| blob | 045d15e43bce338dc115f0cfb0a2aac9d213276e |
1 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
2 /* vim: set ts=8 sts=2 et sw=2 tw=80: */
3 /* This Source Code Form is subject to the terms of the Mozilla Public
4 * License, v. 2.0. If a copy of the MPL was not distributed with this
5 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
7 /* struct containing the input to nsIFrame::Reflow */
11 #include <algorithm>
45 }
47 /**
48 * Adjusts the margin for a list (ol, ul), if necessary, depending on
49 * font inflation settings. Unfortunately, because bullets from a list are
50 * placed in the margin area, we only have ~40px in which to place the
51 * bullets. When they are inflated, however, this causes problems, since
52 * the text takes up more space than is available in the margin.
53 *
54 * This method will return a small amount (in app units) by which the
55 * margin can be adjusted, so that the space is available for list
56 * bullets to be rendered with font inflation enabled.
57 */
61 }
63 // We only want to adjust the margins if we're dealing with an ordered list.
67 }
72 }
77 }
79 // The HTML spec states that the default padding for ordered lists
80 // begins at 40px, indicating that we have 40px of space to place a
81 // bullet. When performing font inflation calculations, we add space
82 // equivalent to this, but simply inflated at the same amount as the
83 // text, in app units.
87 }
94 }
97 }
109 }
119 }
121 // Initialize a <b>root</b> reflow input with a rendering context to
122 // use for measuring things.
135 }
138 }
142 }
143 // When we encounter a PageContent frame this will be set to true.
145 }
147 // Initialize a reflow input for a child frame's reflow. Some state
148 // is copied from the parent reflow input; the remaining state is
149 // computed.
154 InitFlags aFlags,
156 ComputeSizeFlags aComputeSizeFlags)
180 // If we're setting up for an orthogonal flow, and the parent reflow input
181 // had a constrained ComputedBSize, we can use that as our AvailableISize
182 // in preference to leaving it unconstrained.
186 }
187 }
189 // Note: mFlags was initialized as a copy of aParentReflowInput.mFlags up in
190 // this constructor's init list, so the only flags that we need to explicitly
191 // initialize here are those that may need a value other than our parent's.
203 // aPresContext->IsPaginated() and the named pages pref should have been
204 // checked when constructing the root ReflowInput.
208 }
210 {
214 // PageContent requires paginated reflow.
218 "mFlags.mCanHaveClassABreakpoints should have been "
227 // Never allow breakpoints inside of out-of-flow frames.
230 }
231 // This frame type can have class A breakpoints, inherit this flag
232 // from the parent (this is done for all flags during construction).
233 // This also includes Canvas frames, as each PageContent frame always
234 // has exactly one child which is a Canvas frame.
235 // Do NOT include the subclasses of BlockFrame here, as the ones for
236 // which this could be applicable (ColumnSetWrapper and the MathML
237 // frames) cannot have class A breakpoints.
244 }
245 }
251 }
255 }
256 }
271 return mFrame
274 aSize)
276 }
285 }
287 }
295 }
300 }
302 }
305 // Note that we could make a stronger optimization for IsBResize if
306 // we use it in a ShouldReflowChild test that replaces the current
307 // checks of NS_FRAME_IS_DIRTY | NS_FRAME_HAS_DIRTY_CHILDREN, if it
308 // were tested there along with NS_FRAME_CONTAINS_RELATIVE_BSIZE.
309 // This would need to be combined with a slight change in which
310 // frames NS_FRAME_CONTAINS_RELATIVE_BSIZE is marked on.
315 }
318 ResetResizeFlags aFlags) {
319 // It'd be nice to assert that |frame| is not in reflow, but this fails
320 // because viewport frames reset the computed isize on a copy of their reflow
321 // input when reflowing fixed-pos kids. In that case we actually don't want
322 // to mess with the resize flags, because comparing the frame's rect to the
323 // munged computed isize is pointless.
329 }
330 }
331 }
334 ResetResizeFlags aFlags) {
335 // It'd be nice to assert that |frame| is not in reflow, but this fails
336 // for the same reason as above.
342 }
343 }
344 }
351 // Look up the parent chain for an orthogonal inline limit,
352 // and reset AvailableISize() if found.
359 }
360 }
361 }
364 "have unconstrained inline-size; this should only "
365 "result from very large sizes, not attempts at "
377 // Placeholders have a no-op Reflow method that doesn't need the rest of
378 // this initialization, so we bail out early.
381 }
396 // An SVG foreignObject frame is inherently constrained block-size.
403 // Don't set NS_FRAME_IN_CONSTRAINED_BSIZE on body or html elements.
406 // If our block-size was specified as a percentage, then this could
407 // actually resolve to 'auto', based on:
408 // http://www.w3.org/TR/CSS21/visudet.html#the-height-property
421 // If we've reached the top of the tree, then we don't have
422 // a constrained block-size.
425 }
431 }
432 }
435 }
436 }
440 // Orthogonal frames are always reflowed with an unconstrained
441 // dimension to avoid incomplete reflow across an orthogonal
442 // boundary. Normally this is the block-size, but for column sets
443 // with auto-height it's the inline-size, so that they can add
444 // columns in the container's block direction
450 }
451 }
454 // In the case that a box is size contained in block axis, we want to ensure
455 // that it is also monolithic. We do this by setting AvailableBSize() to an
456 // unconstrained size to avoid fragmentation.
458 }
464 "have unconstrained inline-size; this should only "
465 "result from very large sizes, not attempts at "
467 }
472 // Keep this in sync with nsIFrame::GetContainingBlock.
476 }
478 }
484 }
488 }
490 // To avoid a long walk up the frame tree check if the parent frame can be a
491 // containing block for mFrame.
493 mStyleDisplay) &&
496 // Inner table frames need to use the containing block of the outer
497 // table frame.
502 }
505 }
506 }
508 /* Check whether CalcQuirkContainingBlockHeight would stop on the
509 * given reflow input, using its block as a height. (essentially
510 * returns false for any case in which CalcQuirkContainingBlockHeight
511 * has a "continue" in its main loop.)
