| blob | 1ada6e5394900d11ce9816b4ae2c36d77adee2bb |
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>
47 }
49 /**
50 * Adjusts the margin for a list (ol, ul), if necessary, depending on
51 * font inflation settings. Unfortunately, because bullets from a list are
52 * placed in the margin area, we only have ~40px in which to place the
53 * bullets. When they are inflated, however, this causes problems, since
54 * the text takes up more space than is available in the margin.
55 *
56 * This method will return a small amount (in app units) by which the
57 * margin can be adjusted, so that the space is available for list
58 * bullets to be rendered with font inflation enabled.
59 */
63 }
65 // We only want to adjust the margins if we're dealing with an ordered list.
69 }
74 }
76 // The HTML spec states that the default padding for ordered lists
77 // begins at 40px, indicating that we have 40px of space to place a
78 // bullet. When performing font inflation calculations, we add space
79 // equivalent to this, but simply inflated at the same amount as the
80 // text, in app units.
86 }
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 }
263 return mFrame
266 aSize)
268 }
279 nscoord outside =
284 }
293 }
295 }
298 // Note that we could make a stronger optimization for IsBResize if
299 // we use it in a ShouldReflowChild test that replaces the current
300 // checks of NS_FRAME_IS_DIRTY | NS_FRAME_HAS_DIRTY_CHILDREN, if it
301 // were tested there along with NS_FRAME_CONTAINS_RELATIVE_BSIZE.
302 // This would need to be combined with a slight change in which
303 // frames NS_FRAME_CONTAINS_RELATIVE_BSIZE is marked on.
308 }
311 ResetResizeFlags aFlags) {
312 // It'd be nice to assert that |frame| is not in reflow, but this fails
313 // because viewport frames reset the computed isize on a copy of their reflow
314 // input when reflowing fixed-pos kids. In that case we actually don't want
315 // to mess with the resize flags, because comparing the frame's rect to the
316 // munged computed isize is pointless.
322 }
323 }
324 }
327 ResetResizeFlags aFlags) {
328 // It'd be nice to assert that |frame| is not in reflow, but this fails
329 // for the same reason as above.
334 }
335 }
342 // Look up the parent chain for an orthogonal inline limit,
343 // and reset AvailableISize() if found.
350 }
351 }
352 }
355 "have unconstrained inline-size; this should only "
356 "result from very large sizes, not attempts at "
368 // Placeholders have a no-op Reflow method that doesn't need the rest of
369 // this initialization, so we bail out early.
372 }
387 // An SVG foreignObject frame is inherently constrained block-size.
394 // Don't set NS_FRAME_IN_CONSTRAINED_BSIZE on body or html elements.
397 // If our block-size was specified as a percentage, then this could
398 // actually resolve to 'auto', based on:
399 // http://www.w3.org/TR/CSS21/visudet.html#the-height-property
412 // If we've reached the top of the tree, then we don't have
413 // a constrained block-size.
416 }
422 }
423 }
426 }
427 }
431 // Orthogonal frames are always reflowed with an unconstrained
432 // dimension to avoid incomplete reflow across an orthogonal
433 // boundary. Normally this is the block-size, but for column sets
434 // with auto-height it's the inline-size, so that they can add
435 // columns in the container's block direction
441 }
442 }
445 // In the case that a box is size contained in block axis, we want to ensure
446 // that it is also monolithic. We do this by setting AvailableBSize() to an
447 // unconstrained size to avoid fragmentation.
449 }
455 "have unconstrained inline-size; this should only "
456 "result from very large sizes, not attempts at "
458 }
463 // Keep this in sync with nsIFrame::GetContainingBlock.
467 }
469 }
475 }
479 }
481 // To avoid a long walk up the frame tree check if the parent frame can be a
482 // containing block for mFrame.
484 mStyleDisplay) &&
487 // Inner table frames need to use the containing block of the outer
488 // table frame.
493 }
496 }
497 }
499 /* Check whether CalcQuirkContainingBlockHeight would stop on the
500 * given reflow input, using its block as a height. (essentially
501 * returns false for any case in which CalcQuirkContainingBlockHeight
502 * has a "continue" in its main loop.)
503 *
504 * XXX Maybe refactor CalcQuirkContainingBlockHeight so it uses
505 * this function as well
506 */
508 LayoutFrameType aFrameType) {
511 // Note: This next condition could change due to a style change,
512 // but that would cause a style reflow anyway, which means we're ok.
516 }
517 }
518 }
520 }
523 LayoutFrameType aFrameType) {
529 // We should report that we have a resize in the inline dimension if
530 // *either* the border-box size or the content-box size in that
531 // dimension has changed. It might not actually be necessary to do
532 // this if the border-box size has changed and the content-box size
533 // has not changed, but since we've historically used the flag to mean
534 // border-box size change, continue to do that. It's possible for
535 // the content-box size to change without a border-box size change or
536 // a style change given (1) a fixed width (possibly fixed by max-width
537 // or min-width), box-sizing:border-box, and percentage padding;
538 // (2) box-sizing:content-box, M% width, and calc(Npx - M%) padding.
539 //
540 // However, we don't actually have the information at this point to tell
541 // whether the content-box size has changed, since both style data and the
542 // UsedPaddingProperty() have already been updated in
543 // SizeComputationInput::InitOffsets(). So, we check the HasPaddingChange()
544 // bit for the cases where it's possible for the content-box size to have
545 // changed without either (a) a change in the border-box size or (b) an
546 // nsChangeHint_NeedDirtyReflow change hint due to change in border or
547 // padding.
548 //
549 // We don't clear the HasPaddingChange() bit here, since sometimes we
550 // construct reflow input (e.g. in nsBlockFrame::ReflowBlockFrame to compute
551 // margin collapsing) without reflowing the frame. Instead, we clear it in
552 // nsIFrame::DidReflow().
