graph_editor_view.hpp

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#pragma once
 
// GraphEditorView — canvas-based node editor on top of pulp::canvas.
//
// Renders a SignalGraph as a draggable, connectable node graph. Drag-to-
// connect creates audio / MIDI / automation / feedback edges (modifier keys
// distinguish the variants). Live-patchable: every connection mutation
// invalidates the SignalGraph's CompiledGraph snapshot, so the audio thread
// transitions through one block of silence and back without tearing.
//
// iOS skip: pulp::host is not linked on iOS (App Store policy disallows
// dlopen of third-party plugins). `__has_include` short-circuits the entire
// declaration on platforms where the host headers are not on the include
// path — downstream code that conditionally instantiates GraphEditorView
// must mirror the same guard.
//
// GraphEditorView is an opt-in host-backed widget, not part of the view-only
// link surface. Desktop consumers that instantiate it must link both
// `pulp::view` and `pulp::host`.
 
#if defined(__has_include) && __has_include(<pulp/host/signal_graph.hpp>)
#define PULP_VIEW_HAS_GRAPH_EDITOR_VIEW 1
 
#include <functional>
#include <memory>
#include <pulp/canvas/canvas.hpp>
#include <pulp/host/signal_graph.hpp>
#include <pulp/view/hosted_editor_attachment.hpp>
#include <pulp/view/view.hpp>
#include <string>
#include <unordered_map>
 
namespace pulp::view::widgets {
 
class GraphEditorView : public View {
  public:
    explicit GraphEditorView(host::SignalGraph& graph) : graph_(graph) {
        auto_layout();
    }
 
    // Position a node manually (by default add_*_node positions are auto-
    // assigned in a grid). Persist positions in your own StateTree if you
    // want them to survive save/load.
    void set_node_position(host::NodeId id, float x, float y) {
        positions_[id] = {x, y};
    }
 
    // Recompute auto-layout. Called from the constructor; call again after
    // adding/removing nodes if you don't want to set_node_position manually.
    void auto_layout();
 
    void paint(canvas::Canvas& c) override;
 
    // Use the dispatched legacy mouse callbacks (down/up/drag) so press
    // and release each get their own entry point — on_mouse_event would
    // require disambiguating press/release/drag from MouseEvent::is_down,
    // which platforms set inconsistently during in-flight drags.
    void on_mouse_down(Point pos) override;
    void on_mouse_drag(Point pos) override;
    void on_mouse_up(Point pos) override;
 
    // Modifier-key state for the next on_mouse_up: the legacy down/up
    // callbacks pass only Point, so we capture modifiers via on_mouse_event
    // (which fires before the dispatch to legacy handlers) and consume
    // them in on_mouse_up to pick the connect variant.
    void on_mouse_event(const MouseEvent& ev) override;
    bool wants_mouse_input() const override {
        return true;
    }
 
    enum class EdgeKind { Audio, Midi, Automation, Feedback };
 
    // ── Hosted plugin editors ───────────────────────────────────────
    // Open a node's plugin editor, embedded via EditorAttachment. The provider
    // supplies the WindowHost the editor attaches into — e.g. a floating editor
    // window the app owns. Without a provider, or for a node with no plugin /
    // no embeddable editor on this platform, open_node_editor() is a no-op that
    // returns false. The attachment co-owns the node's PluginSlot, so an open
    // editor stays valid even if the node is removed from the graph.
    void set_editor_host_provider(std::function<WindowHost*(host::NodeId)> provider) {
        editor_host_provider_ = std::move(provider);
    }

    bool open_node_editor(host::NodeId id);

    void close_node_editor(host::NodeId id);

    bool is_editor_open(host::NodeId id) const {
        return open_editors_.find(id) != open_editors_.end();
    }
 
  private:
    struct Pos {
        float x, y;
    };
 
    static constexpr float kNodeWidth = 160.0f;
    static constexpr float kNodeHeight = 80.0f;
    static constexpr float kPortRadius = 6.0f;
    static constexpr float kPortSpacing = 18.0f;
    static constexpr float kCornerRadius = 8.0f;
 
    // ── Geometry helpers ────────────────────────────────────────────
    Pos node_origin_(host::NodeId id) const;
    Pos input_port_pos_(host::NodeId id, int port) const;
    Pos output_port_pos_(host::NodeId id, int port) const;
    bool hit_node_(float mx, float my, host::NodeId& out_id) const;
    bool hit_input_port_(float mx, float my, host::NodeId& out_id, int& out_port) const;
    bool hit_output_port_(float mx, float my, host::NodeId& out_id, int& out_port) const;
 
    void paint_node_(canvas::Canvas& c, const host::GraphNode& n);
    void paint_connection_(canvas::Canvas& c, const host::Connection& conn);
    void paint_ghost_(canvas::Canvas& c);
 
    // ── State ───────────────────────────────────────────────────────
    host::SignalGraph& graph_;
    std::unordered_map<host::NodeId, Pos> positions_;
 
    // Drag-to-connect state.
    bool dragging_ = false;
    host::NodeId drag_src_node_ = 0;
    int drag_src_port_ = -1;
    bool drag_src_is_output_ = true;
    Pos drag_cursor_{0, 0};
 
    // Selection (for delete via backspace; not yet wired into key events).
    host::NodeId selected_node_ = 0;
 
    // Last-seen modifier state from on_mouse_event, consumed in on_mouse_up
    // to pick the connect/connect_midi/connect_feedback variant.
    uint16_t last_modifiers_ = 0;
 
    // Hosted plugin editors, keyed by node. Each EditorAttachment co-owns the
    // node's PluginSlot for its lifetime.
    std::function<WindowHost*(host::NodeId)> editor_host_provider_;
    std::unordered_map<host::NodeId, std::unique_ptr<EditorAttachment>> open_editors_;
};
 
} // namespace pulp::view::widgets
 
#else // !__has_include(<pulp/host/signal_graph.hpp>)
#define PULP_VIEW_HAS_GRAPH_EDITOR_VIEW 0
#endif