512 *
513 * XXX Maybe refactor CalcQuirkContainingBlockHeight so it uses
514 * this function as well
515 */
517 LayoutFrameType aFrameType) {
520 // Note: This next condition could change due to a style change,
521 // but that would cause a style reflow anyway, which means we're ok.
525 }
526 }
527 }
529 }
532 LayoutFrameType aFrameType) {
538 // We should report that we have a resize in the inline dimension if
539 // *either* the border-box size or the content-box size in that
540 // dimension has changed. It might not actually be necessary to do
541 // this if the border-box size has changed and the content-box size
542 // has not changed, but since we've historically used the flag to mean
543 // border-box size change, continue to do that. It's possible for
544 // the content-box size to change without a border-box size change or
545 // a style change given (1) a fixed width (possibly fixed by max-width
546 // or min-width), box-sizing:border-box, and percentage padding;
547 // (2) box-sizing:content-box, M% width, and calc(Npx - M%) padding.
548 //
549 // However, we don't actually have the information at this point to tell
550 // whether the content-box size has changed, since both style data and the
551 // UsedPaddingProperty() have already been updated in
552 // SizeComputationInput::InitOffsets(). So, we check the HasPaddingChange()
553 // bit for the cases where it's possible for the content-box size to have
554 // changed without either (a) a change in the border-box size or (b) an
555 // nsChangeHint_NeedDirtyReflow change hint due to change in border or
556 // padding.
557 //
558 // We don't clear the HasPaddingChange() bit here, since sometimes we
559 // construct reflow input (e.g. in nsBlockFrame::ReflowBlockFrame to compute
560 // margin collapsing) without reflowing the frame. Instead, we clear it in
561 // nsIFrame::DidReflow().
563 // is the border-box resizing?
566 // or is the content-box resizing? (see comment above)
571 // Create our font inflation data if we don't have it already, and
572 // give it our current width information.
574 // Avoid running this at the box-to-block interface
575 // (where we shouldn't be inflating anyway, and where
576 // reflow input construction is probably to construct a
577 // dummy parent reflow input anyway).
581 // When font size inflation is enabled, a change in either:
582 // * the effective width of a font inflation flow root
583 // * the width of the frame
584 // needs to cause a dirty reflow since they change the font size
585 // inflation calculations, which in turn change the size of text,
586 // line-heights, etc. This is relatively similar to a classic
587 // case of style change reflow, except that because inflation
588 // doesn't affect the intrinsic sizing codepath, there's no need
589 // to invalidate intrinsic sizes.
590 //
591 // Note that this makes horizontal resizing a good bit more
592 // expensive. However, font size inflation is targeted at a set of
593 // devices (zoom-and-pan devices) where the main use case for
594 // horizontal resizing needing to be efficient (window resizing) is
595 // not present. It does still increase the cost of dynamic changes
596 // caused by script where a style or content change in one place
597 // causes a resize in another (e.g., rebalancing a table).
599 // FIXME: This isn't so great for the cases where
600 // ReflowInput::SetComputedWidth is called, if the first time
601 // we go through InitResizeFlags we set IsHResize() to true, and then
602 // the second time we'd set it to false even without the
603 // NS_FRAME_IS_DIRTY bit already set.
605 // Foreign object frames use dirty bits in a special way.
610 }
613 }
615 // Mark intrinsic widths on all descendants dirty. We need to do
616 // this (1) since we're changing the size of text and need to
617 // clear text runs on text frames and (2) since we actually are
618 // changing some intrinsic widths, but only those that live inside
619 // of containers.
621 // It makes sense to do this for descendants but not ancestors
622 // (which is unusual) because we're only changing the unusual
623 // inflation-dependent intrinsic widths (i.e., ones computed with
624 // nsPresContext::mInflationDisabledForShrinkWrap set to false),
625 // which should never affect anything outside of their inflation
626 // flow root (or, for that matter, even their inflation
627 // container).
629 // This is also different from what PresShell::FrameNeedsReflow
630 // does because it doesn't go through placeholders. It doesn't
631 // need to because we're actually doing something that cares about
632 // frame tree geometry (the width on an ancestor) rather than
633 // style.
644 }
645 }
647 }
648 }
652 // XXX Should we really need to null check mCBReflowInput? (We do for
653 // at least nsBoxFrame).
655 // When we have an nsChangeHint_UpdateComputedBSize, we'll set a bit
656 // on the frame to indicate we're resizing. This might catch cases,
657 // such as a change between auto and a length, where the box doesn't
658 // actually resize but children with percentages resize (since those
659 // percentages become auto if their containing block is auto).
662 // We don't clear the HasBSizeChange state here, since sometimes we
663 // construct a ReflowInput (e.g. in nsBlockFrame::ReflowBlockFrame to
664 // compute margin collapsing) without reflowing the frame. Instead, we
665 // clear it in nsIFrame::DidReflow.
671 // We have a percentage (or calc-with-percentage) block-size, and the
672 // value it's relative to has changed.
678 NS_TABLE_CELL_HAD_SPECIAL_REFLOW)) &&
680 // Need to set the bit on the cell so that
681 // mCBReflowInput->IsBResize() is set correctly below when
682 // reflowing descendant.
686 // XXX Is this problematic for relatively positioned inlines acting
687 // as containing block for absolutely positioned elements?
688 // Possibly; in that case we should at least be checking
689 // IsSubtreeDirty(), I'd think.
694 // We have an 'auto' block-size.
696 mCBReflowInput) {
697 // FIXME: This should probably also check IsIResize().
701 }
704 // We have a non-'auto' block-size, i.e., a length. Set the BResize
705 // flag to whether the size is actually different.
709 }
712 // FIXME: condition this on not-abspos?
719 // If mFrame is a flex item, and mFrame's block axis is the flex container's
720 // main axis (e.g. in a column-oriented flex container with same
721 // writing-mode), then its block-size depends on its CB size, if its
722 // flex-basis has a percentage.
