From 2abf9c66a4fbf06e06b7ecc092448a921a2e97ca Mon Sep 17 00:00:00 2001
From: Robin Gareus <robin@gareus.org>
Date: Sat, 30 Jan 2021 02:18:56 +0100
Subject: [PATCH] Fix size-request that rely on Pango::Layout

A Pango::Layout created by Gtk::Widget::get_pango_context ()
does not have any font set. The Font is inherited from the
layout's context.

The actual font is set when the layout is used in
on_expose_event() via get_window ()->create_cairo_context ().

In some cases we rely on the font-size to calculate the widget's
size before rendering. At this point in time there is no drawing
context from which to inherit the style.

Furthermore, even after a call to `ensure_style()` in the c'tor
of a Widget get_font() simply returns the default value.

All Widgets that rely an Pango::Layout font size during
size-requests have to explicitly set the font.

This fixes various overlarge buttons with the initial default layout.
---
 libs/widgets/ardour_button.cc        | 19 +++++++++++++++----
 libs/widgets/ardour_fader.cc         | 14 ++++++++------
 libs/widgets/widgets/ardour_button.h |  4 +++-
 3 files changed, 26 insertions(+), 11 deletions(-)

diff --git a/libs/widgets/ardour_button.cc b/libs/widgets/ardour_button.cc
index cbe38bb3b0..8f0eb9bf02 100644
--- a/libs/widgets/ardour_button.cc
+++ b/libs/widgets/ardour_button.cc
@@ -66,6 +66,7 @@ ArdourButton::ArdourButton (Element e, bool toggle)
 	, _char_pixel_width (0)
 	, _char_pixel_height (0)
 	, _char_avg_pixel_width (0)
+	, _custom_font_set (false)
 	, _text_width (0)
 	, _text_height (0)
 	, _diameter (0)
@@ -113,6 +114,7 @@ ArdourButton::ArdourButton (const std::string& str, Element e, bool toggle)
 	, _char_pixel_width (0)
 	, _char_pixel_height (0)
 	, _char_avg_pixel_width (0)
+	, _custom_font_set (false)
 	, _text_width (0)
 	, _text_height (0)
 	, _diameter (0)
@@ -179,6 +181,7 @@ ArdourButton::set_layout_font (const Pango::FontDescription& fd)
 		queue_resize ();
 		_char_pixel_width = 0;
 		_char_pixel_height = 0;
+		_custom_font_set = true;
 	}
 }
 
@@ -974,7 +977,7 @@ ArdourButton::on_size_allocate (Allocation& alloc)
 	setup_led_rect ();
 	if (_layout) {
 		/* re-center text */
-		_layout->get_pixel_size (_text_width, _text_height);
+		//_layout->get_pixel_size (_text_width, _text_height);
 	}
 }
 
@@ -1047,13 +1050,20 @@ ArdourButton::action_toggled ()
 }
 
 void
-ArdourButton::on_style_changed (const RefPtr<Gtk::Style>&)
+ArdourButton::on_style_changed (const RefPtr<Gtk::Style>& style)
 {
-	_update_colors = true;
+	CairoWidget::on_style_changed (style);
+	Glib::RefPtr<Gtk::Style> const& new_style = get_style();
+
 	CairoWidget::set_dirty ();
+	_update_colors = true;
 	_char_pixel_width = 0;
 	_char_pixel_height = 0;
-	if (is_realized()) {
+
+	if (!_custom_font_set && _layout && _layout->get_font_description () != new_style->get_font ()) {
+		_layout->set_font_description (new_style->get_font ());
+		queue_resize ();
+	} else if (is_realized()) {
 		queue_resize ();
 	}
 }
@@ -1288,6 +1298,7 @@ ArdourButton::ensure_layout ()
 	if (!_layout) {
 		ensure_style ();
 		_layout = Pango::Layout::create (get_pango_context());
+		_layout->set_font_description (get_style()->get_font());
 		_layout->set_ellipsize(_ellipsis);
 		if (_layout_ellipsize_width > 3 * PANGO_SCALE) {
 			_layout->set_width (_layout_ellipsize_width - 3* PANGO_SCALE);
diff --git a/libs/widgets/ardour_fader.cc b/libs/widgets/ardour_fader.cc
index 42891310e4..21e4b3da3e 100644
--- a/libs/widgets/ardour_fader.cc
+++ b/libs/widgets/ardour_fader.cc
@@ -713,13 +713,15 @@ ArdourFader::on_state_changed (Gtk::StateType old_state)
 }
 
 void
-ArdourFader::on_style_changed (const Glib::RefPtr<Gtk::Style>&)
+ArdourFader::on_style_changed (const Glib::RefPtr<Gtk::Style>& style)
 {
-	if (_layout) {
-		std::string txt = _layout->get_text();
-		_layout.clear (); // drop reference to existing layout
-		_text = "";
-		set_text (txt, _centered_text, false);
+	CairoWidget::on_style_changed (style);
+	Glib::RefPtr<Gtk::Style> const& new_style = get_style ();
+	if (_layout && (_layout->get_font_description ().gobj () == 0 || _layout->get_font_description () != new_style->get_font ())) {
+		_layout->set_font_description (new_style->get_font ());
+		queue_resize ();
+	} else if (is_realized ()) {
+		queue_resize ();
 	}
 	/* patterns are cached and re-created as needed
 	 * during 'expose' in the GUI thread */
diff --git a/libs/widgets/widgets/ardour_button.h b/libs/widgets/widgets/ardour_button.h
index 75690c4da6..8a8b03c356 100644
--- a/libs/widgets/widgets/ardour_button.h
+++ b/libs/widgets/widgets/ardour_button.h
@@ -165,9 +165,11 @@ class LIBWIDGETS_API ArdourButton : public CairoWidget , public Gtkmm2ext::Activ
 
 	void set_text_internal ();
 	void recalc_char_pixel_geometry ();
+
 	unsigned int _char_pixel_width;
 	unsigned int _char_pixel_height;
-	float _char_avg_pixel_width;
+	float        _char_avg_pixel_width;
+	bool         _custom_font_set;
 
 	int   _text_width;
 	int   _text_height;