feat: implement configurable font settings for VTK viewports and GUI elements with persistent preferences.

src/Core/FontConfig.h

@@ -0,0 +1,48 @@
+#ifndef U_CORE_FONTCONFIG_H
+#define U_CORE_FONTCONFIG_H
+
+#include <string>
+#include <ostream>
+#include <boost/serialization/nvp.hpp>
+
+namespace uLib {
+
+/**
+ * @struct FontConfig
+ * @brief Basic font configuration for text properties.
+ */
+struct FontConfig {
+    std::string family;
+    int size;
+    bool bold;
+    bool italic;
+
+    FontConfig() : family("Arial"), size(10), bold(false), italic(false) {}
+    FontConfig(const std::string& fam, int sz, bool b = false, bool i = false)
+        : family(fam), size(sz), bold(b), italic(i) {}
+
+    bool operator==(const FontConfig& other) const {
+        return family == other.family && size == other.size && 
+               bold == other.bold && italic == other.italic;
+    }
+    bool operator!=(const FontConfig& other) const { return !(*this == other); }
+
+    template<class Archive>
+    void serialize(Archive& ar, const unsigned int version) {
+        ar & boost::serialization::make_nvp("family", family);
+        ar & boost::serialization::make_nvp("size", size);
+        ar & boost::serialization::make_nvp("bold", bold);
+        ar & boost::serialization::make_nvp("italic", italic);
+    }
+};
+
+inline std::ostream& operator<<(std::ostream& os, const FontConfig& f) {
+    os << f.family << " " << f.size;
+    if (f.bold) os << " Bold";
+    if (f.italic) os << " Italic";
+    return os;
+}
+
+} // namespace uLib
+
+#endif // U_CORE_FONTCONFIG_H

src/Vtk/vtkViewport.cpp

@@ -123,10 +123,9 @@ void Viewport::SetupPipeline(vtkRenderWindowInteractor* iren)
     iren->SetInteractorStyle(style);
 
     // Corner annotation
-    pv->m_Annotation->GetTextProperty()->SetColor(1, 1, 1);
-    pv->m_Annotation->GetTextProperty()->SetFontFamilyToArial();
+    SetFontColor(Vector3d(1.0, 1.0, 1.0));
+    SetFont(FontConfig("Arial", 10));
     pv->m_Annotation->GetTextProperty()->SetOpacity(0.5);
-    pv->m_Annotation->SetMaximumFontSize(10);
     pv->m_Annotation->SetText(0, "uLib VTK viewer.");
     pv->m_Renderer->AddViewProp(pv->m_Annotation);
 
@@ -603,6 +602,44 @@ bool Viewport::GetParallelProjection() const
     return false;
 }
 
+void Viewport::SetFont(const FontConfig& font) {
+    if (!pv->m_Annotation) return;
+    auto* prop = pv->m_Annotation->GetTextProperty();
+    if (font.family == "Arial") prop->SetFontFamilyToArial();
+    else if (font.family == "Courier") prop->SetFontFamilyToCourier();
+    else if (font.family == "Times") prop->SetFontFamilyToTimes();
+    else prop->SetFontFamilyToArial(); // fallback
+
+    pv->m_Annotation->SetMaximumFontSize(font.size);
+    prop->SetBold(font.bold);
+    prop->SetItalic(font.italic);
+    this->Render();
+}
+
+FontConfig Viewport::GetFont() const {
+    if (!pv->m_Annotation) return FontConfig();
+    auto* prop = pv->m_Annotation->GetTextProperty();
+    FontConfig f;
+    f.family = prop->GetFontFamilyAsString();
+    f.size = pv->m_Annotation->GetMaximumFontSize();
+    f.bold = prop->GetBold();
+    f.italic = prop->GetItalic();
+    return f;
+}
+
+void Viewport::SetFontColor(const Vector3d& color) {
+    if (!pv->m_Annotation) return;
+    pv->m_Annotation->GetTextProperty()->SetColor(color.x(), color.y(), color.z());
+    this->Render();
+}
+
+Vector3d Viewport::GetFontColor() const {
+    if (!pv->m_Annotation) return Vector3d(1,1,1);
+    double c[3];
+    pv->m_Annotation->GetTextProperty()->GetColor(c);
+    return Vector3d(c[0], c[1], c[2]);
+}
+
 void Viewport::SetGridAxis(Axis axis)
 {
     m_GridAxis = axis;

src/Vtk/vtkViewport.h

@@ -4,6 +4,8 @@
 #include "uLibVtkInterface.h"
 #include <vector>
 #include <map>
+#include "Core/FontConfig.h"
+#include "Math/Dense.h"
 
 namespace uLib { class Object; }
 
@@ -83,6 +85,12 @@ public:
     void SetParallelProjection(bool parallel);
     bool GetParallelProjection() const;
 
+    // Font configuration
+    void SetFont(const FontConfig& font);
+    FontConfig GetFont() const;
+    void SetFontColor(const Vector3d& color);
+    Vector3d GetFontColor() const;
+
 protected:
     void SetupPipeline(vtkRenderWindowInteractor* iren);
 

src/Vtk/vtkViewportProperties.h

@@ -0,0 +1,56 @@
+#ifndef ULIB_VTK_VIEWPORTPROPERTIES_H
+#define ULIB_VTK_VIEWPORTPROPERTIES_H
+
+#include "uLibVtkInterface.h"
+#include "vtkViewport.h"
+#include "Core/Property.h"
+
+namespace uLib {
+namespace Vtk {
+
+/**
+ * @class ViewportProperties
+ * @brief Exposes Viewport settings as a uLib::Object for the properties panel.
+ */
+class ViewportProperties : public uLib::Object {
+public:
+    uLibTypeMacro(ViewportProperties, uLib::Object)
+
+    ViewportProperties(Viewport* vp) : m_Viewport(vp)
+    {
+        SetInstanceName("Viewport Settings");
+
+        // Initialize properties from viewport
+        Font.Set(vp->GetFont());
+        Color.Set(vp->GetFontColor());
+        GridVisible.Set(vp->GetGridVisible());
+        Parallel.Set(vp->GetParallelProjection());
+
+        // Connect properties to viewport setters
+        uLib::Object::connect(&Font, &Property<FontConfig>::Updated, [this](){
+            if (m_Viewport) m_Viewport->SetFont(Font.Get());
+        });
+        uLib::Object::connect(&Color, &Property<Vector3d>::Updated, [this](){
+            if (m_Viewport) m_Viewport->SetFontColor(Color.Get());
+        });
+        uLib::Object::connect(&GridVisible, &Property<bool>::Updated, [this](){
+            if (m_Viewport) m_Viewport->SetGridVisible(GridVisible.Get());
+        });
+        uLib::Object::connect(&Parallel, &Property<bool>::Updated, [this](){
+            if (m_Viewport) m_Viewport->SetParallelProjection(Parallel.Get());
+        });
+    }
+
+    ULIB_PROPERTY(FontConfig, Font, FontConfig())
+    ULIB_PROPERTY(Vector3d, Color, Vector3d(1.0, 1.0, 1.0))
+    ULIB_PROPERTY(bool, GridVisible, true)
+    ULIB_PROPERTY(bool, Parallel, false)
+
+private:
+    Viewport* m_Viewport;
+};
+
+} // namespace Vtk
+} // namespace uLib
+
+#endif // ULIB_VTK_VIEWPORTPROPERTIES_H