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Qt�Q�FontMetrics

Sat, 03 Aug 2013 10:27:00 GMT

在一个Rect的正中间�l�制文本: rect的中点与文本的中炚w��?

int cx = rect.x + rect.width / 2;

int fx = cx - fm.width(text);

int cy = rect.y + rect.height / 2;

int fy = cy + fm.xHeight / 2;

@import url(http://www.shnenglu.com/CuteSoft_Client/CuteEditor/Load.ashx?type=style&file=SyntaxHighlighter.css);@import url(/css/cuteeditor.css);

逛奔的蜗�?/a> 2013-08-03 18:27 发表评论

C�Q�函数指针数�l�的定义

Thu, 25 Jul 2013 23:56:00 GMT

// [[1]] 使用typedef定义函数指针��Z��个类型，更喜�Ƣ这�U�方�?/font>

typedef int (*MYFUN)(int, int);

MYFUN funcs[10];

// [[2]] 使用typedef定义函数指针数组��Z��个类型，不是很直�?/font>

typedef int (*MYFUN2[10])(int, int);

MYFUN2 funcs2;

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

    funcs[0] = add;

    qDebug() << (*funcs[0])(2, 3); // 也可以用 funcs[0](2, 3).

    funcs2[0] = add;

    qDebug() << (*funcs2[0])(2, 3);

    return 0;

@import url(http://www.shnenglu.com/CuteSoft_Client/CuteEditor/Load.ashx?type=style&file=SyntaxHighlighter.css);@import url(/css/cuteeditor.css);

逛奔的蜗�?/a> 2013-07-26 07:56 发表评论

Qt�Q�解读Q_GLOBAL_STATIC(QFontDatabasePrivate, privateDb)

Wed, 26 Jun 2013 02:02:00 GMT

From: http://zhgw01.blog.163.com/blog/static/1041481220105253491586/
�Ҏ�� src/corelib/global.h

template
class QGlobalStatic
{
public:
    T *pointer;
    inline QGlobalStatic(T *p) : pointer(p) { }
    inline ~QGlobalStatic() { pointer = 0; }
};

#define Q_GLOBAL_STATIC(TYPE, NAME)                              \
    static TYPE *NAME()                                          \
    {                                                            \
        static TYPE this_##NAME;                                 \
        static QGlobalStatic global_##NAME(&this_##NAME); \
        return global_##NAME.pointer;                            \
    }

上面的展开�?/span>

static QFontDatabasePrivate *privateDb()
{
static QFontDatabasePrivate this_privateDb; // 注意�W�一�ơ引用的时候会开始进行初始化, 以后不再生成
static QGLobalStatic global_privateDb(&this_privateDb); //对上面生成的对象的指针进行包装，同上�Q�只有第一�ơ才会生�?br />
return global_privateDb;
}

QFontDatabase的构造函��C��会调用createDatabase �Q�里面调用了initializeDb), initializeDb里调用了privateDb(),一个这个时候是�W�一�ơ调用，会生成QFontDatabasePrivate对象

QFontDatabasePrivate中的QDataStream *stream成员才是真正处理qte的字�?/p>

逛奔的蜗�?/a> 2013-06-26 10:02 发表评论

Tue, 25 Jun 2013 15:26:00 GMT

From: http://blog.csdn.net/henreash/article/details/7264489@import url(http://www.shnenglu.com/CuteSoft_Client/CuteEditor/Load.ashx?type=style&file=SyntaxHighlighter.css);@import url(/css/cuteeditor.css);

创徏一个QT的库��目,删除自动生成�?h�?cpp文�g,��d��一个接口定�?h文�g和一个接口实现类(一�?h一�?cpp).代码如下:

1.接口文�g源码

#ifndef PLUGININTERFACE_H
#define PLUGININTERFACE_H

#include

class EchoInterface
{
public:
virtual ~EchoInterface() {}
virtual QString echo(const QString &message) = 0;
};

QT_BEGIN_NAMESPACE
Q_DECLARE_INTERFACE(EchoInterface, "com.hollysys.plugin.EchoIntrface/1.0");
QT_END_NAMESPACE

#endif

2.接口实现�c�d��文�g

#ifndef PLUGIN_H
#define PLUGIN_H

//#include "plugin_global.h"
#include
#include "plugininterface.h"

class Plugin : public QObject, EchoInterface
{
Q_OBJECT
Q_INTERFACES(EchoInterface)
public:
Plugin();
~Plugin();
public:
QString echo(const QString &message);

};

#endif // PLUGIN_H

3.接口实现�c�cpp文�g

#include "plugin.h"
#include

Plugin::Plugin()
{

}

Plugin::~Plugin()
{

}

QString Plugin::echo(const QString &message)
{
return message;
}

Q_EXPORT_PLUGIN2("echoPlugin", Plugin);

�~�译生成dll格式的插�?�q�里可能会遇到LNK2001错误,因�ؓ插�g接口定义依赖于QT的元数据,而在代码中手动添加Q_OBJECT宏后,�~�译器不会自动�ؓ我们生成moc_XXXX.cpp文�g,因此需要��用命令行生成moc元数据文�?cmd-->cd 源码所在命�?-->moc -o moc_XXXX.cpp XXXX.h.�q�样��可以手动创建出moc元数据文�?解决LNK2001�~�译错误.

