some modest improvements in the html rendering of key bindings, plus use of normal...
[ardour.git] / libs / gtkmm2ext / pixfader.cc
index 744f234a85cbddaabe0a186aa13c90f711803b7a..64ee449646e5f310d824258bccd61a29d6150933 100644 (file)
@@ -33,25 +33,31 @@ using namespace Gtkmm2ext;
 using namespace Gtk;
 using namespace std;
 
-#define CORNER_RADIUS 4
+#define CORNER_RADIUS 2.5
 #define CORNER_SIZE   2
 #define CORNER_OFFSET 1
-#define FADER_RESERVE 5
+#define FADER_RESERVE 6
 
 std::list<PixFader::FaderImage*> PixFader::_patterns;
 
 PixFader::PixFader (Gtk::Adjustment& adj, int orientation, int fader_length, int fader_girth)
-       : adjustment (adj)
-       , span (fader_length)
-       , girth (fader_girth)
+       : _layout (0)
+       , _tweaks (Tweaks(0))
+       , _adjustment (adj)
+       , _text_width (0)
+       , _text_height (0)
+       , _span (fader_length)
+       , _girth (fader_girth)
+       , _min_span (fader_length)
+       , _min_girth (fader_girth)
        , _orien (orientation)
-       , pattern (0)
+       , _pattern (0)
        , _hovering (false)
-       , last_drawn (-1)
-       , dragging (false)
+       , _dragging (false)
+       , _centered_text (true)
        , _current_parent (0)
 {
-       default_value = adjustment.get_value();
+       _default_value = _adjustment.get_value();
        update_unity_position ();
 
        add_events (
@@ -63,21 +69,31 @@ PixFader::PixFader (Gtk::Adjustment& adj, int orientation, int fader_length, int
                        | Gdk::LEAVE_NOTIFY_MASK
                        );
 
-       adjustment.signal_value_changed().connect (mem_fun (*this, &PixFader::adjustment_changed));
-       adjustment.signal_changed().connect (mem_fun (*this, &PixFader::adjustment_changed));
-
+       _adjustment.signal_value_changed().connect (mem_fun (*this, &PixFader::adjustment_changed));
+       _adjustment.signal_changed().connect (mem_fun (*this, &PixFader::adjustment_changed));
+       signal_grab_broken_event ().connect (mem_fun (*this, &PixFader::on_grab_broken_event));
        if (_orien == VERT) {
-               DrawingArea::set_size_request(girth, span);
+               CairoWidget::set_size_request(_girth, _span);
        } else {
-               DrawingArea::set_size_request(span, girth);
+               CairoWidget::set_size_request(_span, _girth);
        }
 }
 
 PixFader::~PixFader ()
 {
        if (_parent_style_change) _parent_style_change.disconnect();
+       if (_layout) _layout.clear (); // drop reference to existing layout
+}
+
+void
+PixFader::flush_pattern_cache () {
+       for (list<FaderImage*>::iterator f = _patterns.begin(); f != _patterns.end(); ++f) {
+               cairo_pattern_destroy ((*f)->pattern);
+       }
+       _patterns.clear();
 }
 
+
 cairo_pattern_t*
 PixFader::find_pattern (double afr, double afg, double afb,
                        double abr, double abg, double abb,
@@ -108,13 +124,6 @@ PixFader::create_patterns ()
        bg = c.get_green_p ();
        bb = c.get_blue_p ();
 
-       if ( _layout && !_text.empty()) {
-               _layout->get_pixel_size (_text_width, _text_height);
-       } else {
-               _text_width = 0;
-               _text_height = 0;
-       }
-
        cairo_surface_t* surface;
        cairo_t* tc = 0;
 
@@ -122,7 +131,7 @@ PixFader::create_patterns ()
                return;
        }
 
