On Fri, Oct 1, 2010 at 8:34 AM, Werner LEMBERG
<address@hidden> wrote:
> I think I've found a bug in the cff renderer algorithm or I'm doing
> something seriously wrong. When rendering glyphs with cff outlines
> (otf, pfb fonts) the control points which are located under the
> baseline are connected with straight lines, for ttf fonts all the
> glyphs are rendered correctly. This problem occurs only when I use
> direct rendering with the FT_RASTER_FLAG_DIRECT flag, if I render
> the glyph to a bitmap with FT the problem doesn't occur. This
> problem is present in every version of FT that I've tested (2.1,
> 2.2, 2.3, 2.4).
>
> [...] this
> <http://www.filefactory.com/file/b36458b/n/renderer_problem.zip> is
> the example app, and this
> <http://www.filefactory.com/file/b36458c/n/letter_g.png> is how FT
> renders glyphs.
I've now downloaded your files, but please tell me how to compile it,
since I've never done Qt development...
Maybe others find the problem more quickly than me; I've thus attached
the image and the source code files.
Werner
#include <QtGui/QApplication>
#include <QWidget>
#include <QPainter>
#include <QFile>
#include <QImage>
#include <iostream>
#include <ft2build.h>
#include FT_FREETYPE_H
#include FT_GLYPH_H
#include FT_TYPES_H
#include FT_OUTLINE_H
#include FT_RENDER_H
QString g_usageText = "usage:\n"
"renderer_problem FONT_PATH CHARACTER SIZE "
"DIRECT_RENDERING_MODE(1|0)";
#define TRUNC(x) ((x) >> 6)
class Widget : public QWidget
{
Q_OBJECT
public:
Widget(const QString& fileName, QChar character, int pointSize
,bool directRender
,QWidget *parent = 0)
:QWidget(parent), m_directRender(directRender)
{
FT_Error error = 0;
m_face = 0;
m_library = 0;
error = FT_Init_FreeType(&m_library);
if(!error)
{
error = FT_New_Face(m_library, fileName.toAscii().constData(), 0,
&m_face);
if(!error)
{
error = FT_Set_Char_Size(m_face,
0,
pointSize * 64,
physicalDpiX(),
physicalDpiY());
FT_UInt glyph_index = 0;
glyph_index = FT_Get_Char_Index(m_face, character.unicode());
error = FT_Load_Glyph(m_face, glyph_index, FT_LOAD_DEFAULT);
FT_Pos left = m_face->glyph->metrics.horiBearingX;
FT_Pos right = m_face->glyph->metrics.horiBearingX
+ m_face->glyph->metrics.width;
FT_Pos top = m_face->glyph->metrics.horiBearingY;
FT_Pos bottom = m_face->glyph->metrics.horiBearingY
- m_face->glyph->metrics.height;
m_glyphRect = QRect(QPoint(TRUNC(left),
-TRUNC(top) + 1),
QSize(TRUNC(right-left) + 1,
TRUNC(top-bottom) + 1));
setFixedSize(m_glyphRect.width(), m_glyphRect.height());
}
}
}
~Widget()
{
FT_Done_Face(m_face);
FT_Done_Library(m_library);
}
private:
FT_Library m_library;
FT_Face m_face;
QRect m_glyphRect;
bool m_directRender;
static void graySpans(int y, int count, const FT_Span_ *spans, void *user)
{
QPainter *painter = (QPainter *)user;
y = -y;
for(int i = 0; i < count; i++)
{
const FT_Span span = spans[i];
qreal opacity = (qreal(span.coverage) / 255.0);
painter->setOpacity(opacity);
if(span.len > 0)
{
painter->drawLine(span.x, y, span.x + span.len, y);
}
}
}
protected:
void paintEvent(QPaintEvent *event)
{
QWidget::paintEvent(event);
if(m_library && m_face)
{
FT_Error error = 0;
QPainter painter(this);
painter.translate(-m_glyphRect.x(), -m_glyphRect.y());
if(m_directRender)
{
FT_Raster_Params params;
params.target = 0;
params.flags = FT_RASTER_FLAG_DIRECT | FT_RASTER_FLAG_AA;
params.user = &painter;
params.gray_spans = &Widget::graySpans;
params.black_spans = 0;
params.bit_set = 0;
params.bit_test = 0;
FT_Outline* outline = &m_face->glyph->outline;
FT_Outline_Render(m_library, outline, ¶ms);
}
else
{
error = FT_Render_Glyph(m_face->glyph, FT_RENDER_MODE_NORMAL);
QImage glyphImage(m_face->glyph->bitmap.buffer
,m_face->glyph->bitmap.width
,m_face->glyph->bitmap.rows
,m_face->glyph->bitmap.pitch
,QImage::Format_Indexed8);
painter.translate(m_glyphRect.x(), m_glyphRect.y());
QVector<QRgb> colorTable;
for(int i = 0; i < 256; ++i)
colorTable << qRgba(0, 0, 0, i);
glyphImage.setColorTable(colorTable);
painter.drawImage(QPoint(0, 0), glyphImage);
}
}
}
};
int main(int argc, char **argv)
{
bool status = false;
if(argc == 5)
{
bool isSizeOk = false;
QString path = argv[1];
QChar character = *argv[2];
int size = QString(argv[3]).toInt(&isSizeOk);
bool directRender = QString(argv[4]).toInt();
if(QFile::exists(path) && isSizeOk)
{
status = true;
QApplication a(argc, argv);
Widget w(path, character, size, directRender);
w.show();
return a.exec();
}
}
if(!status)
{
std::cout << qPrintable(g_usageText) << std::endl;
return 0;
}
}
#include "main.moc"
QT += core gui
TARGET = renderer_problem
TEMPLATE = app
SOURCES += main.cpp
MOC_DIR = ./moc
LIBS += -lz -lfreetype
INCLUDEPATH += $$MOC_DIR \
/usr/local/include \
/usr/local/include/freetype2