+ Cairo::RefPtr<Cairo::Context> context = get_window()->create_cairo_context();
+
+ int width, height;
+ double pos = position_control->get_value (); /* 0..1 */
+ double swidth = width_control->get_value (); /* -1..+1 */
+ double fswidth = fabs (swidth);
+ uint32_t o, f, t, b, r;
+ State state;
+ const double corner_radius = 5.0;
+
+ width = get_width();
+ height = get_height ();
+
+ if (swidth == 0.0) {
+ state = Mono;
+ } else if (swidth < 0.0) {
+ state = Inverted;
+ } else {
+ state = Normal;
+ }
+
+ o = colors[state].outline;
+ f = colors[state].fill;
+ t = colors[state].text;
+ b = colors[state].background;
+ r = colors[state].rule;
+
+ /* background */
+
+ context->set_source_rgba (UINT_RGBA_R_FLT(b), UINT_RGBA_G_FLT(b), UINT_RGBA_B_FLT(b), UINT_RGBA_A_FLT(b));
+ cairo_rectangle (context->cobj(), 0, 0, width, height);
+ context->fill ();
+
+ /* the usable width is reduced from the real width, because we need space for
+ the two halves of LR boxes that will extend past the actual left/right
+ positions (indicated by the vertical line segment above them).
+ */
+
+ double usable_width = width - lr_box_size;
+
+ /* compute the centers of the L/R boxes based on the current stereo width */
+
+ if (fmod (usable_width,2.0) == 0) {
+ /* even width, but we need odd, so that there is an exact center.
+ So, offset cairo by 1, and reduce effective width by 1
+ */
+ usable_width -= 1.0;
+ context->translate (1.0, 0.0);
+ }
+
+ double center = (lr_box_size/2.0) + (usable_width * pos);
+ const double pan_spread = (fswidth * usable_width)/2.0;
+ const double half_lr_box = lr_box_size/2.0;
+ int left;
+ int right;
+
+ left = center - pan_spread; // center of left box
+ right = center + pan_spread; // center of right box
+
+ /* center line */
+
+ context->set_line_width (1.0);
+ context->move_to ((usable_width + lr_box_size)/2.0, 0);
+ context->rel_line_to (0, height);
+ context->set_source_rgba (UINT_RGBA_R_FLT(r), UINT_RGBA_G_FLT(r), UINT_RGBA_B_FLT(r), UINT_RGBA_A_FLT(r));
+ context->stroke ();
+
+ /* compute & draw the line through the box */
+
+ context->set_line_width (2);
+ context->set_source_rgba (UINT_RGBA_R_FLT(o), UINT_RGBA_G_FLT(o), UINT_RGBA_B_FLT(o), UINT_RGBA_A_FLT(o));
+ context->move_to (left, top_step+(pos_box_size/2.0)+step_down);
+ context->line_to (left, top_step+(pos_box_size/2.0));
+ context->line_to (right, top_step+(pos_box_size/2.0));
+ context->line_to (right, top_step+(pos_box_size/2.0) + step_down);
+ context->stroke ();
+
+ /* left box */
+
+ rounded_rectangle (context, left - half_lr_box,
+ half_lr_box+step_down,
+ lr_box_size, lr_box_size, corner_radius);
+ context->set_source_rgba (UINT_RGBA_R_FLT(o), UINT_RGBA_G_FLT(o), UINT_RGBA_B_FLT(o), UINT_RGBA_A_FLT(o));
+ context->stroke_preserve ();
+ context->set_source_rgba (UINT_RGBA_R_FLT(f), UINT_RGBA_G_FLT(f), UINT_RGBA_B_FLT(f), UINT_RGBA_A_FLT(f));
+ context->fill ();
+
+ /* add text */
+
+ context->move_to (left - half_lr_box + 3,
+ (lr_box_size/2) + step_down + 13);
+ context->select_font_face ("sans-serif", Cairo::FONT_SLANT_NORMAL, Cairo::FONT_WEIGHT_BOLD);
+
+ if (state != Mono) {
+ context->set_source_rgba (UINT_RGBA_R_FLT(t), UINT_RGBA_G_FLT(t), UINT_RGBA_B_FLT(t), UINT_RGBA_A_FLT(t));
+ if (swidth < 0.0) {
+ context->show_text (_("R"));
+ } else {
+ context->show_text (_("L"));
+ }
+ }
+
+ /* right box */
+
+ rounded_rectangle (context, right - half_lr_box,
+ half_lr_box+step_down,
+ lr_box_size, lr_box_size, corner_radius);
+ context->set_source_rgba (UINT_RGBA_R_FLT(o), UINT_RGBA_G_FLT(o), UINT_RGBA_B_FLT(o), UINT_RGBA_A_FLT(o));
+ context->stroke_preserve ();
+ context->set_source_rgba (UINT_RGBA_R_FLT(f), UINT_RGBA_G_FLT(f), UINT_RGBA_B_FLT(f), UINT_RGBA_A_FLT(f));
+ context->fill ();
+
+ /* add text */
+
+ context->move_to (right - half_lr_box + 3, (lr_box_size/2)+step_down + 13);
+ context->set_source_rgba (UINT_RGBA_R_FLT(t), UINT_RGBA_G_FLT(t), UINT_RGBA_B_FLT(t), UINT_RGBA_A_FLT(t));
+
+ if (state == Mono) {
+ context->show_text (_("M"));
+ } else {
+ if (swidth < 0.0) {
+ context->show_text (_("L"));
+ } else {
+ context->show_text (_("R"));
+ }
+ }
+
+ /* draw the central box */
+
+ context->set_line_width (2.0);
+ context->move_to (center + (pos_box_size/2.0), top_step); /* top right */
+ context->rel_line_to (0.0, pos_box_size); /* lower right */
+ context->rel_line_to (-pos_box_size/2.0, 4.0); /* bottom point */
+ context->rel_line_to (-pos_box_size/2.0, -4.0); /* lower left */
+ context->rel_line_to (0.0, -pos_box_size); /* upper left */
+ context->close_path ();
+
+ context->set_source_rgba (UINT_RGBA_R_FLT(o), UINT_RGBA_G_FLT(o), UINT_RGBA_B_FLT(o), UINT_RGBA_A_FLT(o));
+ context->stroke_preserve ();
+ context->set_source_rgba (UINT_RGBA_R_FLT(f), UINT_RGBA_G_FLT(f), UINT_RGBA_B_FLT(f), UINT_RGBA_A_FLT(f));
+ context->fill ();