drawOutline method Null safety
Implementation
void drawOutline(Canvas canvas, double width, double height) {
final thickW = table.thickLineWidth;
RRect frame = RRect.fromLTRBR(thickW / 2, thickW / 2, width - thickW / 2,
height - thickW / 2, const Radius.circular(0.1));
canvas.drawRRect(frame, thickLine);
}