建立一个GUI��试��目,代码如下:

#include "test.h"
#include
#include
#include

Test::Test(QWidget *parent, Qt::WFlags flags)
: QMainWindow(parent, flags)
{
ui.setupUi(this);
QObject::connect(ui.pushButton, SIGNAL(clicked()), this, SLOT(ButtonClicked()));
loadPlugin();
}

Test::~Test()
{

}

bool Test::loadPlugin()
{
QDir pluginsDir(qApp->applicationDirPath());
foreach (QString filename, pluginsDir.entryList(QDir::Files))
{
  QPluginLoader pluginLoader(pluginsDir.absoluteFilePath(filename));
  QObject *plugin = pluginLoader.instance();
  if(plugin)
  {
   echoInterface = qobject_cast(plugin);//echoInterface是成员变�?br />    if(echoInterface)
    return true;
  }
}
}

void Test::ButtonClicked()
{
QString plugin = ui.lineEdit->text();
QMessageBox::information(NULL, "", echoInterface->echo(plugin));
}

分析代码可见,�q�里�Ҏ��有与exe文�g同目录的文�g��试加蝲插�g,如果加蝲成功则返�?代码实现非常��z?在正式开发中可将已加载的插�g接口存放在列表中,在需要的时候依�ơ调用即�?

另外如果惌��取插件中�c�d��义的元数�?可以使插件接口类从QObject�l�承,�q��用Q_CLASSINFO宏添加键值对,如Q_CLASSINFO("Author**", "Henreash**").�q�从�ȝ��序中使用插�g对象元数据获取这些键值对:

const QMetaObject *mo = echoInterface->metaObject();
for(int i = 0; i < mo->classInfoCount(); i++)
{
qDebug() << mo->classInfo(i).name() << mo->classInfo(i).value();
}

使用�q�个机制可以在定义插件类的时候向�ȝ��序传递一些特�D�信�?

��试发现,如果在插件接口类中定义一个静态变�?那么�q�个静态变量在插�g中的地址和在�ȝ��序中的地址是不相同�?

逛奔的蜗�?/a> 2013-06-25 23:26 发表评论

C++�Q�单�?Singleton

Tue, 25 Jun 2013 13:46:00 GMT

From: http://zh.wikipedia.org/wiki/单例模式

�?a title="C++"

