gecko/layout/generic/nsHTMLReflowState.h
Ehsan Akhgari 5682d40581 Bug 157681 - Part 2: Optimize positioned frame offset changes by moving the frame as opposed to reflowing it in case we know that the size of the frame will not change; r=dbaron
This patch adds a change hint to signal that one of the offsets on a
frame has been changed.  When processing the hint, we do one of the
following things based on the position property of the frame.

* For static frames, we ignore the offset changes completely, as they
  will not change the layout.
* For relative positioned frames, this patch refactors the
  nsHTMLReflowState::ComputeRelativeOffsets function so that it can be
  used from other callers, and it uses that to compute the new relative
  offsets, and uses the offsets computed previously to compute the new
  position of the frame.
* For absolute positioned frames, we set up a fake parent reflow state
  object, and then we create a new reflow state object for the frame in
  question.  This setup is similar to what nsFrame::BoxReflow does.
  Once we have the new reflow state object, we use it to compute the
  absolute offsets, and then we use the computed offsets to set the new
  position of the frame.  The offset computation is similar to what
  nsAbsoluteContainingBlock::ReflowAbsoluteFrame does.  In some cases
  where it is possible for the dimensions of the frame to change based
  on the offset changes, we fall back to a full reflow.
2012-06-06 00:53:48 -04:00

527 lines
22 KiB
C++

/* -*- 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/. */
/* struct containing the input to nsIFrame::Reflow */
#ifndef nsHTMLReflowState_h___
#define nsHTMLReflowState_h___
#include "nsMargin.h"
#include "nsStyleCoord.h"
#include "nsIFrame.h"
#include "mozilla/AutoRestore.h"
class nsPresContext;
class nsRenderingContext;
class nsFloatManager;
class nsLineLayout;
class nsIPercentHeightObserver;
struct nsStyleDisplay;
struct nsStyleVisibility;
struct nsStylePosition;
struct nsStyleBorder;
struct nsStyleMargin;
struct nsStylePadding;
struct nsStyleText;
struct nsHypotheticalBox;
template <class NumericType>
NumericType
NS_CSS_MINMAX(NumericType aValue, NumericType aMinValue, NumericType aMaxValue)
{
NumericType result = aValue;
if (aMaxValue < result)
result = aMaxValue;
if (aMinValue > result)
result = aMinValue;
return result;
}
/**
* Constant used to indicate an unconstrained size.
*
* @see #Reflow()
*/
#define NS_UNCONSTRAINEDSIZE NS_MAXSIZE
/**
* CSS Frame type. Included as part of the reflow state.
*/
typedef PRUint32 nsCSSFrameType;
#define NS_CSS_FRAME_TYPE_UNKNOWN 0
#define NS_CSS_FRAME_TYPE_INLINE 1
#define NS_CSS_FRAME_TYPE_BLOCK 2 /* block-level in normal flow */
#define NS_CSS_FRAME_TYPE_FLOATING 3
#define NS_CSS_FRAME_TYPE_ABSOLUTE 4
#define NS_CSS_FRAME_TYPE_INTERNAL_TABLE 5 /* row group frame, row frame, cell frame, ... */
/**
* Bit-flag that indicates whether the element is replaced. Applies to inline,
* block-level, floating, and absolutely positioned elements
*/
#define NS_CSS_FRAME_TYPE_REPLACED 0x08000
/**
* Bit-flag that indicates that the element is replaced and contains a block
* (eg some form controls). Applies to inline, block-level, floating, and
* absolutely positioned elements. Mutually exclusive with
* NS_CSS_FRAME_TYPE_REPLACED.
