layout/svg/base/src/nsSVGTextPathFrame.cpp

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  15  * The Original Code is the Mozilla SVG project.
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  17  * The Initial Developer of the Original Code is IBM Corporation.
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  36
  37 #include "nsSVGTextPathFrame.h"
  38 #include "nsIDOMSVGTextPathElement.h"
  39 #include "nsSVGLength2.h"
  40 #include "nsIDOMSVGURIReference.h"
  41 #include "nsSVGEffects.h"
  42 #include "nsContentUtils.h"
  43 #include "nsSVGPathElement.h"
  44 #include "nsSVGTextPathElement.h"
  45
  46 //----------------------------------------------------------------------
  47 // Implementation
  48
  49 nsIFrame*
  50 NS_NewSVGTextPathFrame(nsIPresShell* aPresShell, nsIContent* aContent,
  51                        nsIFrame* parentFrame, nsStyleContext* aContext)
  52 {
  53   NS_ASSERTION(parentFrame, "null parent");
  54   if (parentFrame->GetType() != nsGkAtoms::svgTextFrame) {
  55     NS_ERROR("trying to construct an SVGTextPathFrame for an invalid container");
  56     return nsnull;
  57   }
  58
  59   nsCOMPtr<nsIDOMSVGTextPathElement> textPath = do_QueryInterface(aContent);
  60   if (!textPath) {
  61     NS_ERROR("Can't create frame! Content is not an SVG textPath");
  62     return nsnull;
  63   }
  64
  65   return new (aPresShell) nsSVGTextPathFrame(aContext);
  66 }
  67
  68 nsIAtom *
  69 nsSVGTextPathFrame::GetType() const
  70 {
  71   return nsGkAtoms::svgTextPathFrame;
  72 }
  73
  74
  75 NS_IMETHODIMP_(already_AddRefed<nsIDOMSVGLengthList>)
  76 nsSVGTextPathFrame::GetX()
  77 {
  78   return nsnull;
  79 }
  80
  81 NS_IMETHODIMP_(already_AddRefed<nsIDOMSVGLengthList>)
  82 nsSVGTextPathFrame::GetY()
  83 {
  84   return nsnull;
  85 }
  86
  87 NS_IMETHODIMP_(already_AddRefed<nsIDOMSVGLengthList>)
  88 nsSVGTextPathFrame::GetDx()
  89 {
  90   return nsnull;
  91 }
  92
  93 NS_IMETHODIMP_(already_AddRefed<nsIDOMSVGLengthList>)
  94 nsSVGTextPathFrame::GetDy()
  95 {
  96   return nsnull;
  97 }
  98
  99 //----------------------------------------------------------------------
 100 // nsSVGTextPathFrame methods:
 101
 102 nsIFrame *
 103 nsSVGTextPathFrame::GetPathFrame()
 104 {
 105   nsSVGTextPathProperty *property =
 106     static_cast<nsSVGTextPathProperty*>(GetProperty(nsGkAtoms::href));
 107
 108   if (!property) {
 109     nsSVGTextPathElement *tp = static_cast<nsSVGTextPathElement*>(mContent);
 110     const nsString &href = tp->mStringAttributes[nsSVGTextPathElement::HREF].GetAnimValue();
 111     if (href.IsEmpty()) {
 112       return nsnull; // no URL
 113     }
 114
 115     nsCOMPtr<nsIURI> targetURI;
 116     nsCOMPtr<nsIURI> base = mContent->GetBaseURI();
 117     nsContentUtils::NewURIWithDocumentCharset(getter_AddRefs(targetURI), href,
 118                                               mContent->GetCurrentDoc(), base);
 119
 120     property = nsSVGEffects::GetTextPathProperty(
 121                                targetURI, this, nsGkAtoms::href);
 122     if (!property)
 123       return nsnull;
 124   }
 125
 126   nsIFrame *result = property->GetReferencedFrame();
 127   if (!result || result->GetType() != nsGkAtoms::svgPathGeometryFrame)
 128     return nsnull;
 129
 130   return result;
 131 }
 132
 133 already_AddRefed<gfxFlattenedPath>
 134 nsSVGTextPathFrame::GetFlattenedPath()
 135 {
 136   nsIFrame *path = GetPathFrame();
 137   return path ? GetFlattenedPath(path) : nsnull;
 138 }
 139
 140 already_AddRefed<gfxFlattenedPath>
 141 nsSVGTextPathFrame::GetFlattenedPath(nsIFrame *path)
 142 {
 143   NS_PRECONDITION(path, "Unexpected null path");
 144   nsSVGPathGeometryElement *element = static_cast<nsSVGPathGeometryElement*>
 145                                                  (path->GetContent());
 146
 147   nsCOMPtr<nsIDOMSVGMatrix> localTM = element->GetLocalTransformMatrix();
 148
 149   return element->GetFlattenedPath(localTM);
 150 }
 151
 152 gfxFloat
 153 nsSVGTextPathFrame::GetStartOffset()
 154 {
 155   nsSVGTextPathElement *tp = static_cast<nsSVGTextPathElement*>(mContent);
 156   nsSVGLength2 *length = &tp->mLengthAttributes[nsSVGTextPathElement::STARTOFFSET];
 157   float val = length->GetAnimValInSpecifiedUnits();
 158
 159   if (val == 0.0f)
 160     return 0.0;
 161
 162   if (length->IsPercentage()) {
 163     nsRefPtr<gfxFlattenedPath> data = GetFlattenedPath();
 164     return data ? (val * data->GetLength() / 100.0) : 0.0;
 165   } else {
 166     return val * GetPathScale();
 167   }
 168 }
 169
 170 gfxFloat
 171 nsSVGTextPathFrame::GetPathScale()
 172 {
 173   nsIFrame *pathFrame = GetPathFrame();
 174   if (!pathFrame)
 175     return 1.0;
 176
 177   nsSVGPathElement *path = static_cast<nsSVGPathElement*>(pathFrame->GetContent());
 178   float pl = path->mPathLength.GetAnimValue();
 179
 180   if (pl == 0.0f)
 181     return 1.0;
 182
 183   nsRefPtr<gfxFlattenedPath> data = GetFlattenedPath(pathFrame);
 184   return data ? data->GetLength() / pl : 1.0;
 185 }
 186
 187 //----------------------------------------------------------------------
 188 // nsIFrame methods
 189
 190 NS_IMETHODIMP
 191 nsSVGTextPathFrame::AttributeChanged(PRInt32         aNameSpaceID,
 192                                      nsIAtom*        aAttribute,
 193                                      PRInt32         aModType)
 194 {
 195   if (aNameSpaceID == kNameSpaceID_None &&
 196       aAttribute == nsGkAtoms::startOffset) {
 197     NotifyGlyphMetricsChange();
 198   } else if (aNameSpaceID == kNameSpaceID_XLink &&
 199              aAttribute == nsGkAtoms::href) {
 200     // Blow away our reference, if any
 201     DeleteProperty(nsGkAtoms::href);
 202     NotifyGlyphMetricsChange();
 203   }
 204
 205   return NS_OK;
 206 }