554 // is the border-box resizing?
557 // or is the content-box resizing? (see comment above)
562 // Create our font inflation data if we don't have it already, and
563 // give it our current width information.
565 // Avoid running this at the box-to-block interface
566 // (where we shouldn't be inflating anyway, and where
567 // reflow input construction is probably to construct a
568 // dummy parent reflow input anyway).
572 // When font size inflation is enabled, a change in either:
573 // * the effective width of a font inflation flow root
574 // * the width of the frame
575 // needs to cause a dirty reflow since they change the font size
576 // inflation calculations, which in turn change the size of text,
577 // line-heights, etc. This is relatively similar to a classic
578 // case of style change reflow, except that because inflation
579 // doesn't affect the intrinsic sizing codepath, there's no need
580 // to invalidate intrinsic sizes.
581 //
582 // Note that this makes horizontal resizing a good bit more
583 // expensive. However, font size inflation is targeted at a set of
584 // devices (zoom-and-pan devices) where the main use case for
585 // horizontal resizing needing to be efficient (window resizing) is
586 // not present. It does still increase the cost of dynamic changes
587 // caused by script where a style or content change in one place
588 // causes a resize in another (e.g., rebalancing a table).
590 // FIXME: This isn't so great for the cases where
591 // ReflowInput::SetComputedWidth is called, if the first time
592 // we go through InitResizeFlags we set IsHResize() to true, and then
593 // the second time we'd set it to false even without the
594 // NS_FRAME_IS_DIRTY bit already set.
596 // Foreign object frames use dirty bits in a special way.
601 }
604 }
606 // Mark intrinsic widths on all descendants dirty. We need to do
607 // this (1) since we're changing the size of text and need to
608 // clear text runs on text frames and (2) since we actually are
609 // changing some intrinsic widths, but only those that live inside
610 // of containers.
612 // It makes sense to do this for descendants but not ancestors
613 // (which is unusual) because we're only changing the unusual
614 // inflation-dependent intrinsic widths (i.e., ones computed with
615 // nsPresContext::mInflationDisabledForShrinkWrap set to false),
616 // which should never affect anything outside of their inflation
617 // flow root (or, for that matter, even their inflation
618 // container).
620 // This is also different from what PresShell::FrameNeedsReflow
621 // does because it doesn't go through placeholders. It doesn't
622 // need to because we're actually doing something that cares about
623 // frame tree geometry (the width on an ancestor) rather than
624 // style.
635 }
636 }
638 }
639 }
643 // XXX Should we really need to null check mCBReflowInput? (We do for
644 // at least nsBoxFrame).
646 // When we have an nsChangeHint_UpdateComputedBSize, we'll set a bit
647 // on the frame to indicate we're resizing. This might catch cases,
648 // such as a change between auto and a length, where the box doesn't
649 // actually resize but children with percentages resize (since those
650 // percentages become auto if their containing block is auto).
653 // We don't clear the HasBSizeChange state here, since sometimes we
654 // construct a ReflowInput (e.g. in nsBlockFrame::ReflowBlockFrame to
655 // compute margin collapsing) without reflowing the frame. Instead, we
656 // clear it in nsIFrame::DidReflow.
662 // We have a percentage (or calc-with-percentage) block-size, and the
663 // value it's relative to has changed.
669 NS_TABLE_CELL_HAD_SPECIAL_REFLOW)) &&
671 // Need to set the bit on the cell so that
672 // mCBReflowInput->IsBResize() is set correctly below when
673 // reflowing descendant.
677 // XXX Is this problematic for relatively positioned inlines acting
678 // as containing block for absolutely positioned elements?
679 // Possibly; in that case we should at least be checking
680 // IsSubtreeDirty(), I'd think.
685 // We have an 'auto' block-size.
687 mCBReflowInput) {
688 // FIXME: This should probably also check IsIResize().
692 }
695 // We have a non-'auto' block-size, i.e., a length. Set the BResize
696 // flag to whether the size is actually different.
700 }
703 // FIXME: condition this on not-abspos?
710 // If mFrame is a flex item, and mFrame's block axis is the flex container's
711 // main axis (e.g. in a column-oriented flex container with same
712 // writing-mode), then its block-size depends on its CB size, if its
713 // flex-basis has a percentage.
718 }
721 // line-height depends on block bsize
723 // but only on containing blocks if this frame is not a suitable block
725 }
727 // If we're the descendant of a table cell that performs special bsize
728 // reflows and we could be the child that requires them, always set
729 // the block-axis resize in case this is the first pass before the
730 // special bsize reflow. However, don't do this if it actually is
731 // the special bsize reflow, since in that case it will already be
732 // set correctly above if we need it set.
739 }
741 // Set NS_FRAME_CONTAINS_RELATIVE_BSIZE if it's needed.
743 // It would be nice to check that |ComputedBSize != NS_UNCONSTRAINEDSIZE|
744 // &&ed with the percentage bsize check. However, this doesn't get
745 // along with table special bsize reflows, since a special bsize
746 // reflow (a quirk that makes such percentage height work on children
747 // of table cells) can cause not just a single percentage height to
748 // become fixed, but an entire descendant chain of percentage height
749 // to become fixed.
757 }
761 }
764 // Keep track of whether we've hit the containing block, because
765 // we need to go at least that far.
768 }
770 // XXX What about orthogonal flows? It doesn't make sense to
771 // keep propagating this bit across an orthogonal boundary,
772 // where the meaning of BSize changes. Bug 1175517.
776 // Note: We actually don't need to set the
777 // NS_FRAME_CONTAINS_RELATIVE_BSIZE bit for the cases
778 // where we hit the early break statements in
779 // CalcQuirkContainingBlockHeight. But it doesn't hurt
780 // us to set the bit in these cases.
