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Diffstat (limited to 'src/client/util/InteractionUtils.ts')
| -rw-r--r-- | src/client/util/InteractionUtils.ts | 109 |
1 files changed, 109 insertions, 0 deletions
diff --git a/src/client/util/InteractionUtils.ts b/src/client/util/InteractionUtils.ts new file mode 100644 index 000000000..f8088825a --- /dev/null +++ b/src/client/util/InteractionUtils.ts @@ -0,0 +1,109 @@ +export namespace InteractionUtils { + export const MOUSE = "mouse"; + export const TOUCH = "touch"; + + export function IsType(e: PointerEvent, type: PointerTypes): boolean { + return e.pointerType === type; + } + + export function TwoPointEuclidist(pt1: React.Touch, pt2: React.Touch): number { + return Math.sqrt(Math.pow(pt1.clientX - pt2.clientX, 2) + Math.pow(pt1.clientY - pt2.clientY, 2)); + } + + /** + * Returns the centroid of an n-arbitrary long list of points (takes the average the x and y components of each point) + * @param pts - n-arbitrary long list of points + */ + export function CenterPoint(pts: React.Touch[]): { X: number, Y: number } { + let centerX = pts.map(pt => pt.clientX).reduce((a, b) => a + b, 0) / pts.length; + let centerY = pts.map(pt => pt.clientY).reduce((a, b) => a + b, 0) / pts.length; + return { X: centerX, Y: centerY }; + } + + /** + * Returns -1 if pinching out, 0 if not pinching, and 1 if pinching in + * @param pt1 - new point that corresponds to oldPoint1 + * @param pt2 - new point that corresponds to oldPoint2 + * @param oldPoint1 - previous point 1 + * @param oldPoint2 - previous point 2 + */ + export function Pinching(pt1: React.Touch, pt2: React.Touch, oldPoint1: React.Touch, oldPoint2: React.Touch): number { + const leniency = 10; + let dist1 = TwoPointEuclidist(oldPoint1, pt1) + leniency; + let dist2 = TwoPointEuclidist(oldPoint2, pt2) + leniency; + + if (Math.sign(dist1) === Math.sign(dist2)) { + let oldDist = TwoPointEuclidist(oldPoint1, oldPoint2); + let newDist = TwoPointEuclidist(pt1, pt2); + return Math.sign(oldDist - newDist); + } + return 0; + } + + /** + * Returns the type of Touch Interaction from a list of points. + * Also returns any data that is associated with a Touch Interaction + * @param pts - List of points + */ + // export function InterpretPointers(pts: React.Touch[]): { type: Opt<TouchInteraction>, data?: any } { + // const leniency = 200; + // switch (pts.length) { + // case 1: + // return { type: OneFinger }; + // case 2: + // return { type: TwoSeperateFingers }; + // case 3: + // let pt1 = pts[0]; + // let pt2 = pts[1]; + // let pt3 = pts[2]; + // if (pt1 && pt2 && pt3) { + // let dist12 = TwoPointEuclidist(pt1, pt2); + // let dist23 = TwoPointEuclidist(pt2, pt3); + // let dist13 = TwoPointEuclidist(pt1, pt3); + // console.log(`distances: ${dist12}, ${dist23}, ${dist13}`); + // let dist12close = dist12 < leniency; + // let dist23close = dist23 < leniency; + // let dist13close = dist13 < leniency; + // let xor2313 = dist23close ? !dist13close : dist13close; + // let xor = dist12close ? !xor2313 : xor2313; + // // three input xor because javascript doesn't have logical xor's + // if (xor) { + // let points: number[] = []; + // let min = Math.min(dist12, dist23, dist13); + // switch (min) { + // case dist12: + // points = [0, 1, 2]; + // break; + // case dist23: + // points = [1, 2, 0]; + // break; + // case dist13: + // points = [0, 2, 1]; + // break; + // } + // return { type: TwoToOneFingers, data: points }; + // } + // else { + // return { type: ThreeSeperateFingers, data: null }; + // } + // } + // default: + // return { type: undefined }; + // } + // } + + export function IsDragging(oldTouches: Map<number, React.Touch>, newTouches: TouchList, leniency: number): boolean { + for (let i = 0; i < newTouches.length; i++) { + let touch = newTouches.item(i); + if (touch) { + let oldTouch = oldTouches.get(touch.identifier); + if (oldTouch) { + if (TwoPointEuclidist(touch, oldTouch) >= leniency) { + return true; + } + } + } + } + return false; + } +}
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