layout/generic/TextOverflow.cpp

   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/. */
   6
   7 #include "TextOverflow.h"
   8 #include <algorithm>
   9
  10 // Please maintain alphabetical order below
  11 #include "gfxContext.h"
  12 #include "nsBlockFrame.h"
  13 #include "nsCaret.h"
  14 #include "nsContentUtils.h"
  15 #include "nsCSSAnonBoxes.h"
  16 #include "nsFontMetrics.h"
  17 #include "nsGfxScrollFrame.h"
  18 #include "nsIScrollableFrame.h"
  19 #include "nsLayoutUtils.h"
  20 #include "nsPresContext.h"
  21 #include "nsRect.h"
  22 #include "nsTextFrame.h"
  23 #include "nsIFrameInlines.h"
  24 #include "mozilla/ArrayUtils.h"
  25 #include "mozilla/Likely.h"
  26 #include "mozilla/PresShell.h"
  27 #include "mozilla/dom/Selection.h"
  28 #include "TextDrawTarget.h"
  29
  30 using mozilla::layout::TextDrawTarget;
  31
  32 namespace mozilla {
  33 namespace css {
  34
  35 class LazyReferenceRenderingDrawTargetGetterFromFrame final
  36     : public gfxFontGroup::LazyReferenceDrawTargetGetter {
  37  public:
  38   typedef mozilla::gfx::DrawTarget DrawTarget;
  39
  40   explicit LazyReferenceRenderingDrawTargetGetterFromFrame(nsIFrame* aFrame)
  41       : mFrame(aFrame) {}
  42   virtual already_AddRefed<DrawTarget> GetRefDrawTarget() override {
  43     UniquePtr<gfxContext> ctx =
  44         mFrame->PresShell()->CreateReferenceRenderingContext();
  45     RefPtr<DrawTarget> dt = ctx->GetDrawTarget();
  46     return dt.forget();
  47   }
  48
  49  private:
  50   nsIFrame* mFrame;
  51 };
  52
  53 static gfxTextRun* GetEllipsisTextRun(nsIFrame* aFrame) {
  54   RefPtr<nsFontMetrics> fm =
  55       nsLayoutUtils::GetInflatedFontMetricsForFrame(aFrame);
  56   LazyReferenceRenderingDrawTargetGetterFromFrame lazyRefDrawTargetGetter(
  57       aFrame);
  58   return fm->GetThebesFontGroup()->GetEllipsisTextRun(
  59       aFrame->PresContext()->AppUnitsPerDevPixel(),
  60       nsLayoutUtils::GetTextRunOrientFlagsForStyle(aFrame->Style()),
  61       lazyRefDrawTargetGetter);
  62 }
  63
  64 static nsIFrame* GetSelfOrNearestBlock(nsIFrame* aFrame) {
  65   MOZ_ASSERT(aFrame);
  66   return aFrame->IsBlockFrameOrSubclass()
  67              ? aFrame
  68              : nsLayoutUtils::FindNearestBlockAncestor(aFrame);
  69 }
  70
  71 // Return true if the frame is an atomic inline-level element.
  72 // It's not supposed to be called for block frames since we never
  73 // process block descendants for text-overflow.
  74 static bool IsAtomicElement(nsIFrame* aFrame, LayoutFrameType aFrameType) {
  75   MOZ_ASSERT(!aFrame->IsBlockFrameOrSubclass() || !aFrame->IsBlockOutside(),
  76              "unexpected block frame");
  77   MOZ_ASSERT(aFrameType != LayoutFrameType::Placeholder,
  78              "unexpected placeholder frame");
  79   return !aFrame->IsLineParticipant();
  80 }
  81
  82 static bool IsFullyClipped(nsTextFrame* aFrame, nscoord aLeft, nscoord aRight,
  83                            nscoord* aSnappedLeft, nscoord* aSnappedRight) {
  84   *aSnappedLeft = aLeft;
  85   *aSnappedRight = aRight;
  86   if (aLeft <= 0 && aRight <= 0) {
  87     return false;
  88   }
  89   return !aFrame->MeasureCharClippedText(aLeft, aRight, aSnappedLeft,
  90                                          aSnappedRight);
  91 }
  92
  93 static bool IsInlineAxisOverflowVisible(nsIFrame* aFrame) {
  94   MOZ_ASSERT(aFrame && aFrame->IsBlockFrameOrSubclass(),
  95              "expected a block frame");
  96
  97   nsIFrame* f = aFrame;
  98   while (f && f->Style()->IsAnonBox() && !f->IsScrollFrame()) {
  99     f = f->GetParent();
 100   }
 101   if (!f) {
 102     return true;
 103   }
 104   auto overflow = aFrame->GetWritingMode().IsVertical()
 105                       ? f->StyleDisplay()->mOverflowY
 106                       : f->StyleDisplay()->mOverflowX;
 107   return overflow == StyleOverflow::Visible;
 108 }
 109
 110 static void ClipMarker(const nsRect& aContentArea, const nsRect& aMarkerRect,
 111                        DisplayListClipState::AutoSaveRestore& aClipState) {
 112   nscoord rightOverflow = aMarkerRect.XMost() - aContentArea.XMost();
 113   nsRect markerRect = aMarkerRect;
 114   if (rightOverflow > 0) {
 115     // Marker overflows on the right side (content width < marker width).