781 }
783 // If we're reflowing everything, then we'll find out if we need
784 // to re-set this.
786 }
787 }
794 }
795 }
802 }
805 // We consider mFrame with a prev-in-flow being in a fragmented context
806 // because nsColumnSetFrame can reflow its last column with an unconstrained
807 // available block-size.
809 }
811 /* static */
818 // Compute the 'inlineStart' and 'inlineEnd' values. 'inlineStart'
819 // moves the boxes to the end of the line, and 'inlineEnd' moves the
820 // boxes to the start of the line. The computed values are always:
821 // inlineStart=-inlineEnd
827 // If neither 'inlineStart' nor 'inlineEnd' is auto, then we're
828 // over-constrained and we ignore one of them
831 }
835 // If both are 'auto' (their initial values), the computed values are 0
838 // 'inlineEnd' isn't 'auto' so compute its value
842 // Computed value for 'inlineStart' is minus the value of 'inlineEnd'
844 }
849 // 'InlineStart' isn't 'auto' so compute its value
853 // Computed value for 'inlineEnd' is minus the value of 'inlineStart'
855 }
857 // Compute the 'blockStart' and 'blockEnd' values. The 'blockStart'
858 // and 'blockEnd' properties move relatively positioned elements in
859 // the block progression direction. They also must be each other's
860 // negative
866 // Check for percentage based values and a containing block block-size
867 // that depends on the content block-size. Treat them like 'auto'
871 }
874 }
875 }
877 // If neither is 'auto', 'block-end' is ignored
880 }
884 // If both are 'auto' (their initial values), the computed values are 0
887 // 'blockEnd' isn't 'auto' so compute its value
891 // Computed value for 'blockStart' is minus the value of 'blockEnd'
893 }
898 // 'blockStart' isn't 'auto' so compute its value
902 // Computed value for 'blockEnd' is minus the value of 'blockStart'
904 }
906 // Convert the offsets to physical coordinates and store them on the frame
914 }
921 }
923 /* static */
929 "We assume that changing the 'position' property causes "
930 "frame reconstruction. If that ever changes, this code "
931 "should call "
934 }
936 // Store the normal position
945 // Sticky positioning for elements with multiple frames needs to be
946 // computed all at once. We can't safely do that here because we might be
947 // partway through (re)positioning the frames, so leave it until the scroll
948 // container reflows and calls StickyScrollContainer::UpdatePositions.
949 // For single-frame sticky positioned elements, though, go ahead and apply
950 // it now to avoid unnecessary overflow updates later.
955 }
956 }
957 }
959 // static
961 WritingMode aContainingBlockWM,
969 // Note that this case is different from the neither-'auto'
970 // case below, where the spec says to ignore 'left'/'right'.
971 // Ignore the specified value for 'margin-right'.
974 // Both 'margin-left' and 'margin-right' are 'auto', so they get
975 // equal values
979 }
981 // Just 'margin-left' is 'auto'
983 }
986 // Just 'margin-right' is 'auto'
989 // We're over-constrained so use the direction of the containing
990 // block to dictate which value to ignore. (And note that the
991 // spec says to ignore 'left' or 'right' rather than
992 // 'margin-left' or 'margin-right'.)
993 // Note that this case is different from the both-'auto' case
994 // above, where the spec says to ignore
995 // 'margin-left'/'margin-right'.
996 // Ignore the specified value for 'right'.
998 }
999 }
1000 }
1002 // static
1004 WritingMode aContainingBlockWM,
1011 // Both 'margin-top' and 'margin-bottom' are 'auto', so they get
1012 // equal values
1017 // Just margin-block-start is 'auto'
1019 }
1022 // Just margin-block-end is 'auto'
1025 // We're over-constrained so ignore the specified value for
1026 // block-end. (And note that the spec says to ignore 'bottom'
1027 // rather than 'margin-bottom'.)
1029 }
1030 }
1031 }
1037 // Subtract the size of the frame from the container size that we
1038 // use for converting between the logical and physical origins of
1039 // the frame. This accounts for the fact that logical origins in RTL
1040 // coordinate systems are at the top right of the frame instead of
1041 // the top left.
1043 nsPoint pos =
1049 }
1057 /* Now aFrame is the containing block we want */
1059 /* Check whether the containing block is currently being reflowed.
1060 If so, use the info from the reflow input. */
1066 /* do nothing */
1067 }
1070 }
1078 /* Didn't find a reflow reflowInput for aFrame. Just compute the
1079 information we want, on the assumption that aFrame already knows its
1080 size. This really ought to be true by now. */
1084 // Compute CB's offset & content-box size by subtracting borderpadding from
1085 // frame size.
1089 }
1092 }
1095 // offset from inline-start edge of containing block (which is a padding edge)
1096 nscoord mIStart;
1097 // offset from block-start edge of containing block (which is a padding edge)
1098 nscoord mBStart;
1099 WritingMode mWritingMode;
1100 };
1102 /**
1103 * aInsideBoxSizing returns the part of the padding, border, and margin
1104 * in the aAxis dimension that goes inside the edge given by box-sizing;
1105 * aOutsideBoxSizing returns the rest.
1106 */
1117 nscoord borderStartEnd =
1122 // See if the style system can provide us the padding directly
1127 // We have to compute the start and end values
1134 }
1136 // See if the style system can provide us the margin directly
1141 // We have to compute the start and end values
1143 // We set this to 0 for now, and fix it up later in
1144 // InitAbsoluteConstraints (which is caller of this function, via
1145 // CalculateHypotheticalPosition).
1150 }
1152 // We set this to 0 for now, and fix it up later in
1153 // InitAbsoluteConstraints (which is caller of this function, via
1154 // CalculateHypotheticalPosition).
1159 }
1161 }
1167 }
1171 }
1173 /**
1174 * Returns true iff a pre-order traversal of the normal child
1175 * frames rooted at aFrame finds no non-empty frame before aDescendant.
