d3-canvas-brush-zoom-06

d3-canvas-brush-zoom-06.js

function brush_brushEvent() {
   if (brushStartPoint !== null) {
       const scale = width / height;
       const sourceEvent = d3.event.sourceEvent;
       const mouse = {
           x: sourceEvent.screenX,
           y: sourceEvent.screenY
       };
       if (mouse.x < 0) { mouse.x = 0; }
       if (mouse.y < 0) { mouse.y = 0; }
       let distance = mouse.y - brushStartPoint.mouse.y;
       let yPosition = brushStartPoint.y + distance;
       let xCorMulti = 1;

       if ((distance < 0 && mouse.x > brushStartPoint.mouse.x) || (distance > 0 && mouse.x < brushStartPoint.mouse.x)) {
           xCorMulti = -1;
       }
       
       ...