diff options
Diffstat (limited to 'src/client/views/GestureOverlay.tsx')
| -rw-r--r-- | src/client/views/GestureOverlay.tsx | 53 |
1 files changed, 25 insertions, 28 deletions
diff --git a/src/client/views/GestureOverlay.tsx b/src/client/views/GestureOverlay.tsx index 6a4f55bef..bbf21f22c 100644 --- a/src/client/views/GestureOverlay.tsx +++ b/src/client/views/GestureOverlay.tsx @@ -726,39 +726,36 @@ export class GestureOverlay extends Touchable { break; case "circle": - + // Approximation of a circle using 4 Bézier curves in which the constant "c" reduces the maximum radial drift to 0.019608%, + // making the curves indistinguishable from a circle. + // Source: https://spencermortensen.com/articles/bezier-circle/ + const c = 0.551915024494; const centerX = (Math.max(left, right) + Math.min(left, right)) / 2; const centerY = (Math.max(top, bottom) + Math.min(top, bottom)) / 2; const radius = Math.max(centerX - Math.min(left, right), centerY - Math.min(top, bottom)); - if (centerX - Math.min(left, right) < centerY - Math.min(top, bottom)) { - for (var y = Math.min(top, bottom); y < Math.max(top, bottom); y++) { - const x = Math.sqrt(Math.pow(radius, 2) - (Math.pow((y - centerY), 2))) + centerX; - this._points.push({ X: x, Y: y }); - } - for (var y = Math.max(top, bottom); y > Math.min(top, bottom); y--) { - const x = Math.sqrt(Math.pow(radius, 2) - (Math.pow((y - centerY), 2))) + centerX; - const newX = centerX - (x - centerX); - this._points.push({ X: newX, Y: y }); - } - this._points.push({ X: Math.sqrt(Math.pow(radius, 2) - (Math.pow((Math.min(top, bottom) - centerY), 2))) + centerX, Y: Math.min(top, bottom) }); - this._points.push({ X: Math.sqrt(Math.pow(radius, 2) - (Math.pow((Math.min(top, bottom) - centerY), 2))) + centerX, Y: Math.min(top, bottom) - 1 }); + // Dividing the circle into four equal sections, and fitting each section to a cubic Bézier curve. + this._points.push({ X: centerX - radius, Y: centerY }); + this._points.push({ X: centerX - radius, Y: centerY + (c * radius) }); + this._points.push({ X: centerX - (c * radius), Y: centerY + radius }); + this._points.push({ X: centerX, Y: centerY + radius }); + + this._points.push({ X: centerX, Y: centerY + radius }); + this._points.push({ X: centerX + (c * radius), Y: centerY + radius }); + this._points.push({ X: centerX + radius, Y: centerY + (c * radius) }); + this._points.push({ X: centerX + radius, Y: centerY }); + + this._points.push({ X: centerX + radius, Y: centerY }); + this._points.push({ X: centerX + radius, Y: centerY - (c * radius) }); + this._points.push({ X: centerX + (c * radius), Y: centerY - radius }); + this._points.push({ X: centerX, Y: centerY - radius }); + + this._points.push({ X: centerX, Y: centerY - radius }); + this._points.push({ X: centerX - (c * radius), Y: centerY - radius }); + this._points.push({ X: centerX - radius, Y: centerY - (c * radius) }); + this._points.push({ X: centerX - radius, Y: centerY }); - - } else { - for (var x = Math.min(left, right); x < Math.max(left, right); x++) { - const y = Math.sqrt(Math.pow(radius, 2) - (Math.pow((x - centerX), 2))) + centerY; - this._points.push({ X: x, Y: y }); - } - for (var x = Math.max(left, right); x > Math.min(left, right); x--) { - const y = Math.sqrt(Math.pow(radius, 2) - (Math.pow((x - centerX), 2))) + centerY; - const newY = centerY - (y - centerY); - this._points.push({ X: x, Y: newY }); - } - this._points.push({ X: Math.min(left, right), Y: Math.sqrt(Math.pow(radius, 2) - (Math.pow((Math.min(left, right) - centerX), 2))) + centerY }); - this._points.push({ X: Math.min(left, right), Y: Math.sqrt(Math.pow(radius, 2) - (Math.pow((Math.min(left, right) - centerX), 2))) + centerY - 1 }); - - } break; + case "line": if (Math.abs(firstx - lastx) < 20) { lastx = firstx; |