*/
#define NS_CSS_FRAME_TYPE_REPLACED_CONTAINS_BLOCK 0x10000
/**
* Helper macros for telling whether items are replaced
*/
#define NS_FRAME_IS_REPLACED_NOBLOCK(_ft) \
(NS_CSS_FRAME_TYPE_REPLACED == ((_ft) & NS_CSS_FRAME_TYPE_REPLACED))
#define NS_FRAME_IS_REPLACED(_ft) \
(NS_FRAME_IS_REPLACED_NOBLOCK(_ft) || \
NS_FRAME_IS_REPLACED_CONTAINS_BLOCK(_ft))
#define NS_FRAME_REPLACED(_ft) \
(NS_CSS_FRAME_TYPE_REPLACED | (_ft))
#define NS_FRAME_IS_REPLACED_CONTAINS_BLOCK(_ft) \
(NS_CSS_FRAME_TYPE_REPLACED_CONTAINS_BLOCK == \
((_ft) & NS_CSS_FRAME_TYPE_REPLACED_CONTAINS_BLOCK))
#define NS_FRAME_REPLACED_CONTAINS_BLOCK(_ft) \
(NS_CSS_FRAME_TYPE_REPLACED_CONTAINS_BLOCK | (_ft))
/**
* A macro to extract the type. Masks off the 'replaced' bit-flag
*/
#define NS_FRAME_GET_TYPE(_ft) \
((_ft) & ~(NS_CSS_FRAME_TYPE_REPLACED | \
NS_CSS_FRAME_TYPE_REPLACED_CONTAINS_BLOCK))
#define NS_INTRINSICSIZE NS_UNCONSTRAINEDSIZE
#define NS_AUTOHEIGHT NS_UNCONSTRAINEDSIZE
#define NS_AUTOMARGIN NS_UNCONSTRAINEDSIZE
#define NS_AUTOOFFSET NS_UNCONSTRAINEDSIZE
// NOTE: there are assumptions all over that these have the same value, namely NS_UNCONSTRAINEDSIZE
// if any are changed to be a value other than NS_UNCONSTRAINEDSIZE
// at least update AdjustComputedHeight/Width and test ad nauseum
// A base class of nsHTMLReflowState that computes only the padding,
// border, and margin, since those values are needed more often.
struct nsCSSOffsetState {
public:
// the frame being reflowed
nsIFrame* frame;
// rendering context to use for measurement
nsRenderingContext* rendContext;
// Computed margin values
nsMargin mComputedMargin;
// Cached copy of the border + padding values
nsMargin mComputedBorderPadding;
// Computed padding values
nsMargin mComputedPadding;
// Callers using this constructor must call InitOffsets on their own.
nsCSSOffsetState(nsIFrame *aFrame, nsRenderingContext *aRenderingContext)
: frame(aFrame)
, rendContext(aRenderingContext)
{
}
nsCSSOffsetState(nsIFrame *aFrame, nsRenderingContext *aRenderingContext,
nscoord aContainingBlockWidth)
: frame(aFrame)
, rendContext(aRenderingContext)
{
InitOffsets(aContainingBlockWidth, frame->GetType());
}
#ifdef DEBUG
// Reflow trace methods. Defined in nsFrame.cpp so they have access
// to the display-reflow infrastructure.
static void* DisplayInitOffsetsEnter(nsIFrame* aFrame,
nsCSSOffsetState* aState,
nscoord aCBWidth,
const nsMargin* aBorder,
const nsMargin* aPadding);
static void DisplayInitOffsetsExit(nsIFrame* aFrame,
nsCSSOffsetState* aState,
void* aValue);
#endif
private:
/**
* Computes margin values from the specified margin style information, and
* fills in the mComputedMargin member.
* @return true if the margin is dependent on the containing block width
*/
bool ComputeMargin(nscoord aContainingBlockWidth);
/**
* Computes padding values from the specified padding style information, and
* fills in the mComputedPadding member.
* @return true if the padding is dependent on the containing block width
*/
bool ComputePadding(nscoord aContainingBlockWidth, nsIAtom* aFrameType);
protected:
void InitOffsets(nscoord aContainingBlockWidth,
nsIAtom* aFrameType,
const nsMargin *aBorder = nsnull,
const nsMargin *aPadding = nsnull);
/*
* Convert nsStyleCoord to nscoord when percentages depend on the
* containing block width, and enumerated values are for width,
* min-width, or max-width. Does not handle auto widths.
*/
inline nscoord ComputeWidthValue(nscoord aContainingBlockWidth,
nscoord aContentEdgeToBoxSizing,
nscoord aBoxSizingToMarginEdge,
const nsStyleCoord& aCoord);
// same as previous, but using mComputedBorderPadding, mComputedPadding,
// and mComputedMargin
nscoord ComputeWidthValue(nscoord aContainingBlockWidth,
PRUint8 aBoxSizing,
const nsStyleCoord& aCoord);
};
/**
* State passed to a frame during reflow or intrinsic size calculation.