727 }
730 // line-height depends on block bsize
732 // but only on containing blocks if this frame is not a suitable block
734 }
736 // If we're the descendant of a table cell that performs special bsize
737 // reflows and we could be the child that requires them, always set
738 // the block-axis resize in case this is the first pass before the
739 // special bsize reflow. However, don't do this if it actually is
740 // the special bsize reflow, since in that case it will already be
741 // set correctly above if we need it set.
748 }
750 // Set NS_FRAME_CONTAINS_RELATIVE_BSIZE if it's needed.
752 // It would be nice to check that |ComputedBSize != NS_UNCONSTRAINEDSIZE|
753 // &&ed with the percentage bsize check. However, this doesn't get
754 // along with table special bsize reflows, since a special bsize
755 // reflow (a quirk that makes such percentage height work on children
756 // of table cells) can cause not just a single percentage height to
757 // become fixed, but an entire descendant chain of percentage height
758 // to become fixed.
766 }
770 }
773 // Keep track of whether we've hit the containing block, because
774 // we need to go at least that far.
777 }
779 // XXX What about orthogonal flows? It doesn't make sense to
780 // keep propagating this bit across an orthogonal boundary,
781 // where the meaning of BSize changes. Bug 1175517.
785 // Note: We actually don't need to set the
786 // NS_FRAME_CONTAINS_RELATIVE_BSIZE bit for the cases
787 // where we hit the early break statements in
788 // CalcQuirkContainingBlockHeight. But it doesn't hurt
789 // us to set the bit in these cases.
790 }
792 // If we're reflowing everything, then we'll find out if we need
793 // to re-set this.
795 }
796 }
803 }
804 }
811 }
814 // We consider mFrame with a prev-in-flow being in a fragmented context
815 // because nsColumnSetFrame can reflow its last column with an unconstrained
816 // available block-size.
818 }
820 /* static */
827 // Compute the 'inlineStart' and 'inlineEnd' values. 'inlineStart'
828 // moves the boxes to the end of the line, and 'inlineEnd' moves the
829 // boxes to the start of the line. The computed values are always:
830 // inlineStart=-inlineEnd
836 // If neither 'inlineStart' nor 'inlineEnd' is auto, then we're
837 // over-constrained and we ignore one of them
840 }
844 // If both are 'auto' (their initial values), the computed values are 0
847 // 'inlineEnd' isn't 'auto' so compute its value
851 // Computed value for 'inlineStart' is minus the value of 'inlineEnd'
853 }
858 // 'InlineStart' isn't 'auto' so compute its value
862 // Computed value for 'inlineEnd' is minus the value of 'inlineStart'
864 }
866 // Compute the 'blockStart' and 'blockEnd' values. The 'blockStart'
867 // and 'blockEnd' properties move relatively positioned elements in
868 // the block progression direction. They also must be each other's
869 // negative
875 // Check for percentage based values and a containing block block-size
876 // that depends on the content block-size. Treat them like 'auto'
880 }
883 }
884 }
886 // If neither is 'auto', 'block-end' is ignored
889 }
893 // If both are 'auto' (their initial values), the computed values are 0
896 // 'blockEnd' isn't 'auto' so compute its value
900 // Computed value for 'blockStart' is minus the value of 'blockEnd'
902 }
907 // 'blockStart' isn't 'auto' so compute its value
911 // Computed value for 'blockEnd' is minus the value of 'blockStart'
913 }
915 // Convert the offsets to physical coordinates and store them on the frame
923 }
930 }
932 /* static */
938 "We assume that changing the 'position' property causes "
939 "frame reconstruction. If that ever changes, this code "
940 "should call "
943 }
945 // Store the normal position
951 }
952 // For sticky positioned elements, we'll leave them until the scroll container
953 // reflows and calls StickyScrollContainer::UpdatePositions() to update their
954 // positions.
955 }
957 // static
959 WritingMode aContainingBlockWM,
967 // Note that this case is different from the neither-'auto'
968 // case below, where the spec says to ignore 'left'/'right'.
969 // Ignore the specified value for 'margin-right'.
972 // Both 'margin-left' and 'margin-right' are 'auto', so they get
973 // equal values
977 }
979 // Just 'margin-left' is 'auto'
981 }
984 // Just 'margin-right' is 'auto'
987 // We're over-constrained so use the direction of the containing
988 // block to dictate which value to ignore. (And note that the
989 // spec says to ignore 'left' or 'right' rather than
990 // 'margin-left' or 'margin-right'.)
991 // Note that this case is different from the both-'auto' case
992 // above, where the spec says to ignore
993 // 'margin-left'/'margin-right'.
994 // Ignore the specified value for 'right'.
996 }
997 }
998 }
1000 // static
1002 WritingMode aContainingBlockWM,
1009 // Both 'margin-top' and 'margin-bottom' are 'auto', so they get
1010 // equal values
1015 // Just margin-block-start is 'auto'
1017 }
1020 // Just margin-block-end is 'auto'
1023 // We're over-constrained so ignore the specified value for
1024 // block-end. (And note that the spec says to ignore 'bottom'
1025 // rather than 'margin-bottom'.)
1027 }
1028 }
1029 }
1035 // Subtract the size of the frame from the container size that we
1036 // use for converting between the logical and physical origins of
1037 // the frame. This accounts for the fact that logical origins in RTL
1038 // coordinate systems are at the top right of the frame instead of
1039 // the top left.
1041 nsPoint pos =
1047 }
1055 /* Now aFrame is the containing block we want */
1057 /* Check whether the containing block is currently being reflowed.
1058 If so, use the info from the reflow input. */
1064 /* do nothing */
1065 }
1068 }
1076 /* Didn't find a reflow reflowInput for aFrame. Just compute the
1077 information we want, on the assumption that aFrame already knows its
1078 size. This really ought to be true by now. */
1082 // Compute CB's offset & content-box size by subtracting borderpadding from
1083 // frame size.
1087 }
1090 }
1093 // offset from inline-start edge of containing block (which is a padding edge)
1095 // offset from block-start edge of containing block (which is a padding edge)
1097 WritingMode mWritingMode;
1098 };
1100 /**
1101 * aInsideBoxSizing returns the part of the padding, border, and margin
1102 * in the aAxis dimension that goes inside the edge given by box-sizing;
1103 * aOutsideBoxSizing returns the rest.
