Adding upstream version 1:115.7.0.upstream/1%115.7.0upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 781 insertions, 0 deletions

diff --git a/layout/generic/nsPageSequenceFrame.cpp b/layout/generic/nsPageSequenceFrame.cpp
new file mode 100644
index 0000000000..1e84e13973
--- /dev/null
+++ b/layout/generic/nsPageSequenceFrame.cpp
@@ -0,0 +1,781 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsPageSequenceFrame.h"
+
+#include "mozilla/intl/AppDateTimeFormat.h"
+#include "mozilla/Logging.h"
+#include "mozilla/PresShell.h"
+#include "mozilla/PrintedSheetFrame.h"
+#include "mozilla/dom/HTMLCanvasElement.h"
+#include "mozilla/StaticPresData.h"
+
+#include "nsCOMPtr.h"
+#include "nsDeviceContext.h"
+#include "nsPresContext.h"
+#include "gfxContext.h"
+#include "nsGkAtoms.h"
+#include "nsIFrame.h"
+#include "nsIFrameInlines.h"
+#include "nsIPrintSettings.h"
+#include "nsPageFrame.h"
+#include "nsSubDocumentFrame.h"
+#include "nsRegion.h"
+#include "nsCSSFrameConstructor.h"
+#include "nsContentUtils.h"
+#include "nsDisplayList.h"
+#include "nsHTMLCanvasFrame.h"
+#include "nsICanvasRenderingContextInternal.h"
+#include "nsServiceManagerUtils.h"
+#include <algorithm>
+#include <limits>
+
+using namespace mozilla;
+using namespace mozilla::dom;
+
+mozilla::LazyLogModule gLayoutPrintingLog("printing-layout");
+
+#define PR_PL(_p1) MOZ_LOG(gLayoutPrintingLog, mozilla::LogLevel::Debug, _p1)
+
+nsPageSequenceFrame* NS_NewPageSequenceFrame(PresShell* aPresShell,
+                                             ComputedStyle* aStyle) {
+  return new (aPresShell)
+      nsPageSequenceFrame(aStyle, aPresShell->GetPresContext());
+}
+
+NS_IMPL_FRAMEARENA_HELPERS(nsPageSequenceFrame)
+
+static const nsPagesPerSheetInfo kSupportedPagesPerSheet[] = {
+    /* Members are: {mNumPages, mLargerNumTracks} */
+    // clang-format off
+    {1, 1},
+    {2, 2},
+    {4, 2},
+    {6, 3},
+    {9, 3},
+    {16, 4},
+    // clang-format on
+};
+
+inline void SanityCheckPagesPerSheetInfo() {
+#ifdef DEBUG
+  // Sanity-checks:
+  MOZ_ASSERT(ArrayLength(kSupportedPagesPerSheet) > 0,
+             "Should have at least one pages-per-sheet option.");
+  MOZ_ASSERT(kSupportedPagesPerSheet[0].mNumPages == 1,
+             "The 0th index is reserved for default 1-page-per-sheet entry");
+
+  uint16_t prevInfoPPS = 0;
+  for (const auto& info : kSupportedPagesPerSheet) {
+    MOZ_ASSERT(info.mNumPages > prevInfoPPS,
+               "page count field should be positive & monotonically increase");
+    MOZ_ASSERT(info.mLargerNumTracks > 0,
+               "page grid has to have a positive number of tracks");
+    MOZ_ASSERT(info.mNumPages % info.mLargerNumTracks == 0,
+               "page count field should be evenly divisible by "
+               "the given track-count");
+    prevInfoPPS = info.mNumPages;
+  }
+#endif
+}
+
+const nsPagesPerSheetInfo& nsPagesPerSheetInfo::LookupInfo(int32_t aPPS) {
+  SanityCheckPagesPerSheetInfo();
+
+  // Walk the array, looking for a match:
+  for (const auto& info : kSupportedPagesPerSheet) {
+    if (aPPS == info.mNumPages) {
+      return info;
+    }
+  }
+
+  NS_WARNING("Unsupported pages-per-sheet value");
+  // If no match was found, return the first entry (for 1 page per sheet).
+  return kSupportedPagesPerSheet[0];
+}
+
+const nsPagesPerSheetInfo* nsSharedPageData::PagesPerSheetInfo() {
+  if (mPagesPerSheetInfo) {
+    return mPagesPerSheetInfo;
+  }
+
+  int32_t pagesPerSheet;
+  if (!mPrintSettings ||
+      NS_FAILED(mPrintSettings->GetNumPagesPerSheet(&pagesPerSheet))) {
+    // If we can't read the value from print settings, just fall back to 1.