 116     markerRect.width -= rightOverflow;
 117     aClipState.ClipContentDescendants(markerRect);
 118   } else {
 119     nscoord leftOverflow = aContentArea.x - aMarkerRect.x;
 120     if (leftOverflow > 0) {
 121       // Marker overflows on the left side
 122       markerRect.width -= leftOverflow;
 123       markerRect.x += leftOverflow;
 124       aClipState.ClipContentDescendants(markerRect);
 125     }
 126   }
 127 }
 128
 129 static void InflateIStart(WritingMode aWM, LogicalRect* aRect, nscoord aDelta) {
 130   nscoord iend = aRect->IEnd(aWM);
 131   aRect->IStart(aWM) -= aDelta;
 132   aRect->ISize(aWM) = std::max(iend - aRect->IStart(aWM), 0);
 133 }
 134
 135 static void InflateIEnd(WritingMode aWM, LogicalRect* aRect, nscoord aDelta) {
 136   aRect->ISize(aWM) = std::max(aRect->ISize(aWM) + aDelta, 0);
 137 }
 138
 139 static bool IsFrameDescendantOfAny(
 140     nsIFrame* aChild, const TextOverflow::FrameHashtable& aSetOfFrames,
 141     nsIFrame* aCommonAncestor) {
 142   for (nsIFrame* f = aChild; f && f != aCommonAncestor;
 143        f = nsLayoutUtils::GetCrossDocParentFrameInProcess(f)) {
 144     if (aSetOfFrames.Contains(f)) {
 145       return true;
 146     }
 147   }
 148   return false;
 149 }
 150
 151 class nsDisplayTextOverflowMarker final : public nsPaintedDisplayItem {
 152  public:
 153   nsDisplayTextOverflowMarker(nsDisplayListBuilder* aBuilder, nsIFrame* aFrame,
 154                               const nsRect& aRect, nscoord aAscent,
 155                               const StyleTextOverflowSide& aStyle)
 156       : nsPaintedDisplayItem(aBuilder, aFrame),
 157         mRect(aRect),
 158         mStyle(aStyle),
 159         mAscent(aAscent) {
 160     MOZ_COUNT_CTOR(nsDisplayTextOverflowMarker);
 161   }
 162
 163   MOZ_COUNTED_DTOR_OVERRIDE(nsDisplayTextOverflowMarker)
 164
 165   virtual nsRect GetBounds(nsDisplayListBuilder* aBuilder,
 166                            bool* aSnap) const override {
 167     *aSnap = false;
 168     nsRect shadowRect = nsLayoutUtils::GetTextShadowRectsUnion(mRect, mFrame);
 169     return mRect.Union(shadowRect);
 170   }
 171
 172   virtual nsRect GetComponentAlphaBounds(
 173       nsDisplayListBuilder* aBuilder) const override {
 174     if (gfxPlatform::GetPlatform()->RespectsFontStyleSmoothing()) {
 175       // On OS X, web authors can turn off subpixel text rendering using the
 176       // CSS property -moz-osx-font-smoothing. If they do that, we don't need
 177       // to use component alpha layers for the affected text.
 178       if (mFrame->StyleFont()->mFont.smoothing == NS_FONT_SMOOTHING_GRAYSCALE) {
 179         return nsRect();
 180       }
 181     }
 182     bool snap;
 183     return GetBounds(aBuilder, &snap);
 184   }
 185
 186   virtual void Paint(nsDisplayListBuilder* aBuilder, gfxContext* aCtx) override;
 187
 188   void PaintTextToContext(gfxContext* aCtx, nsPoint aOffsetFromRect);
 189
 190   virtual bool CreateWebRenderCommands(
 191       mozilla::wr::DisplayListBuilder& aBuilder,
 192       mozilla::wr::IpcResourceUpdateQueue& aResources,
 193       const StackingContextHelper& aSc,
 194       layers::RenderRootStateManager* aManager,
 195       nsDisplayListBuilder* aDisplayListBuilder) override;
 196
 197   NS_DISPLAY_DECL_NAME("TextOverflow", TYPE_TEXT_OVERFLOW)
 198  private:
 199   nsRect mRect;  // in reference frame coordinates
 200   const StyleTextOverflowSide mStyle;
 201   nscoord mAscent;  // baseline for the marker text in mRect
 202 };
 203
 204 static void PaintTextShadowCallback(gfxContext* aCtx, nsPoint aShadowOffset,
 205                                     const nscolor& aShadowColor, void* aData) {
 206   reinterpret_cast<nsDisplayTextOverflowMarker*>(aData)->PaintTextToContext(
 207       aCtx, aShadowOffset);
 208 }
 209
 210 void nsDisplayTextOverflowMarker::Paint(nsDisplayListBuilder* aBuilder,
 211                                         gfxContext* aCtx) {
 212   nscolor foregroundColor =
 213       nsLayoutUtils::GetColor(mFrame, &nsStyleText::mWebkitTextFillColor);
 214
 215   // Paint the text-shadows for the overflow marker
 216   nsLayoutUtils::PaintTextShadow(mFrame, aCtx, mRect,
 217                                  GetPaintRect(aBuilder, aCtx), foregroundColor,
 218                                  PaintTextShadowCallback, (void*)this);
 219   aCtx->SetColor(gfx::sRGBColor::FromABGR(foregroundColor));
 220   PaintTextToContext(aCtx, nsPoint(0, 0));
 221 }
 222
 223 void nsDisplayTextOverflowMarker::PaintTextToContext(gfxContext* aCtx,
 224                                                      nsPoint aOffsetFromRect) {
 225   WritingMode wm = mFrame->GetWritingMode();
 226   nsPoint pt(mRect.x, mRect.y);
 227   if (wm.IsVertical()) {
 228     if (wm.IsVerticalLR()) {
 229       pt.x = NSToCoordFloor(
 230           nsLayoutUtils::GetSnappedBaselineX(mFrame, aCtx, pt.x, mAscent));
 231     } else {
 232       pt.x = NSToCoordFloor(nsLayoutUtils::GetSnappedBaselineX(
 233           mFrame, aCtx, pt.x + mRect.width, -mAscent));
 234     }
 235   } else {
 236     pt.y = NSToCoordFloor(
