Lua: Expose stretch function in box layout

Change-Id: I52bb81e01561950785252d362d31d6142844fcac
Reviewed-by: <lie@spyro-soft.com>
Reviewed-by: Marcus Tillmanns <marcus.tillmanns@qt.io>

src/libs/utils/layoutbuilder.cpp

@@ -686,6 +686,12 @@ void Layout::setFieldGrowthPolicy(int policy)
         lt->setFieldGrowthPolicy(QFormLayout::FieldGrowthPolicy(policy));
 }
 
+void Layout::setStretch(int index, int stretch)
+{
+    if (auto lt = asBox())
+        lt->setStretch(index, stretch);
+}
+
 QWidget *Layout::emerge() const
 {
     const_cast<Layout *>(this)->flush();
@@ -1143,6 +1149,11 @@ LayoutModifier spacing(int space)
     return [space](Layout *layout) { layout->setSpacing(space); };
 }
 
+LayoutModifier stretch(int index, int stretch)
+{
+    return [index, stretch](Layout *layout) { layout->setStretch(index, stretch); };
+}
+
 void addToLayout(Layout *layout, const Space &inner)
 {
     if (auto lt = layout->asBox())

src/libs/utils/layoutbuilder.h

@@ -122,6 +122,7 @@ public:
     void setColumnStretch(int cols, int rows);
     void setSpacing(int space);
     void setFieldGrowthPolicy(int policy);
+    void setStretch(int index, int stretch);
 
     void attachTo(QWidget *);
 
@@ -614,6 +615,7 @@ QTCREATOR_UTILS_EXPORT void hr(Layout *);
 QTCREATOR_UTILS_EXPORT void tight(Layout *); // noMargin + spacing(0)
 
 QTCREATOR_UTILS_EXPORT LayoutModifier spacing(int space);
+QTCREATOR_UTILS_EXPORT LayoutModifier stretch(int index, int stretch);
 
 // Convenience
 

src/plugins/lua/bindings/gui.cpp

@@ -700,6 +700,7 @@ void setupGuiModule()
         gui["normalMargin"] = &normalMargin;
         gui["withFormAlignment"] = &withFormAlignment;
         gui["spacing"] = &spacing;
+        gui["stretch"] = &stretch;
 
         return gui;
     });

src/plugins/lua/meta/gui.lua

@@ -260,6 +260,11 @@ function gui.normalMargin() end
 ---Sets the alignment of a Grid layout according to the Form layout rules.
 function gui.withFormAlignment() end
 
+---Sets the stretch factor at position index to stretch.
+---@param index integer The widget index.
+---@param stretch integer The stretch factor.
+function gui.stretch(index, stretch) end
+
 --- Enum representing Text interaction flags
 ---@enum TextInteractionFlag
 gui.TextInteractionFlag {