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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)
181 // If we're setting up for an orthogonal flow, and the parent reflow input
182 // had a constrained ComputedBSize, we can use that as our AvailableISize
183 // in preference to leaving it unconstrained.
187 }
188 }
190 // Note: mFlags was initialized as a copy of aParentReflowInput.mFlags up in
191 // this constructor's init list, so the only flags that we need to explicitly
192 // initialize here are those that may need a value other than our parent's.
204 // aPresContext->IsPaginated() and the named pages pref should have been
205 // checked when constructing the root ReflowInput.
209 }
211 {
215 // PageContent requires paginated reflow.
219 "mFlags.mCanHaveClassABreakpoints should have been "
228 // Never allow breakpoints inside of out-of-flow frames.
231 }
232 // This frame type can have class A breakpoints, inherit this flag
233 // from the parent (this is done for all flags during construction).
234 // This also includes Canvas frames, as each PageContent frame always
235 // has exactly one child which is a Canvas frame.
236 // Do NOT include the subclasses of BlockFrame here, as the ones for
237 // which this could be applicable (ColumnSetWrapper and the MathML
238 // frames) cannot have class A breakpoints.
245 }
246 }
252 }
256 }
257 }
264 return mFrame
267 aSize)
269 }
280 nscoord outside =
285 }
294 }
296 }
299 // Note that we could make a stronger optimization for IsBResize if
300 // we use it in a ShouldReflowChild test that replaces the current
301 // checks of NS_FRAME_IS_DIRTY | NS_FRAME_HAS_DIRTY_CHILDREN, if it
302 // were tested there along with NS_FRAME_CONTAINS_RELATIVE_BSIZE.
303 // This would need to be combined with a slight change in which
304 // 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 }
388 // An SVG foreignObject frame is inherently constrained block-size.
395 // Don't set NS_FRAME_IN_CONSTRAINED_BSIZE on body or html elements.
398 // If our block-size was specified as a percentage, then this could
399 // actually resolve to 'auto', based on:
400 // http://www.w3.org/TR/CSS21/visudet.html#the-height-property
413 // If we've reached the top of the tree, then we don't have
414 // a constrained block-size.
417 }
423 }
424 }
427 }
428 }
432 // Orthogonal frames are always reflowed with an unconstrained
433 // dimension to avoid incomplete reflow across an orthogonal
434 // boundary. Normally this is the block-size, but for column sets
435 // with auto-height it's the inline-size, so that they can add
436 // columns in the container's block direction
442 }
443 }
446 // In the case that a box is size contained in block axis, we want to ensure
447 // that it is also monolithic. We do this by setting AvailableBSize() to an
448 // unconstrained size to avoid fragmentation.
450 }
456 "have unconstrained inline-size; this should only "
457 "result from very large sizes, not attempts at "
459 }
464 // Keep this in sync with nsIFrame::GetContainingBlock.
468 }
470 }
476 }
480 }
482 // To avoid a long walk up the frame tree check if the parent frame can be a
483 // containing block for mFrame.
485 mStyleDisplay) &&
488 // Inner table frames need to use the containing block of the outer
489 // table frame.
494 }
497 }
498 }
500 /* Check whether CalcQuirkContainingBlockHeight would stop on the
501 * given reflow input, using its block as a height. (essentially
502 * returns false for any case in which CalcQuirkContainingBlockHeight
503 * has a "continue" in its main loop.)
504 *
505 * XXX Maybe refactor CalcQuirkContainingBlockHeight so it uses
506 * this function as well
507 */
509 LayoutFrameType aFrameType) {
512 // Note: This next condition could change due to a style change,
513 // but that would cause a style reflow anyway, which means we're ok.
517 }
518 }
519 }
521 }
524 LayoutFrameType aFrameType) {
530 // We should report that we have a resize in the inline dimension if
531 // *either* the border-box size or the content-box size in that
532 // dimension has changed. It might not actually be necessary to do
533 // this if the border-box size has changed and the content-box size
534 // has not changed, but since we've historically used the flag to mean
535 // border-box size change, continue to do that. It's possible for
536 // the content-box size to change without a border-box size change or
537 // a style change given (1) a fixed width (possibly fixed by max-width
538 // or min-width), box-sizing:border-box, and percentage padding;
539 // (2) box-sizing:content-box, M% width, and calc(Npx - M%) padding.
540 //
541 // However, we don't actually have the information at this point to tell
542 // whether the content-box size has changed, since both style data and the
543 // UsedPaddingProperty() have already been updated in
544 // SizeComputationInput::InitOffsets(). So, we check the HasPaddingChange()
545 // bit for the cases where it's possible for the content-box size to have
546 // changed without either (a) a change in the border-box size or (b) an
547 // nsChangeHint_NeedDirtyReflow change hint due to change in border or
548 // padding.
549 //
550 // We don't clear the HasPaddingChange() bit here, since sometimes we
551 // construct reflow input (e.g. in nsBlockFrame::ReflowBlockFrame to compute
552 // margin collapsing) without reflowing the frame. Instead, we clear it in
553 // nsIFrame::DidReflow().
555 // is the border-box resizing?
