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 public:
  55   friend nsIFrame* NS_NewSpacerFrame(nsIPresShell* aPresShell, nsStyleContext* aContext);
  56
  57   // nsIHTMLReflow
  58   virtual nscoord GetMinWidth(nsIRenderingContext *aRenderingContext);
  59   virtual nscoord GetPrefWidth(nsIRenderingContext *aRenderingContext);
  60   NS_IMETHOD Reflow(nsPresContext*          aPresContext,
  61                     nsHTMLReflowMetrics&     aDesiredSize,
  62                     const nsHTMLReflowState& aReflowState,
  63                     nsReflowStatus&          aStatus);
  64
  65   PRUint8 GetType();
  66
  67 protected:
  68   SpacerFrame(nsStyleContext* aContext) : nsFrame(aContext) {}
  69   virtual ~SpacerFrame();
  70   void GetDesiredSize(nsHTMLReflowMetrics& aMetrics, nsSize aPercentBase);
  71 };
  72
  73 nsIFrame*
  74 NS_NewSpacerFrame(nsIPresShell* aPresShell, nsStyleContext* aContext)
  75 {
  76   return new (aPresShell) SpacerFrame(aContext);
  77 }
  78
  79 SpacerFrame::~SpacerFrame()
  80 {
  81 }
  82
  83 /* virtual */ nscoord
  84 SpacerFrame::GetMinWidth(nsIRenderingContext *aRenderingContext)
  85 {
  86   nsHTMLReflowMetrics metrics;
  87   DISPLAY_MIN_WIDTH(this, metrics.width);
  88   GetDesiredSize(metrics, nsSize(0, 0));
  89   return metrics.width;
  90 }
  91
  92 /* virtual */ nscoord
  93 SpacerFrame::GetPrefWidth(nsIRenderingContext *aRenderingContext)
  94 {
  95   nsHTMLReflowMetrics metrics;
  96   DISPLAY_PREF_WIDTH(this, metrics.width);
  97   GetDesiredSize(metrics, nsSize(0, 0));
  98   return metrics.width;
  99 }
 100
 101 NS_IMETHODIMP
 102 SpacerFrame::Reflow(nsPresContext*          aPresContext,
 103                     nsHTMLReflowMetrics&     aMetrics,
 104                     const nsHTMLReflowState& aReflowState,
 105                     nsReflowStatus&          aStatus)
 106 {
 107   DO_GLOBAL_REFLOW_COUNT("SpacerFrame");
 108   DISPLAY_REFLOW(aPresContext, this, aReflowState, aMetrics, aStatus);
 109   aStatus = NS_FRAME_COMPLETE;
 110
 111   // XXX Bug 379654 Should use containing block size!
 112   nsSize percentBase(aReflowState.availableWidth, aReflowState.availableHeight);
 113   if (percentBase.width == NS_UNCONSTRAINEDSIZE)
 114     percentBase.width = 0;
 115   if (percentBase.height == NS_UNCONSTRAINEDSIZE)
 116     percentBase.height = 0;
 117
 118   if (GetType() == TYPE_LINE)
 119     aStatus = NS_INLINE_LINE_BREAK_AFTER(NS_FRAME_COMPLETE);
 120
 121   GetDesiredSize(aMetrics, percentBase);
 122
 123   NS_FRAME_SET_TRUNCATION(aStatus, aReflowState, aMetrics);
 124   return NS_OK;
 125 }
 126
 127 void
 128 SpacerFrame::GetDesiredSize(nsHTMLReflowMetrics& aMetrics, nsSize aPercentBase)
 129 {
 130   // By default, we have no area
 131   aMetrics.width = 0;
 132   aMetrics.height = 0;
 133
 134   // XXX Bug 379654 This code doesn't handle some value types for width
 135   // and height, doesn't handle min/max-width/height, doesn't handle
 136   // border and padding, doesn't handle 'ch' units, doesn't handle the
 137   // enumerated values on width, etc.  But it probably doesn't much
 138   // matter.
 139
 140   const nsStylePosition* position = GetStylePosition();
 141
 142   PRUint8 type = GetType();
 143   switch (type) {
 144   case TYPE_WORD:
 145     break;
 146
 147   case TYPE_LINE:
 148     if (eStyleUnit_Coord == position->mHeight.GetUnit()) {
 149       aMetrics.height = position->mHeight.GetCoordValue();
 150     }
 151     break;
 152
 153   case TYPE_IMAGE:
 154     // width
 155     nsStyleUnit unit = position->mWidth.GetUnit();
 156     if (eStyleUnit_Coord == unit) {
 157       aMetrics.width = position->mWidth.GetCoordValue();
 158     }
 159     else if (eStyleUnit_Percent == unit)
 160     {
 161       float factor = position->mWidth.GetPercentValue();
 162       aMetrics.width = NSToCoordRound(factor * aPercentBase.width);
 163     }
 164
 165     // height
 166     unit = position->mHeight.GetUnit();
 167     if (eStyleUnit_Coord == unit) {
 168       aMetrics.height = position->mHeight.GetCoordValue();
 169     }
 170     else if (eStyleUnit_Percent == unit)
 171     {
 172       float factor = position->mHeight.GetPercentValue();
 173       aMetrics.height = NSToCoordRound(factor * aPercentBase.height);
 174     }
 175     break;
 176   }
 177
 178   if (aMetrics.width || aMetrics.height) {
 179     // Make sure that the other dimension is non-zero
 180     if (!aMetrics.width) aMetrics.width = 1;
 181     if (!aMetrics.height) aMetrics.height = 1;
 182   }
 183 }
 184
 185 PRUint8
 186 SpacerFrame::GetType()
 187 {
 188   PRUint8 type = TYPE_WORD;
 189   static nsIContent::AttrValuesArray strings[] =
 190     {&nsGkAtoms::line, &nsGkAtoms::vert, &nsGkAtoms::vertical,
 191      &nsGkAtoms::block, nsnull};
 192   switch (mContent->FindAttrValueIn(kNameSpaceID_None, nsGkAtoms::type,
 193                                     strings, eIgnoreCase)) {
 194     case 0:
 195     case 1:
 196     case 2:
 197       return TYPE_LINE;
 198     case 3:
 199       return TYPE_IMAGE;
 200   }
 201   return type;
 202 }