Phase 4.2: Add GridView UIDrawable type (addresses #252)

GridView is a new UIDrawable that renders a GridData object independently.
Multiple GridViews can reference the same Grid for split-screen, minimap,
or different camera/zoom perspectives on shared grid state.

- New files: UIGridView.h/cpp with full rendering pipeline (copied from
  UIGrid::render, adapted to use grid_data pointer)
- Add UIGRIDVIEW to PyObjectsEnum
- Add UIGRIDVIEW cases to all switch(derived_type()) sites:
  Animation.cpp, UICollection.cpp, UIDrawable.cpp, McRFPy_API.cpp,
  ImGuiSceneExplorer.cpp
- Python type: mcrfpy.GridView(grid=, pos=, size=, zoom=, fill_color=)
- Properties: grid, center, zoom, fill_color, texture
- Register type with metaclass for callback support

All 258 existing tests pass. New GridView test suite added.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

src/UIGridView.h

@@ -0,0 +1,158 @@
+#pragma once
+// UIGridView.h - Rendering view for GridData (#252)
+//
+// GridView is a UIDrawable that renders a GridData object. Multiple GridViews
+// can reference the same GridData for split-screen, minimap, etc.
+// GridView holds rendering state (camera, zoom, perspective) independently.
+
+#include "Common.h"
+#include "Python.h"
+#include "structmember.h"
+#include "UIDrawable.h"
+#include "UIBase.h"
+#include "GridData.h"
+#include "PyTexture.h"
+#include "PyColor.h"
+#include "PyVector.h"
+#include "PyCallable.h"
+#include "PyDrawable.h"
+
+// Forward declarations
+class UIGrid;
+class UIGridView;
+
+// Python object struct (UIGridView forward-declared above)
+typedef struct {
+    PyObject_HEAD
+    std::shared_ptr<UIGridView> data;
+    PyObject* weakreflist;
+} PyUIGridViewObject;
+
+class UIGridView : public UIDrawable
+{
+public:
+    UIGridView();
+    ~UIGridView();
+
+    void render(sf::Vector2f offset, sf::RenderTarget& target) override final;
+    PyObjectsEnum derived_type() override final;
+    UIDrawable* click_at(sf::Vector2f point) override final;
+
+    sf::FloatRect get_bounds() const override;
+    void move(float dx, float dy) override;
+    void resize(float w, float h) override;
+
+    // The grid data this view renders
+    std::shared_ptr<GridData> grid_data;
+
+    // Rendering state (independent per view)
+    std::shared_ptr<PyTexture> ptex;
+    sf::RectangleShape box;
+    float center_x = 0, center_y = 0, zoom = 1.0f;
+    float camera_rotation = 0.0f;
+    sf::Color fill_color{8, 8, 8, 255};
+
+    // Perspective (per-view)
+    std::weak_ptr<UIEntity> perspective_entity;
+    bool perspective_enabled = false;
+
+    // Render textures
+    sf::Sprite sprite_proto, output;
+    sf::RenderTexture renderTexture;
+    sf::Vector2u renderTextureSize{0, 0};
+    void ensureRenderTextureSize();
+    sf::RenderTexture rotationTexture;
+    unsigned int rotationTextureSize = 0;
+
+    // Property system for animations
+    bool setProperty(const std::string& name, float value) override;
+    bool setProperty(const std::string& name, const sf::Vector2f& value) override;
+    bool getProperty(const std::string& name, float& value) const override;
+    bool getProperty(const std::string& name, sf::Vector2f& value) const override;
+    bool hasProperty(const std::string& name) const override;
+
+    // Camera positioning
+    void center_camera();
+    void center_camera(float tile_x, float tile_y);
+
+    // Cell coordinate conversion
+    std::optional<sf::Vector2i> screenToCell(sf::Vector2f screen_pos) const;
+    sf::Vector2f getEffectiveCellSize() const;
+
+    static constexpr int DEFAULT_CELL_WIDTH = 16;