*
* XXX Refactor so only a base class (nsSizingState?) is used for intrinsic
* size calculation.
*
* @see nsIFrame#Reflow()
*/
struct nsHTMLReflowState : public nsCSSOffsetState {
// the reflow states are linked together. this is the pointer to the
// parent's reflow state
const nsHTMLReflowState* parentReflowState;
// pointer to the float manager associated with this area
nsFloatManager* mFloatManager;
// LineLayout object (only for inline reflow; set to NULL otherwise)
nsLineLayout* mLineLayout;
// The appropriate reflow state for the containing block (for
// percentage widths, etc.) of this reflow state's frame.
const nsHTMLReflowState *mCBReflowState;
// the available width in which to reflow the frame. The space
// represents the amount of room for the frame's margin, border,
// padding, and content area. The frame size you choose should fit
// within the available width.
nscoord availableWidth;
// A value of NS_UNCONSTRAINEDSIZE for the available height means
// you can choose whatever size you want. In galley mode the
// available height is always NS_UNCONSTRAINEDSIZE, and only page
// mode or multi-column layout involves a constrained height. The
// element's the top border and padding, and content, must fit. If the
// element is complete after reflow then its bottom border, padding
// and margin (and similar for its complete ancestors) will need to
// fit in this height.
nscoord availableHeight;
// The type of frame, from css's perspective. This value is
// initialized by the Init method below.
nsCSSFrameType mFrameType;
// The amount the in-flow position of the block is moving vertically relative
// to its previous in-flow position (i.e. the amount the line containing the
// block is moving).
// This should be zero for anything which is not a block outside, and it
// should be zero for anything which has a non-block parent.
// The intended use of this value is to allow the accurate determination
// of the potential impact of a float
// This takes on an arbitrary value the first time a block is reflowed
nscoord mBlockDelta;
private:
// The computed width specifies the frame's content area width, and it does
// not apply to inline non-replaced elements
//
// For replaced inline frames, a value of NS_INTRINSICSIZE means you should
// use your intrinsic width as the computed width
//
// For block-level frames, the computed width is based on the width of the
// containing block, the margin/border/padding areas, and the min/max width.
nscoord mComputedWidth;
// The computed height specifies the frame's content height, and it does
// not apply to inline non-replaced elements
//
// For replaced inline frames, a value of NS_INTRINSICSIZE means you should
// use your intrinsic height as the computed height
//
// For non-replaced block-level frames in the flow and floated, a value of
// NS_AUTOHEIGHT means you choose a height to shrink wrap around the normal
// flow child frames. The height must be within the limit of the min/max
// height if there is such a limit
//
// For replaced block-level frames, a value of NS_INTRINSICSIZE
// means you use your intrinsic height as the computed height
nscoord mComputedHeight;
public:
// Computed values for 'left/top/right/bottom' offsets. Only applies to
// 'positioned' elements
nsMargin mComputedOffsets;
// Computed values for 'min-width/max-width' and 'min-height/max-height'
// XXXldb The width ones here should go; they should be needed only
// internally.
nscoord mComputedMinWidth, mComputedMaxWidth;
nscoord mComputedMinHeight, mComputedMaxHeight;
// Cached pointers to the various style structs used during intialization
const nsStyleDisplay* mStyleDisplay;
const nsStyleVisibility* mStyleVisibility;
const nsStylePosition* mStylePosition;
const nsStyleBorder* mStyleBorder;
const nsStyleMargin* mStyleMargin;
const nsStylePadding* mStylePadding;
const nsStyleText* mStyleText;
// a frame (e.g. nsTableCellFrame) which may need to generate a special
// reflow for percent height calculations
nsIPercentHeightObserver* mPercentHeightObserver;
// CSS margin collapsing sometimes requires us to reflow
// optimistically assuming that margins collapse to see if clearance
// is required. When we discover that clearance is required, we
// store the frame in which clearance was discovered to the location
// requested here.
nsIFrame** mDiscoveredClearance;
// This value keeps track of how deeply nested a given reflow state
// is from the top of the frame tree.
PRInt16 mReflowDepth;
struct ReflowStateFlags {
PRUint16 mSpecialHeightReflow:1; // used by tables to communicate special reflow (in process) to handle
// percent height frames inside cells which may not have computed heights
PRUint16 mNextInFlowUntouched:1; // nothing in the frame's next-in-flow (or its descendants)
// is changing
PRUint16 mIsTopOfPage:1; // Is the current context at the top of a
// page? When true, we force something
// that's too tall for a page/column to
// fit anyway to avoid infinite loops.