+    pagesPerSheet = 1;
+  }
+
+  mPagesPerSheetInfo = &nsPagesPerSheetInfo::LookupInfo(pagesPerSheet);
+  return mPagesPerSheetInfo;
+}
+
+nsPageSequenceFrame::nsPageSequenceFrame(ComputedStyle* aStyle,
+                                         nsPresContext* aPresContext)
+    : nsContainerFrame(aStyle, aPresContext, kClassID),
+      mMaxSheetSize(mWritingMode),
+      mScrollportSize(mWritingMode),
+      mCalledBeginPage(false),
+      mCurrentCanvasListSetup(false) {
+  mPageData = MakeUnique<nsSharedPageData>();
+  mPageData->mHeadFootFont =
+      *PresContext()
+           ->Document()
+           ->GetFontPrefsForLang(aStyle->StyleFont()->mLanguage)
+           ->GetDefaultFont(StyleGenericFontFamily::Serif);
+  mPageData->mHeadFootFont.size =
+      Length::FromPixels(CSSPixel::FromPoints(10.0f));
+  mPageData->mPrintSettings = aPresContext->GetPrintSettings();
+  MOZ_RELEASE_ASSERT(mPageData->mPrintSettings, "How?");
+
+  // Doing this here so we only have to go get these formats once
+  SetPageNumberFormat("pagenumber", "%1$d", true);
+  SetPageNumberFormat("pageofpages", "%1$d of %2$d", false);
+}
+
+nsPageSequenceFrame::~nsPageSequenceFrame() { ResetPrintCanvasList(); }
+
+NS_QUERYFRAME_HEAD(nsPageSequenceFrame)
+  NS_QUERYFRAME_ENTRY(nsPageSequenceFrame)
+NS_QUERYFRAME_TAIL_INHERITING(nsContainerFrame)
+
+//----------------------------------------------------------------------
+
+float nsPageSequenceFrame::GetPrintPreviewScale() const {
+  nsPresContext* pc = PresContext();
+  float scale = pc->GetPrintPreviewScaleForSequenceFrameOrScrollbars();
+
+  WritingMode wm = GetWritingMode();
+  if (pc->IsScreen() && MOZ_LIKELY(mScrollportSize.ISize(wm) > 0 &&
+                                   mScrollportSize.BSize(wm) > 0)) {
+    // For print preview, scale down as-needed to ensure that each of our
+    // sheets will fit in the the scrollport.
+
+    // Check if the current scale is sufficient for our sheets to fit in inline
+    // axis (and if not, reduce the scale so that it will fit).
+    nscoord scaledISize = NSToCoordCeil(mMaxSheetSize.ISize(wm) * scale);
+    if (scaledISize > mScrollportSize.ISize(wm)) {
+      scale *= float(mScrollportSize.ISize(wm)) / float(scaledISize);
+    }
+
+    // Further reduce the scale (if needed) to be sure each sheet will fit in
+    // block axis, too.
+    // NOTE: in general, a scrollport's BSize *could* be unconstrained,
+    // i.e. sized to its contents. If that happens, then shrinking the contents
+    // to fit the scrollport is not a meaningful operation in this axis, so we
+    // skip over this.  But we can be pretty sure that the print-preview UI
+    // will have given the scrollport a fixed size; hence the MOZ_LIKELY here.
+    if (MOZ_LIKELY(mScrollportSize.BSize(wm) != NS_UNCONSTRAINEDSIZE)) {
+      nscoord scaledBSize = NSToCoordCeil(mMaxSheetSize.BSize(wm) * scale);
+      if (scaledBSize > mScrollportSize.BSize(wm)) {
+        scale *= float(mScrollportSize.BSize(wm)) / float(scaledBSize);
+      }
+    }
+  }
+  return scale;
+}
+
+void nsPageSequenceFrame::PopulateReflowOutput(
+    ReflowOutput& aReflowOutput, const ReflowInput& aReflowInput) {
+  // Aim to fill the whole available space, not only so we can act as a
+  // background in print preview but also handle overflow in child page frames
+  // correctly.
+  // Use availableISize so we don't cause a needless horizontal scrollbar.