558 // or is the content-box resizing? (see comment above)
563 // Create our font inflation data if we don't have it already, and
564 // give it our current width information.
566 // Avoid running this at the box-to-block interface
567 // (where we shouldn't be inflating anyway, and where
568 // reflow input construction is probably to construct a
569 // dummy parent reflow input anyway).
573 // When font size inflation is enabled, a change in either:
574 // * the effective width of a font inflation flow root
575 // * the width of the frame
576 // needs to cause a dirty reflow since they change the font size
577 // inflation calculations, which in turn change the size of text,
578 // line-heights, etc. This is relatively similar to a classic
579 // case of style change reflow, except that because inflation
580 // doesn't affect the intrinsic sizing codepath, there's no need
581 // to invalidate intrinsic sizes.
582 //
583 // Note that this makes horizontal resizing a good bit more
584 // expensive. However, font size inflation is targeted at a set of
585 // devices (zoom-and-pan devices) where the main use case for
586 // horizontal resizing needing to be efficient (window resizing) is
587 // not present. It does still increase the cost of dynamic changes
588 // caused by script where a style or content change in one place
589 // causes a resize in another (e.g., rebalancing a table).
591 // FIXME: This isn't so great for the cases where
592 // ReflowInput::SetComputedWidth is called, if the first time
593 // we go through InitResizeFlags we set IsHResize() to true, and then
594 // the second time we'd set it to false even without the
595 // NS_FRAME_IS_DIRTY bit already set.
597 // Foreign object frames use dirty bits in a special way.
602 }
605 }
607 // Mark intrinsic widths on all descendants dirty. We need to do
608 // this (1) since we're changing the size of text and need to
609 // clear text runs on text frames and (2) since we actually are
610 // changing some intrinsic widths, but only those that live inside
611 // of containers.
613 // It makes sense to do this for descendants but not ancestors
614 // (which is unusual) because we're only changing the unusual
615 // inflation-dependent intrinsic widths (i.e., ones computed with
616 // nsPresContext::mInflationDisabledForShrinkWrap set to false),
617 // which should never affect anything outside of their inflation
618 // flow root (or, for that matter, even their inflation
619 // container).
621 // This is also different from what PresShell::FrameNeedsReflow
622 // does because it doesn't go through placeholders. It doesn't
623 // need to because we're actually doing something that cares about
624 // frame tree geometry (the width on an ancestor) rather than
625 // style.
636 }
637 }
639 }
640 }
644 // XXX Should we really need to null check mCBReflowInput? (We do for
645 // at least nsBoxFrame).
647 // When we have an nsChangeHint_UpdateComputedBSize, we'll set a bit
648 // on the frame to indicate we're resizing. This might catch cases,
649 // such as a change between auto and a length, where the box doesn't
650 // actually resize but children with percentages resize (since those
651 // percentages become auto if their containing block is auto).
654 // We don't clear the HasBSizeChange state here, since sometimes we
655 // construct a ReflowInput (e.g. in nsBlockFrame::ReflowBlockFrame to
656 // compute margin collapsing) without reflowing the frame. Instead, we
657 // clear it in nsIFrame::DidReflow.
663 // We have a percentage (or calc-with-percentage) block-size, and the
664 // value it's relative to has changed.
670 NS_TABLE_CELL_HAD_SPECIAL_REFLOW)) &&
672 // Need to set the bit on the cell so that
673 // mCBReflowInput->IsBResize() is set correctly below when
674 // reflowing descendant.
678 // XXX Is this problematic for relatively positioned inlines acting
679 // as containing block for absolutely positioned elements?
680 // Possibly; in that case we should at least be checking
681 // IsSubtreeDirty(), I'd think.
686 // We have an 'auto' block-size.
688 mCBReflowInput) {
689 // FIXME: This should probably also check IsIResize().
693 }
696 // We have a non-'auto' block-size, i.e., a length. Set the BResize
697 // flag to whether the size is actually different.
701 }
704 // FIXME: condition this on not-abspos?
711 // If mFrame is a flex item, and mFrame's block axis is the flex container's
712 // main axis (e.g. in a column-oriented flex container with same
713 // writing-mode), then its block-size depends on its CB size, if its
714 // flex-basis has a percentage.
719 }
722 // line-height depends on block bsize
724 // but only on containing blocks if this frame is not a suitable block
726 }
728 // If we're the descendant of a table cell that performs special bsize
729 // reflows and we could be the child that requires them, always set
730 // the block-axis resize in case this is the first pass before the
731 // special bsize reflow. However, don't do this if it actually is
732 // the special bsize reflow, since in that case it will already be
733 // set correctly above if we need it set.
740 }
742 // Set NS_FRAME_CONTAINS_RELATIVE_BSIZE if it's needed.
744 // It would be nice to check that |ComputedBSize != NS_UNCONSTRAINEDSIZE|
745 // &&ed with the percentage bsize check. However, this doesn't get
746 // along with table special bsize reflows, since a special bsize
747 // reflow (a quirk that makes such percentage height work on children
748 // of table cells) can cause not just a single percentage height to
749 // become fixed, but an entire descendant chain of percentage height
750 // to become fixed.
758 }
762 }
765 // Keep track of whether we've hit the containing block, because
766 // we need to go at least that far.
