diff options
Diffstat (limited to 'layout/generic/nsPageContentFrame.cpp')
| -rw-r--r-- | layout/generic/nsPageContentFrame.cpp | 452 |
1 files changed, 452 insertions, 0 deletions
diff --git a/layout/generic/nsPageContentFrame.cpp b/layout/generic/nsPageContentFrame.cpp new file mode 100644 index 0000000000..6f277190ee --- /dev/null +++ b/layout/generic/nsPageContentFrame.cpp @@ -0,0 +1,452 @@ +/* -*- 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 "nsPageContentFrame.h" + +#include "mozilla/PresShell.h" +#include "mozilla/PresShellInlines.h" +#include "mozilla/StaticPrefs_layout.h" +#include "mozilla/dom/Document.h" + +#include "nsContentUtils.h" +#include "nsPageFrame.h" +#include "nsCSSFrameConstructor.h" +#include "nsPresContext.h" +#include "nsGkAtoms.h" +#include "nsLayoutUtils.h" +#include "nsPageSequenceFrame.h" + +using namespace mozilla; + +nsPageContentFrame* NS_NewPageContentFrame( + PresShell* aPresShell, ComputedStyle* aStyle, + already_AddRefed<const nsAtom> aPageName) { + return new (aPresShell) nsPageContentFrame( + aStyle, aPresShell->GetPresContext(), std::move(aPageName)); +} + +NS_IMPL_FRAMEARENA_HELPERS(nsPageContentFrame) + +void nsPageContentFrame::Reflow(nsPresContext* aPresContext, + ReflowOutput& aReflowOutput, + const ReflowInput& aReflowInput, + nsReflowStatus& aStatus) { + MarkInReflow(); + DO_GLOBAL_REFLOW_COUNT("nsPageContentFrame"); + DISPLAY_REFLOW(aPresContext, this, aReflowInput, aReflowOutput, aStatus); + MOZ_ASSERT(aStatus.IsEmpty(), "Caller should pass a fresh reflow status!"); + MOZ_ASSERT(mPD, "Need a pointer to nsSharedPageData before reflow starts"); + + if (GetPrevInFlow() && HasAnyStateBits(NS_FRAME_FIRST_REFLOW)) { + nsresult rv = + aPresContext->PresShell()->FrameConstructor()->ReplicateFixedFrames( + this); + if (NS_FAILED(rv)) { + return; + } + } + + // Set our size up front, since some parts of reflow depend on it + // being already set. Note that the computed height may be + // unconstrained; that's ok. Consumers should watch out for that. + const nsSize maxSize(aReflowInput.ComputedWidth(), + aReflowInput.ComputedHeight()); + SetSize(maxSize); + + // Writing mode for the page content frame. + const WritingMode pcfWM = aReflowInput.GetWritingMode(); + aReflowOutput.ISize(pcfWM) = aReflowInput.ComputedISize(); + if (aReflowInput.ComputedBSize() != NS_UNCONSTRAINEDSIZE) { + aReflowOutput.BSize(pcfWM) = aReflowInput.ComputedBSize(); + } + aReflowOutput.SetOverflowAreasToDesiredBounds(); + + // A PageContentFrame must always have one child: the canvas frame. + // Resize our frame allowing it only to be as big as we are + // XXX Pay attention to the page's border and padding... + if (mFrames.NotEmpty()) { + nsIFrame* const frame = mFrames.FirstChild(); + const WritingMode frameWM = frame->GetWritingMode(); + const LogicalSize logicalSize(frameWM, maxSize); + ReflowInput kidReflowInput(aPresContext, aReflowInput, frame, logicalSize); + kidReflowInput.SetComputedBSize(logicalSize.BSize(frameWM)); + ReflowOutput kidReflowOutput(kidReflowInput); + ReflowChild(frame, aPresContext, kidReflowOutput, kidReflowInput, 0, 0, + ReflowChildFlags::Default, aStatus); + + // The document element's background should cover the entire canvas, so + // take into account the combined area and any space taken up by + // absolutely positioned elements + nsMargin padding(0, 0, 0, 0); + + // XXXbz this screws up percentage padding (sets padding to zero + // in the percentage padding case) + frame->StylePadding()->GetPadding(padding); + + // This is for shrink-to-fit, and therefore we want to use the + // scrollable overflow, since the