feat(automation): double-buffered ImGui item table

src/slic3r/CMakeLists.txt

@@ -241,6 +241,8 @@ set(SLIC3R_GUI_SOURCES
     GUI/Automation/AutomationServer.hpp
     GUI/Automation/AutomationRegistry.cpp
     GUI/Automation/AutomationRegistry.hpp
+    GUI/Automation/ImGuiItemTable.cpp
+    GUI/Automation/ImGuiItemTable.hpp
     GUI/I18N.cpp
     GUI/I18N.hpp
     GUI/DragDropPanel.cpp

src/slic3r/GUI/Automation/ImGuiItemTable.cpp

@@ -0,0 +1,31 @@
+#include "ImGuiItemTable.hpp"
+
+namespace Slic3r { namespace GUI { namespace Automation {
+
+ImGuiItemTable& ImGuiItemTable::instance() {
+    static ImGuiItemTable t;
+    return t;
+}
+
+void ImGuiItemTable::record_item(ImGuiItemRecord rec) {
+    std::lock_guard<std::mutex> lk(m_mutex);
+    m_back.items.push_back(std::move(rec));
+}
+
+void ImGuiItemTable::record_window(ImGuiWindowRecord rec) {
+    std::lock_guard<std::mutex> lk(m_mutex);
+    m_back.windows.push_back(std::move(rec));
+}
+
+void ImGuiItemTable::swap_frame() {
+    std::lock_guard<std::mutex> lk(m_mutex);
+    m_front = std::move(m_back);
+    m_back  = ImGuiFrameRecord{};
+}
+
+ImGuiFrameRecord ImGuiItemTable::snapshot() const {
+    std::lock_guard<std::mutex> lk(m_mutex);
+    return m_front;
+}
+
+}}} // namespace

src/slic3r/GUI/Automation/ImGuiItemTable.hpp

@@ -0,0 +1,56 @@
+#pragma once
+#include <mutex>
+#include <string>
+#include <vector>
+
+namespace Slic3r { namespace GUI { namespace Automation {
+
+// One recorded ImGui item. Rect is in ImGui display coords; WxUiBackend maps it
+// to screen coords using the canvas client origin + DPI scale.
+struct ImGuiItemRecord {
+    std::string window_name;
+    std::string label;   // visible label / id
+    std::string type;    // "button", "checkbox", "combo", "slider", "input", ...
+    float       x = 0, y = 0, w = 0, h = 0;
+    bool        enabled = true;
+    bool        has_value = false;
+    std::string value;
+};
+
+// A complete recorded frame: items + window-level info.
+struct ImGuiWindowRecord {
+    std::string name;
+    float       x = 0, y = 0, w = 0, h = 0;
+    bool        visible = true;
+};
+
+struct ImGuiFrameRecord {
+    std::vector<ImGuiItemRecord>   items;
+    std::vector<ImGuiWindowRecord> windows;
+};
+
+// Double-buffered recorder. The drawing code appends to the "back" frame; render()
+// swaps it to "front" at frame end. Readers (GUI thread, after marshaling) read the
+// front frame. All access is on the GUI thread, but we guard with a mutex anyway
+// because the automation read may happen between frames.
+class ImGuiItemTable {
+public:
+    static ImGuiItemTable& instance();
+
+    // Called from ImGuiWrapper drawing hooks (GUI thread). No-op cheap append.
+    void record_item(ImGuiItemRecord rec);
+    void record_window(ImGuiWindowRecord rec);
+
+    // Called at frame end (ImGuiWrapper::render). Promotes back -> front, clears back.
+    void swap_frame();
+
+    // Snapshot the latest complete frame for the backend to read.
+    ImGuiFrameRecord snapshot() const;
+
+private:
+    mutable std::mutex m_mutex;
+    ImGuiFrameRecord   m_back;   // accumulating
+    ImGuiFrameRecord   m_front;  // last complete
+};
+
+}}} // namespace