-       if ((pattern = find_pattern (fr, fg, fb, br, bg, bb, get_width(), get_height())) != 0) {
+       if ((_pattern = find_pattern (fr, fg, fb, br, bg, bb, get_width(), get_height())) != 0) {
                /* found it - use it */
                return;
        }
@@ -135,8 +144,9 @@ PixFader::create_patterns ()
                /* paint background + border */
 
                cairo_pattern_t* shade_pattern = cairo_pattern_create_linear (0.0, 0.0, get_width(), 0);
-               cairo_pattern_add_color_stop_rgba (shade_pattern, 0, br*0.8,bg*0.8,bb*0.8, 1.0);
-               cairo_pattern_add_color_stop_rgba (shade_pattern, 1, br*0.6,bg*0.6,bb*0.6, 1.0);
+               cairo_pattern_add_color_stop_rgba (shade_pattern, 0, br*0.4,bg*0.4,bb*0.4, 1.0);
+               cairo_pattern_add_color_stop_rgba (shade_pattern, 0.25, br*0.6,bg*0.6,bb*0.6, 1.0);
+               cairo_pattern_add_color_stop_rgba (shade_pattern, 1, br*0.8,bg*0.8,bb*0.8, 1.0);
                cairo_set_source (tc, shade_pattern);
                cairo_rectangle (tc, 0, 0, get_width(), get_height() * 2.0);
                cairo_fill (tc);
@@ -155,7 +165,7 @@ PixFader::create_patterns ()
 
                cairo_pattern_destroy (shade_pattern);
 
-               pattern = cairo_pattern_create_for_surface (surface);
+               _pattern = cairo_pattern_create_for_surface (surface);
 
        } else {
 
@@ -165,8 +175,9 @@ PixFader::create_patterns ()
                /* paint right shade (background section)*/
 
                cairo_pattern_t* shade_pattern = cairo_pattern_create_linear (0.0, 0.0, 0.0, get_height());
-               cairo_pattern_add_color_stop_rgba (shade_pattern, 0, br*0.8,bg*0.8,bb*0.8, 1.0);
-               cairo_pattern_add_color_stop_rgba (shade_pattern, 1, br*0.6,bg*0.6,bb*0.6, 1.0);
+               cairo_pattern_add_color_stop_rgba (shade_pattern, 0, br*0.4,bg*0.4,bb*0.4, 1.0);
+               cairo_pattern_add_color_stop_rgba (shade_pattern, 0.25, br*0.6,bg*0.6,bb*0.6, 1.0);
+               cairo_pattern_add_color_stop_rgba (shade_pattern, 1, br*0.8,bg*0.8,bb*0.8, 1.0);
                cairo_set_source (tc, shade_pattern);
                cairo_rectangle (tc, 0, 0, get_width() * 2.0, get_height());
                cairo_fill (tc);
@@ -182,32 +193,25 @@ PixFader::create_patterns ()
                cairo_fill (tc);
                cairo_pattern_destroy (shade_pattern);
 
-               pattern = cairo_pattern_create_for_surface (surface);
+               _pattern = cairo_pattern_create_for_surface (surface);
        }
 
        /* cache it for others to use */
 
-       _patterns.push_back (new FaderImage (pattern, fr, fg, fb, br, bg, bb, get_width(), get_height()));
+       _patterns.push_back (new FaderImage (_pattern, fr, fg, fb, br, bg, bb, get_width(), get_height()));
 
        cairo_destroy (tc);
        cairo_surface_destroy (surface);
 }
 
-bool
-PixFader::on_expose_event (GdkEventExpose* ev)
+void
+PixFader::render (cairo_t *cr, cairo_rectangle_t* area)
 {
-       Cairo::RefPtr<Cairo::Context> context = get_window()->create_cairo_context();
-       cairo_t* cr = context->cobj();
-
-       // clip to expose area
-       cairo_rectangle (cr, ev->area.x, ev->area.y, ev->area.width, ev->area.height);
-       cairo_clip (cr);
-
-       if (!pattern) {
+       if (!_pattern) {
                create_patterns();
        }
 
