QT从字体名获取字库文件路径(从宋体获取到simsun.ttc)

MFC版本的从字体名获取字库文件路径点击此处

最近弄的一份项目需要裁剪ttf字库，故需要用到此功能！

用了几年QT，个人感觉类库是非常强大的！

QT相比VS的话亮点在开源的类库非常的丰富，几乎无所不能的覆盖到位，以及在大型项目中能轻松实现多语言功能！

唯一美中不足的就是他的gcc开发包非常蛋疼，一旦遇到崩溃闪退bug非常难找，有些根本断不到点，甚至切换成QT+VS+DMP都无法定位的！

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从VC6或VS目录拷贝一份user32.lib与gdi32.lib

在pro文件加两行

LIB += user32.lib

LIB += gdi32.lib

#include <windows.h>
#include <sstream>
#include <QApplication>
#include <QSettings>
#include <QDebug>
#include <QFont>
#include <QFontInfo>
#include <QFontComboBox>
#include <QWidget>
#include <QVBoxLayout>
#include <QTextEdit>
#include <QTime>
#include <QDir>

// Get system font file path
std::string GetSystemFontFile(const std::string &faceName) {

	static const LPWSTR fontRegistryPath = L"Software\\Microsoft\\Windows NT\\CurrentVersion\\Fonts";
	HKEY hKey;
	LONG result;
	std::wstring wsFaceName(faceName.begin(), faceName.end());

	// Open Windows font registry key
	result = RegOpenKeyEx(HKEY_LOCAL_MACHINE, fontRegistryPath, 0, KEY_READ, &hKey);
	if (result != ERROR_SUCCESS) {
		return "";
	}

	DWORD maxValueNameSize, maxValueDataSize;
	result = RegQueryInfoKey(hKey, 0, 0, 0, 0, 0, 0, 0, &maxValueNameSize, &maxValueDataSize, 0, 0);
	if (result != ERROR_SUCCESS) {
		return "";
	}

	DWORD valueIndex = 0;
	LPWSTR valueName = new WCHAR[maxValueNameSize];
	LPBYTE valueData = new BYTE[maxValueDataSize];
	DWORD valueNameSize, valueDataSize, valueType;
	std::wstring wsFontFile;

	// Look for a matching font name
	do {

		wsFontFile.clear();
		valueDataSize = maxValueDataSize;
		valueNameSize = maxValueNameSize;

		result = RegEnumValue(hKey, valueIndex, valueName, &valueNameSize, 0, &valueType, valueData, &valueDataSize);

		valueIndex++;

		if (result != ERROR_SUCCESS || valueType != REG_SZ) {
			continue;
		}

		std::wstring wsValueName(valueName, valueNameSize);

		// Found a match
		if (_wcsnicmp(wsFaceName.c_str(), wsValueName.c_str(), wsFaceName.length()) == 0) {

			wsFontFile.assign((LPWSTR)valueData, valueDataSize);
			break;
		}
	}
	while (result != ERROR_NO_MORE_ITEMS);

	delete[] valueName;
	delete[] valueData;

	RegCloseKey(hKey);

	if (wsFontFile.empty()) {
		return "";
	}

	// Build full font file path
	WCHAR winDir[MAX_PATH];
	GetWindowsDirectory(winDir, MAX_PATH);

	std::wstringstream ss;
	ss << winDir << "\\Fonts\\" << wsFontFile;
	wsFontFile = ss.str();

	return std::string(wsFontFile.begin(), wsFontFile.end());
}

#define MAKE_TAG(ch1, ch2, ch3, ch4) (\
	(((quint32)(ch4)) << 24) | \
	(((quint32)(ch3)) << 16) | \
	(((quint32)(ch2)) << 8) | \
	((quint32)(ch1)) \
	)

static inline quint16 getUShort(const unsigned char *p)
{
	quint16 val;
	val = *p++ << 8;
	val |= *p;

	return val;
}

static QString getEnglishName(const uchar *table, quint32 bytes)
{
	QString i18n_name;
	enum {
		NameRecordSize = 12,
		FamilyId = 1,
		MS_LangIdEnglish = 0x009
	};

