QFontDatabase::addApplicationFont return -1

achak

My ( first) app on Windows using QT Creator 5.15 . I try load a font from the Google collection.
I put ttf files into C:/try/gui_0/fonts/SourceSansPro/ folder. Add following line into qrc file:

<file alias="SSP_Regular.ttf">fonts/SourceSansPro/SourceSansPro-Regular.ttf</file>```

I entered following c++ code into main function:

    int fnt_id = QFontDatabase::addApplicationFont(":/fonts/SourceSansPro/SourceSansPro-Regular.ttf");
    int ali_id = QFontDatabase::addApplicationFont(":/fonts/SourceSansPro/SSP_Regular.ttf");
    int shrt_id = QFontDatabase::addApplicationFont(":/SSP_Regular.ttf");
    int an_id = QFontDatabase::addApplicationFont("SSP_Regular.ttf");
    int qrc_id = QFontDatabase::addApplicationFont("qrc:/fonts/SourceSansPro/SourceSansPro-Regular.ttf");
    int fle_id = QFontDatabase::addApplicationFont("C:/try/gui_0/fonts/SourceSansPro/SourceSansPro-Regular.ttf");

Each line bellow returns -1.
Whats a problem?

Christian Ehrlicher

Only the last one can work - the rest is wrong.
Please make sure that the file is really there and readable

QFileInfo fi("C:/try/gui_0/fonts/SourceSansPro/SourceSansPro-Regular.ttf");
if (!fi.exists() || !fi.isReadable()) {
  qWarning() << "Wrong filename";
} else {
  int fle_id = QFontDatabase::addApplicationFont(fi.absoluteFilePath());
  qDebug() << fle_id ;
}

achak

@Christian-Ehrlicher said in QFontDatabase::addApplicationFont return -1:

QFileInfo fi("C:/try/gui_0/fonts/SourceSansPro/SourceSansPro-Regular.ttf");
if (!fi.exists() || !fi.isReadable()) {
qWarning() << "Wrong filename";
} else {
int fle_id = QFontDatabase::addApplicationFont(fi.absoluteFilePath());
qDebug() << fle_id ;
}

Debug output is -1. The font file is exist and readable

Christian Ehrlicher

Then enable the debug logging for qt.qpa.fonts (see detailed description here: https://doc.qt.io/qt-5/qloggingcategory.html#details ) and see what it prints to your console.