769 }
771 // XXX What about orthogonal flows? It doesn't make sense to
772 // keep propagating this bit across an orthogonal boundary,
773 // where the meaning of BSize changes. Bug 1175517.
777 // Note: We actually don't need to set the
778 // NS_FRAME_CONTAINS_RELATIVE_BSIZE bit for the cases
779 // where we hit the early break statements in
780 // CalcQuirkContainingBlockHeight. But it doesn't hurt
781 // us to set the bit in these cases.
782 }
784 // If we're reflowing everything, then we'll find out if we need
785 // to re-set this.
787 }
788 }
795 }
796 }
803 }
806 // We consider mFrame with a prev-in-flow being in a fragmented context
807 // because nsColumnSetFrame can reflow its last column with an unconstrained
808 // available block-size.
810 }
812 /* static */
819 // Compute the 'inlineStart' and 'inlineEnd' values. 'inlineStart'
820 // moves the boxes to the end of the line, and 'inlineEnd' moves the
821 // boxes to the start of the line. The computed values are always:
822 // inlineStart=-inlineEnd
828 // If neither 'inlineStart' nor 'inlineEnd' is auto, then we're
829 // over-constrained and we ignore one of them
832 }
836 // If both are 'auto' (their initial values), the computed values are 0
839 // 'inlineEnd' isn't 'auto' so compute its value
843 // Computed value for 'inlineStart' is minus the value of 'inlineEnd'
845 }
850 // 'InlineStart' isn't 'auto' so compute its value
854 // Computed value for 'inlineEnd' is minus the value of 'inlineStart'
856 }
858 // Compute the 'blockStart' and 'blockEnd' values. The 'blockStart'
859 // and 'blockEnd' properties move relatively positioned elements in
860 // the block progression direction. They also must be each other's
861 // negative
867 // Check for percentage based values and a containing block block-size
868 // that depends on the content block-size. Treat them like 'auto'
872 }
875 }
876 }
878 // If neither is 'auto', 'block-end' is ignored
881 }
885 // If both are 'auto' (their initial values), the computed values are 0
888 // 'blockEnd' isn't 'auto' so compute its value
892 // Computed value for 'blockStart' is minus the value of 'blockEnd'
894 }
899 // 'blockStart' isn't 'auto' so compute its value
903 // Computed value for 'blockEnd' is minus the value of 'blockStart'
905 }
907 // Convert the offsets to physical coordinates and store them on the frame
915 }
922 }
924 /* static */
930 "We assume that changing the 'position' property causes "
931 "frame reconstruction. If that ever changes, this code "
932 "should call "
935 }
937 // Store the normal position
946 // Sticky positioning for elements with multiple frames needs to be
947 // computed all at once. We can't safely do that here because we might be
948 // partway through (re)positioning the frames, so leave it until the scroll
949 // container reflows and calls StickyScrollContainer::UpdatePositions.
950 // For single-frame sticky positioned elements, though, go ahead and apply
951 // it now to avoid unnecessary overflow updates later.
956 }
957 }
958 }
960 // static
962 WritingMode aContainingBlockWM,
970 // Note that this case is different from the neither-'auto'
971 // case below, where the spec says to ignore 'left'/'right'.
972 // Ignore the specified value for 'margin-right'.
975 // Both 'margin-left' and 'margin-right' are 'auto', so they get
976 // equal values
980 }
982 // Just 'margin-left' is 'auto'
984 }
987 // Just 'margin-right' is 'auto'
990 // We're over-constrained so use the direction of the containing
991 // block to dictate which value to ignore. (And note that the
992 // spec says to ignore 'left' or 'right' rather than
993 // 'margin-left' or 'margin-right'.)
994 // Note that this case is different from the both-'auto' case
995 // above, where the spec says to ignore
996 // 'margin-left'/'margin-right'.
997 // Ignore the specified value for 'right'.
999 }
1000 }
1001 }
1003 // static
1005 WritingMode aContainingBlockWM,
1012 // Both 'margin-top' and 'margin-bottom' are 'auto', so they get
1013 // equal values
1018 // Just margin-block-start is 'auto'
1020 }
1023 // Just margin-block-end is 'auto'
1026 // We're over-constrained so ignore the specified value for
1027 // block-end. (And note that the spec says to ignore 'bottom'
1028 // rather than 'margin-bottom'.)
1030 }
1031 }
1032 }
1038 // Subtract the size of the frame from the container size that we
1039 // use for converting between the logical and physical origins of
1040 // the frame. This accounts for the fact that logical origins in RTL
1041 // coordinate systems are at the top right of the frame instead of
1042 // the top left.
1044 nsPoint pos =
1050 }
1058 /* Now aFrame is the containing block we want */
1060 /* Check whether the containing block is currently being reflowed.
1061 If so, use the info from the reflow input. */
1067 /* do nothing */
1068 }
1071 }
1079 /* Didn't find a reflow reflowInput for aFrame. Just compute the
1080 information we want, on the assumption that aFrame already knows its
1081 size. This really ought to be true by now. */
1085 // Compute CB's offset & content-box size by subtracting borderpadding from
1086 // frame size.
