On a second though, the actual error seems to be elsewhere, so still can use proper indexing
#include "preview_image_provider.h"
PreviewImageProvider::PreviewImageProvider()
: QQuickImageProvider(QQuickImageProvider::Pixmap) {}
QPixmap PreviewImageProvider::requestPixmap(const QString &id, QSize *size,
const QSize &requestedSize) {
Q_UNUSED(id);
Q_UNUSED(requestedSize);
if (size) *size = m_px.size();
return m_px;
}
void PreviewImageProvider::setImage(const QImage &preview) {
m_px = QPixmap::fromImage(preview, Qt::ColorOnly);
// QPixmap pxres(px.size());
// QPainter p(&pxres);
// p.fillRect(pxres.rect(), linearGrad);
// p.drawPixmap(0, 0, px);
}