summaryrefslogtreecommitdiffstats
path: root/layout/generic/PrintedSheetFrame.cpp
diff options
context:
space:
mode:
Diffstat (limited to 'layout/generic/PrintedSheetFrame.cpp')
-rw-r--r--layout/generic/PrintedSheetFrame.cpp404
1 files changed, 404 insertions, 0 deletions
diff --git a/layout/generic/PrintedSheetFrame.cpp b/layout/generic/PrintedSheetFrame.cpp
new file mode 100644
index 0000000000..5b8151bbd0
--- /dev/null
+++ b/layout/generic/PrintedSheetFrame.cpp
@@ -0,0 +1,404 @@
+/* -*- 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 https://mozilla.org/MPL/2.0/. */
+
+/* Rendering object for a printed or print-previewed sheet of paper */
+
+#include "mozilla/PrintedSheetFrame.h"
+
+#include <tuple>
+
+#include "mozilla/StaticPrefs_print.h"
+#include "nsCSSFrameConstructor.h"
+#include "nsPageContentFrame.h"
+#include "nsPageFrame.h"
+#include "nsPageSequenceFrame.h"
+
+using namespace mozilla;
+
+PrintedSheetFrame* NS_NewPrintedSheetFrame(PresShell* aPresShell,
+ ComputedStyle* aStyle) {
+ return new (aPresShell)
+ PrintedSheetFrame(aStyle, aPresShell->GetPresContext());
+}
+
+namespace mozilla {
+
+NS_QUERYFRAME_HEAD(PrintedSheetFrame)
+ NS_QUERYFRAME_ENTRY(PrintedSheetFrame)
+NS_QUERYFRAME_TAIL_INHERITING(nsContainerFrame)
+
+NS_IMPL_FRAMEARENA_HELPERS(PrintedSheetFrame)
+
+void PrintedSheetFrame::BuildDisplayList(nsDisplayListBuilder* aBuilder,
+ const nsDisplayListSet& aLists) {
+ if (PresContext()->IsScreen()) {
+ // Draw the background/shadow/etc. of a blank sheet of paper, for
+ // print-preview.
+ DisplayBorderBackgroundOutline(aBuilder, aLists);
+ }
+
+ for (auto* frame : mFrames) {
+ if (!frame->HasAnyStateBits(NS_PAGE_SKIPPED_BY_CUSTOM_RANGE)) {
+ BuildDisplayListForChild(aBuilder, frame, aLists);
+ }
+ }
+}
+
+// If the given page is included in the user's page range, this function
+// returns false. Otherwise, it tags the page with the
+// NS_PAGE_SKIPPED_BY_CUSTOM_RANGE state bit and returns true.
+static bool TagIfSkippedByCustomRange(nsPageFrame* aPageFrame, int32_t aPageNum,
+ nsSharedPageData* aPD) {
+ if (!nsIPrintSettings::IsPageSkipped(aPageNum, aPD->mPageRanges)) {
+ MOZ_ASSERT(!aPageFrame->HasAnyStateBits(NS_PAGE_SKIPPED_BY_CUSTOM_RANGE),
+ "page frames NS_PAGE_SKIPPED_BY_CUSTOM_RANGE state should "
+ "only be set if we actually want to skip the page");
+ return false;
+ }
+
+ aPageFrame->AddStateBits(NS_PAGE_SKIPPED_BY_CUSTOM_RANGE);
+ return true;
+}
+
+void PrintedSheetFrame::ClaimPageFrameFromPrevInFlow() {
+ MoveOverflowToChildList();
+ if (!GetPrevContinuation()) {
+ // The first page content frame of each document will not yet have its page
+ // style set yet. This is because normally page style is set either from
+ // the previous page content frame, or using the new page name when named
+ // pages cause a page break in block reflow. Ensure that, for the first
+ // page, it is set here so that all nsPageContentFrames have their page
+ // style set before reflow.
