NightRa commented on code in PR #21655:
URL: https://github.com/apache/echarts/pull/21655#discussion_r3681754395
##########
src/component/helper/RoamController.ts:
##########
@@ -418,10 +435,52 @@ class RoamController extends
Eventful<RoamEventDefinition> {
) {
return;
}
- const scale = e.pinchScale > 1 ? 1.1 : 1 / 1.1;
- this._checkTriggerMoveZoom(this, 'zoom', null, e, {
- scale: scale, originX: e.pinchX, originY: e.pinchY,
isAvailableBehavior: null
- });
+ const originX = e.pinchX;
+ const originY = e.pinchY;
+
+ // Gate only the beginning of a pinch capture.
+ // Once captured, keep handling movement outside the roam area.
+ // Requiring a native touchstart for a new capture also
+ // prevents another RoamController from picking up an already-moving
pinch.
+ const isTouchStart = e.event.type === 'touchstart';
+ const isPinchStart = !this._pinching || isTouchStart;
+ if (isPinchStart) {
+ if (!isTouchStart || !this._checkPointer(e, originX, originY)) {
+ return;
+ }
+ }
Review Comment:
ZRender does emit a pinch during touchstart once the event contains two
touches. GestureMgr falls back to using the current sample as pinchPre,
producing pinchScale === 1, and Handler.processGesture dispatches that event
while the native event type remains touchstart.
I verified this against ZRender 6.1.0 and the current ZRender source.
Requiring touchstart here is intentional: it ensures pinch ownership is
decided only when the gesture begins. Allowing an uncaptured controller to
start on touchmove would let a pinch be acquired after entering another roam
area, potentially causing unexpected mid-gesture zoom or transferring ownership
between overlapping controllers.
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