-       if (!pattern) {
+       if (!_pattern) {
                /* this isn't supposed to be happen, but some wackiness whereby
                 * the pixfader ends up with a 1xN or Nx1 size allocation
                 * leads to it. the basic wackiness needs fixing but we
@@ -216,11 +220,12 @@ PixFader::on_expose_event (GdkEventExpose* ev)
                 */
 
                CairoWidget::set_source_rgb_a (cr, get_style()->get_bg (get_state()), 1);
-               cairo_rectangle (cr, ev->area.x, ev->area.y, ev->area.width, ev->area.height);
+               cairo_rectangle (cr, area->x, area->y, area->width, area->height);
                cairo_fill (cr);
-               return true;
+               return;
        }
 
+       OnExpose();
        int ds = display_span ();
        const float w = get_width();
        const float h = get_height();
@@ -229,13 +234,13 @@ PixFader::on_expose_event (GdkEventExpose* ev)
        cairo_rectangle (cr, 0, 0, w, h);
        cairo_fill(cr);
 
-       cairo_set_line_width (cr, 1);
+       cairo_set_line_width (cr, 2);
        cairo_set_source_rgba (cr, 0, 0, 0, 1.0);
 
        cairo_matrix_t matrix;
        Gtkmm2ext::rounded_rectangle (cr, CORNER_OFFSET, CORNER_OFFSET, w-CORNER_SIZE, h-CORNER_SIZE, CORNER_RADIUS);
-       // we use a 'trick' here: The stoke is off by .5px but filling the interiour area
-       // results in an outline of 0.5 px the actual outline is exatly 1px at 50% alpha.
+       // we use a 'trick' here: The stoke is off by .5px but filling the interior area
+       // after a stroke of 2px width results in an outline of 1px
        cairo_stroke_preserve(cr);
 
        if (_orien == VERT) {
@@ -245,9 +250,9 @@ PixFader::on_expose_event (GdkEventExpose* ev)
                }
 
                if (!CairoWidget::flat_buttons() ) {
-                       cairo_set_source (cr, pattern);
+                       cairo_set_source (cr, _pattern);
                        cairo_matrix_init_translate (&matrix, 0, (h - ds));
-                       cairo_pattern_set_matrix (pattern, &matrix);
+                       cairo_pattern_set_matrix (_pattern, &matrix);
                } else {
                        CairoWidget::set_source_rgb_a (cr, get_style()->get_bg (get_state()), 1);
                        cairo_fill (cr);
@@ -275,89 +280,96 @@ PixFader::on_expose_event (GdkEventExpose* ev)
                 */
 
                if (!CairoWidget::flat_buttons() ) {
-                       cairo_set_source (cr, pattern);
+                       cairo_set_source (cr, _pattern);
                        cairo_matrix_init_translate (&matrix, w - ds, 0);
-                       cairo_pattern_set_matrix (pattern, &matrix);
+                       cairo_pattern_set_matrix (_pattern, &matrix);
                } else {
                        CairoWidget::set_source_rgb_a (cr, get_style()->get_bg (get_state()), 1);
                        cairo_fill (cr);
                        CairoWidget::set_source_rgb_a (cr, get_style()->get_fg (get_state()), 1);
                        Gtkmm2ext::rounded_rectangle (cr, CORNER_OFFSET, CORNER_OFFSET,
-                                       ds - CORNER_OFFSET, h - CORNER_SIZE, CORNER_RADIUS);
+                                       ds - CORNER_SIZE, h - CORNER_SIZE, CORNER_RADIUS);
                }
                cairo_fill (cr);
        }
 
