Extract image import route planning

src/app_core/document_import.h

@@ -0,0 +1,43 @@
+#pragma once
+
+#include "foundation/result.h"
+
+namespace pp::app {
+
+enum class DocumentImageImportAction {
+    import_equirectangular,
+    place_transform,
+};
+
+struct DocumentImageImportPlan {
+    int width = 0;
+    int height = 0;
+    DocumentImageImportAction action = DocumentImageImportAction::place_transform;
+    bool imports_equirectangular = false;
+    bool enters_transform_mode = false;
+};
+
+[[nodiscard]] inline pp::foundation::Result<DocumentImageImportPlan> plan_document_image_import(
+    int width,
+    int height) noexcept
+{
+    if (width <= 0 || height <= 0) {
+        return pp::foundation::Result<DocumentImageImportPlan>::failure(
+            pp::foundation::Status::invalid_argument("image dimensions must be positive"));
+    }
+
+    const auto wide_equirect = static_cast<long long>(width) == static_cast<long long>(height) * 2LL;
+    const auto vertical_cube_strip = width == height / 6;
+
+    DocumentImageImportPlan plan;
+    plan.width = width;
+    plan.height = height;
+    plan.imports_equirectangular = wide_equirect || vertical_cube_strip;
+    plan.enters_transform_mode = !plan.imports_equirectangular;
+    plan.action = plan.imports_equirectangular
+        ? DocumentImageImportAction::import_equirectangular
+        : DocumentImageImportAction::place_transform;
+    return pp::foundation::Result<DocumentImageImportPlan>::success(plan);
+}
+
+} // namespace pp::app

src/app_layout.cpp

@@ -11,6 +11,7 @@
 #include "app_core/canvas_tool_ui.h"
 #include "app_core/document_layer.h"
 #include "app_core/document_canvas.h"
+#include "app_core/document_import.h"
 #include "app_core/app_status.h"
 #include "app_core/history_ui.h"
 #include "settings.h"
@@ -746,7 +747,11 @@ void App::init_menu_file()
                     pick_image([this](std::string path){
                         Image img;
                         img.load_file(path);
-                        if (img.width == img.height / 6 || img.width == img.height * 2)
+                        const auto import_plan = pp::app::plan_document_image_import(img.width, img.height);
+                        if (!import_plan)
+                            return;
+
+                        if (import_plan.value().imports_equirectangular)
                         {
                             Canvas::I->import_equirectangular(path);
                         }