1090 }
1093 }
1096 // offset from inline-start edge of containing block (which is a padding edge)
1097 nscoord mIStart;
1098 // offset from block-start edge of containing block (which is a padding edge)
1099 nscoord mBStart;
1100 WritingMode mWritingMode;
1101 };
1103 /**
1104 * aInsideBoxSizing returns the part of the padding, border, and margin
1105 * in the aAxis dimension that goes inside the edge given by box-sizing;
1106 * aOutsideBoxSizing returns the rest.
1107 */
1118 nscoord borderStartEnd =
1123 // See if the style system can provide us the padding directly
1128 // We have to compute the start and end values
1135 }
1137 // See if the style system can provide us the margin directly
1142 // We have to compute the start and end values
1144 // We set this to 0 for now, and fix it up later in
1145 // InitAbsoluteConstraints (which is caller of this function, via
1146 // CalculateHypotheticalPosition).
1151 }
1153 // We set this to 0 for now, and fix it up later in
1154 // InitAbsoluteConstraints (which is caller of this function, via
1155 // CalculateHypotheticalPosition).
1160 }
1162 }
1168 }
1172 }
1174 /**
1175 * Returns true iff a pre-order traversal of the normal child
1176 * frames rooted at aFrame finds no non-empty frame before aDescendant.
1177 */
1184 }
1193 }
1198 }
1199 }
1200 }
1203 }
1206 WritingMode aOtherWm) {
1208 // Dedicated short circuit for the common case.
1210 }
1217 Side thisStartSide =
1219 Side otherStartSide =
1222 }
1226 }
1230 }
1232 // Calculate the position of the hypothetical box that the element would have
1233 // if it were in the flow.
1234 // The values returned are relative to the padding edge of the absolute
1235 // containing block. The writing-mode of the hypothetical box position will
1236 // have the same block direction as the absolute containing block, but may
1237 // differ in inline-bidi direction.
1238 // In the code below, |aCBReflowInput->frame| is the absolute containing block,
1239 // while |containingBlock| is the nearest block container of the placeholder
1240 // frame, which may be different from the absolute containing block.
1248 // Find the nearest containing block frame to the placeholder frame,
1249 // and its inline-start edge and width.
1250 nscoord blockIStartContentEdge;
1251 // Dummy writing mode for blockContentSize, will be changed as needed by
1252 // GetHypotheticalBoxContainer.
1257 // Now blockContentSize is in containingBlock's writing mode.
1259 // If it's a replaced element and it has a 'auto' value for
1260 //'inline size', see if we can get the intrinsic size. This will allow
1261 // us to exactly determine both the inline edges
1268 // See if we can get the intrinsic size of the element
1270 }
1272 // See if we can calculate what the box inline size would have been if
1273 // the element had been in the flow
1276 // For non-replaced inline-level elements the 'inline size' property
1277 // doesn't apply, so we don't know what the inline size would have
1278 // been without reflowing it
1281 // It's either a replaced inline-level element or a block-level element
1283 // Determine the total amount of inline direction
1284 // border/padding/margin that the element would have had if it had
1285 // been in the flow. Note that we ignore any 'auto' and 'inherit'
1286 // values
1292 // It's a replaced element with an 'auto' inline size so the box
1293 // inline size is its intrinsic size plus any border/padding/margin
1297 }
1300 // The box inline size is the containing block inline size
1303 // We need to compute it. It's important we do this, because if it's
1304 // percentage based this computed value may be different from the computed
1305 // value calculated using the absolute containing block width
1315 }
1316 }
1318 // Get the placeholder x-offset and y-offset in the coordinate
1319 // space of its containing block
1320 // XXXbz the placeholder is not fully reflowed yet if our containing block is
1321 // relatively positioned...
1322 nsSize containerSize =
1328 containerSize);
1330 // First, determine the hypothetical box's mBStart. We want to check the
1331 // content insertion frame of containingBlock for block-ness, but make
1332 // sure to compute all coordinates in the coordinate system of
1333 // containingBlock.
1337 // Use a null containerSize to convert a LogicalPoint functioning as a
1338 // vector into a physical nsPoint vector.
1342 nullContainerSize);
1346 // Give up. We're probably dealing with somebody using
1347 // position:absolute inside native-anonymous content anyway.
1354 // How we determine the hypothetical box depends on whether the element
1355 // would have been inline-level or block-level
1359 // Use the block-start of the inline box which the placeholder lives in
1360 // as the hypothetical box's block-start.
1363 // The element would have been block-level which means it would
1364 // be below the line containing the placeholder frame, unless
1365 // all the frames before it are empty. In that case, it would
1366 // have been just before this line.
1367 // XXXbz the line box is not fully reflowed yet if our
1368 // containing block is relatively positioned...
1381 }
1382 }
1383 }
1391 }
1393 }
1395 }
1399 // The top of the hypothetical box is the top of the line
1400 // containing the placeholder, since there is nothing in the
1401 // line before our placeholder except empty frames.
1405 // The top of the hypothetical box is just below the line
1406 // containing the placeholder.
1408 }
1410 // Just use the placeholder's block-offset wrt the containing block
1412 }
1413 }
1414 }
1416 // The containing block is not a block, so it's probably something
1417 // like a XUL box, etc.
