native_view_host.hpp

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#pragma once
 
#include <pulp/view/view.hpp>
 
#include <cstdint>
#include <functional>
#include <vector>
 
namespace pulp::view {
 
class WindowHost;
class PluginViewHost;
 
// Platform-native child-view handle (NSView* / UIView* / HWND / X11 Window),
// mirroring the identical alias in plugin_view_host.hpp / web_view.hpp. Declared
// locally so this header stays light (it does not pull in the full host
// headers); a repeated `using` to the same type is a legal, harmless
// redeclaration when those headers are also included.
using NativeViewHandle = void*;

class NativeViewHost : public View {
    friend class PluginViewHost;
    friend class WindowHost;
 
public:
    using SnapshotFn = std::function<std::vector<uint8_t>(uint32_t width,
                                                          uint32_t height)>;
 
    NativeViewHost() = default;
    ~NativeViewHost() override;

    void set_native_child(NativeViewHandle handle, SnapshotFn snapshot = {});

    void clear_native_child();

    NativeViewHandle native_child() const { return handle_; }

    bool is_native_attached() const { return attached_; }
 
    // ── Introspection (headless tests) ──────────────────────────────────────
    Rect computed_child_frame() const { return last_frame_; }
    Rect computed_child_frame_host() const { return last_frame_host_; }
    Rect computed_visible_rect() const { return last_visible_; }
    bool is_clipped() const { return last_clipped_; }
    void update_native_layout();
 
    // ── View overrides ──────────────────────────────────────────────────────
    std::vector<uint8_t> capture_native_overlay_png(uint32_t width,
                                                     uint32_t height) override;
    void paint_all(canvas::Canvas& canvas) override;
    void set_window_host(WindowHost* host) override;
    void set_plugin_view_host(PluginViewHost* host) override;
 
private:
    enum class HostKind { none, plugin, window };

    void compute_geometry(Rect& frame, Rect& visible, bool& clipped) const;

    bool active_viewport_transform(float& sx, float& sy, float& tx,
                                   float& ty) const;

    static void apply_viewport(Rect& r, float sx, float sy, float tx, float ty) {
        r = {r.x * sx + tx, r.y * sy + ty, r.width * sx, r.height * sy};
    }

    bool try_attach();
    void detach_from_host();
    void on_host_destroyed();
    void reconcile_host();
    void push_geometry(const Rect& frame, const Rect& visible, bool clipped);
 
    NativeViewHandle handle_ = nullptr;
    SnapshotFn snapshot_;
 
    bool attached_ = false;
    HostKind attached_kind_ = HostKind::none;
    PluginViewHost* attached_plugin_ = nullptr;
    WindowHost* attached_window_ = nullptr;
 
    // Last computed geometry in ROOT/design space (introspection getters; kept
    // current every layout pump regardless of platform / attach state).
    Rect last_frame_{};
    Rect last_visible_{};
    bool last_clipped_ = false;
    // Last computed frame in HOST space (design frame after the active
    // viewport transform). Equal to last_frame_ when no viewport is active.
    Rect last_frame_host_{};
 
    // Last geometry actually pushed to the host (HOST space), to skip
    // redundant per-frame host calls.
    Rect pushed_frame_{};
    Rect pushed_visible_{};
    bool pushed_clipped_ = false;
    bool have_pushed_ = false;
};
 
} // namespace pulp::view