LibGfx: Add small convenience functions for Lines and AA Painter

This patch adds the following some convenience functions:
- Lines do now support rotated(), scaled() and translated()
- AntiAliasingPainter has now a draw_line function that takes a
  FloatLine as argument

Userland/Libraries/LibGfx/AntiAliasingPainter.h

@@ -28,6 +28,10 @@ public:
 
     void draw_line(IntPoint, IntPoint, Color, float thickness = 1, Painter::LineStyle style = Painter::LineStyle::Solid, Color alternate_color = Color::Transparent, LineLengthMode line_length_mode = LineLengthMode::PointToPoint);
     void draw_line(FloatPoint, FloatPoint, Color, float thickness = 1, Painter::LineStyle style = Painter::LineStyle::Solid, Color alternate_color = Color::Transparent, LineLengthMode line_length_mode = LineLengthMode::PointToPoint);
+    void draw_line(FloatLine line, Color color, float thickness = 1, Painter::LineStyle style = Painter::LineStyle::Solid, Color alternate_color = Color::Transparent, LineLengthMode line_length_mode = LineLengthMode::PointToPoint)
+    {
+        draw_line(line.a(), line.b(), color, thickness, style, alternate_color, line_length_mode);
+    }
     void draw_line_for_path(FloatPoint, FloatPoint, Color, float thickness = 1, Painter::LineStyle style = Painter::LineStyle::Solid, Color alternate_color = Color::Transparent, LineLengthMode line_length_mode = LineLengthMode::PointToPoint);
 
     void fill_path(Path const&, Color, Painter::WindingRule rule = Painter::WindingRule::Nonzero);

Userland/Libraries/LibGfx/Line.h

@@ -129,9 +129,36 @@ public:
     Point<T> const& a() const { return m_a; }
     Point<T> const& b() const { return m_b; }
 
+    Line<T> rotated(float radians)
+    {
+        Gfx::AffineTransform rotation_transform;
+        rotation_transform.rotate_radians(radians);
+
+        Line<T> line = *this;
+        line.set_a(line.a().transformed(rotation_transform));
+        line.set_b(line.b().transformed(rotation_transform));
+        return line;
+    }
+
     void set_a(Point<T> const& a) { m_a = a; }
     void set_b(Point<T> const& b) { m_b = b; }
 
+    Line<T> scaled(T sx, T sy) const
+    {
+        Line<T> line = *this;
+        line.set_a(line.a().scaled(sx, sy));
+        line.set_b(line.b().scaled(sx, sy));
+        return line;
+    }
+
+    Line<T> translated(Point<T> const& delta) const
+    {
+        Line<T> line = *this;
+        line.set_a(line.a().translated(delta));
+        line.set_b(line.b().translated(delta));
+        return line;
+    }
+
     template<typename U>
     requires(!IsSame<T, U>)
     [[nodiscard]] ALWAYS_INLINE constexpr Line<U> to_type() const