PRUint16 mBlinks:1; // Keep track of text-decoration: blink
PRUint16 mHasClearance:1; // Block has clearance
PRUint16 mAssumingHScrollbar:1; // parent frame is an nsIScrollableFrame and it
// is assuming a horizontal scrollbar
PRUint16 mAssumingVScrollbar:1; // parent frame is an nsIScrollableFrame and it
// is assuming a vertical scrollbar
PRUint16 mHResize:1; // Is frame (a) not dirty and (b) a
// different width than before?
PRUint16 mVResize:1; // Is frame (a) not dirty and (b) a
// different height than before or
// (potentially) in a context where
// percent heights have a different
// basis?
PRUint16 mTableIsSplittable:1; // tables are splittable, this should happen only inside a page
// and never insider a column frame
PRUint16 mHeightDependsOnAncestorCell:1; // Does frame height depend on
// an ancestor table-cell?
PRUint16 mIsColumnBalancing:1; // nsColumnSetFrame is balancing columns
} mFlags;
// Note: The copy constructor is written by the compiler automatically. You
// can use that and then override specific values if you want, or you can
// call Init as desired...
// Initialize a <b>root</b> reflow state with a rendering context to
// use for measuring things.
nsHTMLReflowState(nsPresContext* aPresContext,
nsIFrame* aFrame,
nsRenderingContext* aRenderingContext,
const nsSize& aAvailableSpace);
// Initialize a reflow state for a child frames reflow. Some state
// is copied from the parent reflow state; the remaining state is
// computed.
nsHTMLReflowState(nsPresContext* aPresContext,
const nsHTMLReflowState& aParentReflowState,
nsIFrame* aFrame,
const nsSize& aAvailableSpace,
// These two are used by absolute positioning code
// to override default containing block w & h:
nscoord aContainingBlockWidth = -1,
nscoord aContainingBlockHeight = -1,
bool aInit = true);
// This method initializes various data members. It is automatically
// called by the various constructors
void Init(nsPresContext* aPresContext,
nscoord aContainingBlockWidth = -1,
nscoord aContainingBlockHeight = -1,
const nsMargin* aBorder = nsnull,
const nsMargin* aPadding = nsnull);
/**
* Find the content width of the containing block of aReflowState
*/
static nscoord
GetContainingBlockContentWidth(const nsHTMLReflowState* aReflowState);
/**
* Calculate the used line-height property. The return value will be >= 0.
*/
nscoord CalcLineHeight() const;
/**
* Same as CalcLineHeight() above, but doesn't need a reflow state.
*
* @param aBlockHeight The computed height of the content rect of the block
* that the line should fill.
* Only used with line-height:-moz-block-height.
* NS_AUTOHEIGHT results in a normal line-height for
* line-height:-moz-block-height.
* @param aFontSizeInflation The result of the appropriate
* nsLayoutUtils::FontSizeInflationFor call,
* or 1.0 if during intrinsic size
* calculation.
*/
static nscoord CalcLineHeight(nsStyleContext* aStyleContext,
nscoord aBlockHeight,
float aFontSizeInflation);
void ComputeContainingBlockRectangle(nsPresContext* aPresContext,
const nsHTMLReflowState* aContainingBlockRS,
nscoord& aContainingBlockWidth,
nscoord& aContainingBlockHeight);
/**
* Apply the mComputed(Min/Max)(Width/Height) values to the content
* size computed so far. If a passed-in pointer is null, we skip
* adjusting that dimension.
*/
void ApplyMinMaxConstraints(nscoord* aContentWidth, nscoord* aContentHeight) const;
bool ShouldReflowAllKids() const {
// Note that we could make a stronger optimization for mVResize if
// we use it in a ShouldReflowChild test that replaces the current
// checks of NS_FRAME_IS_DIRTY | NS_FRAME_HAS_DIRTY_CHILDREN, if it
// were tested there along with NS_FRAME_CONTAINS_RELATIVE_HEIGHT.
