Add gradients and borders to FormSpec boxes (#8676)

5 files changed, 218 insertions, 47 deletions

diff --git a/doc/lua_api.txt b/doc/lua_api.txt
index ba55033dd..49fbe0d94 100644
--- a/doc/lua_api.txt
+++ b/doc/lua_api.txt
@@ -2442,6 +2442,8 @@ Elements
 * Simple colored box
 * `color` is color specified as a `ColorString`.
   If the alpha component is left blank, the box will be semitransparent.
+  If the color is not specified, the box will use the options specified by
+  its style. If the color is specified, all styling options will be ignored.
 
 ### `dropdown[<X>,<Y>;<W>;<name>;<item 1>,<item 2>, ...,<item n>;<selected idx>;<index event>]`
 
@@ -2708,21 +2710,23 @@ Setting a property to nothing will reset it to the default value. For example:
 Some types may inherit styles from parent types.
 
 * animated_image, inherits from image
+* box
 * button
 * button_exit, inherits from button
 * checkbox
-* scrollbar
-* table
-* textlist
 * dropdown
 * field
-* pwdfield, inherits from field
-* textarea
-* label
-* vertlabel, inherits from field
+* image
 * image_button
 * item_image_button
+* label
+* pwdfield, inherits from field
+* scrollbar
 * tabheader
+* table
+* textarea
+* textlist
+* vertlabel, inherits from label
 
 
 ### Valid Properties
@@ -2731,7 +2735,18 @@ Some types may inherit styles from parent types.
     * noclip - boolean, set to true to allow the element to exceed formspec bounds.
 * box
     * noclip - boolean, set to true to allow the element to exceed formspec bounds.
-        * Default to false in formspec_version version 3 or higher
+        * Defaults to false in formspec_version version 3 or higher
+    * **Note**: `colors`, `bordercolors`, and `borderwidths` accept multiple input types:
+        * Single value (e.g. `#FF0`): All corners/borders.
+        * Two values (e.g. `red,#FFAAFF`): top-left and bottom-right,top-right and bottom-left/
+          top and bottom,left and right.
+        * Four values (e.g. `blue,#A0F,green,#FFFA`): top-left/top and rotates clockwise.
+        * These work similarly to CSS borders.
+    * colors - `ColorString`. Sets the color(s) of the box corners. Default `black`.
+    * bordercolors - `ColorString`. Sets the color(s) of the borders. Default `black`.
+    * borderwidths - Integer. Sets the width(s) of the borders in pixels. If the width is
+      negative, the border will extend inside the box, whereas positive extends outside
+      the box. A width of zero results in no border; this is default.
 * button, button_exit, image_button, item_image_button
     * alpha - boolean, whether to draw alpha in bgimg. Default true.
     * bgcolor - color, sets button tint.
@@ -2767,12 +2782,6 @@ Some types may inherit styles from parent types.
     * textcolor - color, default white.
 * checkbox
     * noclip - boolean, set to true to allow the element to exceed formspec bounds.
-* scrollbar
-    * noclip - boolean, set to true to allow the element to exceed formspec bounds.
-* table, textlist
-    * font - Sets font type. See button `font` property for more information.
-    * font_size - Sets font size. See button `font_size` property for more information.
-    * noclip - boolean, set to true to allow the element to exceed formspec bounds.
 * dropdown
     * noclip - boolean, set to true to allow the element to exceed formspec bounds.
 * field, pwdfield, textarea
@@ -2797,9 +2806,15 @@ Some types may inherit styles from parent types.
     * fgimg_pressed - image when pressed. Defaults to fgimg when not provided.
         * This is deprecated, use states instead.
     * NOTE: The parameters of any given image_button will take precedence over fgimg/fgimg_pressed
+* scrollbar
+    * noclip - boolean, set to true to allow the element to exceed formspec bounds.
 * tabheader
     * noclip - boolean, set to true to allow the element to exceed formspec bounds.
     * textcolor - color. Default white.
+* table, textlist
+    * font - Sets font type. See button `font` property for more information.
+    * font_size - Sets font size. See button `font_size` property for more information.
+    * noclip - boolean, set to true to allow the element to exceed formspec bounds.
 