+ auto* firstChild = PrincipalChildList().FirstChild();
+ MOZ_ASSERT(firstChild && firstChild->IsPageFrame(),
+ "PrintedSheetFrame only has nsPageFrame children");
+ auto* pageFrame = static_cast<nsPageFrame*>(firstChild);
+ pageFrame->PageContentFrame()->EnsurePageName();
+ }
+}
+
+void PrintedSheetFrame::Reflow(nsPresContext* aPresContext,
+ ReflowOutput& aReflowOutput,
+ const ReflowInput& aReflowInput,
+ nsReflowStatus& aStatus) {
+ MarkInReflow();
+ DO_GLOBAL_REFLOW_COUNT("PrintedSheetFrame");
+ DISPLAY_REFLOW(aPresContext, this, aReflowInput, aReflowOutput, aStatus);
+ MOZ_ASSERT(aStatus.IsEmpty(), "Caller should pass a fresh reflow status!");
+
+ // If we have a prev-in-flow, take its overflowing content:
+ MoveOverflowToChildList();
+
+ const WritingMode wm = aReflowInput.GetWritingMode();
+
+ // See the comments for GetSizeForChildren.
+ // Note that nsPageFrame::ComputeSinglePPSPageSizeScale depends on this value
+ // and is currently called while reflowing a single nsPageFrame child (i.e.
+ // before we've finished reflowing ourself). Ideally our children wouldn't be
+ // accessing our dimensions until after we've finished reflowing ourself -
+ // see bug 1835782.
+ mSizeForChildren =
+ nsSize(aReflowInput.AvailableISize(), aReflowInput.AvailableBSize());
+ if (mPD->PagesPerSheetInfo()->mNumPages == 1) {
+ auto* firstChild = PrincipalChildList().FirstChild();
+ MOZ_ASSERT(firstChild && firstChild->IsPageFrame(),
+ "PrintedSheetFrame only has nsPageFrame children");
+ if (static_cast<nsPageFrame*>(firstChild)
+ ->GetPageOrientationRotation(mPD) != 0.0) {
+ std::swap(mSizeForChildren.width, mSizeForChildren.height);
+ }
+ }
+
+ // Count the number of pages that are displayed on this sheet (i.e. how many
+ // child frames we end up laying out, excluding any pages that are skipped
+ // due to not being in the user's page-range selection).
+ uint32_t numPagesOnThisSheet = 0;
+
+ // Target for numPagesOnThisSheet.
+ const uint32_t desiredPagesPerSheet = mPD->PagesPerSheetInfo()->mNumPages;
+
+ if (desiredPagesPerSheet > 1) {
+ ComputePagesPerSheetGridMetrics(mSizeForChildren);
+ }
+
+ // NOTE: I'm intentionally *not* using a range-based 'for' loop here, since
+ // we potentially mutate the frame list (appending to the end) during the
+ // list, which is not generally safe with range-based 'for' loops.
+ for (auto* childFrame = mFrames.FirstChild(); childFrame;
+ childFrame = childFrame->GetNextSibling()) {
+ MOZ_ASSERT(childFrame->IsPageFrame(),
+ "we're only expecting page frames as children");
+ auto* pageFrame = static_cast<nsPageFrame*>(childFrame);
+
+ // Be sure our child has a pointer to the nsSharedPageData and knows its
+ // page number:
+ pageFrame->SetSharedPageData(mPD);
+ pageFrame->DeterminePageNum();
+
+ if (!TagIfSkippedByCustomRange(pageFrame, pageFrame->GetPageNum(), mPD)) {
+ // The page is going to be displayed on this sheet. Tell it its index
+ // among the displayed pages, so we can use that to compute its "cell"
+ // when painting.
+ pageFrame->SetIndexOnSheet(numPagesOnThisSheet);
+ numPagesOnThisSheet++;
+ }
+
+ // This is the app-unit size of the page (in physical & logical units).
+ // Note: The page sizes come from CSS or else from the user selected size;
+ // pages are never reflowed to fit their sheet - if/when necessary they are
+ // scaled to fit their sheet. Hence why we get the page's own dimensions to
+ // use as its "available space"/"container size" here.