1176 */
1183 }
1192 }
1197 }
1198 }
1199 }
1202 }
1205 WritingMode aOtherWm) {
1207 // Dedicated short circuit for the common case.
1209 }
1216 Side thisStartSide =
1218 Side otherStartSide =
1221 }
1225 }
1229 }
1231 // Calculate the position of the hypothetical box that the element would have
1232 // if it were in the flow.
1233 // The values returned are relative to the padding edge of the absolute
1234 // containing block. The writing-mode of the hypothetical box position will
1235 // have the same block direction as the absolute containing block, but may
1236 // differ in inline-bidi direction.
1237 // In the code below, |aCBReflowInput->frame| is the absolute containing block,
1238 // while |containingBlock| is the nearest block container of the placeholder
1239 // frame, which may be different from the absolute containing block.
1247 // Find the nearest containing block frame to the placeholder frame,
1248 // and its inline-start edge and width.
1249 nscoord blockIStartContentEdge;
1250 // Dummy writing mode for blockContentSize, will be changed as needed by
1251 // GetHypotheticalBoxContainer.
1256 // Now blockContentSize is in containingBlock's writing mode.
1258 // If it's a replaced element and it has a 'auto' value for
1259 //'inline size', see if we can get the intrinsic size. This will allow
1260 // us to exactly determine both the inline edges
1267 // See if we can get the intrinsic size of the element
1269 }
1271 // See if we can calculate what the box inline size would have been if
1272 // the element had been in the flow
1275 // For non-replaced inline-level elements the 'inline size' property
1276 // doesn't apply, so we don't know what the inline size would have
1277 // been without reflowing it
1280 // It's either a replaced inline-level element or a block-level element
1282 // Determine the total amount of inline direction
1283 // border/padding/margin that the element would have had if it had
1284 // been in the flow. Note that we ignore any 'auto' and 'inherit'
1285 // values
1291 // It's a replaced element with an 'auto' inline size so the box
1292 // inline size is its intrinsic size plus any border/padding/margin
1296 }
1299 // The box inline size is the containing block inline size
1302 // We need to compute it. It's important we do this, because if it's
1303 // percentage based this computed value may be different from the computed
1304 // value calculated using the absolute containing block width
1314 }
1315 }
1317 // Get the placeholder x-offset and y-offset in the coordinate
1318 // space of its containing block
1319 // XXXbz the placeholder is not fully reflowed yet if our containing block is
1320 // relatively positioned...
1321 nsSize containerSize =
1327 containerSize);
1329 // First, determine the hypothetical box's mBStart. We want to check the
1330 // content insertion frame of containingBlock for block-ness, but make
1331 // sure to compute all coordinates in the coordinate system of
1332 // containingBlock.
1336 // Use a null containerSize to convert a LogicalPoint functioning as a
1337 // vector into a physical nsPoint vector.
1341 nullContainerSize);
1345 // Give up. We're probably dealing with somebody using
1346 // position:absolute inside native-anonymous content anyway.
1353 // How we determine the hypothetical box depends on whether the element
1354 // would have been inline-level or block-level
1358 // Use the block-start of the inline box which the placeholder lives in
1359 // as the hypothetical box's block-start.
1362 // The element would have been block-level which means it would
1363 // be below the line containing the placeholder frame, unless
1364 // all the frames before it are empty. In that case, it would
1365 // have been just before this line.
1366 // XXXbz the line box is not fully reflowed yet if our
1367 // containing block is relatively positioned...
1380 }
1381 }
1382 }
1390 }
1392 }
1394 }
1398 // The top of the hypothetical box is the top of the line
1399 // containing the placeholder, since there is nothing in the
1400 // line before our placeholder except empty frames.
1404 // The top of the hypothetical box is just below the line
1405 // containing the placeholder.
1407 }
1409 // Just use the placeholder's block-offset wrt the containing block
1411 }
1412 }
1413 }
1415 // The containing block is not a block, so it's probably something
1416 // like a XUL box, etc.
1417 // Just use the placeholder's block-offset
1419 }
1421 // Second, determine the hypothetical box's mIStart.
1422 // How we determine the hypothetical box depends on whether the element
1423 // would have been inline-level or block-level
1426 // The placeholder represents the IStart edge of the hypothetical box.
1427 // (Or if mFlags.mIOffsetsNeedCSSAlign is set, it represents the IStart
1428 // edge of the Alignment Container.)
1432 }
1434 // The current coordinate space is that of the nearest block to the
1435 // placeholder. Convert to the coordinate space of the absolute containing
1436 // block.
1437 nsPoint cbOffset =
1445 // If block direction doesn't match (whether orthogonal or antiparallel),
1446 // we'll have to convert aHypotheticalPos to be in terms of cbwm.
1447 // This upcoming conversion must be taken into account for border offsets.
1450 // The specified offsets are relative to the absolute containing block's
1451 // padding edge and our current values are relative to the border edge, so
1452 // translate.
1458 }
1464 }
1465 // At this point, we have computed aHypotheticalPos using the writing mode
1466 // of the placeholder's containing block.
1469 // If the block direction we used in calculating aHypotheticalPos does not
1470 // match the absolute containing block's, we need to convert here so that
1471 // aHypotheticalPos is usable in relation to the absolute containing block.
1472 // This requires computing or measuring the abspos frame's block-size,
1473 // which is not otherwise required/used here (as aHypotheticalPos
1474 // records only the block-start coordinate).
1476 // This is similar to the inline-size calculation for a replaced
1477 // inline-level element or a block-level element (above), except that
1478 // 'auto' sizing is handled differently in the block direction for non-
1479 // replaced elements and replaced elements lacking an intrinsic size.