+  float scale = GetPrintPreviewScale();
+
+  WritingMode wm = aReflowInput.GetWritingMode();
+  nscoord iSize = wm.IsVertical() ? mSize.Height() : mSize.Width();
+  nscoord bSize = wm.IsVertical() ? mSize.Width() : mSize.Height();
+
+  nscoord availableISize = aReflowInput.AvailableISize();
+  nscoord computedBSize = aReflowInput.ComputedBSize();
+  if (MOZ_UNLIKELY(computedBSize == NS_UNCONSTRAINEDSIZE)) {
+    // We have unconstrained BSize, which should only happen if someone calls
+    // SizeToContent() on our window (which we don't expect to happen for
+    // actual user flows, but is possible for fuzzers to trigger). We just nerf
+    // the ReflowInput's contributions to the std::max() expressions below,
+    // which does indeed make us "size to content", via letting std::max()
+    // choose the scaled iSize/bSize expressions.
+    availableISize = computedBSize = 0;
+  }
+  aReflowOutput.ISize(wm) =
+      std::max(NSToCoordFloor(iSize * scale), availableISize);
+  aReflowOutput.BSize(wm) =
+      std::max(NSToCoordFloor(bSize * scale), computedBSize);
+  aReflowOutput.SetOverflowAreasToDesiredBounds();
+}
+
+// Helper function to compute the offset needed to center a child
+// page-frame's margin-box inside our content-box.
+nscoord nsPageSequenceFrame::ComputeCenteringMargin(
+    nscoord aContainerContentBoxWidth, nscoord aChildPaddingBoxWidth,
+    const nsMargin& aChildPhysicalMargin) {
+  // We'll be centering our child's margin-box, so get the size of that:
+  nscoord childMarginBoxWidth =
+      aChildPaddingBoxWidth + aChildPhysicalMargin.LeftRight();
+
+  // When rendered, our child's rect will actually be scaled up by the
+  // print-preview scale factor, via ComputePageSequenceTransform().
+  // We really want to center *that scaled-up rendering* inside of
+  // aContainerContentBoxWidth.  So, we scale up its margin-box here...
+  float scale = GetPrintPreviewScale();
+  nscoord scaledChildMarginBoxWidth =
+      NSToCoordRound(childMarginBoxWidth * scale);
+
+  // ...and see we how much space is left over, when we subtract that scaled-up
+  // size from the container width:
+  nscoord scaledExtraSpace =
+      aContainerContentBoxWidth - scaledChildMarginBoxWidth;
+
+  if (scaledExtraSpace <= 0) {
+    // (Don't bother centering if there's zero/negative space.)
+    return 0;
+  }
+
+  // To center the child, we want to give it an additional left-margin of half
+  // of the extra space.  And then, we have to scale that space back down, so
+  // that it'll produce the correct scaled-up amount when we render (because
+  // rendering will scale it back up):
+  return NSToCoordRound(scaledExtraSpace * 0.5 / scale);
+}
+
+uint32_t nsPageSequenceFrame::GetPagesInFirstSheet() const {
+  nsIFrame* firstSheet = mFrames.FirstChild();
+  if (!firstSheet) {
+    return 0;
+  }
+
+  MOZ_DIAGNOSTIC_ASSERT(firstSheet->IsPrintedSheetFrame());
+  return static_cast<PrintedSheetFrame*>(firstSheet)->GetNumPages();
+}
+
+/*
+ * Note: we largely position/size out our children (page frames) using
+ * \*physical\* x/y/width/height values, because the print preview UI is always
+ * arranged in the same orientation, regardless of writing mode.
+ */
+void nsPageSequenceFrame::Reflow(nsPresContext* aPresContext,
+                                 ReflowOutput& aReflowOutput,
+                                 const ReflowInput& aReflowInput,
+                                 nsReflowStatus& aStatus) {
+  MarkInReflow();
+  MOZ_ASSERT(aPresContext->IsRootPaginatedDocument(),
+             "A Page Sequence is only for real pages");
+  DO_GLOBAL_REFLOW_COUNT("nsPageSequenceFrame");
+  DISPLAY_REFLOW(aPresContext, this, aReflowInput, aReflowOutput, aStatus);
+  MOZ_ASSERT(aStatus.IsEmpty(), "Caller should pass a fresh reflow status!");
+  NS_FRAME_TRACE_REFLOW_IN("nsPageSequenceFrame::Reflow");
+
+  auto CenterPages = [&] {
+    for (nsIFrame* child : mFrames) {
+      nsMargin pageCSSMargin = child->GetUsedMargin();
+      nscoord centeringMargin =
+          ComputeCenteringMargin(aReflowInput.ComputedWidth(),
+                                 child->GetRect().Width(), pageCSSMargin);
+      nscoord newX = pageCSSMargin.left + centeringMargin;
+
+      // Adjust the child's x-position:
+      child->MovePositionBy(nsPoint(newX - child->GetNormalPosition().x, 0));
+    }
+  };
+
+  if (aPresContext->IsScreen()) {
+    // When we're displayed on-screen, the computed size that we're given is
+    // the size of our scrollport. We need to save this for use in
+    // GetPrintPreviewScale.
