/*!
\since 4.2
Returns \c true if the writer supports \a option; otherwise returns
false.
Different image formats support different options. Call this function to
determine whether a certain option is supported by the current format. For
example, the PNG format allows you to embed text into the image's metadata
(see text()).
\snippet code/src_gui_image_qimagewriter.cpp 2
Options can be tested after the writer has been associated with a format.
\sa QImageReader::supportsOption(), setFormat()
*/
bool QImageWriter::supportsOption(QImageIOHandler::ImageOption option) const
{
if (!d->handler && (d->handler = createWriteHandlerHelper(d->device, d->format)) == 0) {
d->imageWriterError = QImageWriter::UnsupportedFormatError;
d->errorString = QImageWriter::tr("Unsupported image format");
return false;
}
return d->handler->supportsOption(option);
}
/*!
Returns true if QImageWriter can write the image; i.e., the image
format is supported and the assigned device is open for reading.
\sa write(), setDevice(), setFormat()
*/
bool QImageWriter::canWrite() const
{
if (d->device && !d->handler && (d->handler = createWriteHandlerHelper(d->device, d->format)) == 0) {
d->imageWriterError = QImageWriter::UnsupportedFormatError;
d->errorString = QT_TRANSLATE_NOOP(QImageWriter,
QLatin1String("Unsupported image format"));
return false;
}
if (d->device && !d->device->isOpen())
d->device->open(QIODevice::WriteOnly);
if (!d->device || !d->device->isWritable()) {
d->imageWriterError = QImageWriter::DeviceError;
d->errorString = QT_TRANSLATE_NOOP(QImageWriter,
QLatin1String("Device not writable"));
return false;
}
return true;
}
bool QImageWriterPrivate::canWriteHelper()
{
if (!device) {
imageWriterError = QImageWriter::DeviceError;
errorString = QImageWriter::tr("Device is not set");
return false;
}
if (!device->isOpen())
device->open(QIODevice::WriteOnly);
if (!device->isWritable()) {
imageWriterError = QImageWriter::DeviceError;
errorString = QImageWriter::tr("Device not writable");
return false;
}
if (!handler && (handler = createWriteHandlerHelper(device, format)) == 0) {
imageWriterError = QImageWriter::UnsupportedFormatError;
errorString = QImageWriter::tr("Unsupported image format");
return false;
}
return true;
}