+ const nsSize physPageSize = pageFrame->ComputePageSize();
+ const LogicalSize pageSize(wm, physPageSize);
+
+ ReflowInput pageReflowInput(aPresContext, aReflowInput, pageFrame,
+ pageSize);
+
+ // For layout purposes, we position *all* our nsPageFrame children at our
+ // origin. Then, if we have multiple pages-per-sheet, we'll shrink & shift
+ // each one into the right position as a paint-time effect, in
+ // BuildDisplayList.
+ LogicalPoint pagePos(wm);
+
+ // Outparams for reflow:
+ ReflowOutput pageReflowOutput(pageReflowInput);
+ nsReflowStatus status;
+
+ ReflowChild(pageFrame, aPresContext, pageReflowOutput, pageReflowInput, wm,
+ pagePos, physPageSize, ReflowChildFlags::Default, status);
+
+ FinishReflowChild(pageFrame, aPresContext, pageReflowOutput,
+ &pageReflowInput, wm, pagePos, physPageSize,
+ ReflowChildFlags::Default);
+
+ // Since we don't support incremental reflow in printed documents (see the
+ // early-return in nsPageSequenceFrame::Reflow), we can assume that this
+ // was the first time that pageFrame has been reflowed, and so there's no
+ // way that it could already have a next-in-flow. If it *did* have a
+ // next-in-flow, we would need to handle it in the 'status' logic below.
+ NS_ASSERTION(!pageFrame->GetNextInFlow(), "bad child flow list");
+
+ // Did this page complete the document, or do we need to generate
+ // another page frame?
+ if (status.IsFullyComplete()) {
+ // The page we just reflowed is the final page! Record its page number
+ // as the number of pages:
+ mPD->mRawNumPages = pageFrame->GetPageNum();
+ } else {
+ // Create a continuation for our page frame. We add the continuation to
+ // our child list, and then potentially push it to our overflow list, if
+ // it really belongs on the next sheet.
+ nsIFrame* continuingPage =
+ PresShell()->FrameConstructor()->CreateContinuingFrame(pageFrame,
+ this);
+ mFrames.InsertFrame(nullptr, pageFrame, continuingPage);
+ const bool isContinuingPageSkipped =
+ TagIfSkippedByCustomRange(static_cast<nsPageFrame*>(continuingPage),
+ pageFrame->GetPageNum() + 1, mPD);
+
+ // If we've already reached the target number of pages for this sheet,
+ // and this continuation page that we just created is meant to be
+ // displayed (i.e. it's in the chosen page range), then we need to push it
+ // to our overflow list so that it'll go onto a subsequent sheet.
+ // Otherwise we leave it on this sheet. This ensures we *only* generate
+ // another sheet IFF there's a displayable page that will end up on it.
+ if (numPagesOnThisSheet >= desiredPagesPerSheet &&
+ !isContinuingPageSkipped) {
+ PushChildrenToOverflow(continuingPage, pageFrame);
+ aStatus.SetIncomplete();
+ }
+ }
+ }
+
+ // This should hold for the first sheet, because our UI should prevent the
+ // user from creating a 0-length page range; and it should hold for
+ // subsequent sheets because we should only create an additional sheet when
+ // we discover a displayable (i.e. non-skipped) page that we need to push
+ // to that new sheet.
+
+ // XXXdholbert In certain edge cases (e.g. after a page-orientation-flip that
+ // reduces the page count), it's possible for us to be given a page range
+ // that is *entirely out-of-bounds* (with "from" & "to" both being larger
+ // than our actual page-number count). This scenario produces a single
+ // PrintedSheetFrame with zero displayable pages on it, which is a weird
+ // state to be in. This is hopefully a scenario that the frontend code can
+ // detect and recover from (e.g. by clamping the range to our reported
+ // `rawNumPages`), but it can't do that until *after* we've completed this
+ // problematic reflow and can reported an up-to-date `rawNumPages` to the
+ // frontend. So: to give the frontend a chance to intervene and apply some
+ // correction/clamping to its print-range parameters, we soften this
+ // assertion *specifically for the first printed sheet*.
