1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/layout/base/nsChangeHint.h Wed Dec 31 06:09:35 2014 +0100
1.3 @@ -0,0 +1,249 @@
1.4 +/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
1.5 +/* This Source Code Form is subject to the terms of the Mozilla Public
1.6 + * License, v. 2.0. If a copy of the MPL was not distributed with this
1.7 + * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
1.8 +
1.9 +/* constants for what needs to be recomputed in response to style changes */
1.10 +
1.11 +#ifndef nsChangeHint_h___
1.12 +#define nsChangeHint_h___
1.13 +
1.14 +#include "nsDebug.h"
1.15 +
1.16 +// Defines for various style related constants
1.17 +
1.18 +enum nsChangeHint {
1.19 + // change was visual only (e.g., COLOR=)
1.20 + // Invalidates all descendant frames (including following
1.21 + // placeholders to out-of-flow frames).
1.22 + nsChangeHint_RepaintFrame = 0x01,
1.23 +
1.24 + // For reflow, we want flags to give us arbitrary FrameNeedsReflow behavior.
1.25 + // just do a FrameNeedsReflow.
1.26 + nsChangeHint_NeedReflow = 0x02,
1.27 +
1.28 + // Invalidate intrinsic widths on the frame's ancestors. Must not be set
1.29 + // without setting nsChangeHint_NeedReflow.
1.30 + nsChangeHint_ClearAncestorIntrinsics = 0x04,
1.31 +
1.32 + // Invalidate intrinsic widths on the frame's descendants. Must not be set
1.33 + // without also setting nsChangeHint_ClearAncestorIntrinsics.
1.34 + nsChangeHint_ClearDescendantIntrinsics = 0x08,
1.35 +
1.36 + // Force unconditional reflow of all descendants. Must not be set without
1.37 + // setting nsChangeHint_NeedReflow, but is independent of both the
1.38 + // Clear*Intrinsics flags.
1.39 + nsChangeHint_NeedDirtyReflow = 0x10,
1.40 +
1.41 + // change requires view to be updated, if there is one (e.g., clip:).
1.42 + // Updates all descendants (including following placeholders to out-of-flows).
1.43 + nsChangeHint_SyncFrameView = 0x20,
1.44 +
1.45 + // The currently shown mouse cursor needs to be updated
1.46 + nsChangeHint_UpdateCursor = 0x40,
1.47 +
1.48 + /**
1.49 + * Used when the computed value (a URI) of one or more of an element's
1.50 + * filter/mask/clip/etc CSS properties changes, causing the element's frame
1.51 + * to start/stop referencing (or reference different) SVG resource elements.
1.52 + * (_Not_ used to handle changes to referenced resource elements.) Using this
1.53 + * hint results in nsSVGEffects::UpdateEffects being called on the element's
1.54 + * frame.
1.55 + */
1.56 + nsChangeHint_UpdateEffects = 0x80,
1.57 +
1.58 + /**
1.59 + * Visual change only, but the change can be handled entirely by
1.60 + * updating the layer(s) for the frame.
1.61 + * Updates all descendants (including following placeholders to out-of-flows).
1.62 + */
1.63 + nsChangeHint_UpdateOpacityLayer = 0x100,
1.64 + /**
1.65 + * Updates all descendants. Any placeholder descendants' out-of-flows
1.66 + * are also descendants of the transformed frame, so they're updated.
1.67 + */
1.68 + nsChangeHint_UpdateTransformLayer = 0x200,
1.69 +
1.70 + /**
1.71 + * Change requires frame change (e.g., display:).
1.72 + * This subsumes all the above. Reconstructs all frame descendants,
1.73 + * including following placeholders to out-of-flows.
1.74 + */
1.75 + nsChangeHint_ReconstructFrame = 0x400,
1.76 +
1.77 + /**
1.78 + * The frame's overflow area has changed, either through a change in its
1.79 + * transform or a change in its position. Does not update any descendant
1.80 + * frames.
1.81 + */
1.82 + nsChangeHint_UpdateOverflow = 0x800,
1.83 +
1.84 + /**
1.85 + * The frame's overflow area has changed, through a change in its transform.
1.86 + * Does not update any descendant frames.
1.87 + */
1.88 + nsChangeHint_UpdatePostTransformOverflow = 0x1000,
1.89 +
1.90 + /**
1.91 + * The children-only transform of an SVG frame changed, requiring the
1.92 + * overflow rects of the frame's immediate children to be updated.
