Function writeBackground

Telegram/SourceFiles/storage/localstorage.cpp:598–654

}

void writeBackground(const Data::WallPaper &paper, const QImage &image) {
	Expects(_settingsWriteAllowed);

	if (!_backgroundCanWrite) {
		return;
	}

	_useGlobalBackgroundKeys = true;
	auto &backgroundKey = Window::Theme::IsNightMode()
		? _backgroundKeyNight
		: _backgroundKeyDay;
	auto imageData = QByteArray();
	if (!image.isNull()) {
		const auto width = qint32(image.width());
		const auto height = qint32(image.height());
		const auto perpixel = (image.depth() >> 3);
		const auto srcperline = image.bytesPerLine();
		const auto srcsize = srcperline * height;
		const auto dstperline = width * perpixel;
		const auto dstsize = dstperline * height;
		const auto copy = (image.format() != kSavedBackgroundFormat)
			? image.convertToFormat(kSavedBackgroundFormat)
			: image;
		imageData.resize(2 * sizeof(qint32) + dstsize);

		auto dst = bytes::make_detached_span(imageData);
		bytes::copy(dst, bytes::object_as_span(&width));
		dst = dst.subspan(sizeof(qint32));
		bytes::copy(dst, bytes::object_as_span(&height));
		dst = dst.subspan(sizeof(qint32));
		const auto src = bytes::make_span(copy.constBits(), srcsize);
		if (srcsize == dstsize) {
			bytes::copy(dst, src);
		} else {
			for (auto y = 0; y != height; ++y) {
				bytes::copy(dst, src.subspan(y * srcperline, dstperline));
				dst = dst.subspan(dstperline);
			}
		}
	}
	if (!backgroundKey) {
		backgroundKey = GenerateKey(_basePath);
		writeSettings();
	}
	const auto serialized = paper.serialize();
	quint32 size = sizeof(qint32)
		+ Serialize::bytearraySize(serialized)
		+ Serialize::bytearraySize(imageData);
	EncryptedDescriptor data(size);
	data.stream
		<< qint32(kWallPaperSerializeTagId)
		<< serialized
		<< imageData;

	FileWriteDescriptor file(backgroundKey, _basePath);
	file.writeEncrypted(data, SettingsKey);
}