From 270d3fd482e820da47e2516ae27b4e20fff724d8 Mon Sep 17 00:00:00 2001
From: Celtic Minstrel <celtic.minstrel.ca@some.place>
Date: Sun, 14 Feb 2016 23:11:03 -0500
Subject: [PATCH] Preferences: Implement a font scaling option

This is currently incomplete - it only works for GUI2 text.
---
 .../default/window/preferences/02_display.cfg    | 14 ++++++++++++++
 src/gui/dialogs/preferences_dialog.cpp           |  9 +++++++--
 src/gui/dialogs/preferences_dialog.hpp           |  3 ++-
 src/preferences.cpp                              | 16 ++++++++++++++++
 src/preferences.hpp                              |  4 ++++
 src/text.cpp                                     |  6 ++++--
 6 files changed, 47 insertions(+), 5 deletions(-)

diff --git a/data/gui/default/window/preferences/02_display.cfg b/data/gui/default/window/preferences/02_display.cfg
index 7ea0a54f229b..08e48d723f66 100644
--- a/data/gui/default/window/preferences/02_display.cfg
+++ b/data/gui/default/window/preferences/02_display.cfg
@@ -208,6 +208,20 @@
 			[/grid]
 		[/column]
 	[/row]
+
+	[row]
+		[column]
+			horizontal_grow = true
+			{_GUI_PREFERENCES_MAIN_COMPOSITE_SLIDER
+				scaling_value ( _ "Font scale:")
+				scaling_slider (
+					minimum_value,maximum_value=100,200
+					step_size=5
+					tooltip= _ "Set the scaling factor of fonts"
+				)
+			}
+		[/column]
+	[/row]
 #enddef
 
 #define _GUI_PREFERENCES_DISPLAY_GRID_2
diff --git a/src/gui/dialogs/preferences_dialog.cpp b/src/gui/dialogs/preferences_dialog.cpp
index f422a4dab00a..bceb9a8f80fa 100644
--- a/src/gui/dialogs/preferences_dialog.cpp
+++ b/src/gui/dialogs/preferences_dialog.cpp
@@ -277,10 +277,10 @@ void tpreferences::bind_status_label(T& parent, const std::string& label_id,
 }
 
 void tpreferences::bind_status_label(tslider& parent, const std::string& label_id,
-		twidget& find_in)
+		twidget& find_in, const std::string& suffix)
 {
 	tcontrol& label = find_widget<tcontrol>(&find_in, label_id, false);
-	label.set_label(lexical_cast<std::string>(parent.get_value_label()));
+	label.set_label(lexical_cast<std::string>(parent.get_value_label()) + suffix);
 
 	connect_signal_notify_modified(parent, boost::bind(
 		&tpreferences::status_label_callback<tslider>,
@@ -554,6 +554,11 @@ void tpreferences::initialize_members(twindow& window)
 		idle_anim(), idle_anim_rate(),
 		set_idle_anim, set_idle_anim_rate, window);
 
+	/** FONT SCALING **/
+	tslider& scale_slider = find_widget<tslider>(&window, "scaling_slider", false);
+	setup_single_slider("scaling_slider", font_scaling(), set_font_scaling, window);
+	bind_status_label(scale_slider, "scaling_value", window, "%");
+
 	/** SELECT THEME **/
 	connect_signal_mouse_left_click(
 			find_widget<tbutton>(&window, "choose_theme", false),
diff --git a/src/gui/dialogs/preferences_dialog.hpp b/src/gui/dialogs/preferences_dialog.hpp
index 4242c0814bd7..9f7104e46461 100644
--- a/src/gui/dialogs/preferences_dialog.hpp
+++ b/src/gui/dialogs/preferences_dialog.hpp
@@ -172,7 +172,8 @@ class tpreferences : public tdialog
 	void bind_status_label(
 		tslider& parent,
 		const std::string& label_id,
-		twidget& find_in);
+		twidget& find_in,
+		const std::string& suffix = "");
 
 	template <typename T>
 	void status_label_callback(T& parent_widget,
diff --git a/src/preferences.cpp b/src/preferences.cpp
index 469f159bf025..05890ad3cdd0 100644
--- a/src/preferences.cpp
+++ b/src/preferences.cpp
@@ -411,6 +411,22 @@ void save_turbo_speed(const double speed)
 {
 	prefs["turbo_speed"] = speed;
 }
+	
+int font_scaling()
+{
+	// Clip at 50 because if it's too low it'll cause crashes
+	return std::max<int>(50, prefs["font_scale"].to_int(100));
+}
+
+void set_font_scaling(int scale)
+{
+	prefs["font_scale"] = scale;
+}
+
+int font_scaled(int size)
+{
+	return (size * font_scaling()) / 100;
+}
 
 bool idle_anim()
 {
diff --git a/src/preferences.hpp b/src/preferences.hpp
index 2af6a17b944c..38564f46cf16 100644
--- a/src/preferences.hpp
+++ b/src/preferences.hpp
@@ -81,6 +81,10 @@ namespace preferences {
 
 	double turbo_speed();
 	void save_turbo_speed(const double speed);
+	
+	int font_scaling();
+	void set_font_scaling(int scale);
+	int font_scaled(int size);
 
 	bool idle_anim();
 	void _set_idle_anim(const bool ison);
diff --git a/src/text.cpp b/src/text.cpp
index 6eb45c61d293..08a2ceaf60fe 100644
--- a/src/text.cpp
+++ b/src/text.cpp
@@ -24,6 +24,7 @@
 #include "serialization/string_utils.hpp"
 #include "serialization/unicode.hpp"
 #include "tstring.hpp"
+#include "preferences.hpp"
 
 #include <boost/foreach.hpp>
 
@@ -404,8 +405,9 @@ ttext& ttext::set_family_class(font::family_class fclass)
 
 ttext& ttext::set_font_size(const unsigned font_size)
 {
-	if(font_size != font_size_) {
-		font_size_ = font_size;
+	unsigned int actual_size = preferences::font_scaled(font_size);
+	if(actual_size != font_size_) {
+		font_size_ = actual_size;
 		calculation_dirty_ = true;
 		surface_dirty_ = true;
 	}