michael@0: /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
michael@0: /* This Source Code Form is subject to the terms of the Mozilla Public
michael@0:  * License, v. 2.0. If a copy of the MPL was not distributed with this
michael@0:  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
michael@0: 
michael@0: /* constants for what needs to be recomputed in response to style changes */
michael@0: 
michael@0: #ifndef nsChangeHint_h___
michael@0: #define nsChangeHint_h___
michael@0: 
michael@0: #include "nsDebug.h"
michael@0: 
michael@0: // Defines for various style related constants
michael@0: 
michael@0: enum nsChangeHint {
michael@0:   // change was visual only (e.g., COLOR=)
michael@0:   // Invalidates all descendant frames (including following
michael@0:   // placeholders to out-of-flow frames).
michael@0:   nsChangeHint_RepaintFrame = 0x01,
michael@0: 
michael@0:   // For reflow, we want flags to give us arbitrary FrameNeedsReflow behavior.
michael@0:   // just do a FrameNeedsReflow.
michael@0:   nsChangeHint_NeedReflow = 0x02,
michael@0: 
michael@0:   // Invalidate intrinsic widths on the frame's ancestors.  Must not be set
michael@0:   // without setting nsChangeHint_NeedReflow.
michael@0:   nsChangeHint_ClearAncestorIntrinsics = 0x04,
michael@0: 
michael@0:   // Invalidate intrinsic widths on the frame's descendants.  Must not be set
michael@0:   // without also setting nsChangeHint_ClearAncestorIntrinsics.
michael@0:   nsChangeHint_ClearDescendantIntrinsics = 0x08,
michael@0: 
michael@0:   // Force unconditional reflow of all descendants.  Must not be set without
michael@0:   // setting nsChangeHint_NeedReflow, but is independent of both the
michael@0:   // Clear*Intrinsics flags.
michael@0:   nsChangeHint_NeedDirtyReflow = 0x10,
michael@0: 
michael@0:   // change requires view to be updated, if there is one (e.g., clip:).
michael@0:   // Updates all descendants (including following placeholders to out-of-flows).
michael@0:   nsChangeHint_SyncFrameView = 0x20,
michael@0: 
michael@0:   // The currently shown mouse cursor needs to be updated
michael@0:   nsChangeHint_UpdateCursor = 0x40,
michael@0: 
michael@0:   /**
michael@0:    * Used when the computed value (a URI) of one or more of an element's
michael@0:    * filter/mask/clip/etc CSS properties changes, causing the element's frame
michael@0:    * to start/stop referencing (or reference different) SVG resource elements.
michael@0:    * (_Not_ used to handle changes to referenced resource elements.) Using this
michael@0:    * hint results in nsSVGEffects::UpdateEffects being called on the element's
michael@0:    * frame.
michael@0:    */
michael@0:   nsChangeHint_UpdateEffects = 0x80,
michael@0: 
michael@0:   /**
michael@0:    * Visual change only, but the change can be handled entirely by
michael@0:    * updating the layer(s) for the frame.
michael@0:    * Updates all descendants (including following placeholders to out-of-flows).
michael@0:    */
michael@0:   nsChangeHint_UpdateOpacityLayer = 0x100,
michael@0:   /**
michael@0:    * Updates all descendants. Any placeholder descendants' out-of-flows
michael@0:    * are also descendants of the transformed frame, so they're updated.
michael@0:    */
michael@0:   nsChangeHint_UpdateTransformLayer = 0x200,
michael@0: 
michael@0:   /**
michael@0:    * Change requires frame change (e.g., display:).
michael@0:    * This subsumes all the above. Reconstructs all frame descendants,
michael@0:    * including following placeholders to out-of-flows.
michael@0:    */
michael@0:   nsChangeHint_ReconstructFrame = 0x400,
michael@0: 
michael@0:   /**
michael@0:    * The frame's overflow area has changed, either through a change in its
michael@0:    * transform or a change in its position. Does not update any descendant
michael@0:    * frames.
michael@0:    */
michael@0:   nsChangeHint_UpdateOverflow = 0x800,
michael@0: 
michael@0:   /**
michael@0:    * The frame's overflow area has changed, through a change in its transform.
michael@0:    * Does not update any descendant frames.
michael@0:    */
michael@0:   nsChangeHint_UpdatePostTransformOverflow = 0x1000,
michael@0: 
michael@0:   /**
michael@0:    * The children-only transform of an SVG frame changed, requiring the
michael@0:    * overflow rects of the frame's immediate children to be updated.