purpose of shrink to fit is to + // make the content that ought to be reachable (represented by the + // scrollable overflow) fit in the page. + if (frame->HasOverflowAreas()) { + // The background covers the content area and padding area, so check + // for children sticking outside the child frame's padding edge + nscoord xmost = kidReflowOutput.ScrollableOverflow().XMost(); + if (xmost > kidReflowOutput.Width()) { + const nscoord widthToFit = + xmost + padding.right + + kidReflowInput.mStyleBorder->GetComputedBorderWidth(eSideRight); + const float ratio = float(maxSize.width) / float(widthToFit); + NS_ASSERTION(ratio >= 0.0 && ratio < 1.0, + "invalid shrink-to-fit ratio"); + mPD->mShrinkToFitRatio = std::min(mPD->mShrinkToFitRatio, ratio); + } + // In the case of pdf.js documents, we also want to consider the height, + // so that we don't clip the page in either axis if the aspect ratio of + // the PDF doesn't match the destination. + if (nsContentUtils::IsPDFJS(PresContext()->Document()->GetPrincipal())) { + nscoord ymost = kidReflowOutput.ScrollableOverflow().YMost(); + if (ymost > kidReflowOutput.Height()) { + const nscoord heightToFit = + ymost + padding.bottom + + kidReflowInput.mStyleBorder->GetComputedBorderWidth(eSideBottom); + const float ratio = float(maxSize.height) / float(heightToFit); + MOZ_ASSERT(ratio >= 0.0 && ratio < 1.0); + mPD->mShrinkToFitRatio = std::min(mPD->mShrinkToFitRatio, ratio); + } + + // pdf.js pages should never overflow given the scaling above. + // nsPrintJob::SetupToPrintContent ignores some ratios close to 1.0 + // though and doesn't reflow us again in that case, so we need to clear + // the overflow area here in case that happens. (bug 1689789) + frame->ClearOverflowRects(); + kidReflowOutput.mOverflowAreas = aReflowOutput.mOverflowAreas; + } + } + + // Place and size the child + FinishReflowChild(frame, aPresContext, kidReflowOutput, &kidReflowInput, 0, + 0, ReflowChildFlags::Default); + + NS_ASSERTION(aPresContext->IsDynamic() || !aStatus.IsFullyComplete() || + !frame->GetNextInFlow(), + "bad child flow list"); + + aReflowOutput.mOverflowAreas.UnionWith(kidReflowOutput.mOverflowAreas); + } + + FinishAndStoreOverflow(&aReflowOutput); + + // Reflow our fixed frames + nsReflowStatus fixedStatus; + ReflowAbsoluteFrames(aPresContext, aReflowOutput, aReflowInput, fixedStatus); + NS_ASSERTION(fixedStatus.IsComplete(), + "fixed frames can be truncated, but not incomplete"); + + if (StaticPrefs::layout_display_list_improve_fragmentation() && + mFrames.NotEmpty()) { + auto* const previous = + static_cast<nsPageContentFrame*>(GetPrevContinuation()); + const nscoord previousPageOverflow = + previous ? previous->mRemainingOverflow : 0; + const nsSize containerSize(aReflowInput.AvailableWidth(), + aReflowInput.AvailableHeight()); + const nscoord pageBSize = GetLogicalRect(containerSize).BSize(pcfWM); + const nscoord overflowBSize = + LogicalRect(pcfWM, ScrollableOverflowRect(), GetSize()).BEnd(pcfWM); + const nscoord currentPageOverflow = overflowBSize - pageBSize; + nscoord remainingOverflow = + std::max(currentPageOverflow, previousPageOverflow - pageBSize); + + if (aStatus.IsFullyComplete() && remainingOverflow > 0) { + // If we have ScrollableOverflow off the end of our page, then we report + // ourselves as overflow-incomplete in order to produce an additional + // content-less page, which we expect to draw our overflow on our behalf. + aStatus.SetOverflowIncomplete(); + } + + mRemainingOverflow = std::max(remainingOverflow, 0); + } +} + +using PageAndOffset = std::pair<nsPageContentFrame*, nscoord>; + +// Returns the previous continuation