+    // (NOTE: It's possible but unlikely that we have an unconstrained BSize
+    // here, if we're being sized to content. GetPrintPreviewScale() checks
+    // for and handles this, when making use of this member-var.)
+    mScrollportSize = aReflowInput.ComputedSize();
+  }
+
+  // Don't do incremental reflow until we've taught tables how to do
+  // it right in paginated mode.
+  if (!HasAnyStateBits(NS_FRAME_FIRST_REFLOW)) {
+    // Return our desired size
+    PopulateReflowOutput(aReflowOutput, aReflowInput);
+    FinishAndStoreOverflow(&aReflowOutput);
+
+    if (GetSize() != aReflowOutput.PhysicalSize()) {
+      CenterPages();
+    }
+    return;
+  }
+
+  nsIntMargin unwriteableTwips =
+      mPageData->mPrintSettings->GetUnwriteableMarginInTwips();
+
+  nsIntMargin edgeTwips = mPageData->mPrintSettings->GetEdgeInTwips();
+
+  // sanity check the values. three inches are sometimes needed
+  int32_t threeInches = NS_INCHES_TO_INT_TWIPS(3.0);
+  edgeTwips.EnsureAtMost(
+      nsIntMargin(threeInches, threeInches, threeInches, threeInches));
+  edgeTwips.EnsureAtLeast(unwriteableTwips);
+
+  mPageData->mEdgePaperMargin = nsPresContext::CSSTwipsToAppUnits(edgeTwips);
+
+  // Get the custom page-range state:
+  mPageData->mPrintSettings->GetPageRanges(mPageData->mPageRanges);
+
+  // We use the CSS "margin" property on the -moz-printed-sheet pseudoelement
+  // to determine the space between each printed sheet in print preview.
+  // Keep a running y-offset for each printed sheet.
+  nscoord y = 0;
+
+  // These represent the maximum sheet size across all our sheets (in each
+  // axis), inflated a bit to account for the -moz-printed-sheet 'margin'.
+  nscoord maxInflatedSheetWidth = 0;
+  nscoord maxInflatedSheetHeight = 0;
+
+  // Tile the sheets vertically
+  for (nsIFrame* kidFrame : mFrames) {
+    // Set the shared data into the page frame before reflow
+    MOZ_ASSERT(kidFrame->IsPrintedSheetFrame(),
+               "we're only expecting PrintedSheetFrame as children");
+    auto* sheet = static_cast<PrintedSheetFrame*>(kidFrame);
+    sheet->SetSharedPageData(mPageData.get());
+
+    // If we want to reliably access the nsPageFrame before reflowing the sheet
+    // frame, we need to call this:
+    sheet->ClaimPageFrameFromPrevInFlow();
+
+    const nsSize sheetSize = sheet->PrecomputeSheetSize(aPresContext);
+
+    // Reflow the sheet
+    ReflowInput kidReflowInput(
+        aPresContext, aReflowInput, kidFrame,
+        LogicalSize(kidFrame->GetWritingMode(), sheetSize));
+    kidReflowInput.mBreakType = ReflowInput::BreakType::Page;
+
+    ReflowOutput kidReflowOutput(kidReflowInput);
+    nsReflowStatus status;
+
+    kidReflowInput.SetComputedISize(kidReflowInput.AvailableISize());
+    // kidReflowInput.SetComputedHeight(kidReflowInput.AvailableHeight());
+    PR_PL(("AV ISize: %d   BSize: %d\n", kidReflowInput.AvailableISize(),
+           kidReflowInput.AvailableBSize()));
+
+    nsMargin pageCSSMargin = kidReflowInput.ComputedPhysicalMargin();
+    y += pageCSSMargin.top;
+
+    nscoord x = pageCSSMargin.left;
+
+    // Place and size the sheet.
