Merge branch 'opacity_color_bindings' into 'master'

Bindings for image color and widget alpha (#6654)

Closes #6654

See merge request OpenMW/openmw!1723

components/lua_ui/image.cpp

@@ -68,6 +68,8 @@ namespace LuaUi
             atlasCoord.height = textureSize.height;
         setImageCoord(atlasCoord);
 
+        setColour(propertyValue("color", MyGUI::Colour(1,1,1,1)));
+
         WidgetExtension::updateProperties();
     }
 }

components/lua_ui/widget.cpp

@@ -259,6 +259,8 @@ namespace LuaUi
         mAnchor = propertyValue("anchor", MyGUI::FloatSize());
         mWidget->setVisible(propertyValue("visible", true));
         mWidget->setPointer(propertyValue("pointer", std::string("arrow")));
+        mWidget->setAlpha(propertyValue("alpha", 1.f));
+        mWidget->setInheritsAlpha(propertyValue("inheritAlpha", true));
     }
 
     void WidgetExtension::updateChildrenCoord()

docs/source/reference/lua-scripting/widgets/image.rst

@@ -20,3 +20,6 @@ Properties
   * - tileV
     - boolean (false)
     - Tile the texture vertically
+  * - color
+    - util.color (1, 1, 1)
+    - Modulate constant color with the color of the image texture.

docs/source/reference/lua-scripting/widgets/widget.rst

@@ -35,6 +35,14 @@ Properties
   * - propagateEvents
     - boolean (true)
     - Allows base widget events to propagate to the widget's parent.
+  * - alpha
+    - number (1.0)
+    - | Set the opacity of the widget and its contents.
+      | If `inheritAlpha` is set to `true`, this becomes the maximum alpha value the widget can take.
+  * - inheritAlpha
+    - boolean (true)
+    - | Modulate `alpha` with parents `alpha`.
+      | If the parent has `inheritAlpha` set to `true`, the value after modulating is passed to the child.
 
 .. TODO: document the mouse pointer property, when API for reading / adding pointer types is available