Text is not good enough while using QPainter::drawText()?

IMAN4K

Hi.
i'm trying to draw text using QPainter::drawText() but the text is not antialiased (comparing to MS word)

void TextLabel::paintEvent(QPaintEvent*) {
    QPainter p(this);
    p.setRenderHint(QPainter::TextAntialiasing);

    QFont font;
    font.setFamily("Roboto medium");
    font.setPointSize(32);
    font.setStyleHint(QFont::Helvetica, QFont::PreferAntialias);

    p.setPen(_brush);
    p.setFont(font);

    p.drawText(rect(), Qt::AlignLeft , _text);
}

Qt Doc says:

QPainter::TextAntialiasing -> Indicates that the engine should antialias text if possible

Is this impossible ?
What should i do ?

The word one : https://drive.google.com/file/d/0B-nmbIyXfagPNlBaaGRyWGhXM2s/view
The Qt one : https://drive.google.com/file/d/0B-nmbIyXfagPR3FiLXd1ZkptREk/view

raven-worx

@IMAN4K

which Qt version do you use?
did you compile Qt yourself?
which platform?

i am not sure if it helps, but try to omit the Helvetica hint. And just set the stragedy:

font.setStyleStrategy(QFont::PreferAntialias)

But your text - in case you didn't downscale the posted images - is already anti-aliased. As you can see when you zoom into the image.
I guess MS word and Qt are just using different anti-aliasing algorithms.

IMAN4K

@raven-worx
Using Qt5.5.1 on Windows.
And no i didn't.

That doesn't work too :(
And yes they are not realy anti-aliased .

raven-worx

@IMAN4K said:

And yes they are realy anti-aliased .

Then i am afraid there is not much you can do. Since Qt doesn't offer an such detailed anti-aliasing API.

IMAN4K

@raven-worx
Ii means there is no way just for a simple text drawing ?

raven-worx

@IMAN4K
as we already agreed anti-aliasing works.
But not the way you would like it to. And the anti-aliasing algorithm can't be explicitly set AFAIK.

IMAN4K

It seems Qt has issue on Window OS (font rendering) and work with some fonts >=48pt and doesn't work with some other.

Issue : https://bugreports.qt.io/browse/QTBUG-40052

We hope they will fix it in the near future.

You can draw with QPainterPath it's more expensive but still helps :

void TextLabel::paintEvent(QPaintEvent*) {
	QPainter painter(this);
	painter.setRenderHint(QPainter::Antialiasing);
	painter.setBrush(Qt::black);

	QFont font;
	font.setPointSize(38);
	font.setFamily("Roboto");

	painter.setFont(font);

	painter.drawText(0, 60, "Google");

	QPainterPath textPath, path0;
	textPath.addText(0, 140, font, "Google");
	painter.drawPath(textPath);
}

Roboto @ 38pt :

Unsolved Text is not good enough while using QPainter::drawText()?