1 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */ 2 /* vim: set ts=8 sts=2 et sw=2 tw=80: */ 3 /* This Source Code Form is subject to the terms of the Mozilla Public 4 * License, v. 2.0. If a copy of the MPL was not distributed with this 5 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */ 6 7 #ifndef mozilla_layers_DoubleTapToZoom_h 8 #define mozilla_layers_DoubleTapToZoom_h 9 10 #include "Units.h" 11 12 template <class T> 13 class RefPtr; 14 15 namespace mozilla { 16 namespace dom { 17 class Document; 18 } 19 20 namespace layers { 21 22 enum class CantZoomOutBehavior : int8_t { Nothing = 0, ZoomIn }; 23 24 struct ZoomTarget { 25 // The preferred target rect that we'd like to zoom in on, if possible. An 26 // empty rect means the browser should zoom out. 27 CSSRect targetRect; 28 29 // If we are asked to zoom out but cannot (due to zoom constraints, etc), then 30 // zoom in some small amount to provide feedback to the user. 31 CantZoomOutBehavior cantZoomOutBehavior = CantZoomOutBehavior::Nothing; 32 33 // If zooming all the way in on |targetRect| is not possible (for example, due 34 // to a max zoom constraint), |elementBoundingRect| may be used to inform a 35 // more optimal target scroll position (for example, we may try to maximize 36 // the area of |elementBoundingRect| that's showing, while keeping 37 // |targetRect| in view and keeping the zoom as close to the desired zoom as 38 // possible). 39 Maybe<CSSRect> elementBoundingRect; 40 41 // The document relative (ie if the content inside the root scroll frame 42 // existed without that scroll frame) pointer position at the time of the 43 // double tap or location of the double tap if we can compute it. Only used if 44 // the rest of this ZoomTarget is asking to zoom out but we are already at the 45 // minimum zoom. In which case we zoom in a small amount on this point. 46 Maybe<CSSPoint> documentRelativePointerPosition; 47 }; 48 49 /** 50 * For a double tap at |aPoint|, return a ZoomTarget struct with contains a rect 51 * to which the browser should zoom in response (see ZoomTarget definition for 52 * more details). An empty rect means the browser should zoom out. |aDocument| 53 * should be the root content document for the content that was tapped. 54 */ 55 ZoomTarget CalculateRectToZoomTo( 56 const RefPtr<mozilla::dom::Document>& aRootContentDocument, 57 const CSSPoint& aPoint); 58 59 } // namespace layers 60 } // namespace mozilla 61 62 #endif /* mozilla_layers_DoubleTapToZoom_h */ 63