1104 */
1115 nscoord borderStartEnd =
1120 // See if the style system can provide us the padding directly
1125 // We have to compute the start and end values
1131 }
1133 // See if the style system can provide us the margin directly
1137 // If the margin is 'auto', ComputeCBDependentValue() will return 0. The
1138 // correct margin value will be computed later in InitAbsoluteConstraints
1139 // (which is caller of this function, via CalculateHypotheticalPosition).
1145 }
1151 }
1155 }
1157 /**
1158 * Returns true iff a pre-order traversal of the normal child
1159 * frames rooted at aFrame finds no non-empty frame before aDescendant.
1160 */
1167 }
1176 }
1181 }
1182 }
1183 }
1186 }
1189 WritingMode aOtherWm) {
1191 // Dedicated short circuit for the common case.
1193 }
1200 Side thisStartSide =
1202 Side otherStartSide =
1205 }
1209 }
1213 }
1215 // In the code below, |aCBReflowInput->mFrame| is the absolute containing block,
1216 // while |containingBlock| is the nearest block container of the placeholder
1217 // frame, which may be different from the absolute containing block.
1224 // Find the nearest containing block frame to the placeholder frame,
1225 // and its inline-start edge and width.
1226 nscoord blockIStartContentEdge;
1227 // Dummy writing mode for blockContentSize, will be changed as needed by
1228 // GetHypotheticalBoxContainer.
1233 // Now blockContentSize is in containingBlock's writing mode.
1235 // If it's a replaced element and it has a 'auto' value for
1236 //'inline size', see if we can get the intrinsic size. This will allow
1237 // us to exactly determine both the inline edges
1244 // See if we can get the intrinsic size of the element
1246 }
1248 // See if we can calculate what the box inline size would have been if
1249 // the element had been in the flow
1252 // For non-replaced inline-level elements the 'inline size' property
1253 // doesn't apply, so we don't know what the inline size would have
1254 // been without reflowing it
1256 // It's either a replaced inline-level element or a block-level element
1258 // Determine the total amount of inline direction
1259 // border/padding/margin that the element would have had if it had
1260 // been in the flow. Note that we ignore any 'auto' and 'inherit'
1261 // values
1268 // It's a replaced element with an 'auto' inline size so the box inline
1269 // size is its intrinsic size plus any border/padding/margin
1272 contentEdgeToBoxSizingISize +
1273 boxSizingToMarginEdgeISize);
1274 }
1276 // The box inline size is the containing block inline size
1279 // We need to compute it. It's important we do this, because if it's
1280 // percentage based this computed value may be different from the computed
1281 // value calculated using the absolute containing block width
1288 mFrame
1291 contentEdgeToBoxSizingBSize),
1295 boxSizingToMarginEdgeISize);
1296 }
1297 }
1299 // Get the placeholder x-offset and y-offset in the coordinate
1300 // space of its containing block
1301 // XXXbz the placeholder is not fully reflowed yet if our containing block is
1302 // relatively positioned...
1303 nsSize containerSize =
1309 containerSize);
1311 // First, determine the hypothetical box's mBStart. We want to check the
1312 // content insertion frame of containingBlock for block-ness, but make
1313 // sure to compute all coordinates in the coordinate system of
1314 // containingBlock.
1318 // Use a null containerSize to convert a LogicalPoint functioning as a
1319 // vector into a physical nsPoint vector.
1323 nullContainerSize);
1327 // Give up. We're probably dealing with somebody using
1328 // position:absolute inside native-anonymous content anyway.
1335 // How we determine the hypothetical box depends on whether the element
1336 // would have been inline-level or block-level
1340 // Use the block-start of the inline box which the placeholder lives in
1341 // as the hypothetical box's block-start.
1344 // The element would have been block-level which means it would
1345 // be below the line containing the placeholder frame, unless
1346 // all the frames before it are empty. In that case, it would
1347 // have been just before this line.
1348 // XXXbz the line box is not fully reflowed yet if our
1349 // containing block is relatively positioned...
1362 }
1363 }
1364 }
1372 }
1374 }
1376 }
1380 // The top of the hypothetical box is the top of the line
1381 // containing the placeholder, since there is nothing in the
1382 // line before our placeholder except empty frames.
1386 // The top of the hypothetical box is just below the line
1387 // containing the placeholder.
1389 }
1391 // Just use the placeholder's block-offset wrt the containing block
1393 }
1394 }
1395 }
1397 // The containing block is not a block, so it's probably something
1398 // like a XUL box, etc.
1399 // Just use the placeholder's block-offset
1401 }
1403 // Second, determine the hypothetical box's mIStart.
1404 // How we determine the hypothetical box depends on whether the element
1405 // would have been inline-level or block-level
1408 // The placeholder represents the IStart edge of the hypothetical box.
1409 // (Or if mFlags.mIOffsetsNeedCSSAlign is set, it represents the IStart
1410 // edge of the Alignment Container.)
1414 }
1416 // The current coordinate space is that of the nearest block to the
1417 // placeholder. Convert to the coordinate space of the absolute containing
1418 // block.
1422 // When the containing block is the ViewportFrame, i.e. we are calculating
1423 // the static position for a fixed-positioned frame, we need to adjust the
1424 // origin to exclude the scrollbar or scrollbar-gutter area. The
1425 // ViewportFrame's containing block rect is passed into
1426 // nsAbsoluteContainingBlock::ReflowAbsoluteFrame(), and it will add the
1427 // rect's origin to the fixed-positioned frame's final position if needed.
1428 //
1429 // Note: The origin of the containing block rect is adjusted in
1430 // ViewportFrame::AdjustReflowInputForScrollbars(). Ensure the code there
1431 // remains in sync with the logic here.
1436 }
1437 }
1444 // If block direction doesn't match (whether orthogonal or antiparallel),
1445 // we'll have to convert aHypotheticalPos to be in terms of cbwm.
1446 // This upcoming conversion must be taken into account for border offsets.
1449 // The specified offsets are relative to the absolute containing block's
1450 // padding edge and our current values are relative to the border edge, so
1451 // translate.