1418 // Just use the placeholder's block-offset
1420 }
1422 // Second, determine the hypothetical box's mIStart.
1423 // How we determine the hypothetical box depends on whether the element
1424 // would have been inline-level or block-level
1427 // The placeholder represents the IStart edge of the hypothetical box.
1428 // (Or if mFlags.mIOffsetsNeedCSSAlign is set, it represents the IStart
1429 // edge of the Alignment Container.)
1433 }
1435 // The current coordinate space is that of the nearest block to the
1436 // placeholder. Convert to the coordinate space of the absolute containing
1437 // block.
1438 nsPoint cbOffset =
1446 // If block direction doesn't match (whether orthogonal or antiparallel),
1447 // we'll have to convert aHypotheticalPos to be in terms of cbwm.
1448 // This upcoming conversion must be taken into account for border offsets.
1451 // The specified offsets are relative to the absolute containing block's
1452 // padding edge and our current values are relative to the border edge, so
1453 // translate.
1459 }
1465 }
1466 // At this point, we have computed aHypotheticalPos using the writing mode
1467 // of the placeholder's containing block.
1470 // If the block direction we used in calculating aHypotheticalPos does not
1471 // match the absolute containing block's, we need to convert here so that
1472 // aHypotheticalPos is usable in relation to the absolute containing block.
1473 // This requires computing or measuring the abspos frame's block-size,
1474 // which is not otherwise required/used here (as aHypotheticalPos
1475 // records only the block-start coordinate).
1477 // This is similar to the inline-size calculation for a replaced
1478 // inline-level element or a block-level element (above), except that
1479 // 'auto' sizing is handled differently in the block direction for non-
1480 // replaced elements and replaced elements lacking an intrinsic size.
1482 // Determine the total amount of block direction
1483 // border/padding/margin that the element would have had if it had
1484 // been in the flow. Note that we ignore any 'auto' and 'inherit'
1485 // values.
1490 nscoord boxBSize;
1494 // It's a replaced element with an 'auto' block size so the box
1495 // block size is its intrinsic size plus any border/padding/margin
1499 // XXX Bug 1191801
1500 // Figure out how to get the correct boxBSize here (need to reflow the
1501 // positioned frame?)
1503 }
1505 // We need to compute it. It's important we do this, because if it's
1506 // percentage-based this computed value may be different from the
1507 // computed value calculated using the absolute containing block height.
1512 }
1517 origin =
1525 }
1526 }
1533 "If any of the block-start and block-end are auto, aBlockSize "
1541 }
1543 // We don't have to compute the inline size by aspect-ratio and the resolved
1544 // block size (from insets) for replaced elements.
1547 }
1549 // If inline size is specified, we should have it by mFrame->ComputeSize()
1550 // already.
1553 }
1555 // If both inline insets are non-auto, mFrame->ComputeSize() should get a
1556 // possible inline size by those insets, so we don't rely on aspect-ratio.
1560 }
1562 // Just an error handling. If |aBlockSize| is NS_UNCONSTRAINEDSIZE, there must
1563 // be something wrong, and we don't want to continue the calculation for
1564 // aspect-ratio. So we return false if this happens.
1566 }
1568 // FIXME: Move this into nsIFrame::ComputeSize() if possible, so most of the
1569 // if-checks can be simplier.
1575 // Two cases we don't want to early return:
1576 // 1. If the block size behaves as initial value and we haven't resolved it in
1577 // ComputeSize() yet, we need to apply |aAutoBSize|.
1578 // Also, we check both computed style and |resultSize.BSize(wm)| to avoid
1579 // applying |aAutoBSize| when the resolved block size is saturated at
1580 // nscoord_MAX, and wrongly treated as NS_UNCONSTRAINEDSIZE because of a
1581 // giant specified block-size.
1582 // 2. If the block size needs to be computed via aspect-ratio and
1583 // |aAutoBSize|, we need to apply |aAutoBSize|. In this case,
1584 // |resultSize.BSize(wm)| may not be NS_UNCONSTRAINEDSIZE because we apply
1585 // aspect-ratio in ComputeSize() for block axis by default, so we have to
1586 // check its computed style.
1592 bSizeBehavesAsInitial &&
1596 }
1598 // For non-replaced elements with block-size auto, the block-size
1599 // fills the remaining space, and we clamp it by min/max size constraints.
1604 }
1606 // Calculate transferred inline size through aspect-ratio.
1607 // For non-replaced elements, we always take box-sizing into account.
1618 "This flag should have been set because nsIFrame::ComputeSize() "
1619 "returns AspectRatioUsage::ToComputeBSize unconditionally for "
1624 }
1629 LayoutFrameType aFrameType) {
1646 // If both 'left' and 'right' are 'auto' or both 'top' and 'bottom' are
1647 // 'auto', then compute the hypothetical box position where the element would
1648 // have been if it had been in the flow
1649 nsHypotheticalPosition hypotheticalPos;
1657 PLACEHOLDER_STATICPOS_NEEDS_CSSALIGN)) {
1660 // If the (as-yet unknown) static position will determine the inline
1661 // and/or block offsets, set flags to note those offsets aren't valid
1662 // until we can do CSS Box Alignment on the OOF frame.
