如何用两点画/形成圆？

Question

我需要画一个圆，我只有两个点。现在我需要找到圆的中心点和半径？ 您可以沿顺时针方向形成圆圈。

提前致谢

Answer 1

这是解决问题的蛮力方法。

编辑

如果两点之间的线沿x几乎笔直（表示半径将接近Infinity ），则添加了最大迭代限制以中断计算。

还有动画，因为这会使一切变得更好:)

 var canvas = document.body.appendChild(document.createElement("canvas")); var ctx = canvas.getContext("2d"); canvas.width = 1000; canvas.height = 1000; var points = [ { x: parseInt(prompt("x1", "110")), y: parseInt(prompt("y1", "120")), r: 5 }, { x: parseInt(prompt("x2", "110")), y: parseInt(prompt("y2", "60")), r: 5 }, ]; function calculateRemainingPoint(points, x, precision, maxIteration) { if (x === void 0) { x = 0; } if (precision === void 0) { precision = 0.001; } if (maxIteration === void 0) { maxIteration = 100000; } var newPoint = { x: x, y: (points[0].y + points[1].y) / 2, r: 50 }; var d0 = distance(points[0].x, points[0].y, x, newPoint.y); var d1 = distance(points[1].x, points[1].y, x, newPoint.y); var iteration = 0; //Bruteforce approach while (Math.abs(d0 - d1) > precision && iteration < maxIteration) { var oldDiff = Math.abs(d0 - d1); var oldY = newPoint.y; iteration++; newPoint.y += oldDiff / 10; d0 = distance(points[0].x, points[0].y, x, newPoint.y); d1 = distance(points[1].x, points[1].y, x, newPoint.y); var diff_1 = Math.abs(d0 - d1); if (diff_1 > oldDiff) { newPoint.y = oldY - oldDiff / 10; d0 = distance(points[0].x, points[0].y, x, newPoint.y); d1 = distance(points[1].x, points[1].y, x, newPoint.y); } } var diff = (points[0].x + points[1].x) / points[0].x; newPoint.r = d0; return newPoint; } points.push(calculateRemainingPoint(points)); function distance(x1, y1, x2, y2) { var a = x1 - x2; var b = y1 - y2; return Math.sqrt(a * a + b * b); } function draw() { ctx.clearRect(0, 0, canvas.width, canvas.height); ctx.beginPath(); ctx.moveTo(-canvas.width, canvas.height / 2); ctx.lineTo(canvas.width, canvas.height / 2); ctx.stroke(); ctx.closePath(); ctx.beginPath(); ctx.moveTo(canvas.width / 2, -canvas.height); ctx.lineTo(canvas.width / 2, canvas.height); ctx.stroke(); ctx.closePath(); for (var pointIndex = 0; pointIndex < points.length; pointIndex++) { var point = points[pointIndex]; ctx.beginPath(); ctx.arc(point.x + canvas.width / 2, canvas.height / 2 - point.y, point.r, 0, Math.PI * 2); ctx.arc(point.x + canvas.width / 2, canvas.height / 2 - point.y, 2, 0, Math.PI * 2); ctx.stroke(); ctx.closePath(); } } setInterval(function () { points = points.slice(0, 2); points[Math.floor(Math.random() * points.length) % points.length][Math.random() > 0.5 ? 'x' : 'y'] = Math.random() * canvas.width - canvas.width / 2; setTimeout(function () { points.push(calculateRemainingPoint(points)); requestAnimationFrame(draw); }, 1000 / 60); }, 1000); draw(); 

Answer 2

没有那是不可能的。

在中心点A + B处创建两个半径相同的圆。在这两个圆的交点处，创建一个半径相同的圆。

然后使用其他半径相同。