C++ nsHTMLReflowMetrics::ScrollableOverflow方法代码示例

void
nsPageContentFrame::Reflow(nsPresContext*           aPresContext,
                           nsHTMLReflowMetrics&     aDesiredSize,
                           const nsHTMLReflowState& aReflowState,
                           nsReflowStatus&          aStatus)
{
  DO_GLOBAL_REFLOW_COUNT("nsPageContentFrame");
  DISPLAY_REFLOW(aPresContext, this, aReflowState, aDesiredSize, aStatus);
  aStatus = NS_FRAME_COMPLETE;  // initialize out parameter

  if (GetPrevInFlow() && (GetStateBits() & 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.
  nsSize  maxSize(aReflowState.ComputedWidth(),
                  aReflowState.ComputedHeight());
  SetSize(maxSize);
 
  // 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* frame = mFrames.FirstChild();
    WritingMode wm = frame->GetWritingMode();
    LogicalSize logicalSize(wm, maxSize);
    nsHTMLReflowState kidReflowState(aPresContext, aReflowState,
                                     frame, logicalSize);
    kidReflowState.SetComputedBSize(logicalSize.BSize(wm));

    // Reflow the page content area
    ReflowChild(frame, aPresContext, aDesiredSize, kidReflowState, 0, 0, 0, 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)
    kidReflowState.mStylePadding->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 = aDesiredSize.ScrollableOverflow().XMost();
      if (xmost > aDesiredSize.Width()) {
        nscoord widthToFit = xmost + padding.right +
          kidReflowState.mStyleBorder->GetComputedBorderWidth(NS_SIDE_RIGHT);
        float ratio = float(maxSize.width) / widthToFit;
        NS_ASSERTION(ratio >= 0.0 && ratio < 1.0, "invalid shrink-to-fit ratio");
        mPD->mShrinkToFitRatio = std::min(mPD->mShrinkToFitRatio, ratio);
      }
    }

    // Place and size the child
    FinishReflowChild(frame, aPresContext, aDesiredSize, &kidReflowState, 0, 0, 0);

    NS_ASSERTION(aPresContext->IsDynamic() || !NS_FRAME_IS_FULLY_COMPLETE(aStatus) ||
                  !frame->GetNextInFlow(), "bad child flow list");
  }

  // Reflow our fixed frames
  nsReflowStatus fixedStatus = NS_FRAME_COMPLETE;
  ReflowAbsoluteFrames(aPresContext, aDesiredSize, aReflowState, fixedStatus);
  NS_ASSERTION(NS_FRAME_IS_COMPLETE(fixedStatus), "fixed frames can be truncated, but not incomplete");

  // Return our desired size
  WritingMode wm = aReflowState.GetWritingMode();
  LogicalSize finalSize(wm);
  finalSize.ISize(wm) = aReflowState.ComputedISize();
  if (aReflowState.ComputedBSize() != NS_UNCONSTRAINEDSIZE) {
    finalSize.BSize(wm) = aReflowState.ComputedBSize();
  }
  aDesiredSize.SetSize(wm, finalSize);
  FinishAndStoreOverflow(&aDesiredSize);

  NS_FRAME_SET_TRUNCATION(aStatus, aReflowState, aDesiredSize);
}

NS_IMETHODIMP
nsPageContentFrame::Reflow(nsPresContext*           aPresContext,
                           nsHTMLReflowMetrics&     aDesiredSize,
                           const nsHTMLReflowState& aReflowState,
                           nsReflowStatus&          aStatus)
{
  DO_GLOBAL_REFLOW_COUNT("nsPageContentFrame");
  DISPLAY_REFLOW(aPresContext, this, aReflowState, aDesiredSize, aStatus);
  aStatus = NS_FRAME_COMPLETE;  // initialize out parameter
  nsresult rv = NS_OK;

  if (GetPrevInFlow() && (GetStateBits() & NS_FRAME_FIRST_REFLOW)) {
    nsresult rv = aPresContext->PresShell()->FrameConstructor()
                    ->ReplicateFixedFrames(this);
    NS_ENSURE_SUCCESS(rv, rv);
  }

  // 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.
  SetSize(nsSize(aReflowState.availableWidth, aReflowState.availableHeight));
 
  // 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* frame = mFrames.FirstChild();
    nsSize  maxSize(aReflowState.availableWidth, aReflowState.availableHeight);
    nsHTMLReflowState kidReflowState(aPresContext, aReflowState, frame, maxSize);
    kidReflowState.SetComputedHeight(aReflowState.availableHeight);

    mPD->mPageContentSize  = aReflowState.availableWidth;

    // Reflow the page content area
    rv = ReflowChild(frame, aPresContext, aDesiredSize, kidReflowState, 0, 0, 0, aStatus);
    NS_ENSURE_SUCCESS(rv, rv);

    // 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)
    kidReflowState.mStylePadding->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 = aDesiredSize.ScrollableOverflow().XMost();
      if (xmost > aDesiredSize.width) {
        mPD->mPageContentXMost =
          xmost +
          kidReflowState.mStyleBorder->GetActualBorderWidth(NS_SIDE_RIGHT) +
          padding.right;
      }
    }

