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-rw-r--r--layout/generic/nsBlockReflowContext.h91
1 files changed, 91 insertions, 0 deletions
diff --git a/layout/generic/nsBlockReflowContext.h b/layout/generic/nsBlockReflowContext.h
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+++ b/layout/generic/nsBlockReflowContext.h
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+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* 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/. */
+
+/* class that a parent frame uses to reflow a block frame */
+
+#ifndef nsBlockReflowContext_h___
+#define nsBlockReflowContext_h___
+
+#include "mozilla/ReflowOutput.h"
+
+class nsIFrame;
+class nsLineBox;
+class nsPresContext;
+class nsReflowStatus;
+namespace mozilla {
+class BlockReflowState;
+} // namespace mozilla
+
+/**
+ * An encapsulation of the state and algorithm for reflowing block frames.
+ */
+class nsBlockReflowContext {
+ using BlockReflowState = mozilla::BlockReflowState;
+ using ReflowInput = mozilla::ReflowInput;
+ using ReflowOutput = mozilla::ReflowOutput;
+
+ public:
+ nsBlockReflowContext(nsPresContext* aPresContext,
+ const ReflowInput& aParentRI);
+ ~nsBlockReflowContext() = default;
+
+ void ReflowBlock(const mozilla::LogicalRect& aSpace, bool aApplyBStartMargin,
+ nsCollapsingMargin& aPrevMargin, nscoord aClearance,
+ nsLineBox* aLine, ReflowInput& aReflowInput,
+ nsReflowStatus& aReflowStatus, BlockReflowState& aState);
+
+ bool PlaceBlock(const ReflowInput& aReflowInput, bool aForceFit,
+ nsLineBox* aLine,
+ nsCollapsingMargin& aBEndMarginResult /* out */,
+ mozilla::OverflowAreas& aOverflowAreas,
+ const nsReflowStatus& aReflowStatus);
+
+ nsCollapsingMargin& GetCarriedOutBEndMargin() {
+ return mMetrics.mCarriedOutBEndMargin;
+ }
+
+ const ReflowOutput& GetMetrics() const { return mMetrics; }
+
+ /**
+ * Computes the collapsed block-start margin (in the context's parent's
+ * writing mode) for a block whose reflow input is in aRI.
+ * The computed margin is added into aMargin, whose writing mode is the
+ * parent's mode as found in mMetrics.GetWritingMode(); note this may not be
+ * the block's own writing mode as found in aRI.
+ * If aClearanceFrame is null then this is the first optimistic pass which
+ * shall assume that no frames have clearance, and we clear the HasClearance
+ * on all frames encountered.
+ * If non-null, this is the second pass and the caller has decided
+ * aClearanceFrame needs clearance (and we will therefore stop collapsing
+ * there); also, this function is responsible for marking it with
+ * SetHasClearance.
+ * If in the optimistic pass any frame is encountered that might possibly
+ * need clearance (i.e., if we really needed the optimism assumption) then
+ * we set aMayNeedRetry to true.
+ * We return true if we changed the clearance state of any line and marked it
+ * dirty.
+ */
+ bool ComputeCollapsedBStartMargin(const ReflowInput& aRI,
+ nsCollapsingMargin* aMargin,
+ nsIFrame* aClearanceFrame,
+ bool* aMayNeedRetry,
+ bool* aIsEmpty = nullptr);
+
+ protected:
+ nsPresContext* mPresContext;
+ const ReflowInput& mOuterReflowInput;
+
+ nsIFrame* mFrame;
+ mozilla::LogicalRect mSpace;
+
+ nscoord mICoord, mBCoord;
+ nsSize mContainerSize;
+ mozilla::WritingMode mWritingMode;
+ ReflowOutput mMetrics;
+ nsCollapsingMargin mBStartMargin;
+};
+
+#endif /* nsBlockReflowContext_h___ */