        /* draw the unity-position line if it's not at either end*/
-       if (unity_loc > 0) {
-               context->set_line_width (1);
-               context->set_line_cap (Cairo::LINE_CAP_ROUND);
+       if (!(_tweaks & NoShowUnityLine) && _unity_loc > CORNER_RADIUS) {
+               cairo_set_line_width(cr, 1);
+               cairo_set_line_cap(cr, CAIRO_LINE_CAP_ROUND);
                Gdk::Color c = get_style()->get_fg (Gtk::STATE_ACTIVE);
-               context->set_source_rgba (c.get_red_p()*1.5, c.get_green_p()*1.5, c.get_blue_p()*1.5, 0.85);
-               if ( _orien == VERT) {
-                       if (unity_loc < h ) {
-                               context->move_to (1.5, unity_loc + CORNER_OFFSET + .5);
-                               context->line_to (girth - 1.5, unity_loc + CORNER_OFFSET + .5);
-                               context->stroke ();
+               cairo_set_source_rgba (cr, c.get_red_p() * 1.5, c.get_green_p() * 1.5, c.get_blue_p() * 1.5, 0.85);
+               if (_orien == VERT) {
+                       if (_unity_loc < h - CORNER_RADIUS) {
+                               cairo_move_to (cr, 1.5, _unity_loc + CORNER_OFFSET + .5);
+                               cairo_line_to (cr, _girth - 1.5, _unity_loc + CORNER_OFFSET + .5);
+                               cairo_stroke (cr);
                        }
                } else {
-                       if ( unity_loc < w ){
-                               context->move_to (unity_loc - CORNER_OFFSET + .5, 1.5);
-                               context->line_to (unity_loc - CORNER_OFFSET + .5, girth - 1.5);
-                               context->stroke ();
+                       if (_unity_loc < w - CORNER_RADIUS) {
+                               cairo_move_to (cr, _unity_loc - CORNER_OFFSET + .5, 1.5);
+                               cairo_line_to (cr, _unity_loc - CORNER_OFFSET + .5, _girth - 1.5);
+                               cairo_stroke (cr);
                        }
                }
        }
 
-       if ( !_text.empty() ) {
-               /* center text */
-               cairo_new_path (cr);
-               cairo_move_to (cr, (get_width() - _text_width)/2.0, get_height()/2.0 - _text_height/2.0);
+       if (_layout && !_text.empty() && _orien == HORIZ) {
+               cairo_save (cr);
+               if (_centered_text) {
+                       /* center text */
+                       cairo_move_to (cr, (w - _text_width)/2.0, h/2.0 - _text_height/2.0);
+               } else if (ds > .5 * w) {
+                       cairo_move_to (cr, CORNER_OFFSET + 3, h/2.0 - _text_height/2.0);
+                       cairo_set_operator(cr, CAIRO_OPERATOR_XOR);
+               } else {
+                       cairo_move_to (cr, w - _text_width - CORNER_OFFSET - 3, h/2.0 - _text_height/2.0);
+               }
                CairoWidget::set_source_rgb_a (cr, get_style()->get_text (get_state()), 1);
                pango_cairo_show_layout (cr, _layout->gobj());
+               cairo_restore (cr);
        }
 
        if (!get_sensitive()) {
                Gtkmm2ext::rounded_rectangle (cr, CORNER_OFFSET, CORNER_OFFSET, w-CORNER_SIZE, h-CORNER_SIZE, CORNER_RADIUS);
                cairo_set_source_rgba (cr, 0.505, 0.517, 0.525, 0.4);
                cairo_fill (cr);
-       } else if (_hovering) {
+       } else if (_hovering && CairoWidget::widget_prelight()) {
                Gtkmm2ext::rounded_rectangle (cr, CORNER_OFFSET, CORNER_OFFSET, w-CORNER_SIZE, h-CORNER_SIZE, CORNER_RADIUS);
                cairo_set_source_rgba (cr, 0.905, 0.917, 0.925, 0.1);
                cairo_fill (cr);
        }
-
-       last_drawn = ds;
-
-       return true;
 }
 
 void
 PixFader::on_size_request (GtkRequisition* req)
 {
        if (_orien == VERT) {
-               req->width = (girth ? girth : -1);
-               req->height = (span ? span : -1);
+               req->width = (_min_girth ? _min_girth : -1);
+               req->height = (_min_span ? _min_span : -1);
        } else {
-               req->height = (girth ? girth : -1);
-               req->width = (span ? span : -1);
+               req->height = (_min_girth ? _min_girth : -1);
+               req->width = (_min_span ? _min_span : -1);
        }
 }
 