+    ReflowChild(kidFrame, aPresContext, kidReflowOutput, kidReflowInput, x, y,
+                ReflowChildFlags::Default, status);
+
+    FinishReflowChild(kidFrame, aPresContext, kidReflowOutput, &kidReflowInput,
+                      x, y, ReflowChildFlags::Default);
+    MOZ_ASSERT(kidFrame->GetSize() == sheetSize,
+               "PrintedSheetFrame::PrecomputeSheetSize gave the wrong size!");
+    y += kidReflowOutput.Height();
+    y += pageCSSMargin.bottom;
+
+    maxInflatedSheetWidth =
+        std::max(maxInflatedSheetWidth,
+                 kidReflowOutput.Width() + pageCSSMargin.LeftRight());
+    maxInflatedSheetHeight =
+        std::max(maxInflatedSheetHeight,
+                 kidReflowOutput.Height() + pageCSSMargin.TopBottom());
+
+    // Is the sheet complete?
+    nsIFrame* kidNextInFlow = kidFrame->GetNextInFlow();
+
+    if (status.IsFullyComplete()) {
+      NS_ASSERTION(!kidNextInFlow, "bad child flow list");
+    } else if (!kidNextInFlow) {
+      // The sheet isn't complete and it doesn't have a next-in-flow, so
+      // create a continuing sheet.
+      nsIFrame* continuingSheet =
+          PresShell()->FrameConstructor()->CreateContinuingFrame(kidFrame,
+                                                                 this);
+
+      // Add it to our child list
+      mFrames.InsertFrame(nullptr, kidFrame, continuingSheet);
+    }
+  }
+
+  nsAutoString formattedDateString;
+  PRTime now = PR_Now();
+  mozilla::intl::DateTimeFormat::StyleBag style;
+  style.date = Some(mozilla::intl::DateTimeFormat::Style::Short);
+  style.time = Some(mozilla::intl::DateTimeFormat::Style::Short);
+  if (NS_SUCCEEDED(mozilla::intl::AppDateTimeFormat::Format(
+          style, now, formattedDateString))) {
+    SetDateTimeStr(formattedDateString);
+  }
+
+  // cache the size so we can set the desired size for the other reflows that
+  // happen.  Since we're tiling our sheets vertically: in the x axis, we are
+  // as wide as our widest sheet (inflated via "margin"); and in the y axis,
+  // we're as tall as the sum of our sheets' inflated heights, which the 'y'
+  // variable is conveniently storing at this point.
+  mSize = nsSize(maxInflatedSheetWidth, y);
+
+  if (aPresContext->IsScreen()) {
+    // Also cache the maximum size of all our sheets, to use together with the
+    // scrollport size (available as our computed size, and captured higher up
+    // in this function), so that we can scale to ensure that every sheet will
+    // fit in the scrollport.
+    WritingMode wm = aReflowInput.GetWritingMode();
+    mMaxSheetSize =
+        LogicalSize(wm, nsSize(maxInflatedSheetWidth, maxInflatedSheetHeight));
+  }
+
+  // Return our desired size
+  // Adjust the reflow size by PrintPreviewScale so the scrollbars end up the
+  // correct size
+  PopulateReflowOutput(aReflowOutput, aReflowInput);
+
+  FinishAndStoreOverflow(&aReflowOutput);
+
+  // Now center our pages.
+  CenterPages();
+
+  NS_FRAME_TRACE_REFLOW_OUT("nsPageSequenceFrame::Reflow", aStatus);
+}
+
+//----------------------------------------------------------------------
+
+#ifdef DEBUG_FRAME_DUMP
+nsresult nsPageSequenceFrame::GetFrameName(nsAString& aResult) const {
+  return MakeFrameName(u"PageSequence"_ns, aResult);
+}
+#endif
+
+// Helper Function
+void nsPageSequenceFrame::SetPageNumberFormat(const char* aPropName,
+                                              const char* aDefPropVal,
+                                              bool aPageNumOnly) {
+  // Doing this here so we only have to go get these formats once
+  nsAutoString pageNumberFormat;
+  // Now go get the Localized Page Formating String
+  nsresult rv = nsContentUtils::GetLocalizedString(
+      nsContentUtils::ePRINTING_PROPERTIES, aPropName, pageNumberFormat);
+  if (NS_FAILED(rv)) {  // back stop formatting
+    pageNumberFormat.AssignASCII(aDefPropVal);
+  }
+
+  SetPageNumberFormat(pageNumberFormat, aPageNumOnly);
+}
+
+nsresult nsPageSequenceFrame::StartPrint(nsPresContext* aPresContext,
+                                         nsIPrintSettings* aPrintSettings,
+                                         const nsAString& aDocTitle,
+                                         const nsAString& aDocURL) {
+  NS_ENSURE_ARG_POINTER(aPresContext);
+  NS_ENSURE_ARG_POINTER(aPrintSettings);
+
+  if (!mPageData->mPrintSettings) {
+    mPageData->mPrintSettings = aPrintSettings;
+  }
+
+  if (!aDocTitle.IsEmpty()) {
+    mPageData->mDocTitle = aDocTitle;
+  }
+  if (!aDocURL.IsEmpty()) {
+    mPageData->mDocURL = aDocURL;
+  }
+
+  // Begin printing of the document
+  mCurrentSheetIdx = 0;
+  return NS_OK;
+}
+
+static void GetPrintCanvasElementsInFrame(
+    nsIFrame* aFrame, nsTArray<RefPtr<HTMLCanvasElement>>* aArr) {
+  if (!aFrame) {
+    return;
+  }
+  for (const auto& childList : aFrame->ChildLists()) {
+    for (nsIFrame* child : childList.mList) {
+      // Check if child is a nsHTMLCanvasFrame.