@import url(http:/

OpenGL�Q�展
Thu, 18 Apr 2013 16:24:00 GMT style="text-decoration: none; color: #0b0080; background-image: none; background-position: initial initial; background-repeat: initial initial; ">C++�~�程语言中，单例模式应用的例子如下述代码所�C�（�q�里仅仅提供一个示例，�q�个例子对多�U�程的情况�ƈ不是安全的）�Q?/p> class="mw-geshi mw-code mw-content-ltr" style="direction: ltr; font-family: monospace, Courier; padding: 1em; border-left-color: #2f6fab; background-color: #f9f9f9; line-height: 1.1em; font-size: 15px; "> class="cpp source-cpp" style="line-height: normal; font-family: monospace; "> style="font-family: monospace, monospace; padding: 0px; border: 0px none white; line-height: 1.2em; font-size: 1em; margin-top: 0px; margin-bottom: 0px; background-image: none; vertical-align: top; ">// ... class="kw2" style="color: #0000ff; ">class lock class="br0" style="color: #008000; ">{ class="kw2" style="color: #0000ff; ">public: class="br0" style="color: #008000; ">(); class="br0" style="color: #008000; ">(lock const & l); class="br0" style="color: #008000; ">(); class="sy3" style="color: #000040; ">& operator =(lock const & l); class="kw4" style="color: #0000ff; ">void request(); class="kw4" style="color: #0000ff; ">void release(); class="co1" style="color: #666666; ">// ... class="br0" style="color: #008000; ">}; class="sy4" style="color: #008080; ">::lock() class="br0" style="color: #008000; ">{ class="co1" style="color: #666666; ">// ... class="br0" style="color: #008000; ">} class="co1" style="color: #666666; ">// ... class="sy4" style="color: #008080; ">::~lock() class="br0" style="color: #008000; ">{ class="co1" style="color: #666666; ">// ... class="br0" style="color: #008000; ">} class="co1" style="color: #666666; ">// ... class="kw4" style="color: #0000ff; ">void lock::request() class="br0" style="color: #008000; ">{ class="co1" style="color: #666666; ">// ... class="br0" style="color: #008000; ">} class="kw4" style="color: #0000ff; ">void lock::release() class="br0" style="color: #008000; ">{ class="co1" style="color: #666666; ">// ... class="br0" style="color: #008000; ">} class="co1" style="color: #666666; ">// ... class="co1" style="color: #666666; ">// assumes _DATA_TYPE_ has a default constructor class="kw2" style="color: #0000ff; ">template<typename _DATA_TYPE_> class="kw2" style="color: #0000ff; ">class singleton class="br0" style="color: #008000; ">{ class="kw2" style="color: #0000ff; ">public: class="kw4" style="color: #0000ff; ">static _DATA_TYPE_ * request(); class="kw4" style="color: #0000ff; ">static void release(); class="kw2" style="color: #0000ff; ">private: class="br0" style="color: #008000; ">(); class="br0" style="color: #008000; ">(singleton<_DATA_TYPE_> const & s); class="br0" style="color: #008000; ">(); class="sy1" style="color: #000080; "><_DATA_TYPE_> & operator =(singleton<_DATA_TYPE_> const & s); class="kw4" style="color: #0000ff; ">static _DATA_TYPE_ * pointer; class="kw4" style="color: #0000ff; ">static lock mutex; class="co1" style="color: #666666; ">// ... class="br0" style="color: #008000; ">}; class="kw2" style="color: #0000ff; ">template<typename _DATA_TYPE_> class="sy2" style="color: #000040; ">* singleton<_DATA_TYPE_>::pointer = 0; class="kw2" style="color: #0000ff; ">template<typename _DATA_TYPE_> id="uiuwagm" class="sy1" style="color: #000080; "><_DATA_TYPE_>::mutex; class="kw2" style="color: #0000ff; ">template<typename _DATA_TYPE_> class="sy2" style="color: #000040; ">* singleton<_DATA_TYPE_>::request() class="br0" style="color: #008000; ">{ class="kw1" style="color: #0000ff; ">if(singleton<_DATA_TYPE_>::pointer == 0) class="br0" style="color: #008000; ">{ class="sy1" style="color: #000080; "><_DATA_TYPE_>::mutex.request(); class="kw1" style="color: #0000ff; ">if(singleton<_DATA_TYPE_>::pointer == 0) class="br0" style="color: #008000; ">{ class="sy1" style="color: #000080; "><_DATA_TYPE_>::pointer = new _DATA_TYPE_; class="br0" style="color: #008000; ">} class="sy1" style="color: #000080; "><_DATA_TYPE_>::mutex.release(); class="br0" style="color: #008000; ">} class="kw1" style="color: #0000ff; ">return singleton<_DATA_TYPE_>::pointer; class="br0" style="color: #008000; ">} class="kw2" style="color: #0000ff; ">template<typename _DATA_TYPE_> class="kw4" style="color: #0000ff; ">void singleton<_DATA_TYPE_>::release() class="br0" style="color: #008000; ">{ class="kw1" style="color: #0000ff; ">if(singleton<_DATA_TYPE_>::pointer != 0) class="br0" style="color: #008000; ">{ class="sy1" style="color: #000080; "><_DATA_TYPE_>::mutex.request(); class="kw1" style="color: #0000ff; ">if(singleton<_DATA_TYPE_>::pointer != 0) class="br0" style="color: #008000; ">{ class="kw3" style="color: #0000dd; ">delete singleton<_DATA_TYPE_>::pointer; class="sy1" style="color: #000080; "><_DATA_TYPE_>::pointer = 0; class="br0" style="color: #008000; ">} class="sy1" style="color: #000080; "><_DATA_TYPE_>::mutex.release(); class="br0" style="color: #008000; ">} class="br0" style="color: #008000; ">} class="kw2" style="color: #0000ff; ">template<typename _DATA_TYPE_> class="sy1" style="color: #000080; "><_DATA_TYPE_>::singleton() class="br0" style="color: #008000; ">{ class="co1" style="color: #666666; ">// ... class="br0" style="color: #008000; ">} class="co1" style="color: #666666; ">// ... class="kw4" style="color: #0000ff; ">int main() class="br0" style="color: #008000; ">{ class="kw4" style="color: #0000ff; ">int * s; class="sy1" style="color: #000080; ">= singleton<int>::request(); class="co1" style="color: #666666; ">// ... class="sy1" style="color: #000080; "><int>::release(); class="kw1" style="color: #0000ff; ">return 0; class="br0" style="color: #008000; ">} class="br0" style="color: #008000; ">
/www.shnenglu.com/CuteSoft_Client/CuteEditor/Load.ashx?type=style&file=SyntaxHighlighter.css);@import url(/css/cuteeditor.css);

逛奔的蜗�?/a> 2013-06-25 21:46 发表评论
�C�OpenGL�Ҏ��的软�gTutors

Tutors

Tutors source code package (tutors-src.zip 920KB)

Source package + Windows executables (tutors-win32.zip 1.24MB)

Source package + Mac OS X universal binaries (tutors-macosx.zip 1.2MB)

Contributions from various people (Unix makefiles, etc).