/* -*- 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/. */
/* constants for what needs to be recomputed in response to style changes */
#ifndef nsChangeHint_h___
#define nsChangeHint_h___
#include "nsDebug.h"
// Defines for various style related constants
enum nsChangeHint {
// change was visual only (e.g., COLOR=)
// Invalidates all descendant frames (including following
// placeholders to out-of-flow frames).
nsChangeHint_RepaintFrame = 0x01,
// For reflow, we want flags to give us arbitrary FrameNeedsReflow behavior.
// just do a FrameNeedsReflow.
nsChangeHint_NeedReflow = 0x02,
// Invalidate intrinsic widths on the frame's ancestors. Must not be set
// without setting nsChangeHint_NeedReflow.
nsChangeHint_ClearAncestorIntrinsics = 0x04,
// Invalidate intrinsic widths on the frame's descendants. Must not be set
// without also setting nsChangeHint_ClearAncestorIntrinsics.
nsChangeHint_ClearDescendantIntrinsics = 0x08,
// Force unconditional reflow of all descendants. Must not be set without
// setting nsChangeHint_NeedReflow, but is independent of both the
// Clear*Intrinsics flags.
nsChangeHint_NeedDirtyReflow = 0x10,
// change requires view to be updated, if there is one (e.g., clip:).
// Updates all descendants (including following placeholders to out-of-flows).
nsChangeHint_SyncFrameView = 0x20,
// The currently shown mouse cursor needs to be updated
nsChangeHint_UpdateCursor = 0x40,
/**
* Used when the computed value (a URI) of one or more of an element's
* filter/mask/clip/etc CSS properties changes, causing the element's frame
* to start/stop referencing (or reference different) SVG resource elements.
* (_Not_ used to handle changes to referenced resource elements.) Using this
* hint results in nsSVGEffects::UpdateEffects being called on the element's
* frame.
*/
nsChangeHint_UpdateEffects = 0x80,
/**
* Visual change only, but the change can be handled entirely by
* updating the layer(s) for the frame.
* Updates all descendants (including following placeholders to out-of-flows).
*/
nsChangeHint_UpdateOpacityLayer = 0x100,
/**
* Updates all descendants. Any placeholder descendants' out-of-flows
* are also descendants of the transformed frame, so they're updated.
*/
nsChangeHint_UpdateTransformLayer = 0x200,
/**
* Change requires frame change (e.g., display:).
* This subsumes all the above. Reconstructs all frame descendants,
* including following placeholders to out-of-flows.
*/
nsChangeHint_ReconstructFrame = 0x400,
/**
* The frame's effect on its ancestors' overflow areas has changed,
* either through a change in its transform or a change in its position.
* Does not update any descendant frames.
*/
nsChangeHint_UpdateOverflow = 0x800,
/**
* The children-only transform of an SVG frame changed, requiring the
* overflow rects of the frame's immediate children to be updated.
*/
nsChangeHint_ChildrenOnlyTransform = 0x1000,
/**
* The frame's offsets have changed, while its dimensions might have
* changed as well. This hint is used for positioned frames if their
* offset changes. If we decide that the dimensions are likely to
* change, this will trigger a reflow.
*
* Note that this should probably be used in combination with
* nsChangeHint_UpdateOverflow in order to get the overflow areas of
* the ancestors updated as well.
*/
nsChangeHint_RecomputePosition = 0x2000,
/**
* Behaves like ReconstructFrame, but only if the frame has descendants
* that are absolutely or fixed position. Use this hint when a style change
* has changed whether the frame is a container for fixed-pos or abs-pos
* elements, but reframing is otherwise not needed.
*/
nsChangeHint_AddOrRemoveTransform = 0x4000,
/**
* This change hint has *no* change handling behavior. However, it
* exists to be a non-inherited hint, because when the border-style
* changes, and it's inherited by a child, that might require a reflow
* due to the border-width change on the child.
*/
nsChangeHint_BorderStyleNoneChange = 0x8000,
/**
* SVG textPath needs to be recomputed because the path has changed.
* This means that the glyph positions of the text need to be recomputed.
*/
nsChangeHint_UpdateTextPath = 0x10000
// IMPORTANT NOTE: When adding new hints, consider whether you need to
// add them to NS_HintsNotHandledForDescendantsIn() below.