1457 }
1463 }
1464 // At this point, we have computed aHypotheticalPos using the writing mode
1465 // of the placeholder's containing block.
1468 // If the block direction we used in calculating aHypotheticalPos does not
1469 // match the absolute containing block's, we need to convert here so that
1470 // aHypotheticalPos is usable in relation to the absolute containing block.
1471 // This requires computing or measuring the abspos frame's block-size,
1472 // which is not otherwise required/used here (as aHypotheticalPos
1473 // records only the block-start coordinate).
1475 // This is similar to the inline-size calculation for a replaced
1476 // inline-level element or a block-level element (above), except that
1477 // 'auto' sizing is handled differently in the block direction for non-
1478 // replaced elements and replaced elements lacking an intrinsic size.
1480 // Determine the total amount of block direction
1481 // border/padding/margin that the element would have had if it had
1482 // been in the flow. Note that we ignore any 'auto' and 'inherit'
1483 // values.
1488 nscoord boxBSize;
1492 // It's a replaced element with an 'auto' block size so the box
1493 // block size is its intrinsic size plus any border/padding/margin
1497 // XXX Bug 1191801
1498 // Figure out how to get the correct boxBSize here (need to reflow the
1499 // positioned frame?)
1501 }
1503 // We need to compute it. It's important we do this, because if it's
1504 // percentage-based this computed value may be different from the
1505 // computed value calculated using the absolute containing block height.
1510 }
1515 origin =
1523 }
1524 }
1531 "If any of the block-start and block-end are auto, aBlockSize "
1539 }
1541 // We don't have to compute the inline size by aspect-ratio and the resolved
1542 // block size (from insets) for replaced elements.
1545 }
1547 // If inline size is specified, we should have it by mFrame->ComputeSize()
1548 // already.
1551 }
1553 // If both inline insets are non-auto, mFrame->ComputeSize() should get a
1554 // possible inline size by those insets, so we don't rely on aspect-ratio.
1558 }
1560 // Just an error handling. If |aBlockSize| is NS_UNCONSTRAINEDSIZE, there must
1561 // be something wrong, and we don't want to continue the calculation for
1562 // aspect-ratio. So we return false if this happens.
1564 }
1566 // FIXME: Move this into nsIFrame::ComputeSize() if possible, so most of the
1567 // if-checks can be simplier.
1573 // Two cases we don't want to early return:
1574 // 1. If the block size behaves as initial value and we haven't resolved it in
1575 // ComputeSize() yet, we need to apply |aAutoBSize|.
1576 // Also, we check both computed style and |resultSize.BSize(wm)| to avoid
1577 // applying |aAutoBSize| when the resolved block size is saturated at
1578 // nscoord_MAX, and wrongly treated as NS_UNCONSTRAINEDSIZE because of a
1579 // giant specified block-size.
1580 // 2. If the block size needs to be computed via aspect-ratio and
1581 // |aAutoBSize|, we need to apply |aAutoBSize|. In this case,
1582 // |resultSize.BSize(wm)| may not be NS_UNCONSTRAINEDSIZE because we apply
1583 // aspect-ratio in ComputeSize() for block axis by default, so we have to
1584 // check its computed style.
1590 bSizeBehavesAsInitial &&
1594 }
1596 // For non-replaced elements with block-size auto, the block-size
1597 // fills the remaining space, and we clamp it by min/max size constraints.
1602 }
1604 // Calculate transferred inline size through aspect-ratio.
1605 // For non-replaced elements, we always take box-sizing into account.
1616 "This flag should have been set because nsIFrame::ComputeSize() "
1617 "returns AspectRatioUsage::ToComputeBSize unconditionally for "
1622 }
1642 // If both 'inline-start' and 'inline-end' are 'auto' or both 'block-start'
1643 // and 'block-end' are 'auto', then compute the hypothetical box position
1644 // where the element would have if it were in the flow.
1645 nsHypotheticalPosition hypotheticalPos;
1653 PLACEHOLDER_STATICPOS_NEEDS_CSSALIGN)) {
1656 // If the (as-yet unknown) static position will determine the inline
1657 // and/or block offsets, set flags to note those offsets aren't valid
1658 // until we can do CSS Box Alignment on the OOF frame.
1661 }
1669 NS_STATE_GRID_IS_ROW_MASONRY)) {
1670 // Disable CSS alignment in Masonry layout since we don't have real grid
1671 // areas in that axis. We'll use the placeholder position instead as it
1672 // was calculated by nsGridContainerFrame::MasonryLayout.
1681 }
1682 }
1684 // XXXmats all this is broken for orthogonal writing-modes: bug 1521988.
1686 hypotheticalPos);
1688 // 'hypotheticalPos' is relative to the padding rect of the CB *frame*.
1689 // In grid layout the CB is the grid area rectangle, so we translate
1690 // 'hypotheticalPos' to be relative that rectangle here.
1700 }
1704 }
1705 }
1706 }
1708 // Size of the containing block in its writing mode
1717 }
1723 }
1732 }
1733 }
1740 }
1746 }
1749 // Treat 'top' like 'static-position'
1752 }
1759 }
1763 }
1764 }
1768 {
1782 }
1790 // XXX Now that we have ComputeSize, can we condense many of the
1791 // branches off of widthIsAuto?
1802 // We know 'right' is not 'auto' anymore thanks to the hypothetical
1803 // box code above.
1804 // Solve for 'left'.
1806 // XXXldb This, and the corresponding code in
1807 // nsAbsoluteContainingBlock.cpp, could probably go away now that
1808 // we always compute widths.
1814 }
1816 // We know 'left' is not 'auto' anymore thanks to the hypothetical
1817 // box code above.
1818 // Solve for 'right'.
1820 // XXXldb This, and the corresponding code in
1821 // nsAbsoluteContainingBlock.cpp, could probably go away now that
1822 // we always compute widths.
1828 }
1831 // Neither 'inline-start' nor 'inline-end' is 'auto'.
1833 // For orthogonal blocks, we need to handle the case where the block had
1834 // unconstrained block-size, which mapped to unconstrained inline-size
1835 // in the containing block's writing mode.