1481 // Determine the total amount of block direction
1482 // border/padding/margin that the element would have had if it had
1483 // been in the flow. Note that we ignore any 'auto' and 'inherit'
1484 // values.
1489 nscoord boxBSize;
1493 // It's a replaced element with an 'auto' block size so the box
1494 // block size is its intrinsic size plus any border/padding/margin
1498 // XXX Bug 1191801
1499 // Figure out how to get the correct boxBSize here (need to reflow the
1500 // positioned frame?)
1502 }
1504 // We need to compute it. It's important we do this, because if it's
1505 // percentage-based this computed value may be different from the
1506 // computed value calculated using the absolute containing block height.
1511 }
1516 origin =
1524 }
1525 }
1532 "If any of the block-start and block-end are auto, aBlockSize "
1540 }
1542 // We don't have to compute the inline size by aspect-ratio and the resolved
1543 // block size (from insets) for replaced elements.
1546 }
1548 // If inline size is specified, we should have it by mFrame->ComputeSize()
1549 // already.
1552 }
1554 // If both inline insets are non-auto, mFrame->ComputeSize() should get a
1555 // possible inline size by those insets, so we don't rely on aspect-ratio.
1559 }
1561 // Just an error handling. If |aBlockSize| is NS_UNCONSTRAINEDSIZE, there must
1562 // be something wrong, and we don't want to continue the calculation for
1563 // aspect-ratio. So we return false if this happens.
1565 }
1567 // FIXME: Move this into nsIFrame::ComputeSize() if possible, so most of the
1568 // if-checks can be simplier.
1574 // Two cases we don't want to early return:
1575 // 1. If the block size behaves as initial value and we haven't resolved it in
1576 // ComputeSize() yet, we need to apply |aAutoBSize|.
1577 // Also, we check both computed style and |resultSize.BSize(wm)| to avoid
1578 // applying |aAutoBSize| when the resolved block size is saturated at
1579 // nscoord_MAX, and wrongly treated as NS_UNCONSTRAINEDSIZE because of a
1580 // giant specified block-size.
1581 // 2. If the block size needs to be computed via aspect-ratio and
1582 // |aAutoBSize|, we need to apply |aAutoBSize|. In this case,
1583 // |resultSize.BSize(wm)| may not be NS_UNCONSTRAINEDSIZE because we apply
1584 // aspect-ratio in ComputeSize() for block axis by default, so we have to
1585 // check its computed style.
1591 bSizeBehavesAsInitial &&
1595 }
1597 // For non-replaced elements with block-size auto, the block-size
1598 // fills the remaining space, and we clamp it by min/max size constraints.
1603 }
1605 // Calculate transferred inline size through aspect-ratio.
1606 // For non-replaced elements, we always take box-sizing into account.
1617 "This flag should have been set because nsIFrame::ComputeSize() "
1618 "returns AspectRatioUsage::ToComputeBSize unconditionally for "
1623 }
1628 LayoutFrameType aFrameType) {
1645 // If both 'left' and 'right' are 'auto' or both 'top' and 'bottom' are
1646 // 'auto', then compute the hypothetical box position where the element would
1647 // have been if it had been in the flow
1648 nsHypotheticalPosition hypotheticalPos;
1656 PLACEHOLDER_STATICPOS_NEEDS_CSSALIGN)) {
1659 // If the (as-yet unknown) static position will determine the inline
1660 // and/or block offsets, set flags to note those offsets aren't valid
1661 // until we can do CSS Box Alignment on the OOF frame.
1664 }
1672 NS_STATE_GRID_IS_ROW_MASONRY)) {
1673 // Disable CSS alignment in Masonry layout since we don't have real grid
1674 // areas in that axis. We'll use the placeholder position instead as it
1675 // was calculated by nsGridContainerFrame::MasonryLayout.
1684 }
1685 }
1687 // XXXmats all this is broken for orthogonal writing-modes: bug 1521988.
1690 aFrameType);
1692 // 'hypotheticalPos' is relative to the padding rect of the CB *frame*.
1693 // In grid layout the CB is the grid area rectangle, so we translate
1694 // 'hypotheticalPos' to be relative that rectangle here.
1704 }
1708 }
1709 }
1710 }
1712 // Initialize the 'left' and 'right' computed offsets
1713 // XXX Handle new 'static-position' value...
1715 // Size of the containing block in its writing mode
1724 }
1730 }
1739 }
1740 }
1747 }
1753 }
1756 // Treat 'top' like 'static-position'
1759 }
1766 }
1770 }
1771 }
1775 {
1789 }
1797 // XXX Now that we have ComputeSize, can we condense many of the
1798 // branches off of widthIsAuto?
1809 // We know 'right' is not 'auto' anymore thanks to the hypothetical
1810 // box code above.
1811 // Solve for 'left'.
1813 // XXXldb This, and the corresponding code in
1814 // nsAbsoluteContainingBlock.cpp, could probably go away now that
1815 // we always compute widths.
1821 }
1823 // We know 'left' is not 'auto' anymore thanks to the hypothetical
1824 // box code above.
1825 // Solve for 'right'.
1827 // XXXldb This, and the corresponding code in
1828 // nsAbsoluteContainingBlock.cpp, could probably go away now that
1829 // we always compute widths.
1835 }
1838 // Neither 'inline-start' nor 'inline-end' is 'auto'.
1840 // For orthogonal blocks, we need to handle the case where the block had
1841 // unconstrained block-size, which mapped to unconstrained inline-size
1842 // in the containing block's writing mode.
1847 // FIXME: Bug 1602669: if |autoISize| happens to be numerically equal to
1848 // NS_UNCONSTRAINEDSIZE, we may get some unexpected behavior. We need a
1849 // better way to distinguish between unconstrained size and resolved
1850 // size.
