add read-only UI contentOffset property

src/graphics/ui/elements/Container.hpp

@@ -30,7 +30,7 @@ namespace gui {
         virtual void scrolled(int value) override;
         virtual void setScrollable(bool flag);
         void listenInterval(float interval, ontimeout callback, int repeat=-1);
-        virtual glm::vec2 contentOffset() override {return glm::vec2(0.0f, scroll);};
+        virtual glm::vec2 getContentOffset() override {return glm::vec2(0.0f, scroll);};
         virtual void setSize(glm::vec2 size) override;
         virtual void refresh() override;
 

src/graphics/ui/elements/TextBox.cpp

@@ -646,7 +646,7 @@ void TextBox::setCaret(size_t position) {
     caretLastMove = Window::time();
     int width = label->getSize().x;
     uint line = label->getLineByTextIndex(caret);
-    int offset = label->getLineYOffset(line) + contentOffset().y;
+    int offset = label->getLineYOffset(line) + getContentOffset().y;
     uint lineHeight = font->getLineHeight()*label->getLineInterval();
     scrollStep = lineHeight;
     if (offset < 0) {

src/graphics/ui/elements/UINode.cpp

@@ -152,7 +152,7 @@ float UINode::getTooltipDelay() const {
 
 glm::vec2 UINode::calcPos() const {
     if (parent) {
-        return pos + parent->calcPos() + parent->contentOffset();
+        return pos + parent->calcPos() + parent->getContentOffset();
     }
     return pos;
 }

src/graphics/ui/elements/UINode.hpp

@@ -209,7 +209,7 @@ namespace gui {
         virtual glm::vec4 calcColor() const;
 
         /// @brief Get inner content offset. Used for scroll
-        virtual glm::vec2 contentOffset() {return glm::vec2(0.0f);};
+        virtual glm::vec2 getContentOffset() {return glm::vec2(0.0f);};
         /// @brief Calculate screen position of the element
         virtual glm::vec2 calcPos() const;
         virtual void setPos(glm::vec2 pos);

src/logic/scripting/lua/libs/libgui.cpp

@@ -292,6 +292,10 @@ static int p_set_interval(UINode* node, lua::State* L) {
     return 0;
 }
 
+static int p_get_content_offset(UINode* node, lua::State* L) {
+    return lua::pushvec(L, node->getContentOffset());
+}
+
 static int p_get_color(UINode* node, lua::State* L) {
     return lua::pushcolor(L, node->getColor());
 }
@@ -344,6 +348,7 @@ static int l_gui_getattr(lua::State* L) {
             {"color", p_get_color},
             {"hoverColor", p_get_hover_color},
             {"pressedColor", p_get_pressed_color},
+            {"contentOffset", p_get_content_offset},
             {"tooltip", p_get_tooltip},
             {"tooltipDelay", p_get_tooltip_delay},
             {"pos", p_get_pos},