layout/generic/nsSpacerFrame.cpp

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  37
  38 /* rendering object for HTML <spacer> element */
  39
  40 #include "nsHTMLParts.h"
  41 #include "nsFrame.h"
  42 #include "nsLineLayout.h"
  43 #include "nsPresContext.h"
  44 #include "nsGkAtoms.h"
  45 #include "nsStyleConsts.h"
  46 #include "nsINameSpaceManager.h"
  47
  48 // Spacer type's
  49 #define TYPE_WORD  0            // horizontal space
  50 #define TYPE_LINE  1            // line-break + vertical space
  51 #define TYPE_IMAGE 2            // acts like a sized image with nothing to see
  52
  53 class SpacerFrame : public nsFrame
  54 {
  55 public:
  56   NS_DECL_FRAMEARENA_HELPERS
  57
  58   friend nsIFrame* NS_NewSpacerFrame(nsIPresShell* aPresShell, nsStyleContext* aContext);
  59
  60   // nsIHTMLReflow
  61   virtual nscoord GetMinWidth(nsIRenderingContext *aRenderingContext);
  62   virtual nscoord GetPrefWidth(nsIRenderingContext *aRenderingContext);
  63   NS_IMETHOD Reflow(nsPresContext*          aPresContext,
  64                     nsHTMLReflowMetrics&     aDesiredSize,
  65                     const nsHTMLReflowState& aReflowState,
  66                     nsReflowStatus&          aStatus);
  67
  68   PRUint8 GetSpacerType();
  69
  70 protected:
  71   SpacerFrame(nsStyleContext* aContext) : nsFrame(aContext) {}
  72   virtual ~SpacerFrame();
  73   void GetDesiredSize(nsHTMLReflowMetrics& aMetrics, nsSize aPercentBase);
  74 };
  75
  76 nsIFrame*
  77 NS_NewSpacerFrame(nsIPresShell* aPresShell, nsStyleContext* aContext)
  78 {
  79 #ifdef DEBUG
  80   const nsStyleDisplay* disp = aContext->GetStyleDisplay();
  81   NS_ASSERTION(!disp->IsAbsolutelyPositioned() && !disp->IsFloating(),
  82                "Spacers should not be positioned and should not float");
  83 #endif
  84
  85   return new (aPresShell) SpacerFrame(aContext);
  86 }
  87
  88 NS_IMPL_FRAMEARENA_HELPERS(SpacerFrame)
  89
  90 SpacerFrame::~SpacerFrame()
  91 {
  92 }
  93
  94 /* virtual */ nscoord
  95 SpacerFrame::GetMinWidth(nsIRenderingContext *aRenderingContext)
  96 {
  97   nsHTMLReflowMetrics metrics;
  98   DISPLAY_MIN_WIDTH(this, metrics.width);
  99   GetDesiredSize(metrics, nsSize(0, 0));
 100   return metrics.width;
 101 }
 102
 103 /* virtual */ nscoord
 104 SpacerFrame::GetPrefWidth(nsIRenderingContext *aRenderingContext)
 105 {
 106   nsHTMLReflowMetrics metrics;
 107   DISPLAY_PREF_WIDTH(this, metrics.width);
 108   GetDesiredSize(metrics, nsSize(0, 0));
 109   return metrics.width;
 110 }
 111
 112 NS_IMETHODIMP
 113 SpacerFrame::Reflow(nsPresContext*          aPresContext,
 114                     nsHTMLReflowMetrics&     aMetrics,
 115                     const nsHTMLReflowState& aReflowState,
 116                     nsReflowStatus&          aStatus)
 117 {
 118   DO_GLOBAL_REFLOW_COUNT("SpacerFrame");
 119   DISPLAY_REFLOW(aPresContext, this, aReflowState, aMetrics, aStatus);
 120   aStatus = NS_FRAME_COMPLETE;
 121
 122   // XXX Bug 379654 Should use containing block size!
 123   nsSize percentBase(aReflowState.availableWidth, aReflowState.availableHeight);
 124   if (percentBase.width == NS_UNCONSTRAINEDSIZE)
 125     percentBase.width = 0;
 126   if (percentBase.height == NS_UNCONSTRAINEDSIZE)
 127     percentBase.height = 0;
 128
 129   if (GetSpacerType() == TYPE_LINE)
 130     aStatus = NS_INLINE_LINE_BREAK_AFTER(NS_FRAME_COMPLETE);
 131
 132   GetDesiredSize(aMetrics, percentBase);
 133
 134   NS_FRAME_SET_TRUNCATION(aStatus, aReflowState, aMetrics);
 135   return NS_OK;
 136 }
 137
 138 void
 139 SpacerFrame::GetDesiredSize(nsHTMLReflowMetrics& aMetrics, nsSize aPercentBase)
 140 {
 141   // By default, we have no area
 142   aMetrics.width = 0;
 143   aMetrics.height = 0;
 144
 145   // XXX Bug 379654 This code doesn't handle some value types for width
 146   // and height, doesn't handle min/max-width/height, doesn't handle
 147   // border and padding, doesn't handle 'ch' units, doesn't handle the
 148   // enumerated values on width, etc.  But it probably doesn't much
 149   // matter.
 150
 151   const nsStylePosition* position = GetStylePosition();
 152
 153   PRUint8 type = GetSpacerType();
 154   switch (type) {
 155   case TYPE_WORD:
 156     break;
 157
 158   case TYPE_LINE:
 159     if (eStyleUnit_Coord == position->mHeight.GetUnit()) {
 160       aMetrics.height = position->mHeight.GetCoordValue();
 161     }
 162     break;
 163
 164   case TYPE_IMAGE:
 165     // width
 166     nsStyleUnit unit = position->mWidth.GetUnit();
 167     if (eStyleUnit_Coord == unit) {
 168       aMetrics.width = position->mWidth.GetCoordValue();
 169     }
 170     else if (eStyleUnit_Percent == unit)
 171     {
 172       float factor = position->mWidth.GetPercentValue();
 173       aMetrics.width = NSToCoordRound(factor * aPercentBase.width);
 174     }
 175
 176     // height
 177     unit = position->mHeight.GetUnit();
 178     if (eStyleUnit_Coord == unit) {
 179       aMetrics.height = position->mHeight.GetCoordValue();
 180     }
 181     else if (eStyleUnit_Percent == unit)
 182     {
 183       float factor = position->mHeight.GetPercentValue();
 184       aMetrics.height = NSToCoordRound(factor * aPercentBase.height);
 185     }
 186     break;
 187   }
 188
 189   if (aMetrics.width || aMetrics.height) {
 190     // Make sure that the other dimension is non-zero
 191     if (!aMetrics.width) aMetrics.width = 1;
 192     if (!aMetrics.height) aMetrics.height = 1;
 193   }
 194 }
 195
 196 PRUint8
 197 SpacerFrame::GetSpacerType()
 198 {
 199   PRUint8 type = TYPE_WORD;
 200   static nsIContent::AttrValuesArray strings[] =
 201     {&nsGkAtoms::line, &nsGkAtoms::vert, &nsGkAtoms::vertical,
 202      &nsGkAtoms::block, nsnull};
 203   switch (mContent->FindAttrValueIn(kNameSpaceID_None, nsGkAtoms::type,
 204                                     strings, eIgnoreCase)) {
 205     case 0:
 206     case 1:
 207     case 2:
 208       return TYPE_LINE;
 209     case 3:
 210       return TYPE_IMAGE;
 211   }
 212   return type;
 213 }