Add style[] tag with button support

builtin/mainmenu/dlg_delete_content.lua

@@ -22,6 +22,7 @@ local function delete_content_formspec(dialogdata)
 		"size[11.5,4.5,true]" ..
 		"label[2,2;" ..
 		fgettext("Are you sure you want to delete \"$1\"?", dialogdata.content.name) .. "]"..
+		"style[dlg_delete_content_confirm;bgcolor;red]" ..
 		"button[3.25,3.5;2.5,0.5;dlg_delete_content_confirm;" .. fgettext("Delete") .. "]" ..
 		"button[5.75,3.5;2.5,0.5;dlg_delete_content_cancel;" .. fgettext("Cancel") .. "]"
 

builtin/mainmenu/dlg_delete_world.lua

@@ -21,6 +21,7 @@ local function delete_world_formspec(dialogdata)
 		"size[10,2.5,true]" ..
 		"label[0.5,0.5;" ..
 		fgettext("Delete World \"$1\"?", dialogdata.delete_name) .. "]" ..
+		"style[world_delete_confirm;bgcolor;red]" ..
 		"button[0.5,1.5;2.5,0.5;world_delete_confirm;" .. fgettext("Delete") .. "]" ..
 		"button[7.0,1.5;2.5,0.5;world_delete_cancel;" .. fgettext("Cancel") .. "]"
 	return retval

builtin/mainmenu/tab_local.lua

@@ -102,6 +102,9 @@ local function get_formspec(tabview, name, tabdata)
 				)
 
 	retval = retval ..
+			"style_type[button;bgcolor;#006699]" ..
+			"style[world_delete;bgcolor;red]" ..
+			"style[world_delete;textcolor;yellow]" ..
 			"button[4,3.95;2.6,1;world_delete;".. fgettext("Delete") .. "]" ..
 			"button[6.5,3.95;2.8,1;world_configure;".. fgettext("Configure") .. "]" ..
 			"button[9.2,3.95;2.5,1;world_create;".. fgettext("New") .. "]" ..

doc/lua_api.txt

@@ -1886,7 +1886,8 @@ For coloured text you can use `minetest.colorize`.
 
 WARNING: Minetest allows you to add elements to every single formspec instance
 using `player:set_formspec_prepend()`, which may be the reason backgrounds are
-appearing when you don't expect them to. See [`no_prepend[]`].
+appearing when you don't expect them to, or why things are styled differently
+to normal. See [`no_prepend[]`] and [Styling Formspecs].
 
 Examples
 --------
@@ -2353,6 +2354,20 @@ Elements
 **Note**: do _not_ use a element name starting with `key_`; those names are
 reserved to pass key press events to formspec!
 
+### `style[<name>;<propery>;<value]`
+
+Set the style for the named element `name`.
+Note: this **must** be before the element's tag.
+
+See [Styling Formspecs].
+
+
+### `style_type[<type>;<propery>;<value>]`
+
+Sets the style for all elements of type `type` which appear after this tag.
+
+See [Styling Formspecs].
+
 Migrating to Real Coordinates
 -----------------------------
 
@@ -2388,6 +2403,28 @@ offsets when migrating:
 | list    |            |         | Spacing is now 0.25 for both directions, meaning lists will be taller in height
 | label   | 0, +0.3    |         | The first line of text is now positioned centered exactly at the position specified
 
+Styling Formspecs
+-----------------
+
+Formspec elements can be themed using the style tags:
+
+	style[ELEMENT_NAME;PROPERTY;VALUE]
+	style_type[ELEMENT_TYPE;PROPERTY;VALUE]
+
+For example:
+
+	style_type[button;bgcolor;#006699]
+	style[world_delete;bgcolor;#ff0000]
+	button[4,3.95;2.6,1;world_delete;Delete]
+
+### Valid Properties
+
+* button and button_exit
+	* bgcolor - sets button tint
+	* textcolor
+* tabheader
+	* bgcolor - tab background
+	* textcolor
 
