Make knobs size requests dynamic

At the point of creation, the automate_button size request is wrong
since it has not the correct style yet. Instead of trying ugly hacks to
fix that, connect to the knob's size_request signal and get the button's
requisition only when needed. If the system font changes to one that has
different extents (even if the point size is the same), the UI will thus
correctly update.

2 files changed, 14 insertions, 3 deletions

diff --git a/gtk2_ardour/generic_pluginui.cc b/gtk2_ardour/generic_pluginui.cc
index f7b30e2d18..14d05df344 100644
--- a/gtk2_ardour/generic_pluginui.cc
+++ b/gtk2_ardour/generic_pluginui.cc
@@ -664,8 +664,6 @@ GenericPluginUI::build_control_ui (const Evoral::Parameter&             param,
 	control_ui->label.set_name ("PluginParameterLabel");
 	control_ui->set_spacing (5);
 
-	Gtk::Requisition req (control_ui->automate_button.size_request());
-
 	if (is_input) {
 
 		if (desc.datatype == Variant::PATH) {
@@ -764,7 +762,9 @@ GenericPluginUI::build_control_ui (const Evoral::Parameter&             param,
 				assert(but);
 				but->set_tweaks(ArdourButton::Square);
 			} else if (use_knob) {
-				control_ui->controller->set_size_request (req.height * 1.5, req.height * 1.5);
+				/* Delay size request so that styles are gotten right */
+				control_ui->controller->widget()->signal_size_request().connect(
+						sigc::bind (sigc::mem_fun (*this, &GenericPluginUI::knob_size_request), control_ui));
 			} else {
 				control_ui->controller->set_size_request (200, -1);
 				control_ui->controller->set_name (X_("ProcessorControlSlider"));
@@ -937,6 +937,15 @@ GenericPluginUI::build_control_ui (const Evoral::Parameter&             param,
 	return control_ui;
 }
 
+void
+GenericPluginUI::knob_size_request(Gtk::Requisition* req, ControlUI* cui) {
+	Gtk::Requisition astate_req (cui->automate_button.size_request());
+	const int size = (int) (astate_req.height * 1.5);
+	req->width = max(req->width, size);
+	req->height = max(req->height, size);
+}
+
+
 bool
 GenericPluginUI::astate_button_event (GdkEventButton* ev, ControlUI* cui)
 {
diff --git a/gtk2_ardour/plugin_ui.h b/gtk2_ardour/plugin_ui.h
index 57aa138af7..4fb052b5f5 100644
--- a/gtk2_ardour/plugin_ui.h
+++ b/gtk2_ardour/plugin_ui.h
@@ -292,6 +292,8 @@ class GenericPluginUI : public PlugUIBase, public Gtk::VBox
 	void set_automation_state (ARDOUR::AutoState state, ControlUI* cui);
 	void set_all_automation (ARDOUR::AutoState state);
 
+	void knob_size_request(Gtk::Requisition* req, ControlUI* cui);
+
 	/* XXX: remove */
 	void print_parameter (char *buf, uint32_t len, uint32_t param);
 	bool integer_printer (char* buf, Gtk::Adjustment &, ControlUI *);