 ### Valid States
 
diff --git a/src/gui/StyleSpec.h b/src/gui/StyleSpec.h
index 67caf4f7b..36ad51a89 100644
--- a/src/gui/StyleSpec.h
+++ b/src/gui/StyleSpec.h
@@ -24,6 +24,7 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 #include "util/string.h"
 #include <algorithm>
 #include <array>
+#include <vector>
 
 #pragma once
 
@@ -50,6 +51,9 @@ public:
 		PADDING,
 		FONT,
 		FONT_SIZE,
+		COLORS,
+		BORDERCOLORS,
+		BORDERWIDTHS,
 		NUM_PROPERTIES,
 		NONE
 	};
@@ -106,6 +110,12 @@ public:
 			return FONT;
 		} else if (name == "font_size") {
 			return FONT_SIZE;
+		} else if (name == "colors") {
+			return COLORS;
+		} else if (name == "bordercolors") {
+			return BORDERCOLORS;
+		} else if (name == "borderwidths") {
+			return BORDERWIDTHS;
 		} else {
 			return NONE;
 		}
@@ -187,6 +197,42 @@ public:
 		return color;
 	}
 
+	std::array<video::SColor, 4> getColorArray(Property prop,
+		std::array<video::SColor, 4> def) const
+	{
+		const auto &val = properties[prop];
+		if (val.empty())
+			return def;
+
+		std::vector<std::string> strs;
+		if (!parseArray(val, strs))
+			return def;
+
+		for (size_t i = 0; i <= 3; i++) {
+			video::SColor color;
+			if (parseColorString(strs[i], color, false, 0xff))
+				def[i] = color;
+		}
+
+		return def;
+	}
+
+	std::array<s32, 4> getIntArray(Property prop, std::array<s32, 4> def) const
+	{
+		const auto &val = properties[prop];
+		if (val.empty())
+			return def;
+
+		std::vector<std::string> strs;
+		if (!parseArray(val, strs))
+			return def;
+
+		for (size_t i = 0; i <= 3; i++)
+			def[i] = stoi(strs[i]);
+
+		return def;
+	}
+
 	irr::core::rect<s32> getRect(Property prop, irr::core::rect<s32> def) const
 	{
 		const auto &val = properties[prop];
@@ -334,6 +380,24 @@ public:
 	}
 
 private:
+	bool parseArray(const std::string &value, std::vector<std::string> &arr) const
+	{
+		std::vector<std::string> strs = split(value, ',');
+
+		if (strs.size() == 1) {
+			arr = {strs[0], strs[0], strs[0], strs[0]};
+		} else if (strs.size() == 2) {
+			arr = {strs[0], strs[1], strs[0], strs[1]};
+		} else if (strs.size() == 4) {
+			arr = strs;
+		} else {
+			warningstream << "Invalid array size (" << strs.size()
+					<< " arguments): \"" << value << "\"" << std::endl;
+			return false;
+		}
+		return true;
+	}
+
 	bool parseRect(const std::string &value, irr::core::rect<s32> *parsed_rect) const
 	{
 		irr::core::rect<s32> rect;
diff --git a/src/gui/guiBox.cpp b/src/gui/guiBox.cpp
index 7f329cc32..99a115daf 100644
--- a/src/gui/guiBox.cpp
+++ b/src/gui/guiBox.cpp
@@ -20,9 +20,14 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 #include "guiBox.h"
 
 GUIBox::GUIBox(gui::IGUIEnvironment *env, gui::IGUIElement *parent, s32 id,
-	const core::rect<s32> &rectangle, const video::SColor &color) :
+	const core::rect<s32> &rectangle,
+	const std::array<video::SColor, 4> &colors,
+	const std::array<video::SColor, 4> &bordercolors,
+	const std::array<s32, 4> &borderwidths) :
 	gui::IGUIElement(gui::EGUIET_ELEMENT, env, parent, id, rectangle),
-	m_color(color)
+	m_colors(colors),
+	m_bordercolors(bordercolors),
+	m_borderwidths(borderwidths)
 {
 }
 