 237         nsLayoutUtils::GetSnappedBaselineY(mFrame, aCtx, pt.y, mAscent));
 238   }
 239   pt += aOffsetFromRect;
 240
 241   if (mStyle.IsEllipsis()) {
 242     gfxTextRun* textRun = GetEllipsisTextRun(mFrame);
 243     if (textRun) {
 244       NS_ASSERTION(!textRun->IsRightToLeft(),
 245                    "Ellipsis textruns should always be LTR!");
 246       gfx::Point gfxPt(pt.x, pt.y);
 247       auto& paletteCache = mFrame->PresContext()->FontPaletteCache();
 248       textRun->Draw(gfxTextRun::Range(textRun), gfxPt,
 249                     gfxTextRun::DrawParams(aCtx, paletteCache));
 250     }
 251   } else {
 252     RefPtr<nsFontMetrics> fm =
 253         nsLayoutUtils::GetInflatedFontMetricsForFrame(mFrame);
 254     NS_ConvertUTF8toUTF16 str16{mStyle.AsString().AsString()};
 255     nsLayoutUtils::DrawString(mFrame, *fm, aCtx, str16.get(), str16.Length(),
 256                               pt);
 257   }
 258 }
 259
 260 bool nsDisplayTextOverflowMarker::CreateWebRenderCommands(
 261     mozilla::wr::DisplayListBuilder& aBuilder,
 262     mozilla::wr::IpcResourceUpdateQueue& aResources,
 263     const StackingContextHelper& aSc, layers::RenderRootStateManager* aManager,
 264     nsDisplayListBuilder* aDisplayListBuilder) {
 265   bool snap;
 266   nsRect bounds = GetBounds(aDisplayListBuilder, &snap);
 267   if (bounds.IsEmpty()) {
 268     return true;
 269   }
 270
 271   // Run the rendering algorithm to capture the glyphs and shadows
 272   RefPtr<TextDrawTarget> textDrawer =
 273       new TextDrawTarget(aBuilder, aResources, aSc, aManager, this, bounds);
 274   MOZ_ASSERT(textDrawer->IsValid());
 275   if (!textDrawer->IsValid()) {
 276     return false;
 277   }
 278   gfxContext captureCtx(textDrawer);
 279   Paint(aDisplayListBuilder, &captureCtx);
 280   textDrawer->TerminateShadows();
 281
 282   return textDrawer->Finish();
 283 }
 284
 285 TextOverflow::TextOverflow(nsDisplayListBuilder* aBuilder,
 286                            nsBlockFrame* aBlockFrame)
 287     : mContentArea(aBlockFrame->GetWritingMode(),
 288                    aBlockFrame->GetContentRectRelativeToSelf(),
 289                    aBlockFrame->GetSize()),
 290       mBuilder(aBuilder),
 291       mBlock(aBlockFrame),
 292       mScrollableFrame(nsLayoutUtils::GetScrollableFrameFor(aBlockFrame)),
 293       mMarkerList(aBuilder),
 294       mBlockSize(aBlockFrame->GetSize()),
 295       mBlockWM(aBlockFrame->GetWritingMode()),
 296       mCanHaveInlineAxisScrollbar(false),
 297       mInLineClampContext(aBlockFrame->IsInLineClampContext()),
 298       mAdjustForPixelSnapping(false) {
 299   if (mScrollableFrame) {
 300     auto scrollbarStyle = mBlockWM.IsVertical()
 301                               ? mScrollableFrame->GetScrollStyles().mVertical
 302                               : mScrollableFrame->GetScrollStyles().mHorizontal;
 303     mCanHaveInlineAxisScrollbar = scrollbarStyle != StyleOverflow::Hidden;
 304     if (!mAdjustForPixelSnapping) {
 305       // Scrolling to the end position can leave some text still overflowing due
 306       // to pixel snapping behaviour in our scrolling code.
 307       mAdjustForPixelSnapping = mCanHaveInlineAxisScrollbar;
 308     }
 309     // Use a null containerSize to convert a vector from logical to physical.
 310     const nsSize nullContainerSize;
 311     mContentArea.MoveBy(
 312         mBlockWM, LogicalPoint(mBlockWM, mScrollableFrame->GetScrollPosition(),
 313                                nullContainerSize));
 314   }
 315   StyleDirection direction = aBlockFrame->StyleVisibility()->mDirection;
 316   const nsStyleTextReset* style = aBlockFrame->StyleTextReset();
 317
 318   const auto& textOverflow = style->mTextOverflow;
 319   bool shouldToggleDirection =
 320       textOverflow.sides_are_logical && (direction == StyleDirection::Rtl);
 321   const auto& leftSide =
 322       shouldToggleDirection ? textOverflow.second : textOverflow.first;
 323   const auto& rightSide =
 324       shouldToggleDirection ? textOverflow.first : textOverflow.second;
 325
 326   if (mBlockWM.IsBidiLTR()) {
 327     mIStart.Init(leftSide);
 328     mIEnd.Init(rightSide);
 329   } else {
 330     mIStart.Init(rightSide);
 331     mIEnd.Init(leftSide);
 332   }
 333   // The left/right marker string is setup in ExamineLineFrames when a line
 334   // has overflow on that side.
 335 }
 336
 337 /* static */
 338 Maybe<TextOverflow> TextOverflow::WillProcessLines(
 339     nsDisplayListBuilder* aBuilder, nsBlockFrame* aBlockFrame) {
 340   // Ignore text-overflow and -webkit-line-clamp for event and frame visibility
 341   // processing.
 342   if (aBuilder->IsForEventDelivery() || aBuilder->IsForFrameVisibility() ||
 343       !CanHaveOverflowMarkers(aBlockFrame)) {
 344     return Nothing();
 345   }
 346   nsIScrollableFrame* scrollableFrame =
 347       nsLayoutUtils::GetScrollableFrameFor(aBlockFrame);
 348   if (scrollableFrame && scrollableFrame->IsTransformingByAPZ()) {
 349     // If the APZ is actively scrolling this, don't bother with markers.
