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130 lines
4.5 KiB
C++
130 lines
4.5 KiB
C++
/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
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/* vim: set ts=8 sts=2 et sw=2 tw=80: */
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/* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
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/*
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* base class for rendering objects that can be split across lines,
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* columns, or pages
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*/
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#ifndef nsSplittableFrame_h___
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#define nsSplittableFrame_h___
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#include "mozilla/Attributes.h"
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#include "nsIFrame.h"
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// Derived class that allows splitting
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class nsSplittableFrame : public nsIFrame {
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public:
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NS_DECL_ABSTRACT_FRAME(nsSplittableFrame)
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void Init(nsIContent* aContent, nsContainerFrame* aParent,
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nsIFrame* aPrevInFlow) override;
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void DestroyFrom(nsIFrame* aDestructRoot,
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PostDestroyData& aPostDestroyData) override;
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/*
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* Frame continuations can be either fluid or non-fluid.
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*
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* Fluid continuations ("in-flows") are the result of line breaking,
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* column breaking, or page breaking.
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*
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* Non-fluid continuations can be the result of BiDi frame splitting,
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* column-span splitting, or <col span="N"> where N > 1.
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*
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* A "flow" is a chain of fluid continuations.
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*
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* For more information, see https://wiki.mozilla.org/Gecko:Continuation_Model
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*/
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// Get the previous/next continuation, regardless of its type (fluid or
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// non-fluid).
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nsIFrame* GetPrevContinuation() const final;
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nsIFrame* GetNextContinuation() const final;
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// Set a previous/next non-fluid continuation.
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void SetPrevContinuation(nsIFrame*) final;
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void SetNextContinuation(nsIFrame*) final;
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// Get the first/last continuation for this frame.
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nsIFrame* FirstContinuation() const final;
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nsIFrame* LastContinuation() const final;
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#ifdef DEBUG
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// Can aFrame2 be reached from aFrame1 by following prev/next continuations?
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static bool IsInPrevContinuationChain(nsIFrame* aFrame1, nsIFrame* aFrame2);
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static bool IsInNextContinuationChain(nsIFrame* aFrame1, nsIFrame* aFrame2);
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#endif
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// Get the previous/next continuation, only if it is fluid (an "in-flow").
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nsIFrame* GetPrevInFlow() const final;
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nsIFrame* GetNextInFlow() const final;
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// Set a previous/next fluid continuation.
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void SetPrevInFlow(nsIFrame*) final;
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void SetNextInFlow(nsIFrame*) final;
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// Get the first/last frame in the current flow.
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nsIFrame* FirstInFlow() const final;
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nsIFrame* LastInFlow() const final;
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// Remove the frame from the flow. Connects the frame's prev-in-flow
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// and its next-in-flow. This should only be called in frame Destroy()
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// methods.
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static void RemoveFromFlow(nsIFrame* aFrame);
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protected:
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nsSplittableFrame(ComputedStyle* aStyle, nsPresContext* aPresContext,
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ClassID aID)
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: nsIFrame(aStyle, aPresContext, aID),
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mPrevContinuation(nullptr),
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mNextContinuation(nullptr) {}
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/**
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* Return the sum of the block-axis content size of our previous
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* continuations.
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*
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* @param aWM a writing-mode to determine the block-axis
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*
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* @note (bz) This makes laying out a splittable frame with N continuations
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* O(N^2)! So, use this function with caution and minimize the number
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* of calls to this method.
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*/
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nscoord ConsumedBSize(mozilla::WritingMode aWM) const;
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/**
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* Retrieve the effective computed block size of this frame, which is the
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* computed block size, minus the block size consumed by any previous
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* continuations.
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*/
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nscoord GetEffectiveComputedBSize(
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const ReflowInput& aReflowInput,
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nscoord aConsumed = NS_UNCONSTRAINEDSIZE) const;
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/**
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* @see nsIFrame::GetLogicalSkipSides()
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*/
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LogicalSides GetLogicalSkipSides(
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const ReflowInput* aReflowInput = nullptr) const override;
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/**
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* A faster version of GetLogicalSkipSides() that is intended to be used
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* inside Reflow before it's known if |this| frame will be COMPLETE or not.
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* It returns a result that assumes this fragment is the last and thus
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* should apply the block-end border/padding etc (except for "true" overflow
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* containers which always skip block sides). You're then expected to
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* recalculate the block-end side (as needed) when you know |this| frame's
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* reflow status is INCOMPLETE.
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* This method is intended for frames that breaks in the block axis.
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*/
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LogicalSides PreReflowBlockLevelLogicalSkipSides() const;
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nsIFrame* mPrevContinuation;
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nsIFrame* mNextContinuation;
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};
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#endif /* nsSplittableFrame_h___ */
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