+    static constexpr int DEFAULT_CELL_HEIGHT = 16;
+
+    // =========================================================================
+    // Python API
+    // =========================================================================
+    static int init(PyUIGridViewObject* self, PyObject* args, PyObject* kwds);
+    static PyObject* repr(PyUIGridViewObject* self);
+
+    static PyObject* get_grid(PyUIGridViewObject* self, void* closure);
+    static int set_grid(PyUIGridViewObject* self, PyObject* value, void* closure);
+    static PyObject* get_center(PyUIGridViewObject* self, void* closure);
+    static int set_center(PyUIGridViewObject* self, PyObject* value, void* closure);
+    static PyObject* get_zoom(PyUIGridViewObject* self, void* closure);
+    static int set_zoom(PyUIGridViewObject* self, PyObject* value, void* closure);
+    static PyObject* get_fill_color(PyUIGridViewObject* self, void* closure);
+    static int set_fill_color(PyUIGridViewObject* self, PyObject* value, void* closure);
+    static PyObject* get_texture(PyUIGridViewObject* self, void* closure);
+
+    static PyMethodDef methods[];
+    static PyGetSetDef getsetters[];
+};
+
+// Forward declaration of methods array
+extern PyMethodDef UIGridView_all_methods[];
+
+namespace mcrfpydef {
+    inline PyTypeObject PyUIGridViewType = {
+        .ob_base = {.ob_base = {.ob_refcnt = 1, .ob_type = NULL}, .ob_size = 0},
+        .tp_name = "mcrfpy.GridView",
+        .tp_basicsize = sizeof(PyUIGridViewObject),
+        .tp_itemsize = 0,
+        .tp_dealloc = (destructor)[](PyObject* self)
+        {
+            PyUIGridViewObject* obj = (PyUIGridViewObject*)self;
+            PyObject_GC_UnTrack(self);
+            if (obj->weakreflist != NULL) {
+                PyObject_ClearWeakRefs(self);
+            }
+            obj->data.reset();
+            Py_TYPE(self)->tp_free(self);
+        },
+        .tp_repr = (reprfunc)UIGridView::repr,
+        .tp_flags = Py_TPFLAGS_DEFAULT | Py_TPFLAGS_BASETYPE | Py_TPFLAGS_HAVE_GC,
+        .tp_doc = PyDoc_STR(
+            "GridView(grid=None, pos=None, size=None, **kwargs)\n\n"
+            "A rendering view for a Grid's data. Multiple GridViews can display\n"
+            "the same Grid with different camera positions, zoom levels, etc.\n\n"
+            "Args:\n"
+            "    grid (Grid): The Grid to render. Required.\n"
+            "    pos (tuple): Position as (x, y). Default: (0, 0)\n"
+            "    size (tuple): Size as (w, h). Default: (256, 256)\n\n"
+            "Keyword Args:\n"
+            "    zoom (float): Zoom level. Default: 1.0\n"
+            "    center (tuple): Camera center (x, y) in pixels. Default: grid center\n"
+            "    fill_color (Color): Background color. Default: dark gray\n"),
+        .tp_traverse = [](PyObject* self, visitproc visit, void* arg) -> int {
+            return 0;
+        },
+        .tp_clear = [](PyObject* self) -> int {
+            return 0;
+        },
+        .tp_methods = UIGridView_all_methods,
+        .tp_getset = UIGridView::getsetters,
+        .tp_base = &mcrfpydef::PyDrawableType,
+        .tp_init = (initproc)UIGridView::init,
+        .tp_new = [](PyTypeObject* type, PyObject* args, PyObject* kwds) -> PyObject*
+        {
+            PyUIGridViewObject* self = (PyUIGridViewObject*)type->tp_alloc(type, 0);
+            if (self) {
+                self->data = std::make_shared<UIGridView>();
+                self->weakreflist = nullptr;
+            }
+            return (PyObject*)self;
+        }
+    };
+}