@@ -31,8 +36,81 @@ void GUIBox::draw()
 	if (!IsVisible)
 		return;
 
-	Environment->getVideoDriver()->draw2DRectangle(m_color, AbsoluteRect,
-			&AbsoluteClippingRect);
+	std::array<s32, 4> negative_borders = {0, 0, 0, 0};
+	std::array<s32, 4> positive_borders = {0, 0, 0, 0};
+
+	for (size_t i = 0; i <= 3; i++) {
+		if (m_borderwidths[i] > 0)
+			positive_borders[i] = m_borderwidths[i];
+		else
+			negative_borders[i] = m_borderwidths[i];
+	}
+
+	v2s32 upperleft = AbsoluteRect.UpperLeftCorner;
+	v2s32 lowerright = AbsoluteRect.LowerRightCorner;
+
+	v2s32 topleft_border = {
+		upperleft.X - positive_borders[3],
+		upperleft.Y - positive_borders[0]
+	};
+	v2s32 topleft_rect = {
+		upperleft.X - negative_borders[3],
+		upperleft.Y - negative_borders[0]
+	};
+
+	v2s32 lowerright_border = {
+		lowerright.X + positive_borders[1],
+		lowerright.Y + positive_borders[2]
+	};
+	v2s32 lowerright_rect = {
+		lowerright.X + negative_borders[1],
+		lowerright.Y + negative_borders[2]
+	};
+
+	core::rect<s32> main_rect(
+		topleft_rect.X,
+		topleft_rect.Y,
+		lowerright_rect.X,
+		lowerright_rect.Y
+	);
+
+	std::array<core::rect<s32>, 4> border_rects;
+
+	border_rects[0] = core::rect<s32>(
+		topleft_border.X,
+		topleft_border.Y,
+		lowerright_border.X,
+		topleft_rect.Y
+	);
+
+	border_rects[1] = core::rect<s32>(
+		lowerright_rect.X,
+		topleft_rect.Y,
+		lowerright_border.X,
+		lowerright_rect.Y
+	);
+
+	border_rects[2] = core::rect<s32>(
+		topleft_border.X,
+		lowerright_rect.Y,
+		lowerright_border.X,
+		lowerright_border.Y
+	);
+
+	border_rects[3] = core::rect<s32>(
+		topleft_border.X,
+		topleft_rect.Y,
+		topleft_rect.X,
+		lowerright_rect.Y
+	);
+
+	video::IVideoDriver *driver = Environment->getVideoDriver();
+
+	driver->draw2DRectangle(main_rect, m_colors[0], m_colors[1], m_colors[3],
+		m_colors[2], nullptr);
+
+	for (size_t i = 0; i <= 3; i++)
+		driver->draw2DRectangle(m_bordercolors[i], border_rects[i], nullptr);
 
 	IGUIElement::draw();
 }
diff --git a/src/gui/guiBox.h b/src/gui/guiBox.h
index 5306fdf65..ca8f83771 100644
--- a/src/gui/guiBox.h
+++ b/src/gui/guiBox.h
@@ -19,16 +19,23 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 
 #pragma once
 
+#include <vector>
+#include <array>
 #include "irrlichttypes_extrabloated.h"
 
 class GUIBox : public gui::IGUIElement
 {
 public:
 	GUIBox(gui::IGUIEnvironment *env, gui::IGUIElement *parent, s32 id,
-		const core::rect<s32> &rectangle, const video::SColor &color);
+		const core::rect<s32> &rectangle,
+		const std::array<video::SColor, 4> &colors,
+		const std::array<video::SColor, 4> &bordercolors,
+		const std::array<s32, 4> &borderwidths);
 
 	virtual void draw() override;
 
 private:
-	video::SColor m_color;
+	std::array<video::SColor, 4> m_colors;
+	std::array<video::SColor, 4> m_bordercolors;
+	std::array<s32, 4> m_borderwidths;
 };
diff --git a/src/gui/guiFormSpecMenu.cpp b/src/gui/guiFormSpecMenu.cpp
index f702b40bf..9bd5f27fd 100644
--- a/src/gui/guiFormSpecMenu.cpp
+++ b/src/gui/guiFormSpecMenu.cpp
@@ -2211,16 +2211,16 @@ void GUIFormSpecMenu::parseItemImageButton(parserData* data, const std::string &
 
