Drawing a line with a linear gradient effect

**toutarrive** · 14th February 2010, 18:06

Hello,

I need for an app to be able to draw simple lines with gradient effect.

After doing some research , i've found in Qt Labs Blog that is possible to set the palette brush on either a painter pen (or a painter brush) using this kind of code :

Qt Code:

Switch view

// Use the QPalette::Button roleâ€™s brush entry as a pen
painter->setPen(QPen(palette.button(), 0));
painter->drawLine(rect.topLeft(), rect.topRight());

// Use the QPalette::Button roleâ€™s brush entry as a pen
painter->setPen(QPen(palette.button(), 0));
painter->drawLine(rect.topLeft(), rect.topRight());

To copy to clipboard, switch view to plain text mode

What i don't get is how to set the QPalette::Button roleâ€™s brush to a gradient.

In Qt Assistant , they say that QPalette::BrightText role can be used as well to draw lines. What are the differences ?

Regards.

Olivier

**Lykurg** · 14th February 2010, 19:35

Salut,

as far as I know you don't have a possibility to get the gradient of a push button. This is because the gradient is composed direct in the styles "paint event" using the defined colours with modifications (QColor::darker() and lighter). So you have to compose your own gradient. Or have a look at the sources of a style how they draw the gradient and take that code to your drawing.

Lykurg

**toutarrive** · 14th February 2010, 22:39

Merci.

I'll have a look at the sources.
I wil, as well,l investigate further on this QPalette::BrightText role.
I do believe KDE as implemented this kind of gradient line. Maybe someone has got some tech specs on that matter.
In case of any progress in this matter, i'll get back to you to you Lukurg.

Auf Wiedersehen.