1.93 + */
1.94 + nsChangeHint_ChildrenOnlyTransform = 0x2000,
1.95 +
1.96 + /**
1.97 + * The frame's offsets have changed, while its dimensions might have
1.98 + * changed as well. This hint is used for positioned frames if their
1.99 + * offset changes. If we decide that the dimensions are likely to
1.100 + * change, this will trigger a reflow.
1.101 + *
1.102 + * Note that this should probably be used in combination with
1.103 + * nsChangeHint_UpdateOverflow in order to get the overflow areas of
1.104 + * the ancestors updated as well.
1.105 + */
1.106 + nsChangeHint_RecomputePosition = 0x4000,
1.107 +
1.108 + /**
1.109 + * Behaves like ReconstructFrame, but only if the frame has descendants
1.110 + * that are absolutely or fixed position. Use this hint when a style change
1.111 + * has changed whether the frame is a container for fixed-pos or abs-pos
1.112 + * elements, but reframing is otherwise not needed.
1.113 + */
1.114 + nsChangeHint_AddOrRemoveTransform = 0x8000,
1.115 +
1.116 + /**
1.117 + * This change hint has *no* change handling behavior. However, it
1.118 + * exists to be a non-inherited hint, because when the border-style
1.119 + * changes, and it's inherited by a child, that might require a reflow
1.120 + * due to the border-width change on the child.
1.121 + */
1.122 + nsChangeHint_BorderStyleNoneChange = 0x10000,
1.123 +
1.124 + /**
1.125 + * SVG textPath needs to be recomputed because the path has changed.
1.126 + * This means that the glyph positions of the text need to be recomputed.
1.127 + */
1.128 + nsChangeHint_UpdateTextPath = 0x20000
1.129 +
1.130 + // IMPORTANT NOTE: When adding new hints, consider whether you need to
1.131 + // add them to NS_HintsNotHandledForDescendantsIn() below.
1.132 +};
1.133 +
1.134 +// Redefine these operators to return nothing. This will catch any use
1.135 +// of these operators on hints. We should not be using these operators
1.136 +// on nsChangeHints
1.137 +inline void operator<(nsChangeHint s1, nsChangeHint s2) {}
1.138 +inline void operator>(nsChangeHint s1, nsChangeHint s2) {}
1.139 +inline void operator!=(nsChangeHint s1, nsChangeHint s2) {}
1.140 +inline void operator==(nsChangeHint s1, nsChangeHint s2) {}
1.141 +inline void operator<=(nsChangeHint s1, nsChangeHint s2) {}
1.142 +inline void operator>=(nsChangeHint s1, nsChangeHint s2) {}
1.143 +
1.144 +// Operators on nsChangeHints
1.145 +
1.146 +// Merge two hints, taking the union
1.147 +inline nsChangeHint NS_CombineHint(nsChangeHint aH1, nsChangeHint aH2) {
1.148 + return (nsChangeHint)(aH1 | aH2);
1.149 +}
1.150 +
1.151 +// Merge two hints, taking the union
1.152 +inline nsChangeHint NS_SubtractHint(nsChangeHint aH1, nsChangeHint aH2) {
1.153 + return (nsChangeHint)(aH1 & ~aH2);
1.154 +}
1.155 +
1.156 +// Merge the "src" hint into the "dst" hint
1.157 +// Returns true iff the destination changed
1.158 +inline bool NS_UpdateHint(nsChangeHint& aDest, nsChangeHint aSrc) {
1.159 + nsChangeHint r = (nsChangeHint)(aDest | aSrc);
1.160 + bool changed = (int)r != (int)aDest;
1.161 + aDest = r;
1.162 + return changed;
1.163 +}
1.164 +
1.165 +// Returns true iff the second hint contains all the hints of the first hint
1.166 +inline bool NS_IsHintSubset(nsChangeHint aSubset, nsChangeHint aSuperSet) {
1.167 + return (aSubset & aSuperSet) == aSubset;
1.168 +}
1.169 +
1.170 +/**
1.171 + * We have an optimization when processing change hints which prevents
1.172 + * us from visiting the descendants of a node when a hint on that node
1.173 + * is being processed. This optimization does not apply in some of the
1.174 + * cases where applying a hint to an element does not necessarily result
1.175 + * in the same hint being handled on the descendants.
