Our first multitouch demo

[Alex2772]

We're continuing our hard work on supporting touchscreens and this time we're introducing A2FingerTransformArea, which is the simplest implementation of pinch-to-zoom and rotate gestures, utilizing the possibility of working with multiple pointers (fingers) in AUI application.

The following example:

_<AView> multitouchDemo() {
  return _new<A2FingerTransformArea>() let {    
      it->setCustomStyle({
        MinSize { 256_dp },
        Border { 1_px, AColor::BLACK },
      });
      _<AView> blackRect = Stacked { _new<ALabel>("A2FingerTransformArea") with_style {
        FixedSize{200_dp, 100_dp},
        BackgroundSolid{AColor::BLACK},
        TextColor{AColor::WHITE},
        ATextAlign::CENTER,
      }};
      ALayoutInflater::inflate(it, Stacked { blackRect });
      connect(it->transformed, blackRect, [blackRect = blackRect.get(),
                                           keptTransform = _new<A2DTransform>()](const A2DTransform& transform) {
          keptTransform->applyDelta(transform);
          blackRect->setCustomStyle({
              TransformOffset{AMetric(keptTransform->offset.x, AMetric::T_PX),
                              AMetric(keptTransform->offset.y, AMetric::T_PX)},
              TransformScale{keptTransform->scale},
              TransformRotate{keptTransform->rotation},
          });
      });
  };

Gives us the following result:

A2FingerTransformArea is designed to be easily injected to the existing code. Also you can implement zoom and rotation limits as you can easily control transform events. Check out our reference for more info.

The feature works on Android and iOS.