+ if (!GetPrevContinuation()) {
+ NS_WARNING_ASSERTION(numPagesOnThisSheet > 0,
+ "Shouldn't create a sheet with no displayable pages "
+ "on it");
+ } else {
+ MOZ_ASSERT(numPagesOnThisSheet > 0,
+ "Shouldn't create a sheet with no displayable pages on it");
+ }
+
+ MOZ_ASSERT(numPagesOnThisSheet <= desiredPagesPerSheet,
+ "Shouldn't have more than desired number of displayable pages "
+ "on this sheet");
+ mNumPages = numPagesOnThisSheet;
+
+ // Populate our ReflowOutput outparam -- just use up all the
+ // available space, for both our desired size & overflow areas.
+ aReflowOutput.ISize(wm) = aReflowInput.AvailableISize();
+ if (aReflowInput.AvailableBSize() != NS_UNCONSTRAINEDSIZE) {
+ aReflowOutput.BSize(wm) = aReflowInput.AvailableBSize();
+ }
+ aReflowOutput.SetOverflowAreasToDesiredBounds();
+
+ FinishAndStoreOverflow(&aReflowOutput);
+}
+
+nsSize PrintedSheetFrame::ComputeSheetSize(const nsPresContext* aPresContext) {
+ // We use the user selected page (sheet) dimensions, and default to the
+ // orientation as specified by the user.
+ nsSize sheetSize = aPresContext->GetPageSize();
+
+ // Don't waste cycles changing the orientation of a square.
+ if (sheetSize.width == sheetSize.height) {
+ return sheetSize;
+ }
+
+ if (!StaticPrefs::
+ print_save_as_pdf_use_page_rule_size_as_paper_size_enabled()) {
+ if (mPD->mPrintSettings->HasOrthogonalPagesPerSheet()) {
+ std::swap(sheetSize.width, sheetSize.height);
+ }
+ return sheetSize;
+ }
+
+ auto* firstChild = PrincipalChildList().FirstChild();
+ MOZ_ASSERT(firstChild->IsPageFrame(),
+ "PrintedSheetFrame only has nsPageFrame children");
+ auto* sheetsFirstPageFrame = static_cast<nsPageFrame*>(firstChild);
+
+ nsSize pageSize = sheetsFirstPageFrame->ComputePageSize();
+
+ // Don't waste cycles changing the orientation of a square.
+ if (pageSize.width == pageSize.height) {
+ return sheetSize;
+ }
+
+ const bool pageIsRotated =
+ sheetsFirstPageFrame->GetPageOrientationRotation(mPD) != 0.0;
+
+ if (pageIsRotated && pageSize.width == pageSize.height) {
+ // Straighforward rotation without needing sheet orientation optimization.
+ std::swap(sheetSize.width, sheetSize.height);
+ return sheetSize;
+ }
+
+ // Try to orient the sheet optimally based on the physical orientation of the
+ // first/sole page on the sheet. (In the multiple pages-per-sheet case, the
+ // first page is the only one that exists at this point in the code, so it is
+ // the only one we can reason about. Any other pages may, or may not, have
+ // the same physical orientation.)
+
+ if (pageIsRotated) {
+ // Fix up for its physical orientation:
+ std::swap(pageSize.width, pageSize.height);
+ }
+
+ const bool pageIsPortrait = pageSize.width < pageSize.height;
+ const bool sheetIsPortrait = sheetSize.width < sheetSize.height;
+
+ // Switch the sheet orientation if the page orientation is different, or
+ // if we need to switch it because the number of pages-per-sheet demands
+ // orthogonal sheet layout, but not if both are true since then we'd
+ // actually need to double switch.