 350     return Nothing();
 351   }
 352   return Some(TextOverflow(aBuilder, aBlockFrame));
 353 }
 354
 355 void TextOverflow::ExamineFrameSubtree(nsIFrame* aFrame,
 356                                        const LogicalRect& aContentArea,
 357                                        const LogicalRect& aInsideMarkersArea,
 358                                        FrameHashtable* aFramesToHide,
 359                                        AlignmentEdges* aAlignmentEdges,
 360                                        bool* aFoundVisibleTextOrAtomic,
 361                                        InnerClipEdges* aClippedMarkerEdges) {
 362   const LayoutFrameType frameType = aFrame->Type();
 363   if (frameType == LayoutFrameType::Br ||
 364       frameType == LayoutFrameType::Placeholder) {
 365     return;
 366   }
 367   const bool isAtomic = IsAtomicElement(aFrame, frameType);
 368   if (aFrame->StyleVisibility()->IsVisible()) {
 369     LogicalRect childRect =
 370         GetLogicalScrollableOverflowRectRelativeToBlock(aFrame);
 371     bool overflowIStart =
 372         childRect.IStart(mBlockWM) < aContentArea.IStart(mBlockWM);
 373     bool overflowIEnd = childRect.IEnd(mBlockWM) > aContentArea.IEnd(mBlockWM);
 374     if (overflowIStart) {
 375       mIStart.mHasOverflow = true;
 376     }
 377     if (overflowIEnd) {
 378       mIEnd.mHasOverflow = true;
 379     }
 380     if (isAtomic && ((mIStart.mActive && overflowIStart) ||
 381                      (mIEnd.mActive && overflowIEnd))) {
 382       aFramesToHide->Insert(aFrame);
 383     } else if (isAtomic || frameType == LayoutFrameType::Text) {
 384       AnalyzeMarkerEdges(aFrame, frameType, aInsideMarkersArea, aFramesToHide,
 385                          aAlignmentEdges, aFoundVisibleTextOrAtomic,
 386                          aClippedMarkerEdges);
 387     }
 388   }
 389   if (isAtomic) {
 390     return;
 391   }
 392
 393   for (nsIFrame* child : aFrame->PrincipalChildList()) {
 394     ExamineFrameSubtree(child, aContentArea, aInsideMarkersArea, aFramesToHide,
 395                         aAlignmentEdges, aFoundVisibleTextOrAtomic,
 396                         aClippedMarkerEdges);
 397   }
 398 }
 399
 400 void TextOverflow::AnalyzeMarkerEdges(nsIFrame* aFrame,
 401                                       LayoutFrameType aFrameType,
 402                                       const LogicalRect& aInsideMarkersArea,
 403                                       FrameHashtable* aFramesToHide,
 404                                       AlignmentEdges* aAlignmentEdges,
 405                                       bool* aFoundVisibleTextOrAtomic,
 406                                       InnerClipEdges* aClippedMarkerEdges) {
 407   MOZ_ASSERT(aFrameType == LayoutFrameType::Text ||
 408              IsAtomicElement(aFrame, aFrameType));
 409   LogicalRect borderRect(mBlockWM,
 410                          nsRect(aFrame->GetOffsetTo(mBlock), aFrame->GetSize()),
 411                          mBlockSize);
 412   nscoord istartOverlap = std::max(
 413       aInsideMarkersArea.IStart(mBlockWM) - borderRect.IStart(mBlockWM), 0);
 414   nscoord iendOverlap = std::max(
 415       borderRect.IEnd(mBlockWM) - aInsideMarkersArea.IEnd(mBlockWM), 0);
 416   bool insideIStartEdge =
 417       aInsideMarkersArea.IStart(mBlockWM) <= borderRect.IEnd(mBlockWM);
 418   bool insideIEndEdge =
 419       borderRect.IStart(mBlockWM) <= aInsideMarkersArea.IEnd(mBlockWM);
 420
 421   if (istartOverlap > 0) {
 422     aClippedMarkerEdges->AccumulateIStart(mBlockWM, borderRect);
 423     if (!mIStart.mActive) {
 424       istartOverlap = 0;
 425     }
 426   }
 427   if (iendOverlap > 0) {
 428     aClippedMarkerEdges->AccumulateIEnd(mBlockWM, borderRect);
 429     if (!mIEnd.mActive) {
 430       iendOverlap = 0;
 431     }
 432   }
 433
 434   if ((istartOverlap > 0 && insideIStartEdge) ||
 435       (iendOverlap > 0 && insideIEndEdge)) {
 436     if (aFrameType == LayoutFrameType::Text) {
 437       auto textFrame = static_cast<nsTextFrame*>(aFrame);
 438       if ((aInsideMarkersArea.IStart(mBlockWM) <
 439            aInsideMarkersArea.IEnd(mBlockWM)) &&
 440           textFrame->HasNonSuppressedText()) {
 441         // a clipped text frame and there is some room between the markers
 442         nscoord snappedIStart, snappedIEnd;
 443         bool isFullyClipped =
 444             mBlockWM.IsBidiLTR()
 445                 ? IsFullyClipped(textFrame, istartOverlap, iendOverlap,
 446                                  &snappedIStart, &snappedIEnd)
 447                 : IsFullyClipped(textFrame, iendOverlap, istartOverlap,
 448                                  &snappedIEnd, &snappedIStart);
 449         if (!isFullyClipped) {
 450           LogicalRect snappedRect = borderRect;
 451           if (istartOverlap > 0) {
 452             snappedRect.IStart(mBlockWM) += snappedIStart;
 453             snappedRect.ISize(mBlockWM) -= snappedIStart;
 454           }
 455           if (iendOverlap > 0) {
 456             snappedRect.ISize(mBlockWM) -= snappedIEnd;
 457           }
 458           aAlignmentEdges->AccumulateInner(mBlockWM, snappedRect);
 459           *aFoundVisibleTextOrAtomic = true;
 460         }
 461       }
 462     } else {
 463       aFramesToHide->Insert(aFrame);
 464     }
 465   } else if (!insideIStartEdge || !insideIEndEdge) {
 466     // frame is outside
 467     if (!insideIStartEdge) {
 468       aAlignmentEdges->AccumulateOuter(mBlockWM, borderRect);
 469     }
 470     if (IsAtomicElement(aFrame, aFrameType)) {
 471       aFramesToHide->Insert(aFrame);
 472     }
 473   } else {
 474     // frame is inside
 475     aAlignmentEdges->AccumulateInner(mBlockWM, borderRect);
 476     if (aFrameType == LayoutFrameType::Text) {
 477       auto textFrame = static_cast<nsTextFrame*>(aFrame);
 478       if (textFrame->HasNonSuppressedText()) {
 479         *aFoundVisibleTextOrAtomic = true;
 480       }
 481     } else {
 482       *aFoundVisibleTextOrAtomic = true;
 483     }
 484   }
 485 }
 486
 487 LogicalRect TextOverflow::ExamineLineFrames(nsLineBox* aLine,
 488                                             FrameHashtable* aFramesToHide,
 489                                             AlignmentEdges* aAlignmentEdges) {
 490   // No ellipsing for 'clip' style.
