Add focused styling to buttons (#13414)

doc/lua_api.txt

@@ -3211,6 +3211,7 @@ Some types may inherit styles from parent types.
 * *all elements*
     * default - Equivalent to providing no states
 * button, button_exit, image_button, item_image_button
+    * focused - Active when button has focus
     * hovered - Active when the mouse is hovering over the element
     * pressed - Active when the button is pressed
 

games/devtest/mods/testformspec/formspec.lua

@@ -190,6 +190,7 @@ local style_fs = [[
 	style[one_btn14:hovered;bgimg=testformspec_bg_hovered.png;fgimg=testformspec_hovered.png;textcolor=yellow]
 	style[one_btn14:pressed;bgimg=testformspec_bg_pressed.png;fgimg=testformspec_pressed.png;textcolor=blue]
 	style[one_btn14:hovered+pressed;textcolor=purple]
+	style[one_btn14:focused;textcolor=red]
 	image_button[0,9.6;1,1;testformspec_button_image.png;one_btn14;Bg]
 
 	style[one_btn15;border=false;bgcolor=#1cc;bgimg=testformspec_bg.png;bgimg_hovered=testformspec_bg_hovered.png;bgimg_pressed=testformspec_bg_pressed.png]
@@ -198,10 +199,10 @@ local style_fs = [[
 	style[one_btn16;border=false;bgimg=testformspec_bg_9slice.png;bgimg_middle=4,6;padding=5,7;fgimg=testformspec_bg.png;fgimg_middle=1]
 	style[one_btn16:hovered;bgimg=testformspec_bg_9slice_hovered.png;fgimg=testformspec_bg_hovered.png]
 	style[one_btn16:pressed;bgimg=testformspec_bg_9slice_pressed.png;fgimg=testformspec_bg_pressed.png]
+	style[one_btn16:focused;bgimg=testformspec_bg_9slice_focused.png;fgimg=testformspec_bg_focused.png]
 	image_button[2.5,9.6;2,1;;one_btn16;9-Slice Bg]
 
 
-
 	container[2.75,0]
 
 	style[one_tb1;textcolor=Yellow]

src/gui/StyleSpec.h

@@ -61,13 +61,16 @@ public:
 		NUM_PROPERTIES,
 		NONE
 	};
-	enum State
+
+	// State is a bitfield, it's possible to have multiple of these at once
+	enum State : u8
 	{
 		STATE_DEFAULT = 0,
-		STATE_HOVERED = 1 << 0,
-		STATE_PRESSED = 1 << 1,
-		NUM_STATES = 1 << 2,
-		STATE_INVALID = 1 << 3,
+		STATE_FOCUSED = 1 << 0,
+		STATE_HOVERED = 1 << 1,
+		STATE_PRESSED = 1 << 2,
+		NUM_STATES = 1 << 3, // This includes all permutations
+		STATE_INVALID = 1 << 4,
 	};
 
 private:
@@ -150,6 +153,8 @@ public:
 	{
 		if (name == "default") {
 			return STATE_DEFAULT;
+		} else if (name == "focused") {
+			return STATE_FOCUSED;
 		} else if (name == "hovered") {
 			return STATE_HOVERED;
 		} else if (name == "pressed") {

src/gui/guiButton.cpp

@@ -200,6 +200,7 @@ bool GUIButton::OnEvent(const SEvent& event)
 			// mouse is outside of the formspec. Thus, we test the position here.
 			if ( !IsPushButton && AbsoluteClippingRect.isPointInside(
 						core::position2d<s32>(event.MouseInput.X, event.MouseInput.Y ))) {
+				Environment->setFocus(this);
 				setPressed(true);
 			}
 
@@ -258,8 +259,10 @@ void GUIButton::draw()
 	// PATCH
 	// Track hovered state, if it has changed then we need to update the style.
 	bool hovered = isHovered();
-	if (hovered != WasHovered) {
+	bool focused = isFocused();
+	if (hovered != WasHovered || focused != WasFocused) {
 		WasHovered = hovered;
+		WasFocused = focused;
 		setFromState();
 	}
 
@@ -387,7 +390,7 @@ EGUI_BUTTON_IMAGE_STATE GUIButton::getImageState(bool pressed, const ButtonImage
 {
 	// figure state we should have
 	EGUI_BUTTON_IMAGE_STATE state = EGBIS_IMAGE_DISABLED;
-	bool focused = Environment->hasFocus((IGUIElement*)this);
+	bool focused = isFocused();
 	bool mouseOver = isHovered();
 	if (isEnabled())
 	{
@@ -582,6 +585,12 @@ bool GUIButton::isHovered() const
 	IGUIElement *hovered = Environment->getHovered();
 	return  hovered == this || (hovered != nullptr && hovered->getParent() == this);
 }
+
+//! Returns if this element (or one of its direct children) is focused
+bool GUIButton::isFocused() const
+{
+	return Environment->hasFocus((IGUIElement*)this, true);
+}
 // END PATCH
 
 //! Sets the pressed state of the button if this is a pushbutton
@@ -662,6 +671,9 @@ void GUIButton::setFromState()
 	if (isHovered())
 		state = static_cast<StyleSpec::State>(state | StyleSpec::STATE_HOVERED);
 
+	if (isFocused())
+		state = static_cast<StyleSpec::State>(state | StyleSpec::STATE_FOCUSED);
+
 	setFromStyle(StyleSpec::getStyleFromStatePropagation(Styles, state));
 }
 

src/gui/guiButton.h

@@ -123,6 +123,9 @@ public:
 	// PATCH
 	//! Returns if this element (or one of its direct children) is hovered
 	bool isHovered() const;
+
+	//! Returns if this element (or one of its direct children) is focused
+	bool isFocused() const;
 	// END PATCH
 
 	//! Sets if the button should use the skin to draw its border
@@ -268,6 +271,7 @@ private:
 	video::SColor Colors[4];
 	// PATCH
 	bool WasHovered = false;
+	bool WasFocused = false;
 	ISimpleTextureSource *TSrc;
 
 	gui::IGUIStaticText *StaticText;