 void GUIFormSpecMenu::parseBox(parserData* data, const std::string &element)
 {
-	std::vector<std::string> parts = split(element,';');
+	std::vector<std::string> parts = split(element, ';');
 
 	if ((parts.size() == 3) ||
 		((parts.size() > 3) && (m_formspec_version > FORMSPEC_API_VERSION)))
 	{
-		std::vector<std::string> v_pos = split(parts[0],',');
-		std::vector<std::string> v_geom = split(parts[1],',');
+		std::vector<std::string> v_pos = split(parts[0], ',');
+		std::vector<std::string> v_geom = split(parts[1], ',');
 
-		MY_CHECKPOS("box",0);
-		MY_CHECKGEOM("box",1);
+		MY_CHECKPOS("box", 0);
+		MY_CHECKGEOM("box", 1);
 
 		v2s32 pos;
 		v2s32 geom;
@@ -2234,36 +2234,43 @@ void GUIFormSpecMenu::parseBox(parserData* data, const std::string &element)
 			geom.Y = stof(v_geom[1]) * spacing.Y;
 		}
 
-		video::SColor tmp_color;
-
-		if (parseColorString(parts[2], tmp_color, false, 0x8C)) {
-			FieldSpec spec(
-				"",
-				L"",
-				L"",
-				258 + m_fields.size(),
-				-2
-			);
-			spec.ftype = f_Box;
+		FieldSpec spec(
+			"",
+			L"",
+			L"",
+			258 + m_fields.size(),
+			-2
+		);
+		spec.ftype = f_Box;
 
-			core::rect<s32> rect(pos, pos + geom);
+		auto style = getDefaultStyleForElement("box", spec.fname);
 
-			GUIBox *e = new GUIBox(Environment, data->current_parent, spec.fid,
-					rect, tmp_color);
+		video::SColor tmp_color;
+		std::array<video::SColor, 4> colors;
+		std::array<video::SColor, 4> bordercolors = {0x0, 0x0, 0x0, 0x0};
+		std::array<s32, 4> borderwidths = {0, 0, 0, 0};
 
-			auto style = getDefaultStyleForElement("box", spec.fname);
-			e->setNotClipped(style.getBool(StyleSpec::NOCLIP, m_formspec_version < 3));
+		if (parseColorString(parts[2], tmp_color, true, 0x8C)) {
+			colors = {tmp_color, tmp_color, tmp_color, tmp_color};
+		} else {
+			colors = style.getColorArray(StyleSpec::COLORS, {0x0, 0x0, 0x0, 0x0});
+			bordercolors = style.getColorArray(StyleSpec::BORDERCOLORS,
+				{0x0, 0x0, 0x0, 0x0});
+			borderwidths = style.getIntArray(StyleSpec::BORDERWIDTHS, {0, 0, 0, 0});
+		}
 
-			e->drop();
+		core::rect<s32> rect(pos, pos + geom);
 
-			m_fields.push_back(spec);
+		GUIBox *e = new GUIBox(Environment, data->current_parent, spec.fid, rect,
+			colors, bordercolors, borderwidths);
+		e->setNotClipped(style.getBool(StyleSpec::NOCLIP, m_formspec_version < 3));
+		e->drop();
 
-		} else {
-			errorstream<< "Invalid Box element(" << parts.size() << "): '" << element << "'  INVALID COLOR"  << std::endl;
-		}
+		m_fields.push_back(spec);
 		return;
 	}
-	errorstream<< "Invalid Box element(" << parts.size() << "): '" << element << "'"  << std::endl;
+	errorstream << "Invalid Box element(" << parts.size() << "): '" << element
+		<< "'" << std::endl;
 }
 
 void GUIFormSpecMenu::parseBackgroundColor(parserData* data, const std::string &element)