Route canvas view execution through app core

src/app_core/canvas_view.h

@@ -1,9 +1,19 @@
 #pragma once
 
+#include "foundation/result.h"
+
 #include <array>
+#include <cmath>
 
 namespace pp::app {
 
+enum class CanvasViewCursorMode {
+    never = 0,
+    small_brush = 1,
+    not_painting = 2,
+    always = 3,
+};
+
 struct CanvasCameraState {
     std::array<float, 16> rotation {};
     std::array<float, 3> position {};
@@ -11,6 +21,24 @@ struct CanvasCameraState {
     std::array<float, 2> pan {};
 };
 
+struct CanvasViewDensityPlan {
+    float density = 1.0F;
+    bool recreates_buffers = true;
+};
+
+struct CanvasViewCursorModePlan {
+    CanvasViewCursorMode mode = CanvasViewCursorMode::never;
+};
+
+class CanvasViewServices {
+public:
+    virtual ~CanvasViewServices() = default;
+
+    virtual void reset_camera(const CanvasCameraState& state) = 0;
+    virtual void set_density(const CanvasViewDensityPlan& plan) = 0;
+    virtual void set_cursor_mode(const CanvasViewCursorModePlan& plan) = 0;
+};
+
 [[nodiscard]] constexpr CanvasCameraState plan_canvas_camera_reset() noexcept
 {
     CanvasCameraState state;
@@ -26,4 +54,62 @@ struct CanvasCameraState {
     return state;
 }
 
+[[nodiscard]] inline pp::foundation::Result<CanvasViewDensityPlan> plan_canvas_view_density(float density)
+{
+    if (!std::isfinite(density) || density <= 0.0F) {
+        return pp::foundation::Result<CanvasViewDensityPlan>::failure(
+            pp::foundation::Status::invalid_argument("canvas view density must be finite and positive"));
+    }
+
+    return pp::foundation::Result<CanvasViewDensityPlan>::success(CanvasViewDensityPlan {
+        .density = density,
+        .recreates_buffers = true,
+    });
+}
+
+[[nodiscard]] inline pp::foundation::Result<CanvasViewCursorModePlan> plan_canvas_view_cursor_mode(int mode)
+{
+    if (mode < static_cast<int>(CanvasViewCursorMode::never)
+        || mode > static_cast<int>(CanvasViewCursorMode::always)) {
+        return pp::foundation::Result<CanvasViewCursorModePlan>::failure(
+            pp::foundation::Status::out_of_range("canvas cursor mode is out of range"));
+    }
+
+    return pp::foundation::Result<CanvasViewCursorModePlan>::success(CanvasViewCursorModePlan {
+        .mode = static_cast<CanvasViewCursorMode>(mode),
+    });
+}
+
+[[nodiscard]] inline pp::foundation::Status execute_canvas_camera_reset(CanvasViewServices& services)
+{
+    services.reset_camera(plan_canvas_camera_reset());
+    return pp::foundation::Status::success();
+}
+
+[[nodiscard]] inline pp::foundation::Status execute_canvas_view_density(
+    float density,
+    CanvasViewServices& services)
+{
+    const auto plan = plan_canvas_view_density(density);
+    if (!plan) {
+        return plan.status();
+    }
+
+    services.set_density(plan.value());
+    return pp::foundation::Status::success();
+}
+
+[[nodiscard]] inline pp::foundation::Status execute_canvas_view_cursor_mode(
+    int mode,
+    CanvasViewServices& services)
+{
+    const auto plan = plan_canvas_view_cursor_mode(mode);
+    if (!plan) {
+        return plan.status();
+    }
+
+    services.set_cursor_mode(plan.value());
+    return pp::foundation::Status::success();
+}
+
 } // namespace pp::app