+ if ((sheetIsPortrait != pageIsPortrait) !=
+ mPD->mPrintSettings->HasOrthogonalPagesPerSheet()) {
+ std::swap(sheetSize.width, sheetSize.height);
+ }
+
+ return sheetSize;
+}
+
+void PrintedSheetFrame::ComputePagesPerSheetGridMetrics(
+ const nsSize& aSheetSize) {
+ MOZ_ASSERT(mPD->PagesPerSheetInfo()->mNumPages > 1,
+ "Unnecessary to call this in a regular 1-page-per-sheet scenario; "
+ "the computed values won't ever be used in that case");
+
+ // Compute the space available for the pages-per-sheet "page grid" (just
+ // subtract the sheet's unwriteable margin area):
+ nsSize availSpaceOnSheet = aSheetSize;
+ nsMargin uwm = mPD->mPrintSettings->GetIgnoreUnwriteableMargins()
+ ? nsMargin{}
+ : nsPresContext::CSSTwipsToAppUnits(
+ mPD->mPrintSettings->GetUnwriteableMarginInTwips());
+
+ // XXXjwatt Once we support heterogeneous sheet orientations, we'll also need
+ // to rotate uwm if this sheet is not the primary orientation.
+ if (mPD->mPrintSettings->HasOrthogonalPagesPerSheet()) {
+ // aSheetSize already takes account of the switch of *sheet* orientation
+ // that we do in this case (the orientation implied by the page size
+ // dimensions in the nsIPrintSettings applies to *pages*). That is not the
+ // case for the unwriteable margins since we got them from the
+ // nsIPrintSettings object ourself, so we need to adjust `uwm` here.
+ //
+ // Note: In practice, sheets with an orientation that is orthogonal to the
+ // physical orientation of sheets output by a printer must be rotated 90
+ // degrees for/by the printer. In that case the convention seems to be that
+ // the "left" edge of the orthogonally oriented sheet becomes the "top",
+ // and so forth. The rotation direction will matter in the case that the
+ // top and bottom unwriteable margins are different, or the left and right
+ // unwriteable margins are different. So we need to match this behavior,
+ // which means we must rotate the `uwm` 90 degrees *counter-clockwise*.
+ nsMargin rotated(uwm.right, uwm.bottom, uwm.left, uwm.top);
+ uwm = rotated;
+ }
+
+ availSpaceOnSheet.width -= uwm.LeftRight();
+ availSpaceOnSheet.height -= uwm.TopBottom();
+
+ if (MOZ_UNLIKELY(availSpaceOnSheet.IsEmpty())) {
+ // This sort of thing should be rare, but it can happen if there are
+ // bizarre page sizes, and/or if there's an unexpectedly large unwriteable
+ // margin area.
+ NS_WARNING("Zero area for pages-per-sheet grid, or zero-sized grid");
+ mGridOrigin = nsPoint(0, 0);
+ mGridNumCols = 1;
+ return;
+ }
+
+ // If there are a different number of rows vs. cols, we'll aim to put
+ // the larger number of items in the longer axis.
+ const auto* ppsInfo = mPD->PagesPerSheetInfo();
+ uint32_t smallerNumTracks = ppsInfo->mNumPages / ppsInfo->mLargerNumTracks;
+ bool sheetIsPortraitLike = aSheetSize.width < aSheetSize.height;
+ auto numCols =
+ sheetIsPortraitLike ? smallerNumTracks : ppsInfo->mLargerNumTracks;
+ auto numRows =
+ sheetIsPortraitLike ? ppsInfo->mLargerNumTracks : smallerNumTracks;
+
+ mGridOrigin = nsPoint(uwm.left, uwm.top);
+ mGridNumCols = numCols;
+ mGridCellWidth = availSpaceOnSheet.width / nscoord(numCols);
+ mGridCellHeight = availSpaceOnSheet.height / nscoord(numRows);
+}
+
+gfx::IntSize PrintedSheetFrame::GetPrintTargetSizeInPoints(
+ const int32_t aAppUnitsPerPhysicalInch) const {
+ const auto size = GetSize();
+ MOZ_ASSERT(size.width > 0 && size.height > 0);
+ const float pointsPerAppUnit =
+ POINTS_PER_INCH_FLOAT / float(aAppUnitsPerPhysicalInch);
+ return IntSize::Ceil(float(size.width) * pointsPerAppUnit,
+ float(size.height) * pointsPerAppUnit);
+}
+
+#ifdef DEBUG_FRAME_DUMP
+nsresult PrintedSheetFrame::GetFrameName(nsAString& aResult) const {
+ return MakeFrameName(u"PrintedSheet"_ns, aResult);
+}
+#endif
+
+} // namespace mozilla