};
// Redefine these operators to return nothing. This will catch any use
// of these operators on hints. We should not be using these operators
// on nsChangeHints
inline void operator<(nsChangeHint s1, nsChangeHint s2) {}
inline void operator>(nsChangeHint s1, nsChangeHint s2) {}
inline void operator!=(nsChangeHint s1, nsChangeHint s2) {}
inline void operator==(nsChangeHint s1, nsChangeHint s2) {}
inline void operator<=(nsChangeHint s1, nsChangeHint s2) {}
inline void operator>=(nsChangeHint s1, nsChangeHint s2) {}
// Operators on nsChangeHints
// Merge two hints, taking the union
inline nsChangeHint NS_CombineHint(nsChangeHint aH1, nsChangeHint aH2) {
return (nsChangeHint)(aH1 | aH2);
}
// Merge two hints, taking the union
inline nsChangeHint NS_SubtractHint(nsChangeHint aH1, nsChangeHint aH2) {
return (nsChangeHint)(aH1 & ~aH2);
}
// Merge the "src" hint into the "dst" hint
// Returns true iff the destination changed
inline bool NS_UpdateHint(nsChangeHint& aDest, nsChangeHint aSrc) {
nsChangeHint r = (nsChangeHint)(aDest | aSrc);
bool changed = (int)r != (int)aDest;
aDest = r;
return changed;
}
// Returns true iff the second hint contains all the hints of the first hint
inline bool NS_IsHintSubset(nsChangeHint aSubset, nsChangeHint aSuperSet) {
return (aSubset & aSuperSet) == aSubset;
}
/**
* We have an optimization when processing change hints which prevents
* us from visiting the descendants of a node when a hint on that node
* is being processed. This optimization does not apply in some of the
* cases where applying a hint to an element does not necessarily result
* in the same hint being handled on the descendants.
*/
// The most hints that NS_HintsNotHandledForDescendantsIn could possibly return:
#define nsChangeHint_Hints_NotHandledForDescendants nsChangeHint( \
nsChangeHint_UpdateTransformLayer | \
nsChangeHint_UpdateEffects | \
nsChangeHint_UpdateOpacityLayer | \
nsChangeHint_UpdateOverflow | \
nsChangeHint_ChildrenOnlyTransform | \
nsChangeHint_RecomputePosition | \
nsChangeHint_AddOrRemoveTransform | \
nsChangeHint_BorderStyleNoneChange | \
nsChangeHint_NeedReflow | \
nsChangeHint_ClearAncestorIntrinsics)
inline nsChangeHint NS_HintsNotHandledForDescendantsIn(nsChangeHint aChangeHint) {
nsChangeHint result = nsChangeHint(aChangeHint & (
nsChangeHint_UpdateTransformLayer |
nsChangeHint_UpdateEffects |
nsChangeHint_UpdateOpacityLayer |
nsChangeHint_UpdateOverflow |
nsChangeHint_ChildrenOnlyTransform |
nsChangeHint_RecomputePosition |
nsChangeHint_AddOrRemoveTransform |
nsChangeHint_BorderStyleNoneChange));
if (!NS_IsHintSubset(nsChangeHint_NeedDirtyReflow, aChangeHint) &&
NS_IsHintSubset(nsChangeHint_NeedReflow, aChangeHint)) {
// If NeedDirtyReflow is *not* set, then NeedReflow is a
// non-inherited hint.
NS_UpdateHint(result, nsChangeHint_NeedReflow);
}
if (!NS_IsHintSubset(nsChangeHint_ClearDescendantIntrinsics, aChangeHint) &&
NS_IsHintSubset(nsChangeHint_ClearAncestorIntrinsics, aChangeHint)) {
// If ClearDescendantIntrinsics is *not* set, then
// ClearAncestorIntrinsics is a non-inherited hint.
NS_UpdateHint(result, nsChangeHint_ClearAncestorIntrinsics);
}
NS_ABORT_IF_FALSE(NS_IsHintSubset(result,
nsChangeHint_Hints_NotHandledForDescendants),
"something is inconsistent");
return result;
}
// Redefine the old NS_STYLE_HINT constants in terms of the new hint structure
#define NS_STYLE_HINT_NONE \
nsChangeHint(0)
#define NS_STYLE_HINT_VISUAL \
nsChangeHint(nsChangeHint_RepaintFrame | nsChangeHint_SyncFrameView)
#define nsChangeHint_AllReflowHints \
nsChangeHint(nsChangeHint_NeedReflow | \
nsChangeHint_ClearAncestorIntrinsics | \
nsChangeHint_ClearDescendantIntrinsics | \
nsChangeHint_NeedDirtyReflow)
#define NS_STYLE_HINT_REFLOW \
nsChangeHint(NS_STYLE_HINT_VISUAL | nsChangeHint_AllReflowHints)
#define NS_STYLE_HINT_FRAMECHANGE \
nsChangeHint(NS_STYLE_HINT_REFLOW | nsChangeHint_ReconstructFrame)
/**
* |nsRestyleHint| is a bitfield for the result of
* |HasStateDependentStyle| and |HasAttributeDependentStyle|. When no
* restyling is necessary, use |nsRestyleHint(0)|.
*/
enum nsRestyleHint {
eRestyle_Self = 0x1,
eRestyle_Subtree = 0x2, /* self and descendants */
eRestyle_LaterSiblings = 0x4 /* implies "and descendants" */
};
#endif /* nsChangeHint_h___ */
