Simplified and improved the glyph margin computation and usage

src/osgPlugins/freetype/FreeTypeFont.cpp

@@ -278,19 +278,6 @@ void FreeTypeFont::setFontResolution(const osgText::FontResolution& fontSize)
 
     int width = fontSize.first;
     int height = fontSize.second;
-    int maxAxis = std::max(width, height);
-    int margin = _facade->getGlyphImageMargin() + (int)((float)maxAxis * _facade->getGlyphImageMarginRatio());
-
-    if ((unsigned int)(width+2*margin) > _facade->getTextureWidthHint() ||
-        (unsigned int)(width+2*margin) > _facade->getTextureHeightHint())
-    {
-        OSG_WARN<<"Warning: FreeTypeFont::setSize("<<width<<","<<height<<") sizes too large,"<<std::endl;
-
-        width = _facade->getTextureWidthHint()-2*margin;
-        height = _facade->getTextureHeightHint()-2*margin;
-
-        OSG_WARN<<"         sizes capped ("<<width<<","<<height<<") to fit int current glyph texture size."<<std::endl;
-    }
 
     FT_Error error = FT_Set_Pixel_Sizes( _face,      /* handle to face object  */
                                          width,      /* pixel_width            */

src/osgText/DefaultFont.cpp

@@ -29,9 +29,6 @@ DefaultFont::DefaultFont()
     _minFilterHint = osg::Texture::LINEAR_MIPMAP_LINEAR;
     _magFilterHint = osg::Texture::NEAREST;
 
-    _margin = 8;
-    _marginRatio = 0.0;
-    _glyphInterval = 16;
 
     constructGlyphs();
 }

src/osgText/Font.cpp

@@ -224,9 +224,6 @@ osg::ref_ptr<Font> osgText::readRefFontStream(std::istream& stream, const osgDB:
 
 Font::Font(FontImplementation* implementation):
     osg::Object(true),
-    _margin(1),
-    _marginRatio(0.02),
-    _glyphInterval(1),
 #if 0
     _glyphTextureFeatures(GlyphTexture::ALL_FEATURES),
 #else
@@ -289,32 +286,6 @@ std::string Font::getFileName() const
     return std::string();
 }
 
-void Font::setGlyphImageMargin(unsigned int margin)
-{
-    _margin = margin;
-}
-
-unsigned int Font::getGlyphImageMargin() const
-{
-    return _margin;
-}
-
-void Font::setGlyphImageMarginRatio(float ratio)
-{
-    _marginRatio = ratio;
-}
-
-float Font::getGlyphImageMarginRatio() const
-{
-    return _marginRatio;
-}
-
-void Font::setGlyphInterval(int interval)
-{
-    _glyphInterval = interval;
-}
-
-
 void Font::setTextureSizeHint(unsigned int width,unsigned int height)
 {
     _textureWidthHint = width;
@@ -514,9 +485,6 @@ void Font::addGlyph(const FontResolution& fontRes, unsigned int charcode, Glyph*
         OSG_INFO<< "   Font " << this<< ", numberOfTexturesAllocated "<<numberOfTexturesAllocated<<std::endl;
 
         // reserve enough space for the glyphs.
-        glyphTexture->setGlyphImageMargin(_margin);
-        glyphTexture->setGlyphImageMarginRatio(_marginRatio);
-        glyphTexture->setGlyphInterval(_glyphInterval);
         glyphTexture->setGlyphTextureFeatures(_glyphTextureFeatures);
         glyphTexture->setTextureSize(_textureWidthHint,_textureHeightHint);
         glyphTexture->setFilter(osg::Texture::MIN_FILTER,_minFilterHint);

src/osgText/Glyph.cpp

@@ -37,9 +37,6 @@ using namespace std;
 #endif
 
 GlyphTexture::GlyphTexture():
-    _margin(1),
-    _marginRatio(0.02f),
-    _interval(1),
     _usedY(0),
     _partUsedX(0),
     _partUsedY(0)
@@ -60,21 +57,39 @@ int GlyphTexture::compare(const osg::StateAttribute& rhs) const
     return 0;
 }
 
