module gradient_triangle; import dguihub; class MainForm : Form { public this() { this.text = "GDI: Gradient Fill Triangle"; this.size = Size(360, 190); this.startPosition = FormStartPosition.centerScreen; this.formBorderStyle = FormBorderStyle.fixedDialog; this.maximizeBox = false; this.minimizeBox = false; } protected override void onPaint(PaintEventArgs e) { Canvas c = e.canvas; c.fillTriangleGradient(10, 180, 180, 10, 350, 180, SystemColors.blue, SystemColors.green, SystemColors.red); super.onPaint(e); } } int main(string[] args) { return Application.run(new MainForm()); // Start the application }