/* -*- 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 "nsStyleStructInlines.h"
#include "nsIFrame.h"
#include "mozilla/Assertions.h"
#include <algorithm>
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;
/**
* @return aValue clamped to [aMinValue, aMaxValue].
*
* @note This function needs to handle aMinValue > aMaxValue. In that case,
* aMinValue is returned.
* @see http://www.w3.org/TR/CSS21/visudet.html#min-max-widths
* @see http://www.w3.org/TR/CSS21/visudet.html#min-max-heights
*/
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 uint32_t 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)
{
}
// NOTE: If we ever want to use nsCSSOffsetState for a flex item or a grid
// item, we need to make it take the containing-block height as well as the
// width, since flex items and grid items resolve vertical percent margins
// and padding against the containing-block height, rather than its width.
nsCSSOffsetState(nsIFrame *aFrame, nsRenderingContext *aRenderingContext,
nscoord aContainingBlockWidth)
: frame(aFrame)
, rendContext(aRenderingContext)
{
MOZ_ASSERT(!aFrame->IsFlexItem(),
"We're about to resolve vertical percent margin & padding "
"values against CB width, which is incorrect for flex items");
InitOffsets(aContainingBlockWidth, 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 aHorizontalPercentBasis,
nscoord aVerticalPercentBasis,
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.
*
* @param aHorizontalPercentBasis
* Length to use for resolving percentage margin values in the horizontal
* axis. Usually the containing block width.
* @param aVerticalPercentBasis
* Length to use for resolving percentage margin values in the vertical
* axis. Usually the containing block width, per CSS21 sec 8.3, but may
* be the containing block *height*, e.g. in CSS3 Flexbox and Grid.
* @return true if the margin is dependent on the containing block size.
*/
bool ComputeMargin(nscoord aHorizontalPercentBasis,
nscoord aVerticalPercentBasis);
/**
* Computes padding values from the specified padding style information, and
* fills in the mComputedPadding member.
*
* @param aHorizontalPercentBasis
* Length to use for resolving percentage padding values in the horizontal
* axis. Usually the containing block width.
* @param aVerticalPercentBasis
* Length to use for resolving percentage padding values in the vertical
* axis. Usually the containing block width, per CSS21 sec 8.4, but may
* be the containing block *height* in e.g. CSS3 Flexbox and Grid.
* @return true if the padding is dependent on the containing block size.
*/
bool ComputePadding(nscoord aHorizontalPercentBasis,
nscoord aVerticalPercentBasis, nsIAtom* aFrameType);
protected:
void InitOffsets(nscoord aHorizontalPercentBasis,
nscoord aVerticalPercentBasis,
nsIAtom* aFrameType,
const nsMargin *aBorder = nullptr,
const nsMargin *aPadding = nullptr);
/*
* 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,
uint8_t aBoxSizing,
const nsStyleCoord& aCoord);
nscoord ComputeHeightValue(nscoord aContainingBlockHeight,
uint8_t 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;
bool IsFloating() const {
return mStyleDisplay->IsFloating(frame);
}
uint8_t GetDisplay() const {
return mStyleDisplay->GetDisplay(frame);
}
// 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.
int16_t mReflowDepth;
struct ReflowStateFlags {
uint16_t mSpecialHeightReflow:1; // used by tables to communicate special reflow (in process) to handle
// percent height frames inside cells which may not have computed heights
uint16_t mNextInFlowUntouched:1; // nothing in the frame's next-in-flow (or its descendants)
// is changing
uint16_t 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.
uint16_t mHasClearance:1; // Block has clearance
uint16_t mAssumingHScrollbar:1; // parent frame is an nsIScrollableFrame and it
// is assuming a horizontal scrollbar
uint16_t mAssumingVScrollbar:1; // parent frame is an nsIScrollableFrame and it
// is assuming a vertical scrollbar
uint16_t mHResize:1; // Is frame (a) not dirty and (b) a
// different width than before?
uint16_t 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?
uint16_t mTableIsSplittable:1; // tables are splittable, this should happen only inside a page
// and never insider a column frame
uint16_t mHeightDependsOnAncestorCell:1; // Does frame height depend on
// an ancestor table-cell?
uint16_t mIsColumnBalancing:1; // nsColumnSetFrame is balancing columns
uint16_t mIsFlexContainerMeasuringHeight:1; // nsFlexContainerFrame is
// reflowing this child to
// measure its intrinsic height.
uint16_t mDummyParentReflowState:1; // a "fake" reflow state made
// in order to be the parent
// of a real one
uint16_t mMustReflowPlaceholders:1; // Should this frame reflow its place-
// holder children? If the available
// height of this frame didn't change,
// but its in a paginated environment
// (e.g. columns), it should always
// reflow its placeholder children.
} 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,
uint32_t aFlags = 0);
// 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);
// Values for |aFlags| passed to constructor
enum {
DUMMY_PARENT_REFLOW_STATE = (1<<0)
};
// 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 = nullptr,
const nsMargin* aPadding = nullptr);
/**
* 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 constraints to the content
* size computed so far.
*/
nscoord ApplyMinMaxWidth(nscoord aWidth) const {
if (NS_UNCONSTRAINEDSIZE != mComputedMaxWidth) {
aWidth = std::min(aWidth, mComputedMaxWidth);
}
return std::max(aWidth, mComputedMinWidth);
}
/**
* Apply the mComputed(Min/Max)Height constraints to the content
* size computed so far.
*/
nscoord ApplyMinMaxHeight(nscoord aHeight) const {
if (NS_UNCONSTRAINEDSIZE != mComputedMaxHeight) {
aHeight = std::min(aHeight, mComputedMaxHeight);
}
return std::max(aHeight, mComputedMinHeight);
}
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(uint8_t 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___ */
