Hi Robert,
I've found a problem when using QFont (osgQt/QFontImplementation.cpp)
to read fonts: only the first character of a whole text is correctly
shown and others are disappeared. I haven't got into the font
implementation so can't explain why this happened and how it should
work under other platforms, but it seems to be fixed by specifying
width and height of the glyph object. The source file is attached for
future developments. At present it just works for my own project. :-)
Cheers,
Wang Rui
/* -*-c++-*- OpenSceneGraph - Copyright (C) 2009-2010 Mathias Froehlich
*
* This library is open source and may be redistributed and/or modified under
* the terms of the OpenSceneGraph Public License (OSGPL) version 0.0 or
* (at your option) any later version. The full license is in LICENSE file
* included with this distribution, and on the openscenegraph.org website.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* OpenSceneGraph Public License for more details.
*/
#include <osgQt/QFontImplementation>
#include <osgDB/FileNameUtils>
#include <osgDB/Registry>
#include <osgText/Font>
#include <QtGui/QFont>
#include <QtGui/QFontMetrics>
#include <QtGui/QImage>
#include <QtGui/QPainter>
namespace osgQt {
QFontImplementation::QFontImplementation(const QFont& font) :
_filename(font.toString().toStdString() + ".qfont"),
_font(font)
{
_currentRes.first = 0;
_currentRes.second = 0;
}
QFontImplementation::~QFontImplementation()
{
}
std::string
QFontImplementation::getFileName() const
{
return _filename;
}
void
QFontImplementation::setFontResolution(const osgText::FontResolution& fontSize)
{
if (fontSize == _currentRes)
return;
_currentRes = fontSize;
_font.setPixelSize(fontSize.second);
}
osgText::Glyph*
QFontImplementation::getGlyph(const osgText::FontResolution& fontRes, unsigned int charcode)
{
setFontResolution(fontRes);
float coord_scale = 1.0f/float(_currentRes.second);
QFontMetrics fontMetrics(_font);
QFontMetricsF fontMetricsF(_font);
QRect rect = fontMetrics.boundingRect(QChar(charcode));
QRectF rectF = fontMetricsF.boundingRect(QChar(charcode));
int margin = 1;
int imageWidth = rect.width() + 2*margin;
int imageHeight = rect.height() + 2*margin;
// Now paint the glyph into the image
QImage image(imageWidth, imageHeight, QImage::Format_ARGB32);
image.fill(0);
QPainter painter(&image);
painter.setRenderHint(QPainter::TextAntialiasing);
painter.setFont(_font);
painter.setBackgroundMode(Qt::TransparentMode);
painter.setBrush(Qt::white);
painter.setPen(Qt::white);
painter.drawText(margin - rect.left(), imageHeight - 1 - (margin + rect.bottom()), QString(QChar(charcode)));
painter.end();
// Transfer the rendered image to osg
osg::ref_ptr<osgText::Glyph> glyph = new osgText::Glyph(_facade, charcode);
unsigned int dataSize = imageWidth*imageHeight;
unsigned char* data = new unsigned char[dataSize];
// copy the qimage into the texture memory
for (int x = 0; x < imageWidth; ++x)
{
for (int y = 0; y < imageHeight; ++y)
{
data[x + y*imageWidth] = qAlpha(image.pixel(x, imageHeight - 1 - y));
}
}
// the glyph texture in osg
glyph->setImage(imageWidth, imageHeight, 1,
GL_ALPHA,
GL_ALPHA, GL_UNSIGNED_BYTE,
data,
osg::Image::USE_NEW_DELETE,
1);
glyph->setInternalTextureFormat(GL_ALPHA);
glyph->setWidth((float)imageWidth * coord_scale);
glyph->setHeight((float)imageHeight * coord_scale);
// Layout parameters
float leftBearing = fontMetricsF.leftBearing(QChar(charcode));
float rightBearing = fontMetricsF.rightBearing(QChar(charcode));
// for horizonal layout
osg::Vec2 bottomLeft(leftBearing - margin, - rectF.bottom() - margin);
glyph->setHorizontalBearing(bottomLeft * coord_scale);
glyph->setHorizontalAdvance(fontMetricsF.width(QChar(charcode)) * coord_scale);
// for vertical layout
osg::Vec2 topMiddle(- margin + 0.5*(leftBearing - rect.width() - rightBearing),
rectF.top() - margin);
glyph->setVerticalBearing(topMiddle * coord_scale);
glyph->setVerticalAdvance((rectF.height() + fontMetricsF.overlinePos() - fontMetricsF.xHeight()) * coord_scale);
// ... ready
//addGlyph(fontRes, charcode, glyph.get());
return glyph.release();
}
osg::Vec2
QFontImplementation::getKerning(unsigned int leftcharcode, unsigned int rightcharcode, osgText::KerningType kerningType)
{
return osg::Vec2(0, 0);
}
bool
QFontImplementation::hasVertical() const
{
return true;
}
}
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