 void
 PixFader::on_size_allocate (Gtk::Allocation& alloc)
 {
-       DrawingArea::on_size_allocate(alloc);
+       int old_girth = _girth;
+       int old_span = _span;
+
+       CairoWidget::on_size_allocate(alloc);
 
        if (_orien == VERT) {
-               girth = alloc.get_width ();
-               span = alloc.get_height ();
+               _girth = alloc.get_width ();
+               _span = alloc.get_height ();
        } else {
-               girth = alloc.get_height ();
-               span = alloc.get_width ();
+               _girth = alloc.get_height ();
+               _span = alloc.get_width ();
        }
 
-       if (is_realized()) {
+       if (is_realized() && ((old_girth != _girth) || (old_span != _span))) {
                /* recreate patterns in case we've changed size */
                create_patterns ();
        }
@@ -365,11 +377,29 @@ PixFader::on_size_allocate (Gtk::Allocation& alloc)
        update_unity_position ();
 }
 
+bool
+PixFader::on_grab_broken_event (GdkEventGrabBroken* ev)
+{
+       if (_dragging) {
+               remove_modal_grab();
+               _dragging = false;
+               gdk_pointer_ungrab (GDK_CURRENT_TIME);
+               StopGesture ();
+       }
+       return (_tweaks & NoButtonForward) ? true : false;
+}
+
 bool
 PixFader::on_button_press_event (GdkEventButton* ev)
 {
        if (ev->type != GDK_BUTTON_PRESS) {
-               return true;
+               if (_dragging) {
+                       remove_modal_grab();
+                       _dragging = false;
+                       gdk_pointer_ungrab (GDK_CURRENT_TIME);
+                       StopGesture ();
+               }
+               return (_tweaks & NoButtonForward) ? true : false;
        }
 
        if (ev->button != 1 && ev->button != 2) {
@@ -377,10 +407,11 @@ PixFader::on_button_press_event (GdkEventButton* ev)
        }
 
        add_modal_grab ();
-       grab_loc = (_orien == VERT) ? ev->y : ev->x;
-       grab_start = (_orien == VERT) ? ev->y : ev->x;
-       grab_window = ev->window;
-       dragging = true;
+       StartGesture ();
+       _grab_loc = (_orien == VERT) ? ev->y : ev->x;
+       _grab_start = (_orien == VERT) ? ev->y : ev->x;
+       _grab_window = ev->window;
+       _dragging = true;
        gdk_pointer_grab(ev->window,false,
                        GdkEventMask( Gdk::POINTER_MOTION_MASK | Gdk::BUTTON_PRESS_MASK |Gdk::BUTTON_RELEASE_MASK),
                        NULL,NULL,ev->time);
@@ -389,39 +420,46 @@ PixFader::on_button_press_event (GdkEventButton* ev)
                set_adjustment_from_event (ev);
        }
 
-       return true;
+       return (_tweaks & NoButtonForward) ? true : false;
 }
 
 bool
 PixFader::on_button_release_event (GdkEventButton* ev)
 {
-       double const ev_pos = (_orien == VERT) ? ev->y : ev->x;
+       double ev_pos = (_orien == VERT) ? ev->y : ev->x;
 
        switch (ev->button) {
        case 1:
-               if (dragging) {
+               if (_dragging) {
                        remove_modal_grab();
-                       dragging = false;
+                       _dragging = false;
                        gdk_pointer_ungrab (GDK_CURRENT_TIME);
+                       StopGesture ();
 
                        if (!_hovering) {
-                               Keyboard::magic_widget_drop_focus();
+                               if (!(_tweaks & NoVerticalScroll)) {
+                                       Keyboard::magic_widget_drop_focus();
+                               }
                                queue_draw ();
                        }
 
-                       if (ev_pos == grab_start) {
-
+                       if (ev_pos == _grab_start) {
                                /* no motion - just a click */
+                               ev_pos = rint(ev_pos);
 