    // Place and size the child
    FinishReflowChild(frame, aPresContext, &kidReflowState, aDesiredSize, 0, 0, 0);

    NS_ASSERTION(aPresContext->IsDynamic() || !NS_FRAME_IS_FULLY_COMPLETE(aStatus) ||
                  !frame->GetNextInFlow(), "bad child flow list");
  }
  // Reflow our fixed frames 
  nsReflowStatus fixedStatus = NS_FRAME_COMPLETE;
  mFixedContainer.Reflow(this, aPresContext, aReflowState, fixedStatus,
                         aReflowState.availableWidth,
                         aReflowState.availableHeight,
                         PR_FALSE, PR_TRUE, PR_TRUE, // XXX could be optimized
                         nsnull /* ignore overflow */);
  NS_ASSERTION(NS_FRAME_IS_COMPLETE(fixedStatus), "fixed frames can be truncated, but not incomplete");

  // Return our desired size
  aDesiredSize.width = aReflowState.availableWidth;
  if (aReflowState.availableHeight != NS_UNCONSTRAINEDSIZE) {
    aDesiredSize.height = aReflowState.availableHeight;
  }

  FinishAndStoreOverflow(&aDesiredSize);

  NS_FRAME_SET_TRUNCATION(aStatus, aReflowState, aDesiredSize);
  return NS_OK;
}

//.........这里部分代码省略.........
      }
    } else {
      nsSize containingBlockSize =
        CalculateContainingBlockSizeForAbsolutes(*reflowState,
                                                 nsSize(aMetrics.width,
                                                        aMetrics.height));

      // Mark frames that depend on changes we just made to this frame as dirty:
      // Now we can assume that the padding edge hasn't moved.
      // We need to reflow the absolutes if one of them depends on
      // its placeholder position, or the containing block size in a
      // direction in which the containing block size might have
      // changed.
      bool cbWidthChanged = aMetrics.width != oldSize.width;
      bool isRoot = !GetContent()->GetParent();
      // If isRoot and we have auto height, then we are the initial
      // containing block and the containing block height is the
      // viewport height, which can't change during incremental
      // reflow.
      bool cbHeightChanged =
        !(isRoot && NS_UNCONSTRAINEDSIZE == reflowState->ComputedHeight()) &&
        aMetrics.height != oldSize.height;

      absoluteContainer->Reflow(this, aPresContext, *reflowState,
                                state.mReflowStatus,
                                containingBlockSize.width,
                                containingBlockSize.height, true,
                                cbWidthChanged, cbHeightChanged,
                                &aMetrics.mOverflowAreas);

      //XXXfr Why isn't this rv (and others in this file) checked/returned?
    }
  }

  // Determine if we need to repaint our border, background or outline
  CheckInvalidateSizeChange(aMetrics);

  FinishAndStoreOverflow(&aMetrics);

  // Clear the float manager pointer in the block reflow state so we
  // don't waste time translating the coordinate system back on a dead
  // float manager.
  if (needFloatManager)
    state.mFloatManager = nsnull;

  aStatus = state.mReflowStatus;

#ifdef DEBUG
  // Between when we drain pushed floats and when we complete reflow,
  // we're allowed to have multiple continuations of the same float on
  // our floats list, since a first-in-flow might get pushed to a later
  // continuation of its containing block.  But it's not permitted
  // outside that time.
  nsLayoutUtils::AssertNoDuplicateContinuations(this, mFloats);

  if (gNoisyReflow) {
    IndentBy(stdout, gNoiseIndent);
    ListTag(stdout);
    printf(": status=%x (%scomplete) metrics=%d,%d carriedMargin=%d",
           aStatus, NS_FRAME_IS_COMPLETE(aStatus) ? "" : "not ",
           aMetrics.width, aMetrics.height,
           aMetrics.mCarriedOutBottomMargin.get());
    if (HasOverflowAreas()) {
      printf(" overflow-vis={%d,%d,%d,%d}",
             aMetrics.VisualOverflow().x,
             aMetrics.VisualOverflow().y,
             aMetrics.VisualOverflow().width,
             aMetrics.VisualOverflow().height);
      printf(" overflow-scr={%d,%d,%d,%d}",
             aMetrics.ScrollableOverflow().x,
             aMetrics.ScrollableOverflow().y,
             aMetrics.ScrollableOverflow().width,
             aMetrics.ScrollableOverflow().height);
    }
    printf("\n");
  }

  if (gLameReflowMetrics) {
    PRTime end = PR_Now();

    PRInt32 ectc = nsLineBox::GetCtorCount();
    PRInt32 numLines = mLines.size();
    if (!numLines) numLines = 1;
    PRTime delta, perLineDelta, lines;
    LL_I2L(lines, numLines);
    LL_SUB(delta, end, start);
    LL_DIV(perLineDelta, delta, lines);

    ListTag(stdout);
    char buf[400];
    PR_snprintf(buf, sizeof(buf),
                ": %lld elapsed (%lld per line) (%d lines; %d new lines)",
                delta, perLineDelta, numLines, ectc - ctc);
    printf("%s\n", buf);
  }
#endif

  NS_FRAME_SET_TRUNCATION(aStatus, (*reflowState), aMetrics);
  return rv;
}