Drawing a line with a linear gradient effect

[toutarrive]

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 :

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

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

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What i don't get is how to set the QPalette::Button role’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