1840 // FIXME: Bug 1602669: if |autoISize| happens to be numerically equal to
1841 // NS_UNCONSTRAINEDSIZE, we may get some unexpected behavior. We need a
1842 // better way to distinguish between unconstrained size and resolved
1843 // size.
1848 LogicalSize computedSizeInWM =
1852 }
1854 // However, the inline-size might
1855 // still not fill all the available space (even though we didn't
1856 // shrink-wrap) in case:
1857 // * inline-size was specified
1858 // * we're dealing with a replaced element
1859 // * width was constrained by min- or max-inline-size.
1861 nscoord availMarginSpace =
1868 }
1873 // solve for block-start
1880 }
1882 // solve for block-end
1889 }
1892 // Neither block-start nor -end is 'auto'.
1896 // FIXME: Bug 1602669: if |autoBSize| happens to be numerically equal to
1897 // NS_UNCONSTRAINEDSIZE, we may get some unexpected behavior. We need a
1898 // better way to distinguish between unconstrained size and resolved size.
1902 // For orthogonal case, the inline size in |wm| should have been handled by
1903 // ComputeSize(). In other words, we only have to apply |autoBSize| to
1904 // the computed size if this value can represent the block size in |wm|.
1906 // We handle the unconstrained block-size in current block's writing
1907 // mode 'wm'.
1908 LogicalSize computedSizeInWM =
1912 }
1914 // The block-size might still not fill all the available space in case:
1915 // * bsize was specified
1916 // * we're dealing with a replaced element
1917 // * bsize was constrained by min- or max-bsize.
1924 }
1930 // If we have auto margins, update our UsedMarginProperty. The property
1931 // will have already been created by InitOffsets if it is needed.
1933 marginBEndIsAuto) {
1936 "UsedMarginProperty should have been created "
1939 }
1940 }
1942 // This will not be converted to abstract coordinates because it's only
1943 // used in CalcQuirkContainingBlockHeight
1948 // zero auto margins
1958 }
1960 /* Get the height based on the viewport of the containing block specified
1961 * in aReflowInput when the containing block has mComputedHeight ==
1962 * NS_UNCONSTRAINEDSIZE This will walk up the chain of containing blocks looking
1963 * for a computed height until it finds the canvas frame, or it encounters a
1964 * frame that is not a block, area, or scroll frame. This handles compatibility
1965 * with IE (see bug 85016 and bug 219693)
1966 *
1967 * When we encounter scrolledContent block frames, we skip over them,
1968 * since they are guaranteed to not be useful for computing the containing
1969 * block.
1970 *
1971 * See also IsQuirkContainingBlockHeight.
1972 */
1978 // initialize the default to NS_UNCONSTRAINEDSIZE as this is the containings
1979 // block computed height when this function is called. It is possible that we
1980 // don't alter this height especially if we are restricted to one level
1986 // if the ancestor is auto height then skip it and continue up if it
1987 // is the first block frame and possibly the body/html
1993 // If the current frame we're looking at is positioned, we don't want to
1994 // go any further (see bug 221784). The behavior we want here is: 1) If
1995 // not auto-height, use this as the percentage base. 2) If auto-height,
1996 // keep looking, unless the frame is positioned.
2002 }
2003 }
2005 // Always continue on to the height calculation
2008 // only use the page content frame for a height basis if it is the first
2009 // in flow
2013 }
2015 // if the ancestor is the page content frame then the percent base is
2016 // the avail height, otherwise it is the computed height
2019 // if unconstrained - don't sutract borders - would result in huge height
2022 // if we got to the canvas or page content frame, then subtract out
2023 // margin/border/padding for the BODY and HTML elements
2029 #ifdef DEBUG
2030 // make sure the first ancestor is the HTML and the second is the BODY
2036 }
2037 }
2043 }
2044 }
2045 #endif
2047 }
2048 // if we got to the html frame (a block child of the canvas) ...
2051 // ... then subtract out margin/border/padding for the BODY element
2053 }
2055 }
2057 // Make sure not to return a negative height here!
2059 }
2061 // Called by InitConstraints() to compute the containing block rectangle for
2062 // the element. Handles the special logic for absolutely positioned elements
2065 // Unless the element is absolutely positioned, the containing block is
2066 // formed by the content edge of the nearest block-level ancestor
2075 "Why provide a percentage basis when the containing block's "
2078 }
2081 // XXXfr hack for making frames behave properly when in overflow
2082 // container lists, see bug 154892; need to revisit later
2087 // See if the ancestor is block-level or inline-level
2090 // Base our size on the actual size of the frame. In cases when this is
2091 // completely bogus (eg initial reflow), this code shouldn't even be
2092 // called, since the code in nsInlineFrame::Reflow will pass in
2093 // the containing block dimensions to our constructor.
2094 // XXXbz we should be taking the in-flows into account too, but
2095 // that's very hard.
2097 LogicalMargin computedBorder =
2099 computedPadding;
2107 // If the ancestor is block-level, the containing block is formed by the
2108 // padding edge of the ancestor
2110 }
2114 };
2115 // an element in quirks mode gets a containing block based on looking for a
2116 // parent with a non-auto height if the element has a percent height.
2117 // Note: We don't emulate this quirk for percents in calc(), or in vertical
2118 // writing modes, or if the containing block is a flex or grid item.
2129 }
2130 }
2131 }
2134 }
2136 // XXX refactor this code to have methods for each set of properties
2137 // we are computing: width,height,line-height; margin; offsets
2142 LayoutFrameType aFrameType) {
2147 // If this is a reflow root, then set the computed width and
2148 // height equal to the available space
2150 // XXXldb This doesn't mean what it used to!
2153 // Override mComputedMargin since reflow roots start from the
2154 // frame's boundary, which is inside the margin.
2170 NS_UNCONSTRAINEDSIZE);
2172 // Get the containing block's reflow input
2177 // If we weren't given a containing block size, then compute one.
2180 }
2182 // See if the containing block height is based on the size of its
2183 // content
2185 // See if the containing block is a cell frame which needs
2186 // to use the mComputedHeight of the cell instead of what the cell block
2187 // passed in.