 491   bool suppressIStart = mIStart.IsSuppressed(mInLineClampContext);
 492   bool suppressIEnd = mIEnd.IsSuppressed(mInLineClampContext);
 493   if (mCanHaveInlineAxisScrollbar) {
 494     LogicalPoint pos(mBlockWM, mScrollableFrame->GetScrollPosition(),
 495                      mBlockSize);
 496     LogicalRect scrollRange(mBlockWM, mScrollableFrame->GetScrollRange(),
 497                             mBlockSize);
 498     // No ellipsing when nothing to scroll to on that side (this includes
 499     // overflow:auto that doesn't trigger a horizontal scrollbar).
 500     if (pos.I(mBlockWM) <= scrollRange.IStart(mBlockWM)) {
 501       suppressIStart = true;
 502     }
 503     if (pos.I(mBlockWM) >= scrollRange.IEnd(mBlockWM)) {
 504       // Except that we always want to display a -webkit-line-clamp ellipsis.
 505       if (!mIEnd.mHasBlockEllipsis) {
 506         suppressIEnd = true;
 507       }
 508     }
 509   }
 510
 511   LogicalRect contentArea = mContentArea;
 512   bool snapStart = true, snapEnd = true;
 513   nscoord startEdge, endEdge;
 514   if (aLine->GetFloatEdges(&startEdge, &endEdge)) {
 515     // Narrow the |contentArea| to account for any floats on this line, and
 516     // don't bother with the snapping quirk on whichever side(s) we narrow.
 517     nscoord delta = endEdge - contentArea.IEnd(mBlockWM);
 518     if (delta < 0) {
 519       nscoord newSize = contentArea.ISize(mBlockWM) + delta;
 520       contentArea.ISize(mBlockWM) = std::max(nscoord(0), newSize);
 521       snapEnd = false;
 522     }
 523     delta = startEdge - contentArea.IStart(mBlockWM);
 524     if (delta > 0) {
 525       contentArea.IStart(mBlockWM) = startEdge;
 526       nscoord newSize = contentArea.ISize(mBlockWM) - delta;
 527       contentArea.ISize(mBlockWM) = std::max(nscoord(0), newSize);
 528       snapStart = false;
 529     }
 530   }
 531   // Save the non-snapped area since that's what we want to use when placing
 532   // the markers (our return value).  The snapped area is only for analysis.
 533   LogicalRect nonSnappedContentArea = contentArea;
 534   if (mAdjustForPixelSnapping) {
 535     const nscoord scrollAdjust = mBlock->PresContext()->AppUnitsPerDevPixel();
 536     if (snapStart) {
 537       InflateIStart(mBlockWM, &contentArea, scrollAdjust);
 538     }
 539     if (snapEnd) {
 540       InflateIEnd(mBlockWM, &contentArea, scrollAdjust);
 541     }
 542   }
 543
 544   LogicalRect lineRect(mBlockWM, aLine->ScrollableOverflowRect(), mBlockSize);
 545   const bool istartWantsMarker =
 546       !suppressIStart &&
 547       lineRect.IStart(mBlockWM) < contentArea.IStart(mBlockWM);
 548   const bool iendWantsTextOverflowMarker =
 549       !suppressIEnd && lineRect.IEnd(mBlockWM) > contentArea.IEnd(mBlockWM);
 550   const bool iendWantsBlockEllipsisMarker =
 551       !suppressIEnd && mIEnd.mHasBlockEllipsis;
 552   const bool iendWantsMarker =
 553       iendWantsTextOverflowMarker || iendWantsBlockEllipsisMarker;
 554   if (!istartWantsMarker && !iendWantsMarker) {
 555     // We don't need any markers on this line.
 556     return nonSnappedContentArea;
 557   }
 558
 559   int pass = 0;
 560   bool retryEmptyLine = true;
 561   bool guessIStart = istartWantsMarker;
 562   bool guessIEnd = iendWantsMarker;
 563   mIStart.mActive = istartWantsMarker;
 564   mIEnd.mActive = iendWantsMarker;
 565   mIStart.mEdgeAligned = mCanHaveInlineAxisScrollbar && istartWantsMarker;
 566   mIEnd.mEdgeAligned =
 567       mCanHaveInlineAxisScrollbar && iendWantsTextOverflowMarker;
 568   bool clippedIStartMarker = false;
 569   bool clippedIEndMarker = false;
 570   do {
 571     // Setup marker strings as needed.
 572     if (guessIStart) {
 573       mIStart.SetupString(mBlock);
 574     }
 575     if (guessIEnd) {
 576       mIEnd.SetupString(mBlock);
 577     }
 578
 579     // If there is insufficient space for both markers then keep the one on the
 580     // end side per the block's 'direction'.
 581     nscoord istartMarkerISize = mIStart.mActive ? mIStart.mISize : 0;
 582     nscoord iendMarkerISize = mIEnd.mActive ? mIEnd.mISize : 0;
 583     if (istartMarkerISize && iendMarkerISize &&
 584         istartMarkerISize + iendMarkerISize > contentArea.ISize(mBlockWM)) {
 585       istartMarkerISize = 0;
 586     }
 587
 588     // Calculate the area between the potential markers aligned at the
 589     // block's edge.
 590     LogicalRect insideMarkersArea = nonSnappedContentArea;
 591     if (guessIStart) {
 592       InflateIStart(mBlockWM, &insideMarkersArea, -istartMarkerISize);
 593     }
 594     if (guessIEnd) {
 595       InflateIEnd(mBlockWM, &insideMarkersArea, -iendMarkerISize);
 596     }
 597
 598     // Analyze the frames on aLine for the overflow situation at the content
 599     // edges and at the edges of the area between the markers.
 600     bool foundVisibleTextOrAtomic = false;
 601     int32_t n = aLine->GetChildCount();
 602     nsIFrame* child = aLine->mFirstChild;
 603     InnerClipEdges clippedMarkerEdges;
 604     for (; n-- > 0; child = child->GetNextSibling()) {
 605       ExamineFrameSubtree(child, contentArea, insideMarkersArea, aFramesToHide,
 606                           aAlignmentEdges, &foundVisibleTextOrAtomic,
 607                           &clippedMarkerEdges);
 608     }
 609     if (!foundVisibleTextOrAtomic && retryEmptyLine) {
 610       aAlignmentEdges->mAssignedInner = false;
 611       aAlignmentEdges->mIEndOuter = 0;
 612       aFramesToHide->Clear();
 613       pass = -1;
 614       if (mIStart.IsNeeded() && mIStart.mActive && !clippedIStartMarker) {
 615         if (clippedMarkerEdges.mAssignedIStart &&
 616             clippedMarkerEdges.mIStart >
 617                 nonSnappedContentArea.IStart(mBlockWM)) {
 618           mIStart.mISize = clippedMarkerEdges.mIStart -
 619                            nonSnappedContentArea.IStart(mBlockWM);
 620           NS_ASSERTION(mIStart.mISize < mIStart.mIntrinsicISize,
 621                        "clipping a marker should make it strictly smaller");
 622           clippedIStartMarker = true;
 623         } else {
 624           mIStart.mActive = guessIStart = false;
 625         }
 626         continue;
 627       }
 628       if (mIEnd.IsNeeded() && mIEnd.mActive && !clippedIEndMarker) {
 629         if (clippedMarkerEdges.mAssignedIEnd &&
 630             nonSnappedContentArea.IEnd(mBlockWM) > clippedMarkerEdges.mIEnd) {
 631           mIEnd.mISize =
 632               nonSnappedContentArea.IEnd(mBlockWM) - clippedMarkerEdges.mIEnd;
 633           NS_ASSERTION(mIEnd.mISize < mIEnd.mIntrinsicISize,
 634                        "clipping a marker should make it strictly smaller");
 635           clippedIEndMarker = true;
 636         } else {
 637           mIEnd.mActive = guessIEnd = false;
 638         }
 639         continue;
 640       }
 641       // The line simply has no visible content even without markers,
 642       // so examine the line again without suppressing markers.
 643       retryEmptyLine = false;
 644       mIStart.mISize = mIStart.mIntrinsicISize;
 645       mIStart.mActive = guessIStart = istartWantsMarker;
 646       mIEnd.mISize = mIEnd.mIntrinsicISize;
 647       mIEnd.mActive = guessIEnd = iendWantsMarker;
 648       // If we wanted to place a block ellipsis but didn't, due to not having
 649       // any visible content to align to or the line's content being scrolled
 650       // out of view, then clip the ellipsis so that it looks like it is aligned
 651       // with the out of view content.
 652       if (mIEnd.IsNeeded() && mIEnd.mActive && mIEnd.mHasBlockEllipsis) {
 653         NS_ASSERTION(nonSnappedContentArea.IStart(mBlockWM) >
 654                          aAlignmentEdges->mIEndOuter,
 655                      "Expected the alignment edge for the out of view content "
 656                      "to be before the start of the content area");
 657         mIEnd.mISize = std::max(
 658             mIEnd.mIntrinsicISize - (nonSnappedContentArea.IStart(mBlockWM) -
 659                                      aAlignmentEdges->mIEndOuter),
 660             0);
 661       }
 662       continue;
 663     }
 664     if (guessIStart == (mIStart.mActive && mIStart.IsNeeded()) &&
 665         guessIEnd == (mIEnd.mActive && mIEnd.IsNeeded())) {
 666       break;
 667     } else {
 668       guessIStart = mIStart.mActive && mIStart.IsNeeded();
 669       guessIEnd = mIEnd.mActive && mIEnd.IsNeeded();
 670       mIStart.Reset();
 671       mIEnd.Reset();
 672       aFramesToHide->Clear();
 673     }
 674     NS_ASSERTION(pass == 0, "2nd pass should never guess wrong");
 675   } while (++pass != 2);
 676   if (!istartWantsMarker || !mIStart.mActive) {
 677     mIStart.Reset();
 678   }
 679   if (!iendWantsMarker || !mIEnd.mActive) {
 680     mIEnd.Reset();
 681   }
 682   return nonSnappedContentArea;
 683 }
 684
 685 void TextOverflow::ProcessLine(const nsDisplayListSet& aLists, nsLineBox* aLine,
 686                                uint32_t aLineNumber) {
 687   if (mIStart.mStyle->IsClip() && mIEnd.mStyle->IsClip() &&
 688       !aLine->HasLineClampEllipsis()) {
 689     return;
 690   }
 691
 692   mIStart.Reset();
 693   mIStart.mActive = !mIStart.mStyle->IsClip();
 694   mIEnd.Reset();
 695   mIEnd.mHasBlockEllipsis = aLine->HasLineClampEllipsis();
 696   mIEnd.mActive = !mIEnd.IsSuppressed(mInLineClampContext);
 697
 698   FrameHashtable framesToHide(64);
 699   AlignmentEdges alignmentEdges;
 700   const LogicalRect contentArea =
 701       ExamineLineFrames(aLine, &framesToHide, &alignmentEdges);
 702   bool needIStart = mIStart.IsNeeded();
 703   bool needIEnd = mIEnd.IsNeeded();
 704   if (!needIStart && !needIEnd) {
 705     return;
 706   }
 707   NS_ASSERTION(!mIStart.IsSuppressed(mInLineClampContext) || !needIStart,
 708                "left marker when not needed");
 709   NS_ASSERTION(!mIEnd.IsSuppressed(mInLineClampContext) || !needIEnd,
 710                "right marker when not needed");
 711
 712   // If there is insufficient space for both markers then keep the one on the
 713   // end side per the block's 'direction'.
 714   if (needIStart && needIEnd &&
 715       mIStart.mISize + mIEnd.mISize > contentArea.ISize(mBlockWM)) {
 716     needIStart = false;
 717   }
 718   LogicalRect insideMarkersArea = contentArea;
 719   if (needIStart) {
 720     InflateIStart(mBlockWM, &insideMarkersArea, -mIStart.mISize);
 721   }
 722   if (needIEnd) {
 723     InflateIEnd(mBlockWM, &insideMarkersArea, -mIEnd.mISize);
 724   }
 725
 726   if (alignmentEdges.mAssignedInner) {
 727     if (mIStart.mEdgeAligned) {
 728       alignmentEdges.mIStart = insideMarkersArea.IStart(mBlockWM);
 729     }
 730     if (mIEnd.mEdgeAligned) {
 731       alignmentEdges.mIEnd = insideMarkersArea.IEnd(mBlockWM);
 732     }
 733     LogicalRect alignmentRect(mBlockWM, alignmentEdges.mIStart,
 734                               insideMarkersArea.BStart(mBlockWM),
 735                               alignmentEdges.ISize(), 1);
 736     insideMarkersArea.IntersectRect(insideMarkersArea, alignmentRect);
 737   } else {
 738     // There was no content on the line that was visible at the current scolled
 739     // position.  If we wanted to place a block ellipsis but failed due to
 740     // having no visible content to align it to, we still need to ensure it
 741     // is displayed.  It goes at the start of the line, even though it's an
 742     // IEnd marker, since that is the side of the line that the content has
 743     // been scrolled past.  We set the insideMarkersArea to a zero-sized
 744     // rectangle placed next to the scrolled-out-of-view content.
 745     if (mIEnd.mHasBlockEllipsis) {
 746       insideMarkersArea = LogicalRect(mBlockWM, alignmentEdges.mIEndOuter,
 747                                       insideMarkersArea.BStart(mBlockWM), 0, 1);
 748     }
 749   }
 750
 751   // Clip and remove display items as needed at the final marker edges.
 752   nsDisplayList* lists[] = {aLists.Content(), aLists.PositionedDescendants()};
 753   for (uint32_t i = 0; i < ArrayLength(lists); ++i) {
 754     PruneDisplayListContents(lists[i], framesToHide, insideMarkersArea);
 755   }
 756   CreateMarkers(aLine, needIStart, needIEnd, insideMarkersArea, contentArea,
 757                 aLineNumber);
 758 }
 759
 760 void TextOverflow::PruneDisplayListContents(
 761     nsDisplayList* aList, const FrameHashtable& aFramesToHide,
 762     const LogicalRect& aInsideMarkersArea) {
 763   for (nsDisplayItem* item : aList->TakeItems()) {
 764     nsIFrame* itemFrame = item->Frame();
 765     if (IsFrameDescendantOfAny(itemFrame, aFramesToHide, mBlock)) {
 766       item->Destroy(mBuilder);
 767       continue;
 768     }
 769
 770     nsDisplayList* wrapper = item->GetSameCoordinateSystemChildren();
 771     if (wrapper) {
 772       if (!itemFrame || GetSelfOrNearestBlock(itemFrame) == mBlock) {
 773         PruneDisplayListContents(wrapper, aFramesToHide, aInsideMarkersArea);
 774       }
 775     }
 776
 777     nsDisplayText* textItem =
 778         itemFrame ? nsDisplayText::CheckCast(item) : nullptr;
 779     if (textItem && GetSelfOrNearestBlock(itemFrame) == mBlock) {
 780       LogicalRect rect =
 781           GetLogicalScrollableOverflowRectRelativeToBlock(itemFrame);
 782       if (mIStart.IsNeeded()) {
 783         nscoord istart =
 784             aInsideMarkersArea.IStart(mBlockWM) - rect.IStart(mBlockWM);
 785         if (istart > 0) {
 786           (mBlockWM.IsBidiLTR() ? textItem->VisIStartEdge()
 787                                 : textItem->VisIEndEdge()) = istart;
 788         }
 789       }
 790       if (mIEnd.IsNeeded()) {
 791         nscoord iend = rect.IEnd(mBlockWM) - aInsideMarkersArea.IEnd(mBlockWM);
 792         if (iend > 0) {
 793           (mBlockWM.IsBidiLTR() ? textItem->VisIEndEdge()
 794                                 : textItem->VisIStartEdge()) = iend;
 795         }
 796       }
 797     }
 798
 799     aList->AppendToTop(item);
 800   }
 801 }
 802
 803 /* static */
 804 bool TextOverflow::HasClippedTextOverflow(nsIFrame* aBlockFrame) {
 805   const nsStyleTextReset* style = aBlockFrame->StyleTextReset();
 806   return style->mTextOverflow.first.IsClip() &&
 807          style->mTextOverflow.second.IsClip();
 808 }
 809
 810 /* static */
 811 bool TextOverflow::HasBlockEllipsis(nsIFrame* aBlockFrame) {
 812   nsBlockFrame* f = do_QueryFrame(aBlockFrame);
 813   return f && f->HasAnyStateBits(NS_BLOCK_HAS_LINE_CLAMP_ELLIPSIS);
 814 }
 815
 816 static bool BlockCanHaveLineClampEllipsis(nsBlockFrame* aBlockFrame,
 817                                           bool aBeforeReflow) {
 818   if (aBeforeReflow) {
 819     return aBlockFrame->IsInLineClampContext();
 820   }
 821   return aBlockFrame->HasAnyStateBits(NS_BLOCK_HAS_LINE_CLAMP_ELLIPSIS);
 822 }
 823
 824 /* static */
 825 bool TextOverflow::CanHaveOverflowMarkers(nsBlockFrame* aBlockFrame,
 826                                           BeforeReflow aBeforeReflow) {
 827   if (BlockCanHaveLineClampEllipsis(aBlockFrame,
 828                                     aBeforeReflow == BeforeReflow::Yes)) {
 829     return true;
 830   }
 831
 832   // Nothing to do for text-overflow:clip or if 'overflow-x/y:visible'.