michael@0:    */
michael@0:   nsChangeHint_ChildrenOnlyTransform = 0x2000,
michael@0: 
michael@0:   /**
michael@0:    * The frame's offsets have changed, while its dimensions might have
michael@0:    * changed as well.  This hint is used for positioned frames if their
michael@0:    * offset changes.  If we decide that the dimensions are likely to
michael@0:    * change, this will trigger a reflow.
michael@0:    *
michael@0:    * Note that this should probably be used in combination with
michael@0:    * nsChangeHint_UpdateOverflow in order to get the overflow areas of
michael@0:    * the ancestors updated as well.
michael@0:    */
michael@0:   nsChangeHint_RecomputePosition = 0x4000,
michael@0: 
michael@0:   /**
michael@0:    * Behaves like ReconstructFrame, but only if the frame has descendants
michael@0:    * that are absolutely or fixed position. Use this hint when a style change
michael@0:    * has changed whether the frame is a container for fixed-pos or abs-pos
michael@0:    * elements, but reframing is otherwise not needed.
michael@0:    */
michael@0:   nsChangeHint_AddOrRemoveTransform = 0x8000,
michael@0: 
michael@0:   /**
michael@0:    * This change hint has *no* change handling behavior.  However, it
michael@0:    * exists to be a non-inherited hint, because when the border-style
michael@0:    * changes, and it's inherited by a child, that might require a reflow
michael@0:    * due to the border-width change on the child.
michael@0:    */
michael@0:   nsChangeHint_BorderStyleNoneChange = 0x10000,
michael@0: 
michael@0:   /**
michael@0:    * SVG textPath needs to be recomputed because the path has changed.
michael@0:    * This means that the glyph positions of the text need to be recomputed.
michael@0:    */
michael@0:   nsChangeHint_UpdateTextPath = 0x20000
michael@0: 
michael@0:   // IMPORTANT NOTE: When adding new hints, consider whether you need to
michael@0:   // add them to NS_HintsNotHandledForDescendantsIn() below.
michael@0: };
michael@0: 
michael@0: // Redefine these operators to return nothing. This will catch any use
michael@0: // of these operators on hints. We should not be using these operators
michael@0: // on nsChangeHints
michael@0: inline void operator<(nsChangeHint s1, nsChangeHint s2) {}
michael@0: inline void operator>(nsChangeHint s1, nsChangeHint s2) {}
michael@0: inline void operator!=(nsChangeHint s1, nsChangeHint s2) {}
michael@0: inline void operator==(nsChangeHint s1, nsChangeHint s2) {}
michael@0: inline void operator<=(nsChangeHint s1, nsChangeHint s2) {}
michael@0: inline void operator>=(nsChangeHint s1, nsChangeHint s2) {}
michael@0: 
michael@0: // Operators on nsChangeHints
michael@0: 
michael@0: // Merge two hints, taking the union
michael@0: inline nsChangeHint NS_CombineHint(nsChangeHint aH1, nsChangeHint aH2) {
michael@0:   return (nsChangeHint)(aH1 | aH2);
michael@0: }
michael@0: 
michael@0: // Merge two hints, taking the union
michael@0: inline nsChangeHint NS_SubtractHint(nsChangeHint aH1, nsChangeHint aH2) {
michael@0:   return (nsChangeHint)(aH1 & ~aH2);
michael@0: }
michael@0: 
michael@0: // Merge the "src" hint into the "dst" hint
michael@0: // Returns true iff the destination changed
michael@0: inline bool NS_UpdateHint(nsChangeHint& aDest, nsChangeHint aSrc) {
michael@0:   nsChangeHint r = (nsChangeHint)(aDest | aSrc);
michael@0:   bool changed = (int)r != (int)aDest;
michael@0:   aDest = r;
michael@0:   return changed;
michael@0: }
michael@0: 
michael@0: // Returns true iff the second hint contains all the hints of the first hint
michael@0: inline bool NS_IsHintSubset(nsChangeHint aSubset, nsChangeHint aSuperSet) {
michael@0:   return (aSubset & aSuperSet) == aSubset;
michael@0: }
michael@0: 
michael@0: /**
michael@0:  * We have an optimization when processing change hints which prevents
michael@0:  * us from visiting the descendants of a node when a hint on that node
michael@0:  * is being processed.  This optimization does not apply in some of the
michael@0:  * cases where applying a hint to an element does not necessarily result
michael@0:  * in the same hint being handled on the descendants.