2188 // XXX It seems like this could lead to bugs with min-height and friends
2191 }
2192 }
2194 // XXX Might need to also pass the CB height (not width) for page boxes,
2195 // too, if we implement them.
2197 // For calculating positioning offsets, margins, borders and
2198 // padding, we use the writing mode of the containing block
2203 // For calculating the size of this box, we use its own writing mode
2207 // Check for a percentage based block size and a containing block
2208 // block size that depends on the content block size
2211 // this if clause enables %-blockSize on replaced inline frames,
2212 // such as images. See bug 54119. The else clause "blockSizeUnit =
2213 // eStyleUnit_Auto;" used to be called exclusively.
2215 // Get the containing block's reflow input
2217 // in quirks mode, get the cb height using the special quirk method
2225 }
2228 }
2229 }
2230 // in standard mode, use the cb block size. if it's "auto",
2231 // as will be the case by default in BODY, use auto block size
2232 // as per CSS2 spec.
2239 }
2240 }
2242 // default to interpreting the blockSize like 'auto'
2244 }
2245 }
2246 }
2248 // Compute our offsets if the element is relatively positioned. We
2249 // need the correct containing block inline-size and block-size
2250 // here, which is why we need to do it after all the quirks-n-such
2251 // above. (If the element is sticky positioned, we need to wait
2252 // until the scroll container knows its size, so we compute offsets
2253 // from StickyScrollContainer::UpdatePositions.)
2259 // Initialize offsets to 0
2261 }
2263 // Calculate the computed values for min and max properties. Note that
2264 // this MUST come after we've computed our border and padding.
2267 // Calculate the computed inlineSize and blockSize.
2268 // This varies by frame type.
2271 // Internal table elements. The rules vary depending on the type.
2272 // Calculate the computed isize
2278 // 'inlineSize' property doesn't apply to table rows and row groups
2281 }
2283 // calc() with both percentages and lengths act like auto on internal
2284 // table elements
2287 // Internal table elements don't have margins. Only tables and
2288 // cells have border and padding
2295 }
2302 }
2304 // Calculate the computed block size
2307 // 'blockSize' property doesn't apply to table columns and column groups
2309 }
2310 // calc() with both percentages and lengths acts like 'auto' on internal
2311 // table elements
2319 }
2321 // Doesn't apply to internal table elements
2324 NS_UNCONSTRAINEDSIZE);
2327 // XXXfr hack for making frames behave properly when in overflow
2328 // container lists, see bug 154892; need to revisit later
2341 }
2342 }
2344 }();
2348 // An inner table frame is not inline-level, even if it happens to
2349 // have 'display:inline-table'. (That makes its table-wrapper frame be
2350 // inline-level, but not the inner table frame)
2352 }
2355 }
2359 // Internal table values on replaced elements behave as inline
2360 // https://drafts.csswg.org/css-tables-3/#table-structure
2361 //
2362 // ... it is handled instead as though the author had declared
2363 // either 'block' (for 'table' display) or 'inline' (for all
2364 // other values)"
2365 //
2366 // FIXME(emilio): The only test that covers this is
2367 // table-anonymous-objects-211.xht, which fails on other browsers (but
2368 // differently to us, if you just remove this condition).
2370 }
2373 // Floats are treated as inline-level and also shrink-wrap.
2375 }
2377 }();
2382 }
2384 // Shrink-wrap replaced elements when in-flow (out of flows are
2385 // handled above). We exclude replaced elements in grid or flex
2386 // contexts, where we don't want to shrink-wrap unconditionally (so
2387 // that stretching can happen). When grid/flex explicitly want
2388 // shrink-wrapping, they can request it directly using the relevant
2389 // flag.
2391 }
2394 // Shrink-wrap blocks that are orthogonal to their container (unless
2395 // we're in a grid?)
2397 }
2399 }();
2403 }
2406 // For orthogonal flows, where we found a parent orthogonal-limit for
2407 // AvailableISize() in Init(), we'll use the same here as well.
2409 }
2429 }
2432 }
2434 // Exclude flex and grid items.
2436 }
2441 // Exclude outside ::markers.
2443 }
2445 // Exclude -moz-column-content since it cannot have any margin.
2447 }
2449 }();
2453 }
2454 }
2455 }
2457 // Save our containing block dimensions
2459 }
2469 }
2472 }
2473 }
2476 LayoutFrameType aFrameType,
2477 ComputeSizeFlags aFlags,
2483 // Compute margins from the specified margin style information. These
2484 // become the default computed values, and may be adjusted below
2485 // XXX fix to provide 0,0 for the top&bottom margins for
2486 // inline-non-replaced elements
2488 // Note that ComputeMargin() simplistically resolves 'auto' margins to 0.
2489 // In formatting contexts where this isn't correct, some later code will
2490 // need to update the UsedMargin() property with the actual resolved value.
2491 // One example of this is ::CalculateBlockSideMargins().
2498 LayoutDeviceIntMargin widgetPadding;
2511 nsMargin stylePadding;
2512 // If the caller passes a padding that doesn't match our style (like
2513 // nsTextControlFrame might due due to theming), then we also need a
2514 // padding prop.
2519 }
2521 // Add [align|justify]-content:baseline padding contribution.
2524 Prop aProp) {
2529 LogicalSide side;
2535 }
2539 // We have a baseline-adjusted block-axis start padding, so
2540 // we need this to mark lines dirty when mIsBResize is true:
2542 }
2543 }
2544 };
2547 }
2550 }
2561 // Do nothing since the border local variable is initialized all zero.
2566 }
2570 // scrollbars may have had their width or height smashed to zero
2571 // by the associated scrollframe, in which case we must not report
2572 // any padding or border.
2577 }
2578 }
2583 // Note: If a padding change is already detectable without resolving the
2584 // percentage, e.g. a padding is changing from 50px to 50%,
2585 // nsIFrame::DidSetComputedStyle() will cache the old padding in
2586 // UsedPaddingProperty().
2589 // Our padding may have changed, but we can't tell at this point.