                                if (ev->state & Keyboard::TertiaryModifier) {
-                                       adjustment.set_value (default_value);
+                                       _adjustment.set_value (_default_value);
                                } else if (ev->state & Keyboard::GainFineScaleModifier) {
-                                       adjustment.set_value (adjustment.get_lower());
-                               } else if ((_orien == VERT && ev_pos < display_span()) || (_orien == HORIZ && ev_pos > display_span())) {
+                                       _adjustment.set_value (_adjustment.get_lower());
+#if 0 // ignore clicks
+                               } else if (ev_pos == slider_pos) {
+                                       ; // click on current position, no move.
+                               } else if ((_orien == VERT && ev_pos < slider_pos) || (_orien == HORIZ && ev_pos > slider_pos)) {
                                        /* above the current display height, remember X Window coords */
-                                       adjustment.set_value (adjustment.get_value() + adjustment.get_step_increment());
+                                       _adjustment.set_value (_adjustment.get_value() + _adjustment.get_step_increment());
                                } else {
-                                       adjustment.set_value (adjustment.get_value() - adjustment.get_step_increment());
+                                       _adjustment.set_value (_adjustment.get_value() - _adjustment.get_step_increment());
+#endif
                                }
                        }
                        return true;
@@ -429,9 +467,10 @@ PixFader::on_button_release_event (GdkEventButton* ev)
                break;
 
        case 2:
-               if (dragging) {
+               if (_dragging) {
                        remove_modal_grab();
-                       dragging = false;
+                       _dragging = false;
+                       StopGesture ();
                        set_adjustment_from_event (ev);
                        gdk_pointer_ungrab (GDK_CURRENT_TIME);
                        return true;
@@ -441,7 +480,6 @@ PixFader::on_button_release_event (GdkEventButton* ev)
        default:
                break;
        }
-
        return false;
 }
 
@@ -453,51 +491,46 @@ PixFader::on_scroll_event (GdkEventScroll* ev)
 
        if (ev->state & Keyboard::GainFineScaleModifier) {
                if (ev->state & Keyboard::GainExtraFineScaleModifier) {
-                       scale = 0.01;
+                       scale = 0.005;
                } else {
-                       scale = 0.05;
+                       scale = 0.1;
                }
        } else {
-               scale = 0.25;
+               scale = 1.0;
        }
 
        if (_orien == VERT) {
-
-               /* should left/right scroll affect vertical faders ? */
-
                switch (ev->direction) {
-
-               case GDK_SCROLL_UP:
-                       adjustment.set_value (adjustment.get_value() + (adjustment.get_page_increment() * scale));
-                       ret = true;
-                       break;
-               case GDK_SCROLL_DOWN:
-                       adjustment.set_value (adjustment.get_value() - (adjustment.get_page_increment() * scale));
-                       ret = true;
-                       break;
-               default:
-                       break;
+                       case GDK_SCROLL_UP:
+                               _adjustment.set_value (_adjustment.get_value() + (_adjustment.get_page_increment() * scale));
+                               ret = true;
+                               break;
+                       case GDK_SCROLL_DOWN:
+                               _adjustment.set_value (_adjustment.get_value() - (_adjustment.get_page_increment() * scale));
+                               ret = true;
+                               break;
+                       default:
+                               break;
                }
        } else {
+               int dir = ev->direction;
 
-               /* up/down scrolls should definitely affect horizontal faders
-                  because they are so much easier to use
-               */
-
-               switch (ev->direction) {
+               if (ev->state & Keyboard::ScrollHorizontalModifier || !(_tweaks & NoVerticalScroll)) {
+                       if (ev->direction == GDK_SCROLL_UP) dir = GDK_SCROLL_RIGHT;
+                       if (ev->direction == GDK_SCROLL_DOWN) dir = GDK_SCROLL_LEFT;
+               }
 