// This would need to be combined with a slight change in which
// frames NS_FRAME_CONTAINS_RELATIVE_HEIGHT is marked on.
return (frame->GetStateBits() & NS_FRAME_IS_DIRTY) ||
mFlags.mHResize ||
(mFlags.mVResize &&
(frame->GetStateBits() & NS_FRAME_CONTAINS_RELATIVE_HEIGHT));
}
nscoord ComputedWidth() const { return mComputedWidth; }
// This method doesn't apply min/max computed widths to the value passed in.
void SetComputedWidth(nscoord aComputedWidth);
nscoord ComputedHeight() const { return mComputedHeight; }
// This method doesn't apply min/max computed heights to the value passed in.
void SetComputedHeight(nscoord aComputedHeight);
void SetComputedHeightWithoutResettingResizeFlags(nscoord aComputedHeight) {
// Viewport frames reset the computed height on a copy of their reflow
// state when reflowing fixed-pos kids. In that case we actually don't
// want to mess with the resize flags, because comparing the frame's rect
// to the munged computed width is pointless.
mComputedHeight = aComputedHeight;
}
void SetTruncated(const nsHTMLReflowMetrics& aMetrics, nsReflowStatus* aStatus) const;
bool WillReflowAgainForClearance() const {
return mDiscoveredClearance && *mDiscoveredClearance;
}
// Compute the offsets for a relative position element
static void ComputeRelativeOffsets(PRUint8 aCBDirection,
nsIFrame* aFrame,
nscoord aContainingBlockWidth,
nscoord aContainingBlockHeight,
nsMargin& aComputedOffsets);
#ifdef DEBUG
// Reflow trace methods. Defined in nsFrame.cpp so they have access
// to the display-reflow infrastructure.
static void* DisplayInitConstraintsEnter(nsIFrame* aFrame,
nsHTMLReflowState* aState,
nscoord aCBWidth,
nscoord aCBHeight,
const nsMargin* aBorder,
const nsMargin* aPadding);
static void DisplayInitConstraintsExit(nsIFrame* aFrame,
nsHTMLReflowState* aState,
void* aValue);
static void* DisplayInitFrameTypeEnter(nsIFrame* aFrame,
nsHTMLReflowState* aState);
static void DisplayInitFrameTypeExit(nsIFrame* aFrame,
nsHTMLReflowState* aState,
void* aValue);
#endif
protected:
void InitFrameType(nsIAtom* aFrameType);
void InitCBReflowState();
void InitResizeFlags(nsPresContext* aPresContext, nsIAtom* aFrameType);
void InitConstraints(nsPresContext* aPresContext,
nscoord aContainingBlockWidth,
nscoord aContainingBlockHeight,
const nsMargin* aBorder,
const nsMargin* aPadding,
nsIAtom* aFrameType);
// Returns the nearest containing block or block frame (whether or not
// it is a containing block) for the specified frame. Also returns
// the left edge and width of the containing block's content area.
// These are returned in the coordinate space of the containing block.
nsIFrame* GetHypotheticalBoxContainer(nsIFrame* aFrame,
nscoord& aCBLeftEdge,
nscoord& aCBWidth);
void CalculateHypotheticalBox(nsPresContext* aPresContext,
nsIFrame* aPlaceholderFrame,
nsIFrame* aContainingBlock,
nscoord aBlockLeftContentEdge,
nscoord aBlockContentWidth,
const nsHTMLReflowState* cbrs,
nsHypotheticalBox& aHypotheticalBox,
nsIAtom* aFrameType);
void InitAbsoluteConstraints(nsPresContext* aPresContext,
const nsHTMLReflowState* cbrs,
nscoord aContainingBlockWidth,
nscoord aContainingBlockHeight,
nsIAtom* aFrameType);
// Calculates the computed values for the 'min-Width', 'max-Width',
// 'min-Height', and 'max-Height' properties, and stores them in the assorted
// data members
void ComputeMinMaxValues(nscoord aContainingBlockWidth,
nscoord aContainingBlockHeight,
const nsHTMLReflowState* aContainingBlockRS);
void CalculateHorizBorderPaddingMargin(nscoord aContainingBlockWidth,
nscoord* aInsideBoxSizing,
nscoord* aOutsideBoxSizing);
void CalculateBlockSideMargins(nscoord aAvailWidth,
nscoord aComputedWidth,
nsIAtom* aFrameType);
};
#endif /* nsHTMLReflowState_h___ */