 833   if (HasClippedTextOverflow(aBlockFrame) ||
 834       IsInlineAxisOverflowVisible(aBlockFrame)) {
 835     return false;
 836   }
 837
 838   // Skip ComboboxControlFrame because it would clip the drop-down arrow.
 839   // Its anon block inherits 'text-overflow' and does what is expected.
 840   if (aBlockFrame->IsComboboxControlFrame()) {
 841     return false;
 842   }
 843
 844   // Inhibit the markers if a descendant content owns the caret.
 845   RefPtr<nsCaret> caret = aBlockFrame->PresShell()->GetCaret();
 846   if (caret && caret->IsVisible()) {
 847     RefPtr<dom::Selection> domSelection = caret->GetSelection();
 848     if (domSelection) {
 849       nsCOMPtr<nsIContent> content =
 850           nsIContent::FromNodeOrNull(domSelection->GetFocusNode());
 851       if (content &&
 852           content->IsInclusiveDescendantOf(aBlockFrame->GetContent())) {
 853         return false;
 854       }
 855     }
 856   }
 857   return true;
 858 }
 859
 860 void TextOverflow::CreateMarkers(const nsLineBox* aLine, bool aCreateIStart,
 861                                  bool aCreateIEnd,
 862                                  const LogicalRect& aInsideMarkersArea,
 863                                  const LogicalRect& aContentArea,
 864                                  uint32_t aLineNumber) {
 865   if (!mBlock->IsVisibleForPainting()) {
 866     return;
 867   }
 868
 869   if (aCreateIStart) {
 870     DisplayListClipState::AutoSaveRestore clipState(mBuilder);
 871
 872     LogicalRect markerLogicalRect(
 873         mBlockWM, aInsideMarkersArea.IStart(mBlockWM) - mIStart.mIntrinsicISize,
 874         aLine->BStart(), mIStart.mIntrinsicISize, aLine->BSize());
 875     nsPoint offset = mBuilder->ToReferenceFrame(mBlock);
 876     nsRect markerRect =
 877         markerLogicalRect.GetPhysicalRect(mBlockWM, mBlockSize) + offset;
 878     ClipMarker(aContentArea.GetPhysicalRect(mBlockWM, mBlockSize) + offset,
 879                markerRect, clipState);
 880
 881     mMarkerList.AppendNewToTopWithIndex<nsDisplayTextOverflowMarker>(
 882         mBuilder, mBlock, /* aIndex = */ (aLineNumber << 1) + 0, markerRect,
 883         aLine->GetLogicalAscent(), *mIStart.mStyle);
 884   }
 885
 886   if (aCreateIEnd) {
 887     DisplayListClipState::AutoSaveRestore clipState(mBuilder);
 888
 889     LogicalRect markerLogicalRect(mBlockWM, aInsideMarkersArea.IEnd(mBlockWM),
 890                                   aLine->BStart(), mIEnd.mIntrinsicISize,
 891                                   aLine->BSize());
 892     nsPoint offset = mBuilder->ToReferenceFrame(mBlock);
 893     nsRect markerRect =
 894         markerLogicalRect.GetPhysicalRect(mBlockWM, mBlockSize) + offset;
 895     ClipMarker(aContentArea.GetPhysicalRect(mBlockWM, mBlockSize) + offset,
 896                markerRect, clipState);
 897
 898     mMarkerList.AppendNewToTopWithIndex<nsDisplayTextOverflowMarker>(
 899         mBuilder, mBlock, /* aIndex = */ (aLineNumber << 1) + 1, markerRect,
 900         aLine->GetLogicalAscent(),
 901         mIEnd.mHasBlockEllipsis ? StyleTextOverflowSide::Ellipsis()
 902                                 : *mIEnd.mStyle);
 903   }
 904 }
 905
 906 void TextOverflow::Marker::SetupString(nsIFrame* aFrame) {
 907   if (mInitialized) {
 908     return;
 909   }
 910
 911   // A limitation here is that at the IEnd of a line, we only ever render one of
 912   // a text-overflow marker and a -webkit-line-clamp block ellipsis.  Since we
 913   // don't track the block ellipsis string and the text-overflow marker string
 914   // separately, if both apply to the element, we will always use "…" as the
 915   // string for text-overflow.
 916   if (HasBlockEllipsis(aFrame) || mStyle->IsEllipsis()) {
 917     gfxTextRun* textRun = GetEllipsisTextRun(aFrame);
 918     if (textRun) {
 919       mISize = textRun->GetAdvanceWidth();
 920     } else {
 921       mISize = 0;
 922     }
 923   } else {
 924     UniquePtr<gfxContext> rc =
 925         aFrame->PresShell()->CreateReferenceRenderingContext();
 926     RefPtr<nsFontMetrics> fm =
 927         nsLayoutUtils::GetInflatedFontMetricsForFrame(aFrame);
 928     mISize = nsLayoutUtils::AppUnitWidthOfStringBidi(
 929         NS_ConvertUTF8toUTF16(mStyle->AsString().AsString()), aFrame, *fm, *rc);
 930   }
 931   mIntrinsicISize = mISize;
 932   mInitialized = true;
 933 }
 934
 935 }  // namespace css
 936 }  // namespace mozilla