1855 LogicalSize computedSizeInWM =
1859 }
1861 // However, the inline-size might
1862 // still not fill all the available space (even though we didn't
1863 // shrink-wrap) in case:
1864 // * inline-size was specified
1865 // * we're dealing with a replaced element
1866 // * width was constrained by min- or max-inline-size.
1868 nscoord availMarginSpace =
1875 }
1880 // solve for block-start
1887 }
1889 // solve for block-end
1896 }
1899 // Neither block-start nor -end is 'auto'.
1903 // FIXME: Bug 1602669: if |autoBSize| happens to be numerically equal to
1904 // NS_UNCONSTRAINEDSIZE, we may get some unexpected behavior. We need a
1905 // better way to distinguish between unconstrained size and resolved size.
1909 // For orthogonal case, the inline size in |wm| should have been handled by
1910 // ComputeSize(). In other words, we only have to apply |autoBSize| to
1911 // the computed size if this value can represent the block size in |wm|.
1913 // We handle the unconstrained block-size in current block's writing
1914 // mode 'wm'.
1915 LogicalSize computedSizeInWM =
1919 }
1921 // The block-size might still not fill all the available space in case:
1922 // * bsize was specified
1923 // * we're dealing with a replaced element
1924 // * bsize was constrained by min- or max-bsize.
1931 }
1937 // If we have auto margins, update our UsedMarginProperty. The property
1938 // will have already been created by InitOffsets if it is needed.
1940 marginBEndIsAuto) {
1943 "UsedMarginProperty should have been created "
1946 }
1947 }
1949 // This will not be converted to abstract coordinates because it's only
1950 // used in CalcQuirkContainingBlockHeight
1955 // zero auto margins
1965 }
1967 /* Get the height based on the viewport of the containing block specified
1968 * in aReflowInput when the containing block has mComputedHeight ==
1969 * NS_UNCONSTRAINEDSIZE This will walk up the chain of containing blocks looking
1970 * for a computed height until it finds the canvas frame, or it encounters a
1971 * frame that is not a block, area, or scroll frame. This handles compatibility
1972 * with IE (see bug 85016 and bug 219693)
1973 *
1974 * When we encounter scrolledContent block frames, we skip over them,
1975 * since they are guaranteed to not be useful for computing the containing
1976 * block.
1977 *
1978 * See also IsQuirkContainingBlockHeight.
1979 */
1985 // initialize the default to NS_UNCONSTRAINEDSIZE as this is the containings
1986 // block computed height when this function is called. It is possible that we
1987 // don't alter this height especially if we are restricted to one level
1993 // if the ancestor is auto height then skip it and continue up if it
1994 // is the first block frame and possibly the body/html
2000 // If the current frame we're looking at is positioned, we don't want to
2001 // go any further (see bug 221784). The behavior we want here is: 1) If
2002 // not auto-height, use this as the percentage base. 2) If auto-height,
2003 // keep looking, unless the frame is positioned.
2009 }
2010 }
2012 // Always continue on to the height calculation
2015 // only use the page content frame for a height basis if it is the first
2016 // in flow
2020 }
2022 // if the ancestor is the page content frame then the percent base is
2023 // the avail height, otherwise it is the computed height
2026 // if unconstrained - don't sutract borders - would result in huge height
2029 // if we got to the canvas or page content frame, then subtract out
2030 // margin/border/padding for the BODY and HTML elements
2036 #ifdef DEBUG
2037 // make sure the first ancestor is the HTML and the second is the BODY
2043 }
2044 }
2050 }
2051 }
2052 #endif
2054 }
2055 // if we got to the html frame (a block child of the canvas) ...
2058 // ... then subtract out margin/border/padding for the BODY element
2060 }
2062 }
2064 // Make sure not to return a negative height here!
2066 }
2068 // Called by InitConstraints() to compute the containing block rectangle for
2069 // the element. Handles the special logic for absolutely positioned elements
2072 // Unless the element is absolutely positioned, the containing block is
2073 // formed by the content edge of the nearest block-level ancestor
2082 "Why provide a percentage basis when the containing block's "
2085 }
2088 // XXXfr hack for making frames behave properly when in overflow
2089 // container lists, see bug 154892; need to revisit later
2094 // See if the ancestor is block-level or inline-level
2097 // Base our size on the actual size of the frame. In cases when this is
2098 // completely bogus (eg initial reflow), this code shouldn't even be
2099 // called, since the code in nsInlineFrame::Reflow will pass in
2100 // the containing block dimensions to our constructor.
2101 // XXXbz we should be taking the in-flows into account too, but
2102 // that's very hard.
2104 LogicalMargin computedBorder =
2106 computedPadding;
2114 // If the ancestor is block-level, the containing block is formed by the
2115 // padding edge of the ancestor
2117 }
2121 };
2122 // an element in quirks mode gets a containing block based on looking for a
2123 // parent with a non-auto height if the element has a percent height.
2124 // Note: We don't emulate this quirk for percents in calc(), or in vertical
2125 // writing modes, or if the containing block is a flex or grid item.
2136 }
2137 }
2138 }
2141 }
2143 // XXX refactor this code to have methods for each set of properties
2144 // we are computing: width,height,line-height; margin; offsets
2149 LayoutFrameType aFrameType) {
2156 // If this is a reflow root, then set the computed width and
2157 // height equal to the available space
2159 // XXXldb This doesn't mean what it used to!
2162 // Override mComputedMargin since reflow roots start from the
2163 // frame's boundary, which is inside the margin.
2179 NS_UNCONSTRAINEDSIZE);
2181 // Get the containing block's reflow input
2186 // If we weren't given a containing block size, then compute one.
2189 }
2191 // See if the containing block height is based on the size of its
2192 // content
2194 // See if the containing block is a cell frame which needs
2195 // to use the mComputedHeight of the cell instead of what the cell block
2196 // passed in.
