c# generate data matrix code 5: Doing More with Qt in C#.NET

Draw Data Matrix 2d barcode in C#.NET 5: Doing More with Qt

CHAPTER 5: Doing More with Qt
Printing DataMatrix In Visual C#.NET
Using Barcode printer for VS .NET Control to generate, create ECC200 image in .NET framework applications.
www.OnBarcode.com
Decoding DataMatrix In C#.NET
Using Barcode decoder for Visual Studio .NET Control to read, scan read, scan image in VS .NET applications.
www.OnBarcode.com
as easily used Qt Mobility s own code to do the calculation. Then the entire item view s HTML is built up using a single template that has a (currently unused) JavaScript initialization, heading, USGS-provided description, our computed distance, and the HTML and JavaScript for the back button, which looks like this:
Creating Data Matrix ECC200 In C#.NET
Using Barcode drawer for VS .NET Control to generate, create Data Matrix ECC200 image in Visual Studio .NET applications.
www.OnBarcode.com
European Article Number 13 Creator In C#.NET
Using Barcode encoder for .NET framework Control to generate, create UPC - 13 image in VS .NET applications.
www.OnBarcode.com
<br/><br/><br/> <p align="center"> <button type="button" onclick="action.trigger()">Back </button> </p>
Making PDF 417 In C#
Using Barcode generation for VS .NET Control to generate, create PDF 417 image in Visual Studio .NET applications.
www.OnBarcode.com
Creating Barcode In Visual C#.NET
Using Barcode creator for .NET framework Control to generate, create Barcode image in .NET applications.
www.OnBarcode.com
The action variable in JavaScript is just the WebProxyAction we created in createActions, back in Listing 5 9. It gets added to the JavaScript context each time the context gets cleared in our addProxyObjects slot, which you see in Listing 5 13.
Making UPC-A Supplement 2 In C#.NET
Using Barcode generation for Visual Studio .NET Control to generate, create UCC - 12 image in VS .NET applications.
www.OnBarcode.com
Draw USPS PLANET Barcode In Visual C#
Using Barcode generation for Visual Studio .NET Control to generate, create Planet image in Visual Studio .NET applications.
www.OnBarcode.com
Listing 5 13. Adding a QObject to the web vie. void MainController::addProxyObjects() { mItemWidget-> page()-> currentFrame()-> addToJavaScriptWindowObject("action", mBackAction, QScriptEngine::QtOwnership); }
DataMatrix Generator In VB.NET
Using Barcode generator for Visual Studio .NET Control to generate, create ECC200 image in .NET framework applications.
www.OnBarcode.com
ECC200 Drawer In Objective-C
Using Barcode creator for iPhone Control to generate, create Data Matrix ECC200 image in iPhone applications.
www.OnBarcode.com
Drawing the Map
Recognize EAN / UCC - 13 In Visual Basic .NET
Using Barcode decoder for .NET Control to read, scan read, scan image in VS .NET applications.
www.OnBarcode.com
Data Matrix 2d Barcode Maker In Java
Using Barcode encoder for Eclipse BIRT Control to generate, create Data Matrix 2d barcode image in BIRT reports applications.
www.OnBarcode.com
The old saying A picture is worth a thousand words is definitely true when it comes to understanding the distribution of spatial data. We added the map to Shake to present earthquake data graphically, giving a quick glance as to where earthquakes had occurred and how big they were. Our goal when creating the map view to Shake was twofold: provide a map that displays something useful and show you the basic idea behind creating your own widget. The result of this goal is the MapItemWidget, a simple class that draws markers of different sizes on a Mercator projection of Earth. The MapItemWidget gets its data from a model, so it additionally shows you how to watch a model s data for changes and rerenders when those changes occur. Listing 5 14 shows the class declaration for the MapItemWidget.
Code 128 Code Set A Creation In Java
Using Barcode drawer for Java Control to generate, create ANSI/AIM Code 128 image in Java applications.
www.OnBarcode.com
Make Barcode In .NET Framework
Using Barcode creator for VS .NET Control to generate, create Barcode image in VS .NET applications.
www.OnBarcode.com
CHAPTER 5: Doing More with Qt
Encoding DataMatrix In .NET
Using Barcode creation for VS .NET Control to generate, create Data Matrix image in .NET applications.
www.OnBarcode.com
Encode Barcode In Java
Using Barcode creation for Android Control to generate, create Barcode image in Android applications.
www.OnBarcode.com
Listing 5 14. The widget for rendering the map #include #include #include #include <QWidget> <QPixmap> <QModelIndex> <QList>
DataMatrix Reader In VS .NET
Using Barcode decoder for VS .NET Control to read, scan read, scan image in Visual Studio .NET applications.
www.OnBarcode.com
Encoding Quick Response Code In None
Using Barcode printer for Font Control to generate, create QR Code image in Font applications.
www.OnBarcode.com
class QAbstractItemModