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->IsFrameOfType(nsIFrame::eLineParticipant);
  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       textRun->Draw(gfxTextRun::Range(textRun), gfxPt,
 248                     gfxTextRun::DrawParams(aCtx));
 249     }
 250   } else {
 251     RefPtr<nsFontMetrics> fm =
 252         nsLayoutUtils::GetInflatedFontMetricsForFrame(mFrame);
 253     NS_ConvertUTF8toUTF16 str16{mStyle.AsString().AsString()};
 254     nsLayoutUtils::DrawString(mFrame, *fm, aCtx, str16.get(), str16.Length(),
 255                               pt);
 256   }
 257 }
 258
 259 bool nsDisplayTextOverflowMarker::CreateWebRenderCommands(
 260     mozilla::wr::DisplayListBuilder& aBuilder,
 261     mozilla::wr::IpcResourceUpdateQueue& aResources,
 262     const StackingContextHelper& aSc, layers::RenderRootStateManager* aManager,
 263     nsDisplayListBuilder* aDisplayListBuilder) {
 264   bool snap;
 265   nsRect bounds = GetBounds(aDisplayListBuilder, &snap);
 266   if (bounds.IsEmpty()) {
 267     return true;
 268   }
 269
 270   // Run the rendering algorithm to capture the glyphs and shadows
 271   RefPtr<TextDrawTarget> textDrawer =
 272       new TextDrawTarget(aBuilder, aResources, aSc, aManager, this, bounds);
 273   MOZ_ASSERT(textDrawer->IsValid());
 274   if (!textDrawer->IsValid()) {
 275     return false;
 276   }
 277   gfxContext captureCtx(textDrawer);
 278   Paint(aDisplayListBuilder, &captureCtx);
 279   textDrawer->TerminateShadows();
 280
 281   return textDrawer->Finish();
 282 }
 283
 284 TextOverflow::TextOverflow(nsDisplayListBuilder* aBuilder,
 285                            nsBlockFrame* aBlockFrame)
 286     : mContentArea(aBlockFrame->GetWritingMode(),
 287                    aBlockFrame->GetContentRectRelativeToSelf(),
 288                    aBlockFrame->GetSize()),
 289       mBuilder(aBuilder),
 290       mBlock(aBlockFrame),
 291       mScrollableFrame(nsLayoutUtils::GetScrollableFrameFor(aBlockFrame)),
 292       mMarkerList(aBuilder),
 293       mBlockSize(aBlockFrame->GetSize()),
 294       mBlockWM(aBlockFrame->GetWritingMode()),
 295       mCanHaveInlineAxisScrollbar(false),
 296       mInLineClampContext(aBlockFrame->IsInLineClampContext()),
 297       mAdjustForPixelSnapping(false) {
 298   if (mScrollableFrame) {
 299     auto scrollbarStyle = mBlockWM.IsVertical()
 300                               ? mScrollableFrame->GetScrollStyles().mVertical
 301                               : mScrollableFrame->GetScrollStyles().mHorizontal;
 302     mCanHaveInlineAxisScrollbar = scrollbarStyle != StyleOverflow::Hidden;
 303     if (!mAdjustForPixelSnapping) {
 304       // Scrolling to the end position can leave some text still overflowing due
 305       // to pixel snapping behaviour in our scrolling code.
 306       mAdjustForPixelSnapping = mCanHaveInlineAxisScrollbar;
 307     }
 308     // Use a null containerSize to convert a vector from logical to physical.
 309     const nsSize nullContainerSize;
 310     mContentArea.MoveBy(
 311         mBlockWM, LogicalPoint(mBlockWM, mScrollableFrame->GetScrollPosition(),
 312                                nullContainerSize));
 313   }
 314   StyleDirection direction = aBlockFrame->StyleVisibility()->mDirection;
 315   const nsStyleTextReset* style = aBlockFrame->StyleTextReset();
 316
 317   const auto& textOverflow = style->mTextOverflow;
 318   bool shouldToggleDirection =
 319       textOverflow.sides_are_logical && (direction == StyleDirection::Rtl);
 320   const auto& leftSide =
 321       shouldToggleDirection ? textOverflow.second : textOverflow.first;
 322   const auto& rightSide =
 323       shouldToggleDirection ? textOverflow.first : textOverflow.second;
 324
 325   if (mBlockWM.IsBidiLTR()) {
 326     mIStart.Init(leftSide);
 327     mIEnd.Init(rightSide);
 328   } else {
 329     mIStart.Init(rightSide);
 330     mIEnd.Init(leftSide);
 331   }
 332   // The left/right marker string is setup in ExamineLineFrames when a line
 333   // has overflow on that side.
 334 }
 335
 336 /* static */
 337 Maybe<TextOverflow> TextOverflow::WillProcessLines(
 338     nsDisplayListBuilder* aBuilder, nsBlockFrame* aBlockFrame) {
 339   // Ignore text-overflow and -webkit-line-clamp for event and frame visibility
 340   // processing.
 341   if (aBuilder->IsForEventDelivery() || aBuilder->IsForFrameVisibility() ||
 342       !CanHaveOverflowMarkers(aBlockFrame)) {
 343     return Nothing();
 344   }
 345   nsIScrollableFrame* scrollableFrame =
 346       nsLayoutUtils::GetScrollableFrameFor(aBlockFrame);
 347   if (scrollableFrame && scrollableFrame->IsTransformingByAPZ()) {
 348     // If the APZ is actively scrolling this, don't bother with markers.
 349     return Nothing();
 350   }
 351   return Some(TextOverflow(aBuilder, aBlockFrame));
 352 }
 353
 354 void TextOverflow::ExamineFrameSubtree(nsIFrame* aFrame,
 355                                        const LogicalRect& aContentArea,
 356                                        const LogicalRect& aInsideMarkersArea,
 357                                        FrameHashtable* aFramesToHide,
 358                                        AlignmentEdges* aAlignmentEdges,
 359                                        bool* aFoundVisibleTextOrAtomic,
 360                                        InnerClipEdges* aClippedMarkerEdges) {
 361   const LayoutFrameType frameType = aFrame->Type();
 362   if (frameType == LayoutFrameType::Br ||
 363       frameType == LayoutFrameType::Placeholder) {
 364     return;
 365   }
 366   const bool isAtomic = IsAtomicElement(aFrame, frameType);
 367   if (aFrame->StyleVisibility()->IsVisible()) {
 368     LogicalRect childRect =
 369         GetLogicalScrollableOverflowRectRelativeToBlock(aFrame);
 370     bool overflowIStart =
 371         childRect.IStart(mBlockWM) < aContentArea.IStart(mBlockWM);
 372     bool overflowIEnd = childRect.IEnd(mBlockWM) > aContentArea.IEnd(mBlockWM);
 373     if (overflowIStart) {
 374       mIStart.mHasOverflow = true;
 375     }
 376     if (overflowIEnd) {
 377       mIEnd.mHasOverflow = true;
 378     }
 379     if (isAtomic && ((mIStart.mActive && overflowIStart) ||
 380                      (mIEnd.mActive && overflowIEnd))) {
 381       aFramesToHide->Insert(aFrame);
 382     } else if (isAtomic || frameType == LayoutFrameType::Text) {
 383       AnalyzeMarkerEdges(aFrame, frameType, aInsideMarkersArea, aFramesToHide,
 384                          aAlignmentEdges, aFoundVisibleTextOrAtomic,
 385                          aClippedMarkerEdges);
 386     }
 387   }
 388   if (isAtomic) {
 389     return;
 390   }
 391
 392   for (nsIFrame* child : aFrame->PrincipalChildList()) {
 393     ExamineFrameSubtree(child, aContentArea, aInsideMarkersArea, aFramesToHide,
 394                         aAlignmentEdges, aFoundVisibleTextOrAtomic,
 395                         aClippedMarkerEdges);
 396   }
 397 }
 398
 399 void TextOverflow::AnalyzeMarkerEdges(nsIFrame* aFrame,
 400                                       LayoutFrameType aFrameType,
 401                                       const LogicalRect& aInsideMarkersArea,
 402                                       FrameHashtable* aFramesToHide,
 403                                       AlignmentEdges* aAlignmentEdges,
 404                                       bool* aFoundVisibleTextOrAtomic,
 405                                       InnerClipEdges* aClippedMarkerEdges) {
 406   MOZ_ASSERT(aFrameType == LayoutFrameType::Text ||
 407              IsAtomicElement(aFrame, aFrameType));
 408   LogicalRect borderRect(mBlockWM,
 409                          nsRect(aFrame->GetOffsetTo(mBlock), aFrame->GetSize()),
 410                          mBlockSize);
 411   nscoord istartOverlap = std::max(
 412       aInsideMarkersArea.IStart(mBlockWM) - borderRect.IStart(mBlockWM), 0);
 413   nscoord iendOverlap = std::max(
 414       borderRect.IEnd(mBlockWM) - aInsideMarkersArea.IEnd(mBlockWM), 0);
 415   bool insideIStartEdge =
 416       aInsideMarkersArea.IStart(mBlockWM) <= borderRect.IEnd(mBlockWM);
 417   bool insideIEndEdge =
 418       borderRect.IStart(mBlockWM) <= aInsideMarkersArea.IEnd(mBlockWM);
 419
 420   if (istartOverlap > 0) {
 421     aClippedMarkerEdges->AccumulateIStart(mBlockWM, borderRect);
 422     if (!mIStart.mActive) {
 423       istartOverlap = 0;
 424     }
 425   }
 426   if (iendOverlap > 0) {
 427     aClippedMarkerEdges->AccumulateIEnd(mBlockWM, borderRect);
 428     if (!mIEnd.mActive) {
 429       iendOverlap = 0;
 430     }
 431   }
 432
 433   if ((istartOverlap > 0 && insideIStartEdge) ||
 434       (iendOverlap > 0 && insideIEndEdge)) {
 435     if (aFrameType == LayoutFrameType::Text) {
 436       auto textFrame = static_cast<nsTextFrame*>(aFrame);
 437       if ((aInsideMarkersArea.IStart(mBlockWM) <
 438            aInsideMarkersArea.IEnd(mBlockWM)) &&
 439           textFrame->HasNonSuppressedText()) {
 440         // a clipped text frame and there is some room between the markers
 441         nscoord snappedIStart, snappedIEnd;
 442         bool isFullyClipped =
 443             mBlockWM.IsBidiLTR()
 444                 ? IsFullyClipped(textFrame, istartOverlap, iendOverlap,
 445                                  &snappedIStart, &snappedIEnd)
 446                 : IsFullyClipped(textFrame, iendOverlap, istartOverlap,
 447                                  &snappedIEnd, &snappedIStart);
 448         if (!isFullyClipped) {
 449           LogicalRect snappedRect = borderRect;
 450           if (istartOverlap > 0) {
 451             snappedRect.IStart(mBlockWM) += snappedIStart;
 452             snappedRect.ISize(mBlockWM) -= snappedIStart;
 453           }
 454           if (iendOverlap > 0) {
 455             snappedRect.ISize(mBlockWM) -= snappedIEnd;
 456           }
 457           aAlignmentEdges->AccumulateInner(mBlockWM, snappedRect);
 458           *aFoundVisibleTextOrAtomic = true;
 459         }
 460       }
 461     } else {
 462       aFramesToHide->Insert(aFrame);
 463     }
 464   } else if (!insideIStartEdge || !insideIEndEdge) {
 465     // frame is outside
 466     if (!insideIStartEdge) {
 467       aAlignmentEdges->AccumulateOuter(mBlockWM, borderRect);
 468     }
 469     if (IsAtomicElement(aFrame, aFrameType)) {
 470       aFramesToHide->Insert(aFrame);
 471     }
 472   } else {
 473     // frame is inside
 474     aAlignmentEdges->AccumulateInner(mBlockWM, borderRect);
 475     if (aFrameType == LayoutFrameType::Text) {
 476       auto textFrame = static_cast<nsTextFrame*>(aFrame);
 477       if (textFrame->HasNonSuppressedText()) {
 478         *aFoundVisibleTextOrAtomic = true;
 479       }
 480     } else {
 481       *aFoundVisibleTextOrAtomic = true;
 482     }
 483   }
 484 }
 485
 486 LogicalRect TextOverflow::ExamineLineFrames(nsLineBox* aLine,
 487                                             FrameHashtable* aFramesToHide,
 488                                             AlignmentEdges* aAlignmentEdges) {
 489   // No ellipsing for 'clip' style.
 490   bool suppressIStart = mIStart.IsSuppressed(mInLineClampContext);
 491   bool suppressIEnd = mIEnd.IsSuppressed(mInLineClampContext);
 492   if (mCanHaveInlineAxisScrollbar) {
 493     LogicalPoint pos(mBlockWM, mScrollableFrame->GetScrollPosition(),
 494                      mBlockSize);
 495     LogicalRect scrollRange(mBlockWM, mScrollableFrame->GetScrollRange(),
 496                             mBlockSize);
 497     // No ellipsing when nothing to scroll to on that side (this includes
 498     // overflow:auto that doesn't trigger a horizontal scrollbar).
 499     if (pos.I(mBlockWM) <= scrollRange.IStart(mBlockWM)) {
 500       suppressIStart = true;
 501     }
 502     if (pos.I(mBlockWM) >= scrollRange.IEnd(mBlockWM)) {
 503       // Except that we always want to display a -webkit-line-clamp ellipsis.
 504       if (!mIEnd.mHasBlockEllipsis) {
 505         suppressIEnd = true;
 506       }
 507     }
 508   }
 509
 510   LogicalRect contentArea = mContentArea;
 511   bool snapStart = true, snapEnd = true;
 512   nscoord startEdge, endEdge;
 513   if (aLine->GetFloatEdges(&startEdge, &endEdge)) {
 514     // Narrow the |contentArea| to account for any floats on this line, and
 515     // don't bother with the snapping quirk on whichever side(s) we narrow.
 516     nscoord delta = endEdge - contentArea.IEnd(mBlockWM);
 517     if (delta < 0) {
 518       nscoord newSize = contentArea.ISize(mBlockWM) + delta;
 519       contentArea.ISize(mBlockWM) = std::max(nscoord(0), newSize);
 520       snapEnd = false;
 521     }
 522     delta = startEdge - contentArea.IStart(mBlockWM);
 523     if (delta > 0) {
 524       contentArea.IStart(mBlockWM) = startEdge;
 525       nscoord newSize = contentArea.ISize(mBlockWM) - delta;
 526       contentArea.ISize(mBlockWM) = std::max(nscoord(0), newSize);
 527       snapStart = false;
 528     }
 529   }
 530   // Save the non-snapped area since that's what we want to use when placing
 531   // the markers (our return value).  The snapped area is only for analysis.
 532   LogicalRect nonSnappedContentArea = contentArea;
 533   if (mAdjustForPixelSnapping) {
 534     const nscoord scrollAdjust = mBlock->PresContext()->AppUnitsPerDevPixel();
 535     if (snapStart) {
 536       InflateIStart(mBlockWM, &contentArea, scrollAdjust);
 537     }
 538     if (snapEnd) {
 539       InflateIEnd(mBlockWM, &contentArea, scrollAdjust);
 540     }
 541   }
 542
 543   LogicalRect lineRect(mBlockWM, aLine->ScrollableOverflowRect(), mBlockSize);
 544   const bool istartWantsMarker =
 545       !suppressIStart &&
 546       lineRect.IStart(mBlockWM) < contentArea.IStart(mBlockWM);
 547   const bool iendWantsTextOverflowMarker =
 548       !suppressIEnd && lineRect.IEnd(mBlockWM) > contentArea.IEnd(mBlockWM);
 549   const bool iendWantsBlockEllipsisMarker =
 550       !suppressIEnd && mIEnd.mHasBlockEllipsis;
 551   const bool iendWantsMarker =
 552       iendWantsTextOverflowMarker || iendWantsBlockEllipsisMarker;
 553   if (!istartWantsMarker && !iendWantsMarker) {
 554     // We don't need any markers on this line.
 555     return nonSnappedContentArea;
 556   }
 557
 558   int pass = 0;
 559   bool retryEmptyLine = true;
 560   bool guessIStart = istartWantsMarker;
 561   bool guessIEnd = iendWantsMarker;
 562   mIStart.mActive = istartWantsMarker;
 563   mIEnd.mActive = iendWantsMarker;
 564   mIStart.mEdgeAligned = mCanHaveInlineAxisScrollbar && istartWantsMarker;
 565   mIEnd.mEdgeAligned =
 566       mCanHaveInlineAxisScrollbar && iendWantsTextOverflowMarker;
 567   bool clippedIStartMarker = false;
 568   bool clippedIEndMarker = false;
 569   do {
 570     // Setup marker strings as needed.
 571     if (guessIStart) {
 572       mIStart.SetupString(mBlock);
 573     }
 574     if (guessIEnd) {
 575       mIEnd.SetupString(mBlock);
 576     }
 577
 578     // If there is insufficient space for both markers then keep the one on the
 579     // end side per the block's 'direction'.
 580     nscoord istartMarkerISize = mIStart.mActive ? mIStart.mISize : 0;
 581     nscoord iendMarkerISize = mIEnd.mActive ? mIEnd.mISize : 0;
 582     if (istartMarkerISize && iendMarkerISize &&
 583         istartMarkerISize + iendMarkerISize > contentArea.ISize(mBlockWM)) {
 584       istartMarkerISize = 0;
 585     }
 586
 587     // Calculate the area between the potential markers aligned at the
 588     // block's edge.
 589     LogicalRect insideMarkersArea = nonSnappedContentArea;
 590     if (guessIStart) {
 591       InflateIStart(mBlockWM, &insideMarkersArea, -istartMarkerISize);
 592     }
 593     if (guessIEnd) {
 594       InflateIEnd(mBlockWM, &insideMarkersArea, -iendMarkerISize);
 595     }
 596
 597     // Analyze the frames on aLine for the overflow situation at the content
 598     // edges and at the edges of the area between the markers.
 599     bool foundVisibleTextOrAtomic = false;
 600     int32_t n = aLine->GetChildCount();
 601     nsIFrame* child = aLine->mFirstChild;
 602     InnerClipEdges clippedMarkerEdges;
 603     for (; n-- > 0; child = child->GetNextSibling()) {
 604       ExamineFrameSubtree(child, contentArea, insideMarkersArea, aFramesToHide,
 605                           aAlignmentEdges, &foundVisibleTextOrAtomic,
 606                           &clippedMarkerEdges);
 607     }
 608     if (!foundVisibleTextOrAtomic && retryEmptyLine) {
 609       aAlignmentEdges->mAssignedInner = false;
 610       aAlignmentEdges->mIEndOuter = 0;
 611       aFramesToHide->Clear();
 612       pass = -1;
 613       if (mIStart.IsNeeded() && mIStart.mActive && !clippedIStartMarker) {
 614         if (clippedMarkerEdges.mAssignedIStart &&
 615             clippedMarkerEdges.mIStart >
 616                 nonSnappedContentArea.IStart(mBlockWM)) {
 617           mIStart.mISize = clippedMarkerEdges.mIStart -
 618                            nonSnappedContentArea.IStart(mBlockWM);
 619           NS_ASSERTION(mIStart.mISize < mIStart.mIntrinsicISize,
 620                        "clipping a marker should make it strictly smaller");
 621           clippedIStartMarker = true;
 622         } else {
 623           mIStart.mActive = guessIStart = false;
 624         }
 625         continue;
 626       }
 627       if (mIEnd.IsNeeded() && mIEnd.mActive && !clippedIEndMarker) {
 628         if (clippedMarkerEdges.mAssignedIEnd &&
 629             nonSnappedContentArea.IEnd(mBlockWM) > clippedMarkerEdges.mIEnd) {
 630           mIEnd.mISize =
 631               nonSnappedContentArea.IEnd(mBlockWM) - clippedMarkerEdges.mIEnd;
 632           NS_ASSERTION(mIEnd.mISize < mIEnd.mIntrinsicISize,
 633                        "clipping a marker should make it strictly smaller");
 634           clippedIEndMarker = true;
 635         } else {
 636           mIEnd.mActive = guessIEnd = false;
 637         }
 638         continue;
 639       }
 640       // The line simply has no visible content even without markers,
 641       // so examine the line again without suppressing markers.
 642       retryEmptyLine = false;
 643       mIStart.mISize = mIStart.mIntrinsicISize;
 644       mIStart.mActive = guessIStart = istartWantsMarker;
 645       mIEnd.mISize = mIEnd.mIntrinsicISize;
 646       mIEnd.mActive = guessIEnd = iendWantsMarker;
 647       // If we wanted to place a block ellipsis but didn't, due to not having
 648       // any visible content to align to or the line's content being scrolled
 649       // out of view, then clip the ellipsis so that it looks like it is aligned
 650       // with the out of view content.
 651       if (mIEnd.IsNeeded() && mIEnd.mActive && mIEnd.mHasBlockEllipsis) {
 652         NS_ASSERTION(nonSnappedContentArea.IStart(mBlockWM) >
 653                          aAlignmentEdges->mIEndOuter,
 654                      "Expected the alignment edge for the out of view content "
 655                      "to be before the start of the content area");
 656         mIEnd.mISize = std::max(
 657             mIEnd.mIntrinsicISize - (nonSnappedContentArea.IStart(mBlockWM) -
 658                                      aAlignmentEdges->mIEndOuter),
 659             0);
 660       }
 661       continue;
 662     }
 663     if (guessIStart == (mIStart.mActive && mIStart.IsNeeded()) &&
 664         guessIEnd == (mIEnd.mActive && mIEnd.IsNeeded())) {
 665       break;
 666     } else {
 667       guessIStart = mIStart.mActive && mIStart.IsNeeded();
 668       guessIEnd = mIEnd.mActive && mIEnd.IsNeeded();
 669       mIStart.Reset();
 670       mIEnd.Reset();
 671       aFramesToHide->Clear();
 672     }
 673     NS_ASSERTION(pass == 0, "2nd pass should never guess wrong");
 674   } while (++pass != 2);
 675   if (!istartWantsMarker || !mIStart.mActive) {
 676     mIStart.Reset();
 677   }
 678   if (!iendWantsMarker || !mIEnd.mActive) {
 679     mIEnd.Reset();
 680   }
 681   return nonSnappedContentArea;
 682 }
 683
 684 void TextOverflow::ProcessLine(const nsDisplayListSet& aLists, nsLineBox* aLine,
 685                                uint32_t aLineNumber) {
 686   if (mIStart.mStyle->IsClip() && mIEnd.mStyle->IsClip() &&
 687       !aLine->HasLineClampEllipsis()) {
 688     return;
 689   }
 690
 691   mIStart.Reset();
 692   mIStart.mActive = !mIStart.mStyle->IsClip();
 693   mIEnd.Reset();
 694   mIEnd.mHasBlockEllipsis = aLine->HasLineClampEllipsis();
 695   mIEnd.mActive = !mIEnd.IsSuppressed(mInLineClampContext);
 696
 697   FrameHashtable framesToHide(64);
 698   AlignmentEdges alignmentEdges;
 699   const LogicalRect contentArea =
 700       ExamineLineFrames(aLine, &framesToHide, &alignmentEdges);
 701   bool needIStart = mIStart.IsNeeded();
 702   bool needIEnd = mIEnd.IsNeeded();
 703   if (!needIStart && !needIEnd) {
 704     return;
 705   }
 706   NS_ASSERTION(!mIStart.IsSuppressed(mInLineClampContext) || !needIStart,
 707                "left marker when not needed");
 708   NS_ASSERTION(!mIEnd.IsSuppressed(mInLineClampContext) || !needIEnd,
 709                "right marker when not needed");
 710
 711   // If there is insufficient space for both markers then keep the one on the
 712   // end side per the block's 'direction'.
 713   if (needIStart && needIEnd &&
 714       mIStart.mISize + mIEnd.mISize > contentArea.ISize(mBlockWM)) {
 715     needIStart = false;
 716   }
 717   LogicalRect insideMarkersArea = contentArea;
 718   if (needIStart) {
 719     InflateIStart(mBlockWM, &insideMarkersArea, -mIStart.mISize);
 720   }
 721   if (needIEnd) {
 722     InflateIEnd(mBlockWM, &insideMarkersArea, -mIEnd.mISize);
 723   }
 724
 725   if (alignmentEdges.mAssignedInner) {
 726     if (mIStart.mEdgeAligned) {
 727       alignmentEdges.mIStart = insideMarkersArea.IStart(mBlockWM);
 728     }
 729     if (mIEnd.mEdgeAligned) {
 730       alignmentEdges.mIEnd = insideMarkersArea.IEnd(mBlockWM);
 731     }
 732     LogicalRect alignmentRect(mBlockWM, alignmentEdges.mIStart,
 733                               insideMarkersArea.BStart(mBlockWM),
 734                               alignmentEdges.ISize(), 1);
 735     insideMarkersArea.IntersectRect(insideMarkersArea, alignmentRect);
 736   } else {
 737     // There was no content on the line that was visible at the current scolled
 738     // position.  If we wanted to place a block ellipsis but failed due to
 739     // having no visible content to align it to, we still need to ensure it
 740     // is displayed.  It goes at the start of the line, even though it's an
 741     // IEnd marker, since that is the side of the line that the content has
 742     // been scrolled past.  We set the insideMarkersArea to a zero-sized
 743     // rectangle placed next to the scrolled-out-of-view content.
 744     if (mIEnd.mHasBlockEllipsis) {
 745       insideMarkersArea = LogicalRect(mBlockWM, alignmentEdges.mIEndOuter,
 746                                       insideMarkersArea.BStart(mBlockWM), 0, 1);
 747     }
 748   }
 749
 750   // Clip and remove display items as needed at the final marker edges.
 751   nsDisplayList* lists[] = {aLists.Content(), aLists.PositionedDescendants()};
 752   for (uint32_t i = 0; i < ArrayLength(lists); ++i) {
 753     PruneDisplayListContents(lists[i], framesToHide, insideMarkersArea);
 754   }
 755   CreateMarkers(aLine, needIStart, needIEnd, insideMarkersArea, contentArea,
 756                 aLineNumber);
 757 }
 758
 759 void TextOverflow::PruneDisplayListContents(
 760     nsDisplayList* aList, const FrameHashtable& aFramesToHide,
 761     const LogicalRect& aInsideMarkersArea) {
 762   for (nsDisplayItem* item : aList->TakeItems()) {
 763     nsIFrame* itemFrame = item->Frame();
 764     if (IsFrameDescendantOfAny(itemFrame, aFramesToHide, mBlock)) {
 765       item->Destroy(mBuilder);
 766       continue;
 767     }
 768
 769     nsDisplayList* wrapper = item->GetSameCoordinateSystemChildren();
 770     if (wrapper) {
 771       if (!itemFrame || GetSelfOrNearestBlock(itemFrame) == mBlock) {
 772         PruneDisplayListContents(wrapper, aFramesToHide, aInsideMarkersArea);
 773       }
 774     }
 775
 776     nsDisplayText* textItem =
 777         itemFrame ? nsDisplayText::CheckCast(item) : nullptr;
 778     if (textItem && GetSelfOrNearestBlock(itemFrame) == mBlock) {
 779       LogicalRect rect =
 780           GetLogicalScrollableOverflowRectRelativeToBlock(itemFrame);
 781       if (mIStart.IsNeeded()) {
 782         nscoord istart =
 783             aInsideMarkersArea.IStart(mBlockWM) - rect.IStart(mBlockWM);
 784         if (istart > 0) {
 785           (mBlockWM.IsBidiLTR() ? textItem->VisIStartEdge()
 786                                 : textItem->VisIEndEdge()) = istart;
 787         }
 788       }
 789       if (mIEnd.IsNeeded()) {
 790         nscoord iend = rect.IEnd(mBlockWM) - aInsideMarkersArea.IEnd(mBlockWM);
 791         if (iend > 0) {
 792           (mBlockWM.IsBidiLTR() ? textItem->VisIEndEdge()
 793                                 : textItem->VisIStartEdge()) = iend;
 794         }
 795       }
 796     }
 797
 798     aList->AppendToTop(item);
 799   }
 800 }
 801
 802 /* static */
 803 bool TextOverflow::HasClippedTextOverflow(nsIFrame* aBlockFrame) {
 804   const nsStyleTextReset* style = aBlockFrame->StyleTextReset();
 805   return style->mTextOverflow.first.IsClip() &&
 806          style->mTextOverflow.second.IsClip();
 807 }
 808
 809 /* static */
 810 bool TextOverflow::HasBlockEllipsis(nsIFrame* aBlockFrame) {
 811   nsBlockFrame* f = do_QueryFrame(aBlockFrame);
 812   return f && f->HasAnyStateBits(NS_BLOCK_HAS_LINE_CLAMP_ELLIPSIS);
 813 }
 814
 815 static bool BlockCanHaveLineClampEllipsis(nsBlockFrame* aBlockFrame,
 816                                           bool aBeforeReflow) {
 817   if (aBeforeReflow) {
 818     return aBlockFrame->IsInLineClampContext();
 819   }
 820   return aBlockFrame->HasAnyStateBits(NS_BLOCK_HAS_LINE_CLAMP_ELLIPSIS);
 821 }
 822
 823 /* static */
 824 bool TextOverflow::CanHaveOverflowMarkers(nsBlockFrame* aBlockFrame,
 825                                           BeforeReflow aBeforeReflow) {
 826   if (BlockCanHaveLineClampEllipsis(aBlockFrame,
 827                                     aBeforeReflow == BeforeReflow::Yes)) {
 828     return true;
 829   }
 830
 831   // Nothing to do for text-overflow:clip or if 'overflow-x/y:visible'.
 832   if (HasClippedTextOverflow(aBlockFrame) ||
 833       IsInlineAxisOverflowVisible(aBlockFrame)) {
 834     return false;
 835   }
 836
 837   // Skip ComboboxControlFrame because it would clip the drop-down arrow.
 838   // Its anon block inherits 'text-overflow' and does what is expected.
 839   if (aBlockFrame->IsComboboxControlFrame()) {
 840     return false;
 841   }
 842
 843   // Inhibit the markers if a descendant content owns the caret.
 844   RefPtr<nsCaret> caret = aBlockFrame->PresShell()->GetCaret();
 845   if (caret && caret->IsVisible()) {
 846     RefPtr<dom::Selection> domSelection = caret->GetSelection();
 847     if (domSelection) {
 848       nsCOMPtr<nsIContent> content =
 849           nsIContent::FromNodeOrNull(domSelection->GetFocusNode());
 850       if (content &&
 851           content->IsInclusiveDescendantOf(aBlockFrame->GetContent())) {
 852         return false;
 853       }
 854     }
 855   }
 856   return true;
 857 }
 858
 859 void TextOverflow::CreateMarkers(const nsLineBox* aLine, bool aCreateIStart,
 860                                  bool aCreateIEnd,
 861                                  const LogicalRect& aInsideMarkersArea,
 862                                  const LogicalRect& aContentArea,
 863                                  uint32_t aLineNumber) {
 864   if (!mBlock->IsVisibleForPainting()) {
 865     return;
 866   }
 867
 868   if (aCreateIStart) {
 869     DisplayListClipState::AutoSaveRestore clipState(mBuilder);
 870
 871     LogicalRect markerLogicalRect(
 872         mBlockWM, aInsideMarkersArea.IStart(mBlockWM) - mIStart.mIntrinsicISize,
 873         aLine->BStart(), mIStart.mIntrinsicISize, aLine->BSize());
 874     nsPoint offset = mBuilder->ToReferenceFrame(mBlock);
 875     nsRect markerRect =
 876         markerLogicalRect.GetPhysicalRect(mBlockWM, mBlockSize) + offset;
 877     ClipMarker(aContentArea.GetPhysicalRect(mBlockWM, mBlockSize) + offset,
 878                markerRect, clipState);
 879
 880     mMarkerList.AppendNewToTopWithIndex<nsDisplayTextOverflowMarker>(
 881         mBuilder, mBlock, /* aIndex = */ (aLineNumber << 1) + 0, markerRect,
 882         aLine->GetLogicalAscent(), *mIStart.mStyle);
 883   }
 884
 885   if (aCreateIEnd) {
 886     DisplayListClipState::AutoSaveRestore clipState(mBuilder);
 887
 888     LogicalRect markerLogicalRect(mBlockWM, aInsideMarkersArea.IEnd(mBlockWM),
 889                                   aLine->BStart(), mIEnd.mIntrinsicISize,
 890                                   aLine->BSize());
 891     nsPoint offset = mBuilder->ToReferenceFrame(mBlock);
 892     nsRect markerRect =
 893         markerLogicalRect.GetPhysicalRect(mBlockWM, mBlockSize) + offset;
 894     ClipMarker(aContentArea.GetPhysicalRect(mBlockWM, mBlockSize) + offset,
 895                markerRect, clipState);
 896
 897     mMarkerList.AppendNewToTopWithIndex<nsDisplayTextOverflowMarker>(
 898         mBuilder, mBlock, /* aIndex = */ (aLineNumber << 1) + 1, markerRect,
 899         aLine->GetLogicalAscent(),
 900         mIEnd.mHasBlockEllipsis ? StyleTextOverflowSide::Ellipsis()
 901                                 : *mIEnd.mStyle);
 902   }
 903 }
 904
 905 void TextOverflow::Marker::SetupString(nsIFrame* aFrame) {
 906   if (mInitialized) {
 907     return;
 908   }
 909
 910   // A limitation here is that at the IEnd of a line, we only ever render one of
 911   // a text-overflow marker and a -webkit-line-clamp block ellipsis.  Since we
 912   // don't track the block ellipsis string and the text-overflow marker string
 913   // separately, if both apply to the element, we will always use "…" as the
 914   // string for text-overflow.
 915   if (HasBlockEllipsis(aFrame) || mStyle->IsEllipsis()) {
 916     gfxTextRun* textRun = GetEllipsisTextRun(aFrame);
 917     if (textRun) {
 918       mISize = textRun->GetAdvanceWidth();
 919     } else {
 920       mISize = 0;
 921     }
 922   } else {
 923     UniquePtr<gfxContext> rc =
 924         aFrame->PresShell()->CreateReferenceRenderingContext();
 925     RefPtr<nsFontMetrics> fm =
 926         nsLayoutUtils::GetInflatedFontMetricsForFrame(aFrame);
 927     mISize = nsLayoutUtils::AppUnitWidthOfStringBidi(
 928         NS_ConvertUTF8toUTF16(mStyle->AsString().AsString()), aFrame, *fm, *rc);
 929   }
 930   mIntrinsicISize = mISize;
 931   mInitialized = true;
 932 }
 933
 934 }  // namespace css
 935 }  // namespace mozilla