+      nsHTMLCanvasFrame* canvasFrame = do_QueryFrame(child);
+
+      // If there is a canvasFrame, try to get actual canvas element.
+      if (canvasFrame) {
+        HTMLCanvasElement* canvas =
+            HTMLCanvasElement::FromNodeOrNull(canvasFrame->GetContent());
+        if (canvas && canvas->GetMozPrintCallback()) {
+          aArr->AppendElement(canvas);
+          continue;
+        }
+      }
+
+      if (!child->PrincipalChildList().FirstChild()) {
+        nsSubDocumentFrame* subdocumentFrame = do_QueryFrame(child);
+        if (subdocumentFrame) {
+          // Descend into the subdocument
+          nsIFrame* root = subdocumentFrame->GetSubdocumentRootFrame();
+          child = root;
+        }
+      }
+      // The current child is not a nsHTMLCanvasFrame OR it is but there is
+      // no HTMLCanvasElement on it. Check if children of `child` might
+      // contain a HTMLCanvasElement.
+      GetPrintCanvasElementsInFrame(child, aArr);
+    }
+  }
+}
+
+// Note: this isn't quite a full tree traversal, since we exclude any
+// nsPageFame children that have the NS_PAGE_SKIPPED_BY_CUSTOM_RANGE state-bit.
+static void GetPrintCanvasElementsInSheet(
+    PrintedSheetFrame* aSheetFrame, nsTArray<RefPtr<HTMLCanvasElement>>* aArr) {
+  MOZ_ASSERT(aSheetFrame, "Caller should've null-checked for us already");
+  for (nsIFrame* child : aSheetFrame->PrincipalChildList()) {
+    // Exclude any pages that are technically children but are skipped by a
+    // custom range; they're not meant to be printed, so we don't want to
+    // waste time rendering their canvas descendants.
+    MOZ_ASSERT(child->IsPageFrame(),
+               "PrintedSheetFrame's children must all be nsPageFrames");
+    auto* pageFrame = static_cast<nsPageFrame*>(child);
+    if (!pageFrame->HasAnyStateBits(NS_PAGE_SKIPPED_BY_CUSTOM_RANGE)) {
+      GetPrintCanvasElementsInFrame(pageFrame, aArr);
+    }
+  }
+}
+
+PrintedSheetFrame* nsPageSequenceFrame::GetCurrentSheetFrame() {
+  uint32_t i = 0;
+  for (nsIFrame* child : mFrames) {
+    MOZ_ASSERT(child->IsPrintedSheetFrame(),
+               "Our children must all be PrintedSheetFrame");
+    if (i == mCurrentSheetIdx) {
+      return static_cast<PrintedSheetFrame*>(child);
+    }
+    ++i;
+  }
+  return nullptr;
+}
+
+nsresult nsPageSequenceFrame::PrePrintNextSheet(nsITimerCallback* aCallback,
+                                                bool* aDone) {
+  PrintedSheetFrame* currentSheet = GetCurrentSheetFrame();
+  if (!currentSheet) {
+    *aDone = true;
+    return NS_ERROR_FAILURE;
+  }
+
+  if (!PresContext()->IsRootPaginatedDocument()) {
+    // XXXdholbert I don't think this clause is ever actually visited in
+    // practice... Maybe we should warn & return a failure code?  There used to
+    // be a comment here explaining why we don't need to proceed past this
+    // point for print preview, but in fact, this function isn't even called for
+    // print preview.
