Details
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Bug
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Resolution: Cannot Reproduce
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P1: Critical
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None
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4.8.0
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None
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Windows 7 x64
Windows 7 x86
Microsoft Visual C++ express 2010
MinGW32 4.4.0 toolchain
Description
Qt configured with these options: "-no-qt3support -opensource -graphicssystem opengl -no-dsp -no-vcproj -mp"
Just open LineEdits example program, you will see the incorrectly rendered glyphs, there're always some pixels under each line of text.
But if not use -graphicssystem opengl option, everything works well.
Well this bug can also be reproducible by drawing text on a QGLWidger. For example, compile a version without -graphicssystem opengl option, then launch OpenGL-2D Painting program from qtDemo, you will see the same problem.
Here's the code for testing
#include <QtGui>
#include <QGLWidget>
class GLWidget:public QGLWidget
{
protected:
void paintEvent(QPaintEvent *event)
{
QPainter painter(this);
QString text1 = "ABCDE abcde\n";
QString text2 = "\nABCDE abcde";
QRect rect=this->rect();
QFont font1("Arial",30);
QFont font2("Tahoma");
painter.begin(this);
painter.setFont(font1);
painter.drawText(rect, Qt::AlignCenter, text1);
painter.setFont(font2);
painter.drawText(rect, Qt::AlignCenter, text2);
painter.end();
}
};
int main(int argc, char **argv)
{
QApplication app(argc, argv);
GLWidget w;
w.show();
app.exec();
return 0;
}
Then I try to change the point size of font. Then I found that, you will see the different result when the point size larger than 47. See picture "new".
Here's the code.
#include <QtGui>
#include <QGLWidget>
class GLWidget:public QGLWidget
{
protected:
void paintEvent(QPaintEvent *event)
{
QPainter painter(this);
QString text1 = "ABCDE abcde\n";
QString text2 = "\nABCDE abcde";
QRect rect=this->rect();
QFont font1("Tahoma",47);
QFont font2("Tahoma",48);
painter.begin(this);
painter.setFont(font1);
painter.drawText(rect, Qt::AlignCenter, text1);
painter.setFont(font2);
painter.drawText(rect, Qt::AlignCenter, text2);
painter.end();
}
};
int main(int argc, char **argv)
{
QApplication app(argc, argv);
GLWidget w;
w.show();
app.exec();
return 0;
}
Now I have a "raster" version of qt, and try glwidget program, then I got the same result. See picture "rasterResult". Set graphicssystem option to raster could not fix this problem for me.
I tried this program on another machine, it's a win7 x86 system. The dots gone, but there're still some problem. I uploaded a picture, so you can see the different between size 47 and 48. With 48 point size, smooth seems disabled.