1665 }
1673 NS_STATE_GRID_IS_ROW_MASONRY)) {
1674 // Disable CSS alignment in Masonry layout since we don't have real grid
1675 // areas in that axis. We'll use the placeholder position instead as it
1676 // was calculated by nsGridContainerFrame::MasonryLayout.
1685 }
1686 }
1688 // XXXmats all this is broken for orthogonal writing-modes: bug 1521988.
1691 aFrameType);
1693 // 'hypotheticalPos' is relative to the padding rect of the CB *frame*.
1694 // In grid layout the CB is the grid area rectangle, so we translate
1695 // 'hypotheticalPos' to be relative that rectangle here.
1705 }
1709 }
1710 }
1711 }
1713 // Initialize the 'left' and 'right' computed offsets
1714 // XXX Handle new 'static-position' value...
1716 // Size of the containing block in its writing mode
1725 }
1731 }
1740 }
1741 }
1748 }
1754 }
1757 // Treat 'top' like 'static-position'
1760 }
1767 }
1771 }
1772 }
1776 {
1790 }
1798 // XXX Now that we have ComputeSize, can we condense many of the
1799 // branches off of widthIsAuto?
1810 // We know 'right' is not 'auto' anymore thanks to the hypothetical
1811 // box code above.
1812 // Solve for 'left'.
1814 // XXXldb This, and the corresponding code in
1815 // nsAbsoluteContainingBlock.cpp, could probably go away now that
1816 // we always compute widths.
1822 }
1824 // We know 'left' is not 'auto' anymore thanks to the hypothetical
1825 // box code above.
1826 // Solve for 'right'.
1828 // XXXldb This, and the corresponding code in
1829 // nsAbsoluteContainingBlock.cpp, could probably go away now that
1830 // we always compute widths.
1836 }
1839 // Neither 'inline-start' nor 'inline-end' is 'auto'.
1841 // For orthogonal blocks, we need to handle the case where the block had
1842 // unconstrained block-size, which mapped to unconstrained inline-size
1843 // in the containing block's writing mode.
1848 // FIXME: Bug 1602669: if |autoISize| happens to be numerically equal to
1849 // NS_UNCONSTRAINEDSIZE, we may get some unexpected behavior. We need a
1850 // better way to distinguish between unconstrained size and resolved
1851 // size.
1856 LogicalSize computedSizeInWM =
1860 }
1862 // However, the inline-size might
1863 // still not fill all the available space (even though we didn't
1864 // shrink-wrap) in case:
1865 // * inline-size was specified
1866 // * we're dealing with a replaced element
1867 // * width was constrained by min- or max-inline-size.
1869 nscoord availMarginSpace =
1876 }
1881 // solve for block-start
1888 }
1890 // solve for block-end
1897 }
1900 // Neither block-start nor -end is 'auto'.
1904 // FIXME: Bug 1602669: if |autoBSize| happens to be numerically equal to
1905 // NS_UNCONSTRAINEDSIZE, we may get some unexpected behavior. We need a
1906 // better way to distinguish between unconstrained size and resolved size.
1910 // For orthogonal case, the inline size in |wm| should have been handled by
1911 // ComputeSize(). In other words, we only have to apply |autoBSize| to
1912 // the computed size if this value can represent the block size in |wm|.
1914 // We handle the unconstrained block-size in current block's writing
1915 // mode 'wm'.
1916 LogicalSize computedSizeInWM =
1920 }
1922 // The block-size might still not fill all the available space in case:
1923 // * bsize was specified
1924 // * we're dealing with a replaced element
1925 // * bsize was constrained by min- or max-bsize.
1932 }
1938 // If we have auto margins, update our UsedMarginProperty. The property
1939 // will have already been created by InitOffsets if it is needed.
1941 marginBEndIsAuto) {
1944 "UsedMarginProperty should have been created "
1947 }
1948 }
1950 // This will not be converted to abstract coordinates because it's only
1951 // used in CalcQuirkContainingBlockHeight
1956 // zero auto margins
1966 }
1968 /* Get the height based on the viewport of the containing block specified
1969 * in aReflowInput when the containing block has mComputedHeight ==
1970 * NS_UNCONSTRAINEDSIZE This will walk up the chain of containing blocks looking
1971 * for a computed height until it finds the canvas frame, or it encounters a
1972 * frame that is not a block, area, or scroll frame. This handles compatibility
1973 * with IE (see bug 85016 and bug 219693)
1974 *
1975 * When we encounter scrolledContent block frames, we skip over them,
1976 * since they are guaranteed to not be useful for computing the containing
1977 * block.
1978 *
1979 * See also IsQuirkContainingBlockHeight.
1980 */
1986 // initialize the default to NS_UNCONSTRAINEDSIZE as this is the containings
1987 // block computed height when this function is called. It is possible that we
1988 // don't alter this height especially if we are restricted to one level
1994 // if the ancestor is auto height then skip it and continue up if it
1995 // is the first block frame and possibly the body/html
2001 // If the current frame we're looking at is positioned, we don't want to
2002 // go any further (see bug 221784). The behavior we want here is: 1) If
2003 // not auto-height, use this as the percentage base. 2) If auto-height,
2004 // keep looking, unless the frame is positioned.