1.176 + */
1.177 +
1.178 +// The most hints that NS_HintsNotHandledForDescendantsIn could possibly return:
1.179 +#define nsChangeHint_Hints_NotHandledForDescendants nsChangeHint( \
1.180 + nsChangeHint_UpdateTransformLayer | \
1.181 + nsChangeHint_UpdateEffects | \
1.182 + nsChangeHint_UpdateOpacityLayer | \
1.183 + nsChangeHint_UpdateOverflow | \
1.184 + nsChangeHint_UpdatePostTransformOverflow | \
1.185 + nsChangeHint_ChildrenOnlyTransform | \
1.186 + nsChangeHint_RecomputePosition | \
1.187 + nsChangeHint_AddOrRemoveTransform | \
1.188 + nsChangeHint_BorderStyleNoneChange | \
1.189 + nsChangeHint_NeedReflow | \
1.190 + nsChangeHint_ClearAncestorIntrinsics)
1.191 +
1.192 +inline nsChangeHint NS_HintsNotHandledForDescendantsIn(nsChangeHint aChangeHint) {
1.193 + nsChangeHint result = nsChangeHint(aChangeHint & (
1.194 + nsChangeHint_UpdateTransformLayer |
1.195 + nsChangeHint_UpdateEffects |
1.196 + nsChangeHint_UpdateOpacityLayer |
1.197 + nsChangeHint_UpdateOverflow |
1.198 + nsChangeHint_UpdatePostTransformOverflow |
1.199 + nsChangeHint_ChildrenOnlyTransform |
1.200 + nsChangeHint_RecomputePosition |
1.201 + nsChangeHint_AddOrRemoveTransform |
1.202 + nsChangeHint_BorderStyleNoneChange));
1.203 +
1.204 + if (!NS_IsHintSubset(nsChangeHint_NeedDirtyReflow, aChangeHint) &&
1.205 + NS_IsHintSubset(nsChangeHint_NeedReflow, aChangeHint)) {
1.206 + // If NeedDirtyReflow is *not* set, then NeedReflow is a
1.207 + // non-inherited hint.
1.208 + NS_UpdateHint(result, nsChangeHint_NeedReflow);
1.209 + }
1.210 +
1.211 + if (!NS_IsHintSubset(nsChangeHint_ClearDescendantIntrinsics, aChangeHint) &&
1.212 + NS_IsHintSubset(nsChangeHint_ClearAncestorIntrinsics, aChangeHint)) {
1.213 + // If ClearDescendantIntrinsics is *not* set, then
1.214 + // ClearAncestorIntrinsics is a non-inherited hint.
1.215 + NS_UpdateHint(result, nsChangeHint_ClearAncestorIntrinsics);
1.216 + }
1.217 +
1.218 + NS_ABORT_IF_FALSE(NS_IsHintSubset(result,
1.219 + nsChangeHint_Hints_NotHandledForDescendants),
1.220 + "something is inconsistent");
1.221 +
1.222 + return result;
1.223 +}
1.224 +
1.225 +// Redefine the old NS_STYLE_HINT constants in terms of the new hint structure
1.226 +#define NS_STYLE_HINT_NONE \
1.227 + nsChangeHint(0)
1.228 +#define NS_STYLE_HINT_VISUAL \
1.229 + nsChangeHint(nsChangeHint_RepaintFrame | nsChangeHint_SyncFrameView)
1.230 +#define nsChangeHint_AllReflowHints \
1.231 + nsChangeHint(nsChangeHint_NeedReflow | \
1.232 + nsChangeHint_ClearAncestorIntrinsics | \
1.233 + nsChangeHint_ClearDescendantIntrinsics | \
1.234 + nsChangeHint_NeedDirtyReflow)
1.235 +#define NS_STYLE_HINT_REFLOW \
1.236 + nsChangeHint(NS_STYLE_HINT_VISUAL | nsChangeHint_AllReflowHints)
1.237 +#define NS_STYLE_HINT_FRAMECHANGE \
1.238 + nsChangeHint(NS_STYLE_HINT_REFLOW | nsChangeHint_ReconstructFrame)
1.239 +
1.240 +/**
1.241 + * |nsRestyleHint| is a bitfield for the result of
1.242 + * |HasStateDependentStyle| and |HasAttributeDependentStyle|. When no
1.243 + * restyling is necessary, use |nsRestyleHint(0)|.
1.244 + */
1.245 +enum nsRestyleHint {
1.246 + eRestyle_Self = 0x1,
1.247 + eRestyle_Subtree = 0x2, /* self and descendants */
1.248 + eRestyle_LaterSiblings = 0x4 /* implies "and descendants" */
1.249 +};
1.250 +
1.251 +
1.252 +#endif /* nsChangeHint_h___ */