PageContentFrames that have overflow areas, +// and their offsets to the top of the given PageContentFrame |aPage|. Since the +// iteration is done backwards, the returned pages are arranged in descending +// order of page number. +static nsTArray<PageAndOffset> GetPreviousPagesWithOverflow( + nsPageContentFrame* aPage) { + nsTArray<PageAndOffset> pages(8); + + auto GetPreviousPageContentFrame = [](nsPageContentFrame* aPageCF) { + nsIFrame* prevCont = aPageCF->GetPrevContinuation(); + MOZ_ASSERT(!prevCont || prevCont->IsPageContentFrame(), + "Expected nsPageContentFrame or nullptr"); + + return static_cast<nsPageContentFrame*>(prevCont); + }; + + nsPageContentFrame* pageCF = aPage; + // The collective height of all prev-continuations we've traversed so far: + nscoord offsetToCurrentPageBStart = 0; + const auto wm = pageCF->GetWritingMode(); + while ((pageCF = GetPreviousPageContentFrame(pageCF))) { + offsetToCurrentPageBStart += pageCF->BSize(wm); + + if (pageCF->HasOverflowAreas()) { + pages.EmplaceBack(pageCF, offsetToCurrentPageBStart); + } + } + + return pages; +} + +static void BuildPreviousPageOverflow(nsDisplayListBuilder* aBuilder, + nsPageFrame* aPageFrame, + nsPageContentFrame* aCurrentPageCF, + const nsDisplayListSet& aLists) { + const auto previousPagesAndOffsets = + GetPreviousPagesWithOverflow(aCurrentPageCF); + + const auto wm = aCurrentPageCF->GetWritingMode(); + for (const PageAndOffset& pair : Reversed(previousPagesAndOffsets)) { + auto* prevPageCF = pair.first; + const nscoord offsetToCurrentPageBStart = pair.second; + // Only scrollable overflow create new pages, not ink overflow. + const LogicalRect scrollableOverflow( + wm, prevPageCF->ScrollableOverflowRectRelativeToSelf(), + prevPageCF->GetSize()); + const auto remainingOverflow = + scrollableOverflow.BEnd(wm) - offsetToCurrentPageBStart; + if (remainingOverflow <= 0) { + continue; + } + + // This rect represents the piece of prevPageCF's overflow that ends up on + // the current pageContentFrame (in prevPageCF's coordinate system). + // Note that we use InkOverflow here since this is for painting. + LogicalRect overflowRect(wm, prevPageCF->InkOverflowRectRelativeToSelf(), + prevPageCF->GetSize()); + overflowRect.BStart(wm) = offsetToCurrentPageBStart; + overflowRect.BSize(wm) = std::min(remainingOverflow, prevPageCF->BSize(wm)); + + { + // Convert the overflowRect to the coordinate system of aPageFrame, and + // set it as the visible rect for display list building. + const nsRect visibleRect = + overflowRect.GetPhysicalRect(wm, prevPageCF->GetSize()) + + prevPageCF->GetOffsetTo(aPageFrame); + nsDisplayListBuilder::AutoBuildingDisplayList buildingForChild( + aBuilder, aPageFrame, visibleRect, visibleRect); + + // This part is tricky. Because display items are positioned based on the + // frame tree, building a display list for the previous page yields + // display items that are outside of the current page bounds. + // To fix that, an additional reference frame offset is added, which + // shifts the display items down (block axis) as if the current and + // previous page were one long page in the same coordinate system. + const nsSize containerSize = aPageFrame->GetSize(); + LogicalPoint pageOffset(wm, aCurrentPageCF->GetOffsetTo(prevPageCF), + containerSize); + pageOffset.B(wm) -= offsetToCurrentPageBStart; + buildingForChild.SetAdditionalOffset( + pageOffset.GetPhysicalPoint(wm, containerSize)); + + aPageFrame->BuildDisplayListForChild(aBuilder, prevPageCF, aLists); + } + } +} + +/** + * Remove all leaf display items that are not for descendants of + * aBuilder->GetReferenceFrame() from