2197 // XXX It seems like this could lead to bugs with min-height and friends
2200 }
2201 }
2203 // XXX Might need to also pass the CB height (not width) for page boxes,
2204 // too, if we implement them.
2206 // For calculating positioning offsets, margins, borders and
2207 // padding, we use the writing mode of the containing block
2212 // For calculating the size of this box, we use its own writing mode
2216 // Check for a percentage based block size and a containing block
2217 // block size that depends on the content block size
2220 // this if clause enables %-blockSize on replaced inline frames,
2221 // such as images. See bug 54119. The else clause "blockSizeUnit =
2222 // eStyleUnit_Auto;" used to be called exclusively.
2224 // Get the containing block's reflow input
2226 // in quirks mode, get the cb height using the special quirk method
2234 }
2237 }
2238 }
2239 // in standard mode, use the cb block size. if it's "auto",
2240 // as will be the case by default in BODY, use auto block size
2241 // as per CSS2 spec.
2248 }
2249 }
2251 // default to interpreting the blockSize like 'auto'
2253 }
2254 }
2255 }
2257 // Compute our offsets if the element is relatively positioned. We
2258 // need the correct containing block inline-size and block-size
2259 // here, which is why we need to do it after all the quirks-n-such
2260 // above. (If the element is sticky positioned, we need to wait
2261 // until the scroll container knows its size, so we compute offsets
2262 // from StickyScrollContainer::UpdatePositions.)
2268 // Initialize offsets to 0
2270 }
2272 // Calculate the computed values for min and max properties. Note that
2273 // this MUST come after we've computed our border and padding.
2276 // Calculate the computed inlineSize and blockSize.
2277 // This varies by frame type.
2280 // Internal table elements. The rules vary depending on the type.
2281 // Calculate the computed isize
2287 // 'inlineSize' property doesn't apply to table rows and row groups
2290 }
2292 // calc() with both percentages and lengths act like auto on internal
2293 // table elements
2296 // Internal table elements don't have margins. Only tables and
2297 // cells have border and padding
2304 }
2311 }
2313 // Calculate the computed block size
2316 // 'blockSize' property doesn't apply to table columns and column groups
2318 }
2319 // calc() with both percentages and lengths acts like 'auto' on internal
2320 // table elements
2328 }
2330 // Doesn't apply to internal table elements
2333 NS_UNCONSTRAINEDSIZE);
2336 // XXXfr hack for making frames behave properly when in overflow
2337 // container lists, see bug 154892; need to revisit later
2341 aFrameType);
2347 // internal table values on replaced elements behaves as inline
2348 // https://drafts.csswg.org/css-tables-3/#table-structure
2349 // "... it is handled instead as though the author had declared
2350 // either 'block' (for 'table' display) or 'inline' (for all
2351 // other values)"
2355 // The inner table frame always fills its outer wrapper table frame,
2356 // even for 'inline-table'.
2358 // XXX abs.pos. continuations treated like blocks, see comment in
2359 // the else-if condition above.
2365 }
2369 // XXX grid-specific for now; maybe remove this check after we address
2370 // bug 799725
2373 }
2374 }
2376 // Shrink-wrap grid items that will be aligned (rather than stretched)
2377 // in its inline axis.
2387 }
2389 // Shrink-wrap blocks that are orthogonal to their container.
2393 }
2397 }
2398 }
2401 // For orthogonal flows, where we found a parent orthogonal-limit
2402 // for AvailableISize() in Init(), we'll use the same here as well.
2404 }
2424 }
2427 }
2430 }
2432 // Exclude flex and grid items.
2434 }
2439 // Exclude outside ::markers.
2441 }
2443 // Exclude -moz-column-content since it cannot have any margin.
2445 }
2447 }();
2451 }
2452 }
2453 }
2455 // Save our containing block dimensions
2457 }
2467 }
2470 }
2471 }
2474 LayoutFrameType aFrameType,
2475 ComputeSizeFlags aFlags,
2482 // Compute margins from the specified margin style information. These
2483 // become the default computed values, and may be adjusted below
2484 // XXX fix to provide 0,0 for the top&bottom margins for
2485 // inline-non-replaced elements
2487 // Note that ComputeMargin() simplistically resolves 'auto' margins to 0.
2488 // In formatting contexts where this isn't correct, some later code will
2489 // need to update the UsedMargin() property with the actual resolved value.
2490 // One example of this is ::CalculateBlockSideMargins().
2497 LayoutDeviceIntMargin widgetPadding;
2510 nsMargin stylePadding;
2511 // If the caller passes a padding that doesn't match our style (like
2512 // nsTextControlFrame might due due to theming), then we also need a
2513 // padding prop.
2518 }
2520 // Add [align|justify]-content:baseline padding contribution.
2523 Prop aProp) {
2528 LogicalSide side;
2534 }
2538 // We have a baseline-adjusted block-axis start padding, so
2539 // we need this to mark lines dirty when mIsBResize is true:
2541 }
2542 }
2543 };
2546 }
2549 }
2560 // Do nothing since the border local variable is initialized all zero.
2565 }
2569 // scrollbars may have had their width or height smashed to zero
2570 // by the associated scrollframe, in which case we must not report
2571 // any padding or border.
2576 }
2577 }
2582 // Note: If a padding change is already detectable without resolving the
2583 // percentage, e.g. a padding is changing from 50px to 50%,
2584 // nsIFrame::DidSetComputedStyle() will cache the old padding in
2585 // UsedPaddingProperty().
2588 // Our padding may have changed, but we can't tell at this point.