+    *aDone = true;
+    return NS_OK;
+  }
+
+  // If the canvasList is null, then generate it and start the render
+  // process for all the canvas.
+  if (!mCurrentCanvasListSetup) {
+    mCurrentCanvasListSetup = true;
+    GetPrintCanvasElementsInSheet(currentSheet, &mCurrentCanvasList);
+
+    if (!mCurrentCanvasList.IsEmpty()) {
+      nsresult rv = NS_OK;
+
+      // Begin printing of the document
+      nsDeviceContext* dc = PresContext()->DeviceContext();
+      PR_PL(("\n"));
+      PR_PL(("***************** BeginPage *****************\n"));
+      rv = dc->BeginPage();
+      NS_ENSURE_SUCCESS(rv, rv);
+
+      mCalledBeginPage = true;
+
+      UniquePtr<gfxContext> renderingContext = dc->CreateRenderingContext();
+      NS_ENSURE_TRUE(renderingContext, NS_ERROR_OUT_OF_MEMORY);
+
+      DrawTarget* drawTarget = renderingContext->GetDrawTarget();
+      if (NS_WARN_IF(!drawTarget)) {
+        return NS_ERROR_FAILURE;
+      }
+
+      for (HTMLCanvasElement* canvas : Reversed(mCurrentCanvasList)) {
+        nsIntSize size = canvas->GetSize();
+
+        RefPtr<DrawTarget> canvasTarget =
+            drawTarget->CreateSimilarDrawTarget(size, drawTarget->GetFormat());
+        if (!canvasTarget) {
+          continue;
+        }
+
+        nsICanvasRenderingContextInternal* ctx = canvas->GetCurrentContext();
+        if (!ctx) {
+          continue;
+        }
+
+        // Initialize the context with the new DrawTarget.
+        ctx->InitializeWithDrawTarget(nullptr, WrapNotNull(canvasTarget));
+
+        // Start the rendering process.
+        // Note: Other than drawing to our CanvasRenderingContext2D, the
+        // callback cannot access or mutate our static clone document.  It is
+        // evaluated in its original context (the window of the original
+        // document) of course, and our canvas has a strong ref to the
+        // original HTMLCanvasElement (in mOriginalCanvas) so that if the
+        // callback calls GetCanvas() on our CanvasRenderingContext2D (passed
+        // to it via a MozCanvasPrintState argument) it will be given the
+        // original 'canvas' element.
+        AutoWeakFrame weakFrame = this;
+        canvas->DispatchPrintCallback(aCallback);
+        NS_ENSURE_STATE(weakFrame.IsAlive());
+      }
+    }
+  }
+  uint32_t doneCounter = 0;
+  for (HTMLCanvasElement* canvas : mCurrentCanvasList) {
+    if (canvas->IsPrintCallbackDone()) {
+      doneCounter++;
+    }
+  }
+  // If all canvas have finished rendering, return true, otherwise false.
+  *aDone = doneCounter == mCurrentCanvasList.Length();
+
+  return NS_OK;
+}
+
+void nsPageSequenceFrame::ResetPrintCanvasList() {
+  for (int32_t i = mCurrentCanvasList.Length() - 1; i >= 0; i--) {
+    HTMLCanvasElement* canvas = mCurrentCanvasList[i];
+    canvas->ResetPrintCallback();
+  }
+
+  mCurrentCanvasList.Clear();
+  mCurrentCanvasListSetup = false;
+}
+
+nsresult nsPageSequenceFrame::PrintNextSheet() {
+  // Note: When print al the pages or a page range the printed page shows the
+  // actual page number, when printing selection it prints the page number
+  // starting with the first page of the selection. For example if the user has
+  // a selection that starts on page 2 and ends on page 3, the page numbers when
+  // print are 1 and then two (which is different than printing a page range,
+  // where the page numbers would have been 2 and then 3)
+
+  PrintedSheetFrame* currentSheetFrame = GetCurrentSheetFrame();
+  if (!currentSheetFrame) {
+    return NS_ERROR_FAILURE;
+  }
+
+  nsresult rv = NS_OK;
+
+  nsDeviceContext* dc = PresContext()->DeviceContext();
+
+  if (PresContext()->IsRootPaginatedDocument()) {
+    if (!mCalledBeginPage) {
+      // We must make sure BeginPage() has been called since some printing
+      // backends can't give us a valid rendering context for a [physical]
+      // page otherwise.
