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我有一段代碼，用於使用Nokia Qt導出透明圖像&。但是，它不起作用。我總是看到有很多噪音的黑色背景。我必須用白色填充背景，但我需要透明度，而不是白色。請提供建議。如何使用Nokia Qt C++繪製和導出透明圖像？
#include <QtGui/QApplication>
#include <QtGui>
int main(int argc, char *argv[])
{
QApplication app(argc, argv);
{
QImage pix(260, 50, QImage::Format_ARGB32_Premultiplied);
QPainter painter(&pix);
painter.setBackgroundMode(Qt::TransparentMode);
painter.setRenderHint(QPainter::Antialiasing, true);
painter.setRenderHint(QPainter::TextAntialiasing, true);
painter.setPen(QColor(0x00, 0x00, 0x00, 0xff));
painter.setBrush(QColor(0x00, 0x00, 0x00, 0xff));
painter.setFont(QFont("AvantGarde Md BT", 32));
painter.setBackgroundMode(Qt::TransparentMode);
// I don't like the white color, but I must put otherwise you'll see dumb & black background
painter.fillRect(0, 0, pix.width(), pix.height(), QColor(0xff, 0xff, 0xff, 0xff));
QString text("My Text");
QFontMetrics fm(painter.font());
int w = fm.width(text);
int h = fm.height();
painter.drawText((pix.width() - w)/2, (pix.height() + h/2)/2, text);
pix.save(QString("mytext.png"));
}
}