/cc @crawshaw Is the following comment no longer true?

// It is widely reported that the iPhone can handle up to 5 simultaneous
// touch events, while the iPad can handle 11.

patch & log

diff --git a/app/darwin_armx.go b/app/darwin_armx.go
index 5344e27..f6fa027 100644
--- a/app/darwin_armx.go
+++ b/app/darwin_armx.go
@@ -132,6 +132,7 @@ var touchEvents struct {

 //export sendTouch
 func sendTouch(cTouch, cTouchType uintptr, x, y float32) {
+       log.Println(cTouch, cTouchType, x, y)
        id := -1
        for i, val := range touchIDs {
                if val == cTouch {

2015/12/05 22:25:26 5601104144 0 149 62
2015/12/05 22:25:26 5602228320 0 832 231
2015/12/05 22:25:26 5601879616 0 1090 337
2015/12/05 22:25:26 5601973040 0 428 117
2015/12/05 22:25:35 5601128704 0 239 91
2015/12/05 22:25:35 5601104144 0 299 612
2015/12/05 22:25:35 5601118880 0 990 122
2015/12/05 22:25:35 5601111664 0 619 133
2015/12/05 22:25:35 5601092240 0 603 327
2015/12/05 22:25:35 5601077024 0 817 107
2015/12/05 22:25:35 5601860816 0 560 597
2015/12/05 22:25:37 5602222480 0 656 160
2015/12/05 22:25:37 5602223728 0 583 597
panic: out of touchIDs

device: iPhone5s
iOS: 9.1(13B143)

6 fingers touch and release on iPhone5S.

expect:

• 6 touch.TypeBegin events receive.
• 6 touch.TypeEnd events receive.

instead:

• 6 touch.TypeBegin events receive.
• These touch.TypeEnd events disappeared.

No problem if less than 6 fingers.

need handle touchesCancelled ?

CL https://golang.org/cl/18180 mentions this issue.

No occur panic in Android, but there was a problem of lost touch sequence (similar IOS).
cancel-events must handle for real-device.

• AMOTION_EVENT_ACTION_CANCEL for android
• touchesCancelled for iOS

Proposal:

• Add const value "TypeCancel" to "event/touch/touch.go".
• cancel-event send to app.
• touchIDs delete cancelled ID for iOS

@nobonobo I missed your comment before submitting your CL. Want to move this to #13859?