + 20 ); */
 /*             fl_line_style( FL_SOLID, 0 ); */
 
-            Point p = angle_to_axes( a );
-//            printf( "%d: %f, %f\n", i, p.x, p.y );
+/*             Point p = angle_to_axes( a ); */
+/* //            printf( "%d: %f, %f\n", i, p.x, p.y ); */
 
             {
                 float A;
@@ -207,17 +202,21 @@ Panner::draw ( void )
 
         fl_color( (Fl_Color) 10 + i );
 
-        const int bx = tx + ((tw / 2) * p->x + (tw / 2));
-        const int by = ty + ((th / 2) * p->y + (th / 2));
+        float px, py;
+
+        p->axes( &px, &py );
 
-        fl_rectf( bx, by, pw(), ph() );
+        const int bx = tx + ((tw / 2) * px + (tw / 2));
+        const int by = ty + ((th / 2) * py + (th / 2));
+
+        fl_pie( bx, by, pw(), ph(), 0, 360 );
 
         char pat[4];
         snprintf( pat, 4, "%d", i + 1 );
 
         fl_color( FL_BLACK );
         fl_font( FL_HELVETICA, ph() + 2 );
-        fl_draw( pat, bx, by + ph() );
+        fl_draw( pat, bx + 1, by + 1, pw() - 1, ph() - 1, FL_ALIGN_CENTER );
     }
 }
 
@@ -246,10 +245,12 @@ Panner::handle ( int m )
             float X = Fl::event_x() - x();
             float Y = Fl::event_y() - y();
 
-            drag->x = (float)(X / (w() / 2)) - 1.0f;
-            drag->y = (float)(Y / (h() / 2)) - 1.0f;
+            drag->angle( (float)(X / (w() / 2)) - 1.0f, (float)(Y / (h() / 2)) - 1.0f );
+
+/*             drag->x = (float)(X / (w() / 2)) - 1.0f; */
+/*             drag->y = (float)(Y / (h() / 2)) - 1.0f; */
 
-            printf( "%f\n", drag->distance( angle_to_axes( _configs[ _outs ][ 0 ] ) ) );
+/*             printf( "%f\n", drag->distance( angle_to_axes( _configs[ _outs ][ 0 ] ) ) ); */
 
             redraw();
 

Panner.H

@@ -34,18 +34,67 @@ class Panner : public Fl_Widget
     struct Point
     {
         /* axes */
-        float x, y;
 
-        Point ( ) : x( 0.0f ), y( 0.0f ) { }
-        Point ( float X, float Y ) : x( X ), y( Y ) { }
+        /* distance from center (from 0 to 1) */
+        float d;
+        /* angle */
+        float a;
 
+        Point ( ) : d( 0.0f ), a( 0.0f ) { }
+        Point ( float X, float Y ) : d( X ), a( Y ) { }
 
-        /* return the distance between the point and that referenced by /p/ */
+        /** translate angle /a/ into x/y coords and place the result in /X/ and /Y/ */
+        void
+        axes ( float *X, float *Y ) const
+            {
+                /* rotate */
+                float A = ( 270 - a ) * ( M_PI / 180 );
+
+                *X = -d * cosf( A );
+                *Y = d * sinf( A );
+            }
+
+        void
+        angle ( float X1, float Y1 )
+            {
+
+                float X2, Y2;
+
+                Y2 = X2 = 0;
+
+                float t;
+
+                t = atan2( X2 - X1, Y2 - Y1 );
+
+                a = t * (180 / M_PI);
+
+                if ( a < 0 )
+                    a = 360 + a;
+
+                a = 360 - a;
+
+                /* standard distance calculation */
+                d = sqrt( pow( X2 - X1, 2 ) + pow( Y2 - Y1, 2 ) );
+
+                if ( d > 1.0f )
+                    d = 1.0f;
+            }
+
+        /** return the distance between the point and that referenced by /p/ */
         float
         distance ( const Point &p )
             {
-                return sqrt( pow( x - p.x, 2 ) + pow( y - p.y, 2 ) );
+                /* first, transform point coords */
+
+                float x1, y1, x2, y2;
+
+                axes( &x1, &y1 );
+                p.axes( &x2, &y2 );
+
+                /* standard distance calculation */
+                return sqrt( pow( x1 - x2, 2 ) + pow( y1 - y2, 2 ) );
             }
+
     };
 
 
@@ -55,8 +104,8 @@ class Panner : public Fl_Widget
 
     vector <Point> _points;
 
-    static int pw ( void ) { return 6; }
-    static int ph ( void ) { return 6; }
+    static int pw ( void ) { return 12; }
+    static int ph ( void ) { return 12; }
 
     static int _configs[][12];
 
@@ -71,16 +120,28 @@ class Panner : public Fl_Widget
     Point * event_point ( void );
     Point angle_to_axes ( float a );
 
+    enum {
+        NONE = -1,
+        R    = 90,
+        L    = 270,
+        C   = 0,
+        FL   = 315,
+        FR   = 45,
+        RL   = 225,
+        RR   = 135,
+    };
+
 public:
 
+
     Panner ( int X, int Y, int W, int H, const char *L = 0 ) :
         Fl_Widget( X, Y, W, H, L )
         {
             _ins = _outs = 4;
-            _points.push_back( Point( -1, -1 ) );
-            _points.push_back( Point( 1, 1 ) );
-            _points.push_back( Point( -1, 1 ) );
-            _points.push_back( Point( 1, -1 ) );
+            _points.push_back( Point( 1, FL ) );
+            _points.push_back( Point( 1, FR ) );
+            _points.push_back( Point( 1, RL ) );
+            _points.push_back( Point( 1, RR ) );
 
             _outs = 5;
         }