viewer_imgui.h

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/********************************************************************
 * @file viewer_imgui.h
 * @brief ViewerImGui class header based on the Easy3D ImGui example.
 *
 * This class extends Easy3D's Viewer to include an ImGui-based GUI
 * system for rendering widgets, menus, and overlays in an OpenGL
 * context. It integrates ImGui input handling and layout management.
 ********************************************************************/
 
#ifndef EASY3D_TUTORIAL_VIEWER_IMGUI_H
#define EASY3D_TUTORIAL_VIEWER_IMGUI_H
 
 
#include <easy3d/viewer/viewer.h>
 
 
 
// Forward declaration to avoid including full ImGui headers in this file
struct ImGuiContext;
 
 
namespace easy3d
{
    class ViewerImGui : public Viewer
    {
    public:
        explicit ViewerImGui(
            const std::string& title = "Easy3D ViewerImGui",
            int samples = 4,
            int gl_major = 3,   // must >= 3
            int gl_minor = 2,   // must >= 2
            bool full_screen = false,
            bool resizable = true,
            int depth_bits = 24,
            int stencil_bits = 8,
            int width = 800,
            int height = 600
        );
        ~ViewerImGui() override;
 
    protected:
 
        void init() override;
 
        void pre_draw() override;
 
        void post_draw() override;
        void post_resize(int w, int h) override;
        bool callback_event_cursor_pos(double x, double y) override;
        bool callback_event_mouse_button(int button, int action, int modifiers) override;
        bool callback_event_keyboard(int key, int action, int modifiers) override;
        bool callback_event_character(unsigned int codepoint) override;
        bool callback_event_scroll(double dx, double dy) override;
        void draw_menu_file();
        void draw_menu_view();
 
    protected:
        float pixel_ratio();
        float widget_scaling() { return dpi_scaling() / pixel_ratio(); }
 
        void  reload_font(int font_size = 16);
 
    protected:
        static ImGuiContext *   context_;
        float menu_height_;
    };
 
}
 
#endif  // EASY3D_TUTORIAL_VIEWER_IMGUI_H