2010 }
2011 }
2013 // Always continue on to the height calculation
2016 // only use the page content frame for a height basis if it is the first
2017 // in flow
2021 }
2023 // if the ancestor is the page content frame then the percent base is
2024 // the avail height, otherwise it is the computed height
2027 // if unconstrained - don't sutract borders - would result in huge height
2030 // if we got to the canvas or page content frame, then subtract out
2031 // margin/border/padding for the BODY and HTML elements
2037 #ifdef DEBUG
2038 // make sure the first ancestor is the HTML and the second is the BODY
2044 }
2045 }
2051 }
2052 }
2053 #endif
2055 }
2056 // if we got to the html frame (a block child of the canvas) ...
2059 // ... then subtract out margin/border/padding for the BODY element
2061 }
2063 }
2065 // Make sure not to return a negative height here!
2067 }
2069 // Called by InitConstraints() to compute the containing block rectangle for
2070 // the element. Handles the special logic for absolutely positioned elements
2073 // Unless the element is absolutely positioned, the containing block is
2074 // formed by the content edge of the nearest block-level ancestor
2081 }
2084 // XXXfr hack for making frames behave properly when in overflow
2085 // container lists, see bug 154892; need to revisit later
2090 // See if the ancestor is block-level or inline-level
2093 // Base our size on the actual size of the frame. In cases when this is
2094 // completely bogus (eg initial reflow), this code shouldn't even be
2095 // called, since the code in nsInlineFrame::Reflow will pass in
2096 // the containing block dimensions to our constructor.
2097 // XXXbz we should be taking the in-flows into account too, but
2098 // that's very hard.
2100 LogicalMargin computedBorder =
2102 computedPadding;
2110 // If the ancestor is block-level, the containing block is formed by the
2111 // padding edge of the ancestor
2113 }
2117 };
2118 // an element in quirks mode gets a containing block based on looking for a
2119 // parent with a non-auto height if the element has a percent height.
2120 // Note: We don't emulate this quirk for percents in calc(), or in vertical
2121 // writing modes, or if the containing block is a flex or grid item.
2132 }
2133 }
2134 }
2137 }
2139 // XXX refactor this code to have methods for each set of properties
2140 // we are computing: width,height,line-height; margin; offsets
2145 LayoutFrameType aFrameType) {
2152 // If this is a reflow root, then set the computed width and
2153 // height equal to the available space
2155 // XXXldb This doesn't mean what it used to!
2158 // Override mComputedMargin since reflow roots start from the
2159 // frame's boundary, which is inside the margin.
2175 NS_UNCONSTRAINEDSIZE);
2177 // Get the containing block's reflow input
2182 // If we weren't given a containing block size, then compute one.
2185 }
2187 // See if the containing block height is based on the size of its
2188 // content
2190 // See if the containing block is a cell frame which needs
2191 // to use the mComputedHeight of the cell instead of what the cell block
2192 // passed in.
2193 // XXX It seems like this could lead to bugs with min-height and friends
2196 }
2197 }
2199 // XXX Might need to also pass the CB height (not width) for page boxes,
2200 // too, if we implement them.
2202 // For calculating positioning offsets, margins, borders and
2203 // padding, we use the writing mode of the containing block
2208 // For calculating the size of this box, we use its own writing mode
2212 // Check for a percentage based block size and a containing block
2213 // block size that depends on the content block size
2216 // this if clause enables %-blockSize on replaced inline frames,
2217 // such as images. See bug 54119. The else clause "blockSizeUnit =
2218 // eStyleUnit_Auto;" used to be called exclusively.
2220 // Get the containing block's reflow input
2222 // in quirks mode, get the cb height using the special quirk method
2230 }
2233 }
2234 }
2235 // in standard mode, use the cb block size. if it's "auto",
2236 // as will be the case by default in BODY, use auto block size
2237 // as per CSS2 spec.
2244 }
2245 }
2247 // default to interpreting the blockSize like 'auto'
2249 }
2250 }
2251 }
2253 // Compute our offsets if the element is relatively positioned. We
2254 // need the correct containing block inline-size and block-size
2255 // here, which is why we need to do it after all the quirks-n-such
2256 // above. (If the element is sticky positioned, we need to wait
2257 // until the scroll container knows its size, so we compute offsets
2258 // from StickyScrollContainer::UpdatePositions.)
2264 // Initialize offsets to 0
2266 }
2268 // Calculate the computed values for min and max properties. Note that
2269 // this MUST come after we've computed our border and padding.
2272 // Calculate the computed inlineSize and blockSize.
2273 // This varies by frame type.
2276 // Internal table elements. The rules vary depending on the type.