michael@0:  */
michael@0: 
michael@0: // The most hints that NS_HintsNotHandledForDescendantsIn could possibly return:
michael@0: #define nsChangeHint_Hints_NotHandledForDescendants nsChangeHint( \
michael@0:           nsChangeHint_UpdateTransformLayer | \
michael@0:           nsChangeHint_UpdateEffects | \
michael@0:           nsChangeHint_UpdateOpacityLayer | \
michael@0:           nsChangeHint_UpdateOverflow | \
michael@0:           nsChangeHint_UpdatePostTransformOverflow | \
michael@0:           nsChangeHint_ChildrenOnlyTransform | \
michael@0:           nsChangeHint_RecomputePosition | \
michael@0:           nsChangeHint_AddOrRemoveTransform | \
michael@0:           nsChangeHint_BorderStyleNoneChange | \
michael@0:           nsChangeHint_NeedReflow | \
michael@0:           nsChangeHint_ClearAncestorIntrinsics)
michael@0: 
michael@0: inline nsChangeHint NS_HintsNotHandledForDescendantsIn(nsChangeHint aChangeHint) {
michael@0:   nsChangeHint result = nsChangeHint(aChangeHint & (
michael@0:     nsChangeHint_UpdateTransformLayer |
michael@0:     nsChangeHint_UpdateEffects |
michael@0:     nsChangeHint_UpdateOpacityLayer |
michael@0:     nsChangeHint_UpdateOverflow |
michael@0:     nsChangeHint_UpdatePostTransformOverflow |
michael@0:     nsChangeHint_ChildrenOnlyTransform |
michael@0:     nsChangeHint_RecomputePosition |
michael@0:     nsChangeHint_AddOrRemoveTransform |
michael@0:     nsChangeHint_BorderStyleNoneChange));
michael@0: 
michael@0:   if (!NS_IsHintSubset(nsChangeHint_NeedDirtyReflow, aChangeHint) &&
michael@0:       NS_IsHintSubset(nsChangeHint_NeedReflow, aChangeHint)) {
michael@0:     // If NeedDirtyReflow is *not* set, then NeedReflow is a
michael@0:     // non-inherited hint.
michael@0:     NS_UpdateHint(result, nsChangeHint_NeedReflow);
michael@0:   }
michael@0: 
michael@0:   if (!NS_IsHintSubset(nsChangeHint_ClearDescendantIntrinsics, aChangeHint) &&
michael@0:       NS_IsHintSubset(nsChangeHint_ClearAncestorIntrinsics, aChangeHint)) {
michael@0:     // If ClearDescendantIntrinsics is *not* set, then
michael@0:     // ClearAncestorIntrinsics is a non-inherited hint.
michael@0:     NS_UpdateHint(result, nsChangeHint_ClearAncestorIntrinsics);
michael@0:   }
michael@0: 
michael@0:   NS_ABORT_IF_FALSE(NS_IsHintSubset(result,
michael@0:                                     nsChangeHint_Hints_NotHandledForDescendants),
michael@0:                     "something is inconsistent");
michael@0: 
michael@0:   return result;
michael@0: }
michael@0: 
michael@0: // Redefine the old NS_STYLE_HINT constants in terms of the new hint structure
michael@0: #define NS_STYLE_HINT_NONE \
michael@0:   nsChangeHint(0)
michael@0: #define NS_STYLE_HINT_VISUAL \
michael@0:   nsChangeHint(nsChangeHint_RepaintFrame | nsChangeHint_SyncFrameView)
michael@0: #define nsChangeHint_AllReflowHints                     \
michael@0:   nsChangeHint(nsChangeHint_NeedReflow |                \
michael@0:                nsChangeHint_ClearAncestorIntrinsics |   \
michael@0:                nsChangeHint_ClearDescendantIntrinsics | \
michael@0:                nsChangeHint_NeedDirtyReflow)
michael@0: #define NS_STYLE_HINT_REFLOW \
michael@0:   nsChangeHint(NS_STYLE_HINT_VISUAL | nsChangeHint_AllReflowHints)
michael@0: #define NS_STYLE_HINT_FRAMECHANGE \
michael@0:   nsChangeHint(NS_STYLE_HINT_REFLOW | nsChangeHint_ReconstructFrame)
michael@0: 
michael@0: /**
michael@0:  * |nsRestyleHint| is a bitfield for the result of
michael@0:  * |HasStateDependentStyle| and |HasAttributeDependentStyle|.  When no
michael@0:  * restyling is necessary, use |nsRestyleHint(0)|.
michael@0:  */
michael@0: enum nsRestyleHint {
michael@0:   eRestyle_Self = 0x1,
michael@0:   eRestyle_Subtree = 0x2, /* self and descendants */
michael@0:   eRestyle_LaterSiblings = 0x4 /* implies "and descendants" */
michael@0: };
michael@0: 
michael@0: 
michael@0: #endif /* nsChangeHint_h___ */