bc518174
 王天杨
提交两个项目文件
|
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
|
const ds = (ab) => (ab[0] <= 0 && ab[1] >= 0) || (ab[0] >= 0 && ab[1] <= 0);
const sign = (x) => (x < 0 ? -1 : 1);
export const pinchOrZoom = (event, cache) => {
if (!event.changedTouches) {
return false;
}
if (event.touches.length === 2) {
const oldPoints = [cache[event.touches[0].identifier], cache[event.touches[1].identifier]];
const newPoints = [event.touches[0], event.touches[1]];
if (oldPoints[0] && oldPoints[1]) {
// Calculate the difference between the start and move coordinates
const diffx = [oldPoints[0].clientX - newPoints[0].clientX, oldPoints[1].clientX - newPoints[1].clientX];
const diffy = [oldPoints[0].clientY - newPoints[0].clientY, oldPoints[1].clientY - newPoints[1].clientY];
console.log(diffx, diffy);
if (ds(diffx) || ds(diffy)) {
return {
action: 'zoom',
};
}
const mx = Math.max(Math.abs(diffx[0]), Math.abs(diffx[1]));
const my = Math.max(Math.abs(diffy[0]), Math.abs(diffy[1]));
return {
action: 'pinch',
coords: [mx * sign(diffx[0]), my * sign(diffx[1])],
};
}
}
Array.from(event.changedTouches).forEach((touch) => (cache[touch.identifier] = touch));
return {
action: 'move',
coords: [event.changedTouches[0].clientX, event.changedTouches[0].clientY],
};
};
|