 
 

src/gui/StyleSpec.h

@@ -0,0 +1,102 @@
+/*
+Minetest
+Copyright (C) 2019 rubenwardy
+
+This program is free software; you can redistribute it and/or modify
+it under the terms of the GNU Lesser General Public License as published by
+the Free Software Foundation; either version 2.1 of the License, or
+(at your option) any later version.
+
+This program is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU Lesser General Public License for more details.
+
+You should have received a copy of the GNU Lesser General Public License along
+with this program; if not, write to the Free Software Foundation, Inc.,
+51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+*/
+
+#include "irrlichttypes_extrabloated.h"
+
+#pragma once
+
+
+class StyleSpec
+{
+public:
+	enum Property {
+		NONE = 0,
+		TEXTCOLOR,
+		BGCOLOR,
+		NUM_PROPERTIES
+	};
+
+private:
+	std::unordered_map<Property, std::string> properties;
+
+public:
+	static Property GetPropertyByName(const std::string &name) {
+		if (name == "textcolor") {
+			return TEXTCOLOR;
+		} else if (name == "bgcolor") {
+			return BGCOLOR;
+		} else {
+			return NONE;
+		}
+	}
+
+	std::string get(Property prop, std::string def) const {
+		auto it = properties.find(prop);
+		if (it == properties.end()) {
+			return def;
+		}
+
+		return it->second;
+	}
+
+	void set(Property prop, std::string value) {
+		properties[prop] = std::move(value);
+	}
+
+	video::SColor getColor(Property prop, video::SColor def) const {
+		auto it = properties.find(prop);
+		if (it == properties.end()) {
+			return def;
+		}
+
+		parseColorString(it->second, def, false, 0xFF);
+		return def;
+	}
+
+	video::SColor getColor(Property prop) const {
+		auto it = properties.find(prop);
+		FATAL_ERROR_IF(it == properties.end(), "Unexpected missing property");
+
+		video::SColor color;
+		parseColorString(it->second, color, false, 0xFF);
+		return color;
+	}
+
+	bool hasProperty(Property prop) const {
+		return properties.find(prop) != properties.end();
+	}
+
+	StyleSpec &operator|=(const StyleSpec &other) {
+		for (size_t i = 1; i < NUM_PROPERTIES; i++) {
+			auto prop = (Property)i;
+			if (other.hasProperty(prop)) {
+				properties[prop] = other.get(prop, "");
+			}
+		}
+
+		return *this;
+	}
+
+	StyleSpec operator|(const StyleSpec &other) const {
+		StyleSpec newspec = *this;
+		newspec |= other;
+		return newspec;
+	}
+};
+

src/gui/guiFormSpecMenu.cpp

@@ -701,6 +701,17 @@ void GUIFormSpecMenu::parseButton(parserData* data, const std::string &element,
 			spec.is_exit = true;
 
 		GUIButton *e = GUIButton::addButton(Environment, rect, this, spec.fid, spec.flabel.c_str());
+
+		auto style = getThemeForElement(type, name);
+		if (style.hasProperty(StyleSpec::BGCOLOR)) {
+			e->setColor(style.getColor(StyleSpec::BGCOLOR));
+		}
+		if (style.hasProperty(StyleSpec::TEXTCOLOR)) {
+			e->setOverrideColor(style.getColor(StyleSpec::TEXTCOLOR));
+		}
+
+//		e->setSprite();
+
 		if (spec.fname == data->focused_fieldname) {
 			Environment->setFocus(e);
 		}
@@ -1645,7 +1656,7 @@ void GUIFormSpecMenu::parseTabHeader(parserData* data, const std::string &elemen
 				pos.Y+geom.Y);
 
 		gui::IGUITabControl *e = Environment->addTabControl(rect, this,
-				show_background, show_border, spec.fid);
+				false, show_border, spec.fid);
 		e->setAlignment(irr::gui::EGUIA_UPPERLEFT, irr::gui::EGUIA_UPPERLEFT,
 				irr::gui::EGUIA_UPPERLEFT, irr::gui::EGUIA_LOWERRIGHT);
 		e->setTabHeight(geom.Y);
@@ -1656,9 +1667,17 @@ void GUIFormSpecMenu::parseTabHeader(parserData* data, const std::string &elemen
 
 		e->setNotClipped(true);
 