+int GlyphTexture::getEffectMargin(const Glyph* glyph)
+{
+    if (_glyphTextureFeatures==GREYSCALE) return 0;
+    else return glyph->getFontResolution().second/4;
+}
+
+int GlyphTexture::getTexelMargin(const Glyph* glyph)
+{
+    int width = glyph->s();
+    int height = glyph->t();
+    int effect_margin = getEffectMargin(glyph);
+
+    int max_dimension = std::max(width, height) + 2 * effect_margin;
+    int margin = osg::maximum(max_dimension/4, 2) + effect_margin;
+
+    return margin;
+}
 
 bool GlyphTexture::getSpaceForGlyph(Glyph* glyph, int& posX, int& posY)
 {
-    int maxAxis = osg::maximum(glyph->s(), glyph->t());
-    int margin_from_ratio = (int)((float)maxAxis * _marginRatio);
-    int search_distance = glyph->getFontResolution().second/8;
+    int width = glyph->s();
+    int height = glyph->t();
 
-    int margin = _margin + osg::maximum(margin_from_ratio, search_distance);
+    int margin = getTexelMargin(glyph);
 
-    int width = glyph->s()+2*margin;
-    int height = glyph->t()+2*margin;
+    width += 2*margin;
+    height += 2*margin;
 
-    int partUsedX = ((_partUsedX % _interval) == 0) ? _partUsedX : (((_partUsedX/_interval)+1)*_interval);
-    int partUsedY = ((_partUsedY % _interval) == 0) ? _partUsedY : (((_partUsedY/_interval)+1)*_interval);
-    int usedY = ((_usedY % _interval) == 0) ? _usedY : (((_usedY/_interval)+1)*_interval);
+    int interval = 4;
+
+    int partUsedX = ((_partUsedX % interval) == 0) ? _partUsedX : (((_partUsedX/interval)+1)*interval);
+    int partUsedY = ((_partUsedY % interval) == 0) ? _partUsedY : (((_partUsedY/interval)+1)*interval);
+    int usedY = ((_usedY % interval) == 0) ? _usedY : (((_usedY/interval)+1)*interval);
 
     // first check box (partUsedX, usedY) to (width,height)
     if (width <= (getTextureWidth()-partUsedX) &&
@@ -132,6 +147,9 @@ void GlyphTexture::addGlyph(Glyph* glyph, int posX, int posY)
     glyph->setMaxTexCoord( osg::Vec2( static_cast<float>(posX+glyph->s())/static_cast<float>(getTextureWidth()),
                                       static_cast<float>(posY+glyph->t())/static_cast<float>(getTextureHeight()) ) );
 
+
+    glyph->setTexelMargin(float(getTexelMargin(glyph)));
+
     copyGlyphImage(glyph);
 }
 
@@ -156,7 +174,7 @@ void GlyphTexture::copyGlyphImage(Glyph* glyph)
     int dest_rows = _image->t();
     unsigned char* dest_data = _image->data(glyph->getTexturePositionX(),glyph->getTexturePositionY());
 
-    int search_distance = glyph->getFontResolution().second/4;
+    int search_distance = getEffectMargin(glyph);
 
     int left = -search_distance;
     int right = glyph->s()+search_distance;

src/osgText/Text.cpp

@@ -464,8 +464,6 @@ void Text::computeGlyphRepresentation()
     float hr = _characterHeight;
     float wr = hr/getCharacterAspectRatio();
 
-    float texelMargin = 5.0f;
-
     for(String::iterator itr=_text.begin();
         itr!=_text.end();
         )
@@ -632,6 +630,7 @@ void Text::computeGlyphRepresentation()
                     osg::Vec2 mintc = glyph->getMinTexCoord();
                     osg::Vec2 maxtc = glyph->getMaxTexCoord();
                     osg::Vec2 vDiff = maxtc - mintc;
+                    float texelMargin = glyph->getTexelMargin();
 
                     float fHorizTCMargin = texelMargin / glyph->getTexture()->getTextureWidth();
                     float fVertTCMargin = texelMargin / glyph->getTexture()->getTextureHeight();