A2FingerTransformArea Class Reference

Handles and processes the multitouch scale, transform and rotation events based on two-finger gestures. More...

#include <AUI/View/A2FingerTransformArea.h>

Detailed Description

Represents a translucent area that handles and processes multi-finger transformation gestures (i.e. pinch-to-zoom, move, rotate). A2FingerTransformArea is a container, so the transformed view should be somewhere inside. A2FingerTransformArea does not apply any transformation though, so you can control transformation behaviour.

The transformation data is emitted on delta basis via transform signal. This allows to easily incorporate A2FingerTransformArea to transforming routines, including limit handling.

Consider the following example, where the transformation is applied through ASS styles:

_<AView> multitouchDemo() {
 return _new<A2FingerTransformArea>() AUI_LET {
     it->setCustomStyle({
       MinSize { 256_dp },
       Border { 1_px, AColor::BLACK },
     });
     _<AView> blackRect = Stacked { _new<ALabel>("A2FingerTransformArea") AUI_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},
         });
     });
 };
}

This example renders to the following result:

Member Function Documentation

> All members, including inherited

consumesClick()

bool A2FingerTransformArea::consumesClick ( const glm::ivec2 & pos )

overridevirtual

Parameters

pos	mouse position

Returns

true if AView processes this click

Used in AViewContainer::getViewAt method subset, thus affecting click event handling.

Reimplemented from AView.

onPointerMove()

void A2FingerTransformArea::onPointerMove ( glm::vec2 pos, const APointerMoveEvent & event )

overridevirtual

Parameters

pos	event position
event	event description

Note

If the view is pressed, it would still received move events. Use AView::isMouseHover to check is the pointer actually over view or not. See AView::onPointerReleased for more info.

Reimplemented from AView.

onPointerPressed()

void A2FingerTransformArea::onPointerPressed ( const APointerPressedEvent & event )

overridevirtual

Parameters

event

event

Reimplemented from AView.

onPointerReleased()

void A2FingerTransformArea::onPointerReleased ( const APointerReleasedEvent & event )

overridevirtual

Parameters

event

event

Note

To handle clicks, you should use AView::clicked signal instead. View still receives pointer move and released events even if cursor goes outside the view boundaries, or other exclusive event appeared (i.e. scrollarea scroll). AView::clicked emitted only if release event occurred inside view and no other event has prevented click gesture. See APointerReleasedEvent::triggerClick.

Reimplemented from AView.

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