aList. + * @param aPage the page we're constructing the display list for + * @param aList the list that is modified in-place + */ +static void PruneDisplayListForExtraPage(nsDisplayListBuilder* aBuilder, + nsPageFrame* aPage, + nsDisplayList* aList) { + for (nsDisplayItem* i : aList->TakeItems()) { + if (!i) break; + nsDisplayList* subList = i->GetSameCoordinateSystemChildren(); + if (subList) { + PruneDisplayListForExtraPage(aBuilder, aPage, subList); + i->UpdateBounds(aBuilder); + } else { + nsIFrame* f = i->Frame(); + if (!nsLayoutUtils::IsProperAncestorFrameCrossDocInProcess(aPage, f)) { + // We're throwing this away so call its destructor now. The memory + // is owned by aBuilder which destroys all items at once. + i->Destroy(aBuilder); + continue; + } + } + aList->AppendToTop(i); + } +} + +static void BuildDisplayListForExtraPage(nsDisplayListBuilder* aBuilder, + nsPageFrame* aPage, + nsIFrame* aExtraPage, + nsDisplayList* aList) { + // The only content in aExtraPage we care about is out-of-flow content from + // aPage, whose placeholders have occurred in aExtraPage. If + // NS_FRAME_FORCE_DISPLAY_LIST_DESCEND_INTO is not set, then aExtraPage has + // no such content. + if (!aExtraPage->HasAnyStateBits(NS_FRAME_FORCE_DISPLAY_LIST_DESCEND_INTO)) { + return; + } + nsDisplayList list(aBuilder); + aExtraPage->BuildDisplayListForStackingContext(aBuilder, &list); + PruneDisplayListForExtraPage(aBuilder, aPage, &list); + aList->AppendToTop(&list); +} + +static gfx::Matrix4x4 ComputePageContentTransform(const nsIFrame* aFrame, + float aAppUnitsPerPixel) { + float scale = aFrame->PresContext()->GetPageScale(); + return gfx::Matrix4x4::Scaling(scale, scale, 1); +} + +nsIFrame::ComputeTransformFunction nsPageContentFrame::GetTransformGetter() + const { + return ComputePageContentTransform; +} + +void nsPageContentFrame::BuildDisplayList(nsDisplayListBuilder* aBuilder, + const nsDisplayListSet& aLists) { + MOZ_ASSERT(GetParent()); + MOZ_ASSERT(GetParent()->IsPageFrame()); + auto* pageFrame = static_cast<nsPageFrame*>(GetParent()); + auto pageNum = pageFrame->GetPageNum(); + NS_ASSERTION(pageNum <= 255, "Too many pages to handle OOFs"); + + if (aBuilder->GetBuildingExtraPagesForPageNum()) { + return mozilla::ViewportFrame::BuildDisplayList(aBuilder, aLists); + } + + nsDisplayListCollection set(aBuilder); + + nsDisplayList content(aBuilder); + { + const nsRect clipRect(aBuilder->ToReferenceFrame(this), GetSize()); + DisplayListClipState::AutoSaveRestore clipState(aBuilder); + + // Overwrite current clip, since we're going to wrap in a transform and the + // current clip is no longer meaningful. + clipState.Clear(); + clipState.ClipContentDescendants(clipRect); + + if (StaticPrefs::layout_display_list_improve_fragmentation() && + pageNum <= 255) { + nsDisplayListBuilder::AutoPageNumberSetter p(aBuilder, pageNum); + BuildPreviousPageOverflow(aBuilder, pageFrame, this, set); + } + mozilla::ViewportFrame::BuildDisplayList(aBuilder, set); + + set.SerializeWithCorrectZOrder(&content, GetContent()); + + // We may need to paint out-of-flow frames whose placeholders are on other + // pages. Add those pages to our display list. Note that out-of-flow frames + // can't be placed after their placeholders so + // we don't have to process earlier pages. The display lists for + // these extra pages are pruned so that only display items for the + // page we currently care about (which we would have reached by + // following placeholders to their out-of-flows) end up on the list. + // + // Stacking context frames that wrap content on their normal page, + // as well as OOF content for this