-               case GDK_SCROLL_RIGHT:
-               case GDK_SCROLL_UP:
-                       adjustment.set_value (adjustment.get_value() + (adjustment.get_page_increment() * scale));
-                       ret = true;
-                       break;
-               case GDK_SCROLL_LEFT:
-               case GDK_SCROLL_DOWN:
-                       adjustment.set_value (adjustment.get_value() - (adjustment.get_page_increment() * scale));
-                       ret = true;
-                       break;
-               default:
-                       break;
+               switch (dir) {
+                       case GDK_SCROLL_RIGHT:
+                               _adjustment.set_value (_adjustment.get_value() + (_adjustment.get_page_increment() * scale));
+                               ret = true;
+                               break;
+                       case GDK_SCROLL_LEFT:
+                               _adjustment.set_value (_adjustment.get_value() - (_adjustment.get_page_increment() * scale));
+                               ret = true;
+                               break;
+                       default:
+                               break;
                }
        }
        return ret;
@@ -506,27 +539,29 @@ PixFader::on_scroll_event (GdkEventScroll* ev)
 bool
 PixFader::on_motion_notify_event (GdkEventMotion* ev)
 {
-       if (dragging) {
+       if (_dragging) {
                double scale = 1.0;
                double const ev_pos = (_orien == VERT) ? ev->y : ev->x;
 
-               if (ev->window != grab_window) {
-                       grab_loc = ev_pos;
-                       grab_window = ev->window;
+               if (ev->window != _grab_window) {
+                       _grab_loc = ev_pos;
+                       _grab_window = ev->window;
                        return true;
                }
 
                if (ev->state & Keyboard::GainFineScaleModifier) {
                        if (ev->state & Keyboard::GainExtraFineScaleModifier) {
-                               scale = 0.05;
+                               scale = 0.005;
                        } else {
                                scale = 0.1;
                        }
                }
 
-               double const delta = ev_pos - grab_loc;
-               grab_loc = ev_pos;
+               double const delta = ev_pos - _grab_loc;
+               _grab_loc = ev_pos;
 
+               const double off  = FADER_RESERVE + ((_orien == VERT) ? CORNER_OFFSET : 0);
+               const double span = _span - off;
                double fract = (delta / span);
 
                fract = min (1.0, fract);
@@ -538,7 +573,7 @@ PixFader::on_motion_notify_event (GdkEventMotion* ev)
                        fract = -fract;
                }
 
-               adjustment.set_value (adjustment.get_value() + scale * fract * (adjustment.get_upper() - adjustment.get_lower()));
+               _adjustment.set_value (_adjustment.get_value() + scale * fract * (_adjustment.get_upper() - _adjustment.get_lower()));
        }
 
        return true;
@@ -547,21 +582,23 @@ PixFader::on_motion_notify_event (GdkEventMotion* ev)
 void
 PixFader::adjustment_changed ()
 {
-       if (display_span() != last_drawn) {
-               queue_draw ();
-       }
+       queue_draw ();
 }
 
 /** @return pixel offset of the current value from the right or bottom of the fader */
 int
 PixFader::display_span ()
 {
-       float fract = (adjustment.get_value () - adjustment.get_lower()) / ((adjustment.get_upper() - adjustment.get_lower()));
+       float fract = (_adjustment.get_value () - _adjustment.get_lower()) / ((_adjustment.get_upper() - _adjustment.get_lower()));
        int ds;
        if (_orien == VERT) {
-               ds = (int)floor (span * (1.0 - fract));
+               const double off  = FADER_RESERVE + CORNER_OFFSET;
+               const double span = _span - off;
+               ds = (int)rint (span * (1.0 - fract));
        } else {
-               ds = (int)floor (span * fract);
+               const double off  = FADER_RESERVE;
+               const double span = _span - off;
+               ds = (int)rint (span * fract + off);
        }
 