	// get the name table
	quint16 count;
	quint16 string_offset;
	const unsigned char *names;

	int microsoft_id = -1;
	int apple_id = -1;
	int unicode_id = -1;

	if(getUShort(table) != 0)
		goto error;

	count = getUShort(table+2);
	string_offset = getUShort(table+4);
	names = table + 6;

	if(string_offset >= bytes || 6 + count*NameRecordSize > string_offset)
		goto error;

	for(int i = 0; i < count; ++i) {
		// search for the correct name entry

		quint16 platform_id = getUShort(names + i*NameRecordSize);
		quint16 encoding_id = getUShort(names + 2 + i*NameRecordSize);
		quint16 language_id = getUShort(names + 4 + i*NameRecordSize);
		quint16 name_id = getUShort(names + 6 + i*NameRecordSize);

		if(name_id != FamilyId)
			continue;

		enum {
			PlatformId_Unicode = 0,
			PlatformId_Apple = 1,
			PlatformId_Microsoft = 3
		};

		quint16 length = getUShort(names + 8 + i*NameRecordSize);
		quint16 offset = getUShort(names + 10 + i*NameRecordSize);
		if(DWORD(string_offset + offset + length) >= bytes)
			continue;

		if ((platform_id == PlatformId_Microsoft
			&& (encoding_id == 0 || encoding_id == 1))
			&& (language_id & 0x3ff) == MS_LangIdEnglish
			&& microsoft_id == -1)
			microsoft_id = i;
		// not sure if encoding id 4 for Unicode is utf16 or ucs4...
		else if(platform_id == PlatformId_Unicode && encoding_id < 4 && unicode_id == -1)
			unicode_id = i;
		else if(platform_id == PlatformId_Apple && encoding_id == 0 && language_id == 0)
			apple_id = i;
	}
	{
		bool unicode = false;
		int id = -1;
		if(microsoft_id != -1) {
			id = microsoft_id;
			unicode = true;
		} else if(apple_id != -1) {
			id = apple_id;
			unicode = false;
		} else if (unicode_id != -1) {
			id = unicode_id;
			unicode = true;
		}
		if(id != -1) {
			quint16 length = getUShort(names + 8 + id*NameRecordSize);
			quint16 offset = getUShort(names + 10 + id*NameRecordSize);
			if(unicode) {
				// utf16

				length /= 2;
				i18n_name.resize(length);
				QChar *uc = (QChar *) i18n_name.unicode();
				const unsigned char *string = table + string_offset + offset;
				for(int i = 0; i < length; ++i)
					uc[i] = getUShort(string + 2*i);
			} else {
				// Apple Roman

				i18n_name.resize(length);
				QChar *uc = (QChar *) i18n_name.unicode();
				const unsigned char *string = table + string_offset + offset;
				for(int i = 0; i < length; ++i)
					uc[i] = QLatin1Char(string[i]);
			}
		}
	}
error:
	//qDebug("got i18n name of '%s' for font '%s'", i18n_name.latin1(), familyName.toLocal8Bit().data());
	return i18n_name;
}

static QString getEnglishName(const QString &familyName)
{
	QString i18n_name;

	HDC hdc = GetDC( 0 );
	LOGFONT lf;
	memset(&lf, 0, sizeof(LOGFONT));
	memcpy(lf.lfFaceName, familyName.utf16(), qMin(LF_FACESIZE, familyName.length()) * sizeof(wchar_t));
	lf.lfCharSet = DEFAULT_CHARSET;
	HFONT hfont = CreateFontIndirect(&lf);

	if(!hfont) {
		ReleaseDC(0, hdc);
		return QString();
	}

	HGDIOBJ oldobj = SelectObject( hdc, hfont );

	const DWORD name_tag = MAKE_TAG( 'n', 'a', 'm', 'e' );

	// get the name table
	unsigned char *table = 0;

	DWORD bytes = GetFontData( hdc, name_tag, 0, 0, 0 );
	if ( bytes == GDI_ERROR ) {
		// ### Unused variable
		/* int err = GetLastError(); */
		goto error;
	}

	table = new unsigned char[bytes];
	GetFontData(hdc, name_tag, 0, table, bytes);
	if ( bytes == GDI_ERROR )
		goto error;

	i18n_name = getEnglishName(table, bytes);
error:
	delete [] table;
	SelectObject( hdc, oldobj );
	DeleteObject( hfont );
	ReleaseDC( 0, hdc );

	//qDebug("got i18n name of '%s' for font '%s'", i18n_name.latin1(), familyName.toLocal8Bit().data());
	return i18n_name;
}


class TextEdit : public QTextEdit
{
public:
	TextEdit()
	{
		startTimer(1000);
		setReadOnly(true);
	}

	void timerEvent(QTimerEvent *)
	{
		QFont font = currentFont();
		std::string path = GetSystemFontFile(getEnglishName(font.family()).toStdString());
		setText(QString().fromLocal8Bit(path.c_str()));
	}
};

int main(int argc, char *argv[])
{
    QApplication app(argc, argv);

	QWidget widget;
	QFontComboBox fontCombb;
	TextEdit textEdit;
	QVBoxLayout layout;
	QObject::connect(&fontCombb, SIGNAL(currentFontChanged(const QFont&)), &textEdit, SLOT(setCurrentFont(const QFont&)));
	layout.addWidget(&fontCombb);
	layout.addWidget(&textEdit);
	widget.setLayout(&layout);
	widget.show();

    return app.exec();
}