ScrollStyles.cpp (1819B)
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 #include "mozilla/ScrollStyles.h" 8 9 #include "nsStyleStruct.h" // for nsStyleDisplay 10 11 namespace mozilla { 12 13 // https://drafts.csswg.org/css-overflow/#overflow-propagation 14 // "If `visible` is applied to the viewport, it must be interpreted as `auto`. 15 // If `clip` is applied to the viewport, it must be interpreted as `hidden`." 16 static StyleOverflow MapOverflowValueForViewportPropagation( 17 StyleOverflow aOverflow) { 18 switch (aOverflow) { 19 case StyleOverflow::Visible: 20 return StyleOverflow::Auto; 21 case StyleOverflow::Clip: 22 return StyleOverflow::Hidden; 23 default: 24 return aOverflow; 25 } 26 } 27 28 ScrollStyles::ScrollStyles(StyleOverflow aH, StyleOverflow aV) 29 : mHorizontal(aH), mVertical(aV) { 30 MOZ_ASSERT(mHorizontal == StyleOverflow::Auto || 31 mHorizontal == StyleOverflow::Hidden || 32 mHorizontal == StyleOverflow::Scroll); 33 MOZ_ASSERT(mVertical == StyleOverflow::Auto || 34 mVertical == StyleOverflow::Hidden || 35 mVertical == StyleOverflow::Scroll); 36 } 37 38 ScrollStyles::ScrollStyles(const nsStyleDisplay& aDisplay, 39 MapOverflowToValidScrollStyleTag) 40 : ScrollStyles( 41 MapOverflowValueForViewportPropagation(aDisplay.mOverflowX), 42 MapOverflowValueForViewportPropagation(aDisplay.mOverflowY)) {} 43 44 bool ScrollStyles::IsHiddenInBothDirections() const { 45 return mHorizontal == StyleOverflow::Hidden && 46 mVertical == StyleOverflow::Hidden; 47 } 48 49 } // namespace mozilla