        return ds;
@@ -571,9 +608,11 @@ void
 PixFader::update_unity_position ()
 {
        if (_orien == VERT) {
-               unity_loc = (int) rint (span * (1 - ((default_value - adjustment.get_lower()) / (adjustment.get_upper() - adjustment.get_lower())))) - 1;
+               const double span = _span - FADER_RESERVE - CORNER_OFFSET;
+               _unity_loc = (int) rint (span * (1 - ((_default_value - _adjustment.get_lower()) / (_adjustment.get_upper() - _adjustment.get_lower())))) - 1;
        } else {
-               unity_loc = (int) rint ((default_value - adjustment.get_lower()) * span / (adjustment.get_upper() - adjustment.get_lower()));
+               const double span = _span - FADER_RESERVE;
+               _unity_loc = (int) rint (FADER_RESERVE + (_default_value - _adjustment.get_lower()) * span / (_adjustment.get_upper() - _adjustment.get_lower()));
        }
 
        queue_draw ();
@@ -583,7 +622,9 @@ bool
 PixFader::on_enter_notify_event (GdkEventCrossing*)
 {
        _hovering = true;
-       Keyboard::magic_widget_grab_focus ();
+       if (!(_tweaks & NoVerticalScroll)) {
+               Keyboard::magic_widget_grab_focus ();
+       }
        queue_draw ();
        return false;
 }
@@ -591,9 +632,11 @@ PixFader::on_enter_notify_event (GdkEventCrossing*)
 bool
 PixFader::on_leave_notify_event (GdkEventCrossing*)
 {
-       if (!dragging) {
+       if (!_dragging) {
                _hovering = false;
-               Keyboard::magic_widget_drop_focus();
+               if (!(_tweaks & NoVerticalScroll)) {
+                       Keyboard::magic_widget_drop_focus();
+               }
                queue_draw ();
        }
        return false;
@@ -602,37 +645,54 @@ PixFader::on_leave_notify_event (GdkEventCrossing*)
 void
 PixFader::set_adjustment_from_event (GdkEventButton* ev)
 {
-       double fract = (_orien == VERT) ? (1.0 - (ev->y / span)) : (ev->x / span);
+       const double off  = FADER_RESERVE + ((_orien == VERT) ? CORNER_OFFSET : 0);
+       const double span = _span - off;
+       double fract = (_orien == VERT) ? (1.0 - ((ev->y - off) / span)) : ((ev->x - off) / span);
 
        fract = min (1.0, fract);
        fract = max (0.0, fract);
 
-       adjustment.set_value (fract * (adjustment.get_upper () - adjustment.get_lower ()));
+       _adjustment.set_value (fract * (_adjustment.get_upper () - _adjustment.get_lower ()));
 }
 
 void
 PixFader::set_default_value (float d)
 {
-       default_value = d;
+       _default_value = d;
        update_unity_position ();
 }
 
 void
-PixFader::set_text (const std::string& str)
+PixFader::set_tweaks (Tweaks t)
 {
-       _text = str;
+       bool need_redraw = false;
+       if ((_tweaks & NoShowUnityLine) ^ (t & NoShowUnityLine)) {
+               need_redraw = true;
+       }
+       _tweaks = t;
+       if (need_redraw) {
+               queue_draw();
+       }
+}
 
-       if (!_layout && !_text.empty()) {
+void
+PixFader::set_text (const std::string& str, bool centered, bool expose)
+{
+       if (_layout && _text == str) {
+               return;
+       }
+       if (!_layout && !str.empty()) {
                _layout = Pango::Layout::create (get_pango_context());
-               // XXX explicityly unref in dtor?
        }
 
+       _text = str;
+       _centered_text = centered;
        if (_layout) {
                _layout->set_text (str);
                _layout->get_pixel_size (_text_width, _text_height);
+               // queue_resize ();
+               if (expose) queue_draw ();
        }
-
-       queue_resize ();
 }
 
 void
@@ -649,11 +709,12 @@ PixFader::on_style_changed (const Glib::RefPtr<Gtk::Style>&)
        if (_layout) {
                std::string txt = _layout->get_text();
                _layout.clear (); // drop reference to existing layout
-               set_text (txt);
+               _text = "";
+               set_text (txt, _centered_text, false);
        }
-       /* patterns are cached and re-created as needed 
+       /* patterns are cached and re-created as needed
         * during 'expose' in the GUI thread */
-       pattern = 0;
+       _pattern = 0;
        queue_draw ();
 }