2277 // Calculate the computed isize
2283 // 'inlineSize' property doesn't apply to table rows and row groups
2286 }
2288 // calc() with both percentages and lengths act like auto on internal
2289 // table elements
2292 // Internal table elements don't have margins. Only tables and
2293 // cells have border and padding
2300 }
2307 }
2309 // Calculate the computed block size
2312 // 'blockSize' property doesn't apply to table columns and column groups
2314 }
2315 // calc() with both percentages and lengths acts like 'auto' on internal
2316 // table elements
2324 }
2326 // Doesn't apply to internal table elements
2329 NS_UNCONSTRAINEDSIZE);
2332 // XXXfr hack for making frames behave properly when in overflow
2333 // container lists, see bug 154892; need to revisit later
2337 aFrameType);
2343 // internal table values on replaced elements behaves as inline
2344 // https://drafts.csswg.org/css-tables-3/#table-structure
2345 // "... it is handled instead as though the author had declared
2346 // either 'block' (for 'table' display) or 'inline' (for all
2347 // other values)"
2351 // The inner table frame always fills its outer wrapper table frame,
2352 // even for 'inline-table'.
2354 // XXX abs.pos. continuations treated like blocks, see comment in
2355 // the else-if condition above.
2361 }
2365 // XXX grid-specific for now; maybe remove this check after we address
2366 // bug 799725
2369 }
2370 }
2372 // Shrink-wrap grid items that will be aligned (rather than stretched)
2373 // in its inline axis.
2383 }
2385 // Shrink-wrap blocks that are orthogonal to their container.
2389 }
2393 }
2394 }
2397 // For orthogonal flows, where we found a parent orthogonal-limit
2398 // for AvailableISize() in Init(), we'll use the same here as well.
2400 }
2420 }
2423 }
2426 }
2428 // Exclude flex and grid items.
2430 }
2435 // Exclude outside ::markers.
2437 }
2439 // Exclude -moz-column-content since it cannot have any margin.
2441 }
2443 }();
2447 }
2448 }
2449 }
2451 // Save our containing block dimensions
2453 }
2464 }
2467 }
2468 }
2471 LayoutFrameType aFrameType,
2472 ComputeSizeFlags aFlags,
2478 // Since we are in reflow, we don't need to store these properties anymore
2479 // unless they are dependent on width, in which case we store the new value.
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 }
2745 }
2747 }
2750 // For factor units the computed value of the line-height property
2751 // is found by multiplying the factor by the font's computed size
2752 // (adjusted for min-size prefs and text zoom).
2756 }
2761 }
2771 }
2772 // If we don't have a pres context, use a 1.2em fallback.
2775 }
2780 }
2790 }
2797 // Setting used line height can change a frame's block-size if mFrame's
2798 // block-size behaves as auto.
2800 }
2801 }
2803 /* static */
2807 nscoord aBlockBSize,
2814 }
2820 nscoord lineHeight =
2828 // For Web-compatibility, single-line text input elements cannot
2829 // have a line-height smaller than 'normal'.
2836 }
2837 }
2838 }
2841 }
2844 nscoord aPercentBasis,
2845 LayoutFrameType aFrameType) {
2846 // SVG text frames have no margin.
2849 }
2852 // Table frame's margin is inherited to the table wrapper frame via the
2853 // ::-moz-table-wrapper rule in ua.css, so don't set any margins for it.
2856 }
2858 // If style style can provide us the margin directly, then use it.
2861 nsMargin margin;
2864 // We have to compute the value. Note that this calculation is
2865 // performed according to the writing mode of the containing block
2866 // (http://dev.w3.org/csswg/css-writing-modes-3/#orthogonal-flows)
2869 }
2884 }
2886 // ... but font-size-inflation-based margin adjustment uses the
2887 // frame's writing mode
2894 }
2897 }
2900 nscoord aPercentBasis,
2901 LayoutFrameType aFrameType) {
2902 // If style can provide us the padding directly, then use it.
2904 nsMargin padding;
2906 // a table row/col group, row/col doesn't have padding
2907 // XXXldb Neither do border-collapse tables.
2914 // We have to compute the value. This calculation is performed
2915 // according to the writing mode of the containing block
2916 // (http://dev.w3.org/csswg/css-writing-modes-3/#orthogonal-flows)
2917 // clamp negative calc() results to 0
2920 }
2940 }
2942 }
2958 // Convert themed widget's physical dimensions to logical coords.
2959 minWidgetSize = {
2962 // GetMinimumWidgetSize() returns border-box; we need content-box.
2964 }
2966 // NOTE: min-width:auto resolves to 0, except on a flex item. (But
2967 // even there, it's supposed to be ignored (i.e. treated as 0) until
2968 // the flex container explicitly resolves & considers it.)
2974 }
2978 }
2981 // Specified value of 'none'
2986 }
2988 // If the computed value of 'min-width' is greater than the value of
2989 // 'max-width', 'max-width' is set to the value of 'min-width'
2992 }
2994 // Check for percentage based values and a containing block height that
2995 // depends on the content height. Treat them like the initial value.
2996 // Likewise, check for calc() with percentages on internal table elements;
2997 // that's treated as the initial value too.
3003 }
3006 }
3008 };
3010 // NOTE: min-height:auto resolves to 0, except on a flex item. (But
3011 // even there, it's supposed to be ignored (i.e. treated as 0) until
3012 // the flex container explicitly resolves & considers it.)
3019 }
3023 }
3026 // Specified value of 'none'
3032 }
3034 // If the computed value of 'min-height' is greater than the value of
3035 // 'max-height', 'max-height' is set to the value of 'min-height'
3038 }
3039 }
3044 }