+      PR_PL(("\n"));
+      PR_PL(("***************** BeginPage *****************\n"));
+      rv = dc->BeginPage();
+      NS_ENSURE_SUCCESS(rv, rv);
+    }
+  }
+
+  PR_PL(("SeqFr::PrintNextSheet -> %p SheetIdx: %d", currentSheetFrame,
+         mCurrentSheetIdx));
+
+  // CreateRenderingContext can fail
+  UniquePtr<gfxContext> gCtx = dc->CreateRenderingContext();
+  NS_ENSURE_TRUE(gCtx, NS_ERROR_OUT_OF_MEMORY);
+
+  nsRect drawingRect(nsPoint(0, 0), currentSheetFrame->GetSize());
+  nsRegion drawingRegion(drawingRect);
+  nsLayoutUtils::PaintFrame(gCtx.get(), currentSheetFrame, drawingRegion,
+                            NS_RGBA(0, 0, 0, 0),
+                            nsDisplayListBuilderMode::PaintForPrinting,
+                            nsLayoutUtils::PaintFrameFlags::SyncDecodeImages);
+  return rv;
+}
+
+nsresult nsPageSequenceFrame::DoPageEnd() {
+  nsresult rv = NS_OK;
+  if (PresContext()->IsRootPaginatedDocument()) {
+    PR_PL(("***************** End Page (DoPageEnd) *****************\n"));
+    rv = PresContext()->DeviceContext()->EndPage();
+    // Fall through to clean up resources/state below even if EndPage failed.
+  }
+
+  ResetPrintCanvasList();
+  mCalledBeginPage = false;
+
+  mCurrentSheetIdx++;
+
+  return rv;
+}
+
+static gfx::Matrix4x4 ComputePageSequenceTransform(const nsIFrame* aFrame,
+                                                   float aAppUnitsPerPixel) {
+  MOZ_ASSERT(aFrame->IsPageSequenceFrame());
+  float scale =
+      static_cast<const nsPageSequenceFrame*>(aFrame)->GetPrintPreviewScale();
+  return gfx::Matrix4x4::Scaling(scale, scale, 1);
+}
+
+nsIFrame::ComputeTransformFunction nsPageSequenceFrame::GetTransformGetter()
+    const {
+  return ComputePageSequenceTransform;
+}
+
+void nsPageSequenceFrame::BuildDisplayList(nsDisplayListBuilder* aBuilder,
+                                           const nsDisplayListSet& aLists) {
+  aBuilder->SetDisablePartialUpdates(true);
+  DisplayBorderBackgroundOutline(aBuilder, aLists);
+
+  nsDisplayList content(aBuilder);
+
+  {
+    // Clear clip state while we construct the children of the
+    // nsDisplayTransform, since they'll be in a different coordinate system.
+    DisplayListClipState::AutoSaveRestore clipState(aBuilder);
+    clipState.Clear();
+
+    nsIFrame* child = PrincipalChildList().FirstChild();
+    nsRect visible = aBuilder->GetVisibleRect();
+    visible.ScaleInverseRoundOut(GetPrintPreviewScale());
+
+    while (child) {
+      if (child->InkOverflowRectRelativeToParent().Intersects(visible)) {
+        nsDisplayListBuilder::AutoBuildingDisplayList buildingForChild(
+            aBuilder, child, visible - child->GetPosition(),
+            visible - child->GetPosition());
+        child->BuildDisplayListForStackingContext(aBuilder, &content);
+        aBuilder->ResetMarkedFramesForDisplayList(this);
+      }
+      child = child->GetNextSibling();
+    }
+  }
+
+  content.AppendNewToTop<nsDisplayTransform>(
+      aBuilder, this, &content, content.GetBuildingRect(),
+      nsDisplayTransform::WithTransformGetter);
+
+  aLists.Content()->AppendToTop(&content);
+}
+
+//------------------------------------------------------------------------------
+void nsPageSequenceFrame::SetPageNumberFormat(const nsAString& aFormatStr,
+                                              bool aForPageNumOnly) {
+  NS_ASSERTION(mPageData != nullptr, "mPageData string cannot be null!");
+
+  if (aForPageNumOnly) {
+    mPageData->mPageNumFormat = aFormatStr;
+  } else {
+    mPageData->mPageNumAndTotalsFormat = aFormatStr;
+  }
+}
+
+//------------------------------------------------------------------------------
+void nsPageSequenceFrame::SetDateTimeStr(const nsAString& aDateTimeStr) {
+  NS_ASSERTION(mPageData != nullptr, "mPageData string cannot be null!");
+
+  mPageData->mDateTimeStr = aDateTimeStr;
+}