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Diffstat (limited to 'layout/generic/nsAbsoluteContainingBlock.h')
| -rw-r--r-- | layout/generic/nsAbsoluteContainingBlock.h | 174 |
1 files changed, 174 insertions, 0 deletions
diff --git a/layout/generic/nsAbsoluteContainingBlock.h b/layout/generic/nsAbsoluteContainingBlock.h new file mode 100644 index 000000000..92910b815 --- /dev/null +++ b/layout/generic/nsAbsoluteContainingBlock.h @@ -0,0 +1,174 @@ +/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */ +/* This Source Code Form is subject to the terms of the Mozilla Public + * License, v. 2.0. If a copy of the MPL was not distributed with this + * file, You can obtain one at http://mozilla.org/MPL/2.0/. */ + +/* + * code for managing absolutely positioned children of a rendering + * object that is a containing block for them + */ + +#ifndef nsAbsoluteContainingBlock_h___ +#define nsAbsoluteContainingBlock_h___ + +#include "nsFrameList.h" +#include "nsIFrame.h" +#include "mozilla/TypedEnumBits.h" + +class nsContainerFrame; +class nsPresContext; + +/** + * This class contains the logic for being an absolute containing block. This + * class is used within viewport frames (for frames representing content with + * fixed position) and blocks (for frames representing absolutely positioned + * content), since each set of frames is absolutely positioned with respect to + * its parent. + * + * There is no principal child list, just a named child list which contains + * the absolutely positioned frames (kAbsoluteList or kFixedList). + * + * All functions include as the first argument the frame that is delegating + * the request. + */ +class nsAbsoluteContainingBlock +{ + using ReflowInput = mozilla::ReflowInput; + +public: + typedef nsIFrame::ChildListID ChildListID; + + explicit nsAbsoluteContainingBlock(ChildListID aChildListID) +#ifdef DEBUG + : mChildListID(aChildListID) +#endif + { + MOZ_ASSERT(mChildListID == nsIFrame::kAbsoluteList || + mChildListID == nsIFrame::kFixedList, + "should either represent position:fixed or absolute content"); + } + + const nsFrameList& GetChildList() const { return mAbsoluteFrames; } + void AppendChildList(nsTArray<nsIFrame::ChildList>* aLists, + ChildListID aListID) const + { + NS_ASSERTION(aListID == mChildListID, "wrong list ID"); + GetChildList().AppendIfNonempty(aLists, aListID); + } + + void SetInitialChildList(nsIFrame* aDelegatingFrame, + ChildListID aListID, + nsFrameList& aChildList); + void AppendFrames(nsIFrame* aDelegatingFrame, + ChildListID aListID, + nsFrameList& aFrameList); + void InsertFrames(nsIFrame* aDelegatingFrame, + ChildListID aListID, + nsIFrame* aPrevFrame, + nsFrameList& aFrameList); + void RemoveFrame(nsIFrame* aDelegatingFrame, + ChildListID aListID, + nsIFrame* aOldFrame); + + enum class AbsPosReflowFlags { + eConstrainHeight = 0x1, + eCBWidthChanged = 0x2, + eCBHeightChanged = 0x4, + eCBWidthAndHeightChanged = eCBWidthChanged | eCBHeightChanged, + eIsGridContainerCB = 0x8, + }; + + /** + * Called by the delegating frame after it has done its reflow first. This + * function will reflow any absolutely positioned child frames that need to + * be reflowed, e.g., because the absolutely positioned child frame has + * 'auto' for an offset, or a percentage based width or height. + * + * @param aOverflowAreas, if non-null, is unioned with (in the local + * coordinate space) the overflow areas of the absolutely positioned + * children. + * + * @param aReflowStatus is assumed to be already-initialized, e.g. with the + * status of the delegating frame's main reflow. This function merges in the + * statuses of the absolutely positioned children's reflows. + * + * @param aFlags zero or more AbsPosReflowFlags + */ + void Reflow(nsContainerFrame* aDelegatingFrame, + nsPresContext* aPresContext, + const ReflowInput& aReflowInput, + nsReflowStatus& aReflowStatus, + const nsRect& aContainingBlock, + AbsPosReflowFlags aFlags, + nsOverflowAreas* aOverflowAreas); + + void DestroyFrames(nsIFrame* aDelegatingFrame, + nsIFrame* aDestructRoot); + + bool HasAbsoluteFrames() const { return mAbsoluteFrames.NotEmpty(); } + + /** + * Mark our size-dependent absolute frames with NS_FRAME_HAS_DIRTY_CHILDREN + * so that we'll make sure to reflow them. + */ + void MarkSizeDependentFramesDirty(); + + /** + * Mark all our absolute frames with NS_FRAME_IS_DIRTY. + */ + void MarkAllFramesDirty(); + +protected: + /** + * Returns true if the position of aFrame depends on the position of + * its placeholder or if the position or size of aFrame depends on a + * containing block dimension that changed. + */ + bool FrameDependsOnContainer(nsIFrame* aFrame, bool aCBWidthChanged, + bool aCBHeightChanged); + + /** + * After an abspos child's size is known, this method can be used to + * resolve size-dependent values in the ComputedLogicalOffsets on its + * reflow state. (This may involve resolving the inline dimension of + * aLogicalCBSize, too; hence, that variable is an in/outparam.) + * + * aKidSize, aMargin, aOffsets, and aLogicalCBSize are all expected to be + * represented in terms of the absolute containing block's writing-mode. + */ + void ResolveSizeDependentOffsets(nsPresContext* aPresContext, + ReflowInput& aKidReflowInput, + const mozilla::LogicalSize& aKidSize, + const mozilla::LogicalMargin& aMargin, + mozilla::LogicalMargin* aOffsets, + mozilla::LogicalSize* aLogicalCBSize); + + void ReflowAbsoluteFrame(nsIFrame* aDelegatingFrame, + nsPresContext* aPresContext, + const ReflowInput& aReflowInput, + const nsRect& aContainingBlockRect, + AbsPosReflowFlags aFlags, + nsIFrame* aKidFrame, + nsReflowStatus& aStatus, + nsOverflowAreas* aOverflowAreas); + + /** + * Mark our absolute frames dirty. + * @param aMarkAllDirty if true, all will be marked with NS_FRAME_IS_DIRTY. + * Otherwise, the size-dependant ones will be marked with + * NS_FRAME_HAS_DIRTY_CHILDREN. + */ + void DoMarkFramesDirty(bool aMarkAllDirty); + +protected: + nsFrameList mAbsoluteFrames; // additional named child list + +#ifdef DEBUG + ChildListID const mChildListID; // kFixedList or kAbsoluteList +#endif +}; + +namespace mozilla { + MOZ_MAKE_ENUM_CLASS_BITWISE_OPERATORS(nsAbsoluteContainingBlock::AbsPosReflowFlags) +} +#endif /* nsnsAbsoluteContainingBlock_h___ */ |