layout/generic/nsPageContentFrame.cpp

   1 /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* This Source Code Form is subject to the terms of the Mozilla Public
   3  * License, v. 2.0. If a copy of the MPL was not distributed with this
   4  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   5 #include "nsPageContentFrame.h"
   6 #include "nsCSSFrameConstructor.h"
   7 #include "nsPresContext.h"
   8 #include "nsGkAtoms.h"
   9 #include "nsIPresShell.h"
  10 #include "nsSimplePageSequenceFrame.h"
  11
  12 using mozilla::LogicalSize;
  13 using mozilla::WritingMode;
  14
  15 nsPageContentFrame*
  16 NS_NewPageContentFrame(nsIPresShell* aPresShell, nsStyleContext* aContext)
  17 {
  18   return new (aPresShell) nsPageContentFrame(aContext);
  19 }
  20
  21 NS_IMPL_FRAMEARENA_HELPERS(nsPageContentFrame)
  22
  23 void
  24 nsPageContentFrame::Reflow(nsPresContext*           aPresContext,
  25                            nsHTMLReflowMetrics&     aDesiredSize,
  26                            const nsHTMLReflowState& aReflowState,
  27                            nsReflowStatus&          aStatus)
  28 {
  29   DO_GLOBAL_REFLOW_COUNT("nsPageContentFrame");
  30   DISPLAY_REFLOW(aPresContext, this, aReflowState, aDesiredSize, aStatus);
  31   aStatus = NS_FRAME_COMPLETE;  // initialize out parameter
  32
  33   if (GetPrevInFlow() && (GetStateBits() & NS_FRAME_FIRST_REFLOW)) {
  34     nsresult rv = aPresContext->PresShell()->FrameConstructor()
  35                     ->ReplicateFixedFrames(this);
  36     if (NS_FAILED(rv)) {
  37       return;
  38     }
  39   }
  40
  41   // Set our size up front, since some parts of reflow depend on it
  42   // being already set.  Note that the computed height may be
  43   // unconstrained; that's ok.  Consumers should watch out for that.
  44   nsSize  maxSize(aReflowState.ComputedWidth(),
  45                   aReflowState.ComputedHeight());
  46   SetSize(maxSize);
  47
  48   // A PageContentFrame must always have one child: the canvas frame.
  49   // Resize our frame allowing it only to be as big as we are
  50   // XXX Pay attention to the page's border and padding...
  51   if (mFrames.NotEmpty()) {
  52     nsIFrame* frame = mFrames.FirstChild();
  53     WritingMode wm = frame->GetWritingMode();
  54     LogicalSize logicalSize(wm, maxSize);
  55     nsHTMLReflowState kidReflowState(aPresContext, aReflowState,
  56                                      frame, logicalSize);
  57     kidReflowState.SetComputedBSize(logicalSize.BSize(wm));
  58
  59     // Reflow the page content area
  60     ReflowChild(frame, aPresContext, aDesiredSize, kidReflowState, 0, 0, 0, aStatus);
  61
  62     // The document element's background should cover the entire canvas, so
  63     // take into account the combined area and any space taken up by
  64     // absolutely positioned elements
  65     nsMargin padding(0,0,0,0);
  66
  67     // XXXbz this screws up percentage padding (sets padding to zero
  68     // in the percentage padding case)
  69     kidReflowState.mStylePadding->GetPadding(padding);
  70
  71     // This is for shrink-to-fit, and therefore we want to use the
  72     // scrollable overflow, since the purpose of shrink to fit is to
  73     // make the content that ought to be reachable (represented by the
  74     // scrollable overflow) fit in the page.
  75     if (frame->HasOverflowAreas()) {
  76       // The background covers the content area and padding area, so check
  77       // for children sticking outside the child frame's padding edge
  78       nscoord xmost = aDesiredSize.ScrollableOverflow().XMost();
  79       if (xmost > aDesiredSize.Width()) {
  80         nscoord widthToFit = xmost + padding.right +
  81           kidReflowState.mStyleBorder->GetComputedBorderWidth(NS_SIDE_RIGHT);
  82         float ratio = float(maxSize.width) / widthToFit;
  83         NS_ASSERTION(ratio >= 0.0 && ratio < 1.0, "invalid shrink-to-fit ratio");
  84         mPD->mShrinkToFitRatio = std::min(mPD->mShrinkToFitRatio, ratio);
  85       }
  86     }
  87
  88     // Place and size the child
  89     FinishReflowChild(frame, aPresContext, aDesiredSize, &kidReflowState, 0, 0, 0);
  90
  91     NS_ASSERTION(aPresContext->IsDynamic() || !NS_FRAME_IS_FULLY_COMPLETE(aStatus) ||
  92                   !frame->GetNextInFlow(), "bad child flow list");
  93   }
  94
  95   // Reflow our fixed frames
  96   nsReflowStatus fixedStatus = NS_FRAME_COMPLETE;
  97   ReflowAbsoluteFrames(aPresContext, aDesiredSize, aReflowState, fixedStatus);
  98   NS_ASSERTION(NS_FRAME_IS_COMPLETE(fixedStatus), "fixed frames can be truncated, but not incomplete");
  99
 100   // Return our desired size
 101   WritingMode wm = aReflowState.GetWritingMode();
 102   aDesiredSize.ISize(wm) = aReflowState.ComputedISize();
 103   if (aReflowState.ComputedBSize() != NS_UNCONSTRAINEDSIZE) {
 104     aDesiredSize.BSize(wm) = aReflowState.ComputedBSize();
 105   }
 106   FinishAndStoreOverflow(&aDesiredSize);
 107
 108   NS_FRAME_SET_TRUNCATION(aStatus, aReflowState, aDesiredSize);
 109 }
 110
 111 nsIAtom*
 112 nsPageContentFrame::GetType() const
 113 {
 114   return nsGkAtoms::pageContentFrame;
 115 }
 116
 117 #ifdef DEBUG_FRAME_DUMP
 118 nsresult
 119 nsPageContentFrame::GetFrameName(nsAString& aResult) const
 120 {
 121   return MakeFrameName(NS_LITERAL_STRING("PageContent"), aResult);
 122 }
 123 #endif