Improve entry with cutting off text, vertical scroll, text selection, caret movement, copy, etc

include/gui/Entry.hpp

@@ -5,9 +5,17 @@
 
 #include <mglpp/graphics/Color.hpp>
 #include <mglpp/graphics/Text.hpp>
+#include <mglpp/graphics/Rectangle.hpp>
 
 namespace gsr {
-    using EntryValidateHandler = std::function<bool(std::string &str)>;
+    class Entry;
+
+    enum class EntryValidateHandlerResult {
+        DENY,
+        ALLOW,
+        REPLACED
+    };
+    using EntryValidateHandler = std::function<EntryValidateHandlerResult(Entry &entry, const std::string &str)>;
 
     class Entry : public Widget {
     public:
@@ -20,19 +28,39 @@ namespace gsr {
 
         mgl::vec2f get_size() override;
 
-        void set_text(std::string str);
+        EntryValidateHandlerResult set_text(std::string str);
         const std::string& get_text() const;
 
+        // Also updates the cursor position
+        void replace_text(size_t index, size_t size, const std::string &replacement);
+
         // Return false to specify that the string should not be accepted. This reverts the string back to its previous value.
         // The input can be changed by changing the input parameter and returning true.
         EntryValidateHandler validate_handler;
 
         std::function<void(const std::string &text)> on_changed;
     private:
+        EntryValidateHandlerResult set_text_internal(std::string str);
+        void draw_caret(mgl::Window &window, mgl::vec2f draw_pos, mgl::vec2f caret_size);
+        void draw_caret_selection(mgl::Window &window, mgl::vec2f draw_pos, mgl::vec2f caret_size);
+        mgl_index_codepoint_pair find_closest_caret_index_by_position(mgl::vec2f position);
+    private:
+        struct Caret {
+            float offset_x = 0.0f;
+            int utf8_index = 0;
+            int byte_index = 0;
+        };
+
+        mgl::Rectangle background;
         mgl::Text text;
         float max_width;
         bool selected = false;
-        float caret_offset_x = 0.0f;
+        bool selecting_text = false;
+        bool selecting_with_keyboard = false;
+        bool show_selection = false;
+        Caret caret;
+        Caret selection_start_caret;
+        float text_overflow = 0.0f;
     };
 
     EntryValidateHandler create_entry_validator_integer_in_range(int min, int max);

include/gui/Utils.hpp

@@ -2,6 +2,7 @@
 
 #include <mglpp/system/vec.hpp>
 #include <mglpp/graphics/Color.hpp>
+#include <mglpp/window/Window.hpp>
 
 namespace mgl {
     class Window;
@@ -14,4 +15,5 @@ namespace gsr {
     void set_frame_delta_seconds(double frame_delta);
     mgl::vec2f scale_keep_aspect_ratio(mgl::vec2f from, mgl::vec2f to);
     mgl::vec2f clamp_keep_aspect_ratio(mgl::vec2f from, mgl::vec2f to);
+    mgl::Scissor scissor_get_sub_area(mgl::Scissor parent, mgl::Scissor child);
 }