I am rendering a QPixmap inside of a QThread. the code to paint is inside a function. If I declare the painter inside the drawChart function everything seems ok but if I declare the painter inside the run function the image is wrong in the sense that at the edge of a black and white area, the pixels at the interface are overlapped to give a grey. Does anyone know why this is so? Could it be because of the nature of the run function itself?

//This is ok

void RenderThread::run() { QImage image(resultSize, QImage::Format_RGB32); drawChart(&image); emit renderedImage(image, scaleFactor); }

drawChart(&image){ QPainter painter(image); painter.doStuff()(; ... }

//This gives a image that seems to have artifacts void RenderThread::run() { QImage image(resultSize, QImage::Format_RGB32); QPainter painter(image); drawChart(painter); emit renderedImage(image, scaleFactor); }

drawChart(&painter){ painter.doStuff()(; ... }