how does GestureDetector work with canvas.draw circle custom paint

Question

GestureDetector(
                child: SizedBox(
                  width: double.infinity,
                  height: MediaQuery.of(context).size.height,
                  child: InteractiveViewer(
                    transformationController: viewTransformationController,
                    minScale: 0.2,
                    maxScale: 200.2,
                    child: Plotkhan(
                      recognizer: tapGestureRecognizer,
                      indexofitem: indexofitems,
                      height: 400.0,
                      data: _items
                          .map((e) => Point(num.parse(e['x'].toString()),
                              num.parse(e['y'].toString())))
                          .toList(),
                      gridSize: const Offset(1.0, 1.0),
                      style: PlotStyles(
                        pointRadius: 3.0,
                        trace: true,
                        outlineRadius: 1.0,
                        primary: Colors.white,
                        secondary: Colors.orange,
                        textStyle: const TextStyle(
                          fontSize: 8.0,
                          color: Colors.blueGrey,
                        ),
                      ),
                      padding:
                          const EdgeInsets.fromLTRB(40.0, 12.0, 12.0, 40.0),
                    ),
                  ),
                ),
              ),

its a dot connecting app which I have a list of diagram with offset that implements canvas.drawcircle from list. I researched so didn't find any thing related GestureDetector with canvas.drawcircle. the rest of function is working well if I set function on any button, but don't know how to achieve function with canvas.drawcircle.