page will have their container + // items duplicated. We tell the builder to include our page number + // in the unique key for any extra page items so that they can be + // differentiated from the ones created on the normal page. + if (pageNum <= 255) { + const nsRect overflowRect = ScrollableOverflowRectRelativeToSelf(); + nsDisplayListBuilder::AutoPageNumberSetter p(aBuilder, pageNum); + + // The static_cast here is technically unnecessary, but it helps + // devirtualize the GetNextContinuation() function call if pcf has a + // concrete type (with an inherited `final` GetNextContinuation() impl). + auto* pageCF = this; + while ((pageCF = static_cast<nsPageContentFrame*>( + pageCF->GetNextContinuation()))) { + nsRect childVisible = overflowRect + GetOffsetTo(pageCF); + + nsDisplayListBuilder::AutoBuildingDisplayList buildingForChild( + aBuilder, pageCF, childVisible, childVisible); + BuildDisplayListForExtraPage(aBuilder, pageFrame, pageCF, &content); + } + } + + // Add the canvas background color to the bottom of the list. This + // happens after we've built the list so that AddCanvasBackgroundColorItem + // can monkey with the contents if necessary. + const nsRect backgroundRect(aBuilder->ToReferenceFrame(this), GetSize()); + PresShell()->AddCanvasBackgroundColorItem( + aBuilder, &content, this, backgroundRect, NS_RGBA(0, 0, 0, 0)); + } + + content.AppendNewToTop<nsDisplayTransform>( + aBuilder, this, &content, content.GetBuildingRect(), + nsDisplayTransform::WithTransformGetter); + + aLists.Content()->AppendToTop(&content); +} + +void nsPageContentFrame::AppendDirectlyOwnedAnonBoxes( + nsTArray<OwnedAnonBox>& aResult) { + MOZ_ASSERT(mFrames.FirstChild(), + "pageContentFrame must have a canvasFrame child"); + aResult.AppendElement(mFrames.FirstChild()); +} + +void nsPageContentFrame::EnsurePageName() { + MOZ_ASSERT(HasAnyStateBits(NS_FRAME_FIRST_REFLOW), + "Should only have been called on first reflow"); + if (mPageName) { + return; + } + MOZ_ASSERT(!GetPrevInFlow(), + "Only the first page should initially have a null page name."); + // This was the first page, we need to find our own page name and then set + // our computed style based on that. + mPageName = ComputePageValue(); + + MOZ_ASSERT(mPageName, "Page name should never be null"); + // We don't need to resolve any further styling if the page name is empty. + if (mPageName == nsGkAtoms::_empty) { + return; + } + RefPtr<ComputedStyle> pageContentPseudoStyle = + PresShell()->StyleSet()->ResolvePageContentStyle(mPageName); + SetComputedStyleWithoutNotification(pageContentPseudoStyle); +} + +nsIFrame* nsPageContentFrame::FirstContinuation() const { + const nsContainerFrame* const parent = GetParent(); + MOZ_ASSERT(parent && parent->IsPageFrame(), + "Parent of nsPageContentFrame should be nsPageFrame"); + // static cast so the compiler has a chance to devirtualize the call. + const auto* const pageFrameParent = static_cast<const nsPageFrame*>(parent); + nsPageContentFrame* const pageContentFrame = + static_cast<const nsPageFrame*>(pageFrameParent->FirstContinuation()) + ->PageContentFrame(); + MOZ_ASSERT(pageContentFrame && !pageContentFrame->GetPrevContinuation(), + "First descendent of nsPageSequenceFrame should not have a " + "previous continuation"); + return pageContentFrame; +} + +#ifdef DEBUG_FRAME_DUMP +nsresult nsPageContentFrame::GetFrameName(nsAString& aResult) const { + return MakeFrameName(u"PageContent"_ns, aResult); +} +void nsPageContentFrame::ExtraContainerFrameInfo(nsACString& aTo) const { + if (mPageName) { + aTo += " [page="; + aTo += nsAtomCString(mPageName); + aTo += "]"; + } +} +#endif |