+		auto style = getThemeForElement("tabheader", name);
+
 		for (const std::string &button : buttons) {
-			e->addTab(unescape_translate(unescape_string(
+			auto tab = e->addTab(unescape_translate(unescape_string(
 				utf8_to_wide(button))).c_str(), -1);
+			tab->setDrawBackground(false);
+			tab->setBackgroundColor(video::SColor(0xFFFF0000));
+			if (style.hasProperty(StyleSpec::BGCOLOR))
+				tab->setBackgroundColor(style.getColor(StyleSpec::BGCOLOR));
+
+			tab->setTextColor(style.getColor(StyleSpec::TEXTCOLOR, video::SColor(0xFFFFFFFF)));
 		}
 
 		if ((tab_index >= 0) &&
@@ -2020,6 +2039,45 @@ void GUIFormSpecMenu::parseAnchor(parserData *data, const std::string &element)
 			<< "'" << std::endl;
 }
 
+bool GUIFormSpecMenu::parseStyle(parserData *data, const std::string &element, bool style_type)
+{
+	std::vector<std::string> parts = split(element, ';');
+
+	if (parts.size() != 3) {
+		errorstream << "Invalid style element (" << parts.size() << "): '" << element
+					<< "'" << std::endl;
+		return false;
+	}
+
+	std::string selector = trim(parts[0]);
+	std::string propname = trim(parts[1]);
+	std::string value    = trim(parts[2]);
+
+	StyleSpec::Property prop = StyleSpec::GetPropertyByName(propname);
+	if (prop == StyleSpec::NONE) {
+		errorstream << "Invalid style element (Unknown property " << prop << "): '" << element
+					<< "'" << std::endl;
+		return false;
+	}
+
+	StyleSpec spec;
+	spec.set(prop, value);
+
+	if (selector.empty()) {
+		errorstream << "Invalid style element (Selector required): '" << element
+					<< "'" << std::endl;
+		return false;
+	}
+
+	if (style_type) {
+		theme_by_type[selector] |= spec;
+	} else {
+		theme_by_name[selector] |= spec;
+	}
+
+	return true;
+}
+
 void GUIFormSpecMenu::parseElement(parserData* data, const std::string &element)
 {
 	//some prechecks
@@ -2185,6 +2243,16 @@ void GUIFormSpecMenu::parseElement(parserData* data, const std::string &element)
 		return;
 	}
 
+	if (type == "style") {
+		parseStyle(data, description, false);
+		return;
+	}
+
+	if (type == "style_type") {
+		parseStyle(data, description, true);
+		return;
+	}
+
 	// Ignore others
 	infostream << "Unknown DrawSpec: type=" << type << ", data=\"" << description << "\""
 			<< std::endl;
@@ -2255,6 +2323,8 @@ void GUIFormSpecMenu::regenerateGui(v2u32 screensize)
 	m_inventory_rings.clear();
 	m_static_texts.clear();
 	m_dropdowns.clear();
+	theme_by_name.clear();
+	theme_by_type.clear();
 
 	m_bgfullscreen = false;
 
@@ -4044,3 +4114,19 @@ std::wstring GUIFormSpecMenu::getLabelByID(s32 id)
 	}
 	return L"";
 }
+
+StyleSpec GUIFormSpecMenu::getThemeForElement(const std::string &type, const std::string &name) {
+	StyleSpec ret;
+
+	auto it = theme_by_type.find(type);
+	if (it != theme_by_type.end()) {
+		ret |= it->second;
+	}
+
+	it = theme_by_name.find(name);
+	if (it != theme_by_name.end()) {
+		ret |= it->second;
+	}
+
+	return ret;
+}

src/gui/guiFormSpecMenu.h

@@ -30,6 +30,7 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 #include "client/joystick_controller.h"
 #include "util/string.h"
 #include "util/enriched_string.h"
+#include "StyleSpec.h"
 
 class InventoryManager;
 class ISimpleTextureSource;
@@ -401,6 +402,11 @@ protected:
 			const std::vector<std::string> &v_pos);
 	v2s32 getRealCoordinateGeometry(const std::vector<std::string> &v_geom);
 
+	std::unordered_map<std::string, StyleSpec> theme_by_type;
+	std::unordered_map<std::string, StyleSpec> theme_by_name;
+
+	StyleSpec getThemeForElement(const std::string &type, const std::string &name);
+
 	v2s32 padding;
 	v2f32 spacing;
 	v2s32 imgsize;
@@ -537,6 +543,7 @@ private:
 	void parsePosition(parserData *data, const std::string &element);
 	bool parseAnchorDirect(parserData *data, const std::string &element);
 	void parseAnchor(parserData *data, const std::string &element);
+	bool parseStyle(parserData *data, const std::string &element, bool style_type);
 
 	void tryClose();