2591 }
2592 // Keep mHasPaddingChange bit set until we've done reflow. We'll clear it in
2593 // nsIFrame::DidReflow()
2598 }
2600 // This code enforces section 10.3.3 of the CSS2 spec for this formula:
2601 //
2602 // 'margin-left' + 'border-left-width' + 'padding-left' + 'width' +
2603 // 'padding-right' + 'border-right-width' + 'margin-right'
2604 // = width of containing block
2605 //
2606 // Note: the width unit is not auto when this is called
2611 // Calculations here are done in the containing block's writing mode,
2612 // which is where margins will eventually be applied: we're calculating
2613 // margins that will be used by the container in its inline direction,
2614 // which in the case of an orthogonal contained block will correspond to
2615 // the block direction of this reflow input. So in the orthogonal-flow
2616 // case, "CalculateBlock*Side*Margins" will actually end up adjusting
2617 // the BStart/BEnd margins; those are the "sides" of the block from its
2618 // container's point of view.
2619 WritingMode cbWM =
2625 // For orthogonal flows, where we found a parent orthogonal-limit
2626 // for AvailableISize() in Init(), we don't have meaningful sizes to
2627 // adjust. Act like the sum is already correct (below).
2629 }
2633 "have unconstrained inline-size; this should only "
2634 "result from very large sizes, not attempts at "
2640 computedISizeCBWM;
2642 // The sum is already correct
2644 }
2646 // Determine the start and end margin values. The isize value
2647 // remains constant while we do this.
2649 // Calculate how much space is available for margins
2652 // If the available margin space is negative, then don't follow the
2653 // usual overconstraint rules.
2658 }
2660 // The css2 spec clearly defines how block elements should behave
2661 // in section 10.3.3.
2666 // Neither margin is 'auto' so we're over constrained. Use the
2667 // 'direction' property of the parent to tell which margin to
2668 // ignore
2669 // First check if there is an HTML alignment that we should honor
2671 mParentReflowInput
2683 }
2684 }
2685 // Otherwise apply the CSS rules, and ignore one margin by forcing
2686 // it to 'auto', depending on 'direction'.
2689 }
2690 }
2692 // Logic which is common to blocks and tables
2693 // The computed margins need not be zero because the 'auto' could come from
2694 // overconstraint or from HTML alignment so values need to be accumulated
2698 // Both margins are 'auto' so the computed addition should be equal
2704 }
2707 }
2711 // Update the UsedMargin property if we were tracking it already.
2715 }
2716 }
2717 }
2719 // For "normal" we use the font's normal line height (em height + leading).
2720 // If both internal leading and external leading specified by font itself are
2721 // zeros, we should compensate this by creating extra (external) leading.
2722 // This is necessary because without this compensation, normal line height might
2723 // look too tight.
2732 }
2734 }
2746 }
2748 }
2751 // For factor units the computed value of the line-height property
2752 // is found by multiplying the factor by the font's computed size
2753 // (adjusted for min-size prefs and text zoom).
2756 }
2761 }
2779 }
2780 // If we don't have a pres context, use a 1.2em fallback.
2783 }
2788 }
2798 }
2805 // Setting used line height can change a frame's block-size if mFrame's
2806 // block-size behaves as auto.
2808 }
2809 }
2811 /* static */
2815 nscoord aBlockBSize,
2822 }
2828 nscoord lineHeight =
2837 // For Web-compatibility, single-line text input elements cannot
2838 // have a line-height smaller than 'normal'.
2846 }
2847 }
2848 }
2851 }
2862 }
2865 nscoord aPercentBasis,
2866 LayoutFrameType aFrameType) {
2867 // SVG text frames have no margin.
2870 }
2873 // Table frame's margin is inherited to the table wrapper frame via the
2874 // ::-moz-table-wrapper rule in ua.css, so don't set any margins for it.
2877 }
2879 // If style style can provide us the margin directly, then use it.
2882 nsMargin margin;
2885 // We have to compute the value. Note that this calculation is
2886 // performed according to the writing mode of the containing block
2887 // (http://dev.w3.org/csswg/css-writing-modes-3/#orthogonal-flows)
2890 }
2895 }
2899 }
2901 // ... but font-size-inflation-based margin adjustment uses the
2902 // frame's writing mode
2909 }
2912 }
2915 nscoord aPercentBasis,
2916 LayoutFrameType aFrameType) {
2917 // If style can provide us the padding directly, then use it.
2919 nsMargin padding;
2921 // a table row/col group, row/col doesn't have padding
2922 // XXXldb Neither do border-collapse tables.
2929 // We have to compute the value. This calculation is performed
2930 // according to the writing mode of the containing block
2931 // (http://dev.w3.org/csswg/css-writing-modes-3/#orthogonal-flows)
2932 // clamp negative calc() results to 0
2935 }
2941 }
2946 }
2948 }
2964 // Convert themed widget's physical dimensions to logical coords.
2965 minWidgetSize = {
2968 // GetMinimumWidgetSize() returns border-box; we need content-box.
2970 }
2972 // NOTE: min-width:auto resolves to 0, except on a flex item. (But
2973 // even there, it's supposed to be ignored (i.e. treated as 0) until
2974 // the flex container explicitly resolves & considers it.)
2980 }
2984 }
2987 // Specified value of 'none'
2992 }
2994 // If the computed value of 'min-width' is greater than the value of
2995 // 'max-width', 'max-width' is set to the value of 'min-width'
2998 }
3000 // Check for percentage based values and a containing block height that
3001 // depends on the content height. Treat them like the initial value.
3002 // Likewise, check for calc() with percentages on internal table elements;
3003 // that's treated as the initial value too.
3009 }
3012 }
3014 };
3016 // NOTE: min-height:auto resolves to 0, except on a flex item. (But
3017 // even there, it's supposed to be ignored (i.e. treated as 0) until
3018 // the flex container explicitly resolves & considers it.)
3025 }
3029 }
3032 // Specified value of 'none'
3038 }
3040 // If the computed value of 'min-height' is greater than the value of
3041 // 'max-height', 'max-height' is set to the value of 'min-height'
3044 }
3045 }
3050 }