LibGUI: Add drawing triangle from coordinate list

Author: https://github.com/frhun
Commit: https://github.com/SerenityOS/serenity/commit/b3d1fa4c54
Pull-request: https://github.com/SerenityOS/serenity/pull/14282
Reviewed-by: https://github.com/AtkinsSJ ✅
Reviewed-by: https://github.com/MacDue

Userland/Libraries/LibGfx/Painter.cpp

@@ -671,6 +671,12 @@ void Painter::draw_bitmap(IntPoint const& p, GlyphBitmap const& bitmap, Color co
     }
 }
 
+void Painter::draw_triangle(IntPoint const& offset, Span<IntPoint const> control_points, Color color)
+{
+    VERIFY(control_points.size() == 3);
+    draw_triangle(control_points[0] + offset, control_points[1] + offset, control_points[2] + offset, color);
+}
+
 void Painter::draw_triangle(IntPoint const& a, IntPoint const& b, IntPoint const& c, Color color)
 {
     IntPoint p0(to_physical(a));

Userland/Libraries/LibGfx/Painter.h

@@ -57,6 +57,7 @@ public:
     void draw_scaled_bitmap(IntRect const& dst_rect, Gfx::Bitmap const&, IntRect const& src_rect, float opacity = 1.0f, ScalingMode = ScalingMode::NearestNeighbor);
     void draw_scaled_bitmap(IntRect const& dst_rect, Gfx::Bitmap const&, FloatRect const& src_rect, float opacity = 1.0f, ScalingMode = ScalingMode::NearestNeighbor);
     void draw_triangle(IntPoint const&, IntPoint const&, IntPoint const&, Color);
+    void draw_triangle(IntPoint const& offset, Span<IntPoint const>, Color);
     void draw_ellipse_intersecting(IntRect const&, Color, int thickness = 1);
     void set_pixel(IntPoint const&, Color, bool blend = false);
     void set_pixel(int x, int y, Color color, bool blend = false) { set_pixel({ x, y }, color, blend); }