2590 }
2591 // Keep mHasPaddingChange bit set until we've done reflow. We'll clear it in
2592 // nsIFrame::DidReflow()
2597 }
2599 // This code enforces section 10.3.3 of the CSS2 spec for this formula:
2600 //
2601 // 'margin-left' + 'border-left-width' + 'padding-left' + 'width' +
2602 // 'padding-right' + 'border-right-width' + 'margin-right'
2603 // = width of containing block
2604 //
2605 // Note: the width unit is not auto when this is called
2610 // Calculations here are done in the containing block's writing mode,
2611 // which is where margins will eventually be applied: we're calculating
2612 // margins that will be used by the container in its inline direction,
2613 // which in the case of an orthogonal contained block will correspond to
2614 // the block direction of this reflow input. So in the orthogonal-flow
2615 // case, "CalculateBlock*Side*Margins" will actually end up adjusting
2616 // the BStart/BEnd margins; those are the "sides" of the block from its
2617 // container's point of view.
2618 WritingMode cbWM =
2624 // For orthogonal flows, where we found a parent orthogonal-limit
2625 // for AvailableISize() in Init(), we don't have meaningful sizes to
2626 // adjust. Act like the sum is already correct (below).
2628 }
2632 "have unconstrained inline-size; this should only "
2633 "result from very large sizes, not attempts at "
2639 computedISizeCBWM;
2641 // The sum is already correct
2643 }
2645 // Determine the start and end margin values. The isize value
2646 // remains constant while we do this.
2648 // Calculate how much space is available for margins
2651 // If the available margin space is negative, then don't follow the
2652 // usual overconstraint rules.
2657 }
2659 // The css2 spec clearly defines how block elements should behave
2660 // in section 10.3.3.
2665 // Neither margin is 'auto' so we're over constrained. Use the
2666 // 'direction' property of the parent to tell which margin to
2667 // ignore
2668 // First check if there is an HTML alignment that we should honor
2670 mParentReflowInput
2682 }
2683 }
2684 // Otherwise apply the CSS rules, and ignore one margin by forcing
2685 // it to 'auto', depending on 'direction'.
2688 }
2689 }
2691 // Logic which is common to blocks and tables
2692 // The computed margins need not be zero because the 'auto' could come from
2693 // overconstraint or from HTML alignment so values need to be accumulated
2697 // Both margins are 'auto' so the computed addition should be equal
2703 }
2706 }
2710 // Update the UsedMargin property if we were tracking it already.
2714 }
2715 }
2716 }
2718 // For "normal" we use the font's normal line height (em height + leading).
2719 // If both internal leading and external leading specified by font itself are
2720 // zeros, we should compensate this by creating extra (external) leading.
2721 // This is necessary because without this compensation, normal line height might
2722 // look too tight.
2731 }
2733 }
2744 }
2746 }
2749 // For factor units the computed value of the line-height property
2750 // is found by multiplying the factor by the font's computed size
2751 // (adjusted for min-size prefs and text zoom).
2755 }
2760 }
2770 }
2771 // If we don't have a pres context, use a 1.2em fallback.
2774 }
2779 }
2789 }
2796 // Setting used line height can change a frame's block-size if mFrame's
2797 // block-size behaves as auto.
2799 }
2800 }
2802 /* static */
2806 nscoord aBlockBSize,
2813 }
2819 nscoord lineHeight =
2827 // For Web-compatibility, single-line text input elements cannot
2828 // have a line-height smaller than 'normal'.
2835 }
2836 }
2837 }
2840 }
2843 nscoord aPercentBasis,
2844 LayoutFrameType aFrameType) {
2845 // SVG text frames have no margin.
2848 }
2851 // Table frame's margin is inherited to the table wrapper frame via the
2852 // ::-moz-table-wrapper rule in ua.css, so don't set any margins for it.
2855 }
2857 // If style style can provide us the margin directly, then use it.
2860 nsMargin margin;
2863 // We have to compute the value. Note that this calculation is
2864 // performed according to the writing mode of the containing block
2865 // (http://dev.w3.org/csswg/css-writing-modes-3/#orthogonal-flows)
2868 }
2883 }
2885 // ... but font-size-inflation-based margin adjustment uses the
2886 // frame's writing mode
2893 }
2896 }
2899 nscoord aPercentBasis,
2900 LayoutFrameType aFrameType) {
2901 // If style can provide us the padding directly, then use it.
2903 nsMargin padding;
2905 // a table row/col group, row/col doesn't have padding
2906 // XXXldb Neither do border-collapse tables.
2913 // We have to compute the value. This calculation is performed
2914 // according to the writing mode of the containing block
2915 // (http://dev.w3.org/csswg/css-writing-modes-3/#orthogonal-flows)
2916 // clamp negative calc() results to 0
2919 }
2939 }
2941 }
2957 // Convert themed widget's physical dimensions to logical coords.
2958 minWidgetSize = {
2961 // GetMinimumWidgetSize() returns border-box; we need content-box.
2963 }
2965 // NOTE: min-width:auto resolves to 0, except on a flex item. (But
2966 // even there, it's supposed to be ignored (i.e. treated as 0) until
2967 // the flex container explicitly resolves & considers it.)
2973 }
2977 }
2980 // Specified value of 'none'
2985 }
2987 // If the computed value of 'min-width' is greater than the value of
2988 // 'max-width', 'max-width' is set to the value of 'min-width'
2991 }
2993 // Check for percentage based values and a containing block height that
2994 // depends on the content height. Treat them like the initial value.
2995 // Likewise, check for calc() with percentages on internal table elements;
2996 // that's treated as the initial value too.
3002 }
3005 }
3007 };
3009 // NOTE: min-height:auto resolves to 0, except on a flex item. (But
3010 // even there, it's supposed to be ignored (i.e. treated as 0) until
3011 // the flex container explicitly resolves & considers it.)
3018 }
3022 }
3025 // Specified value of 'none'
3031 }
3033 // If the computed value of 'min-height' is greater than the value of
3034 // 'max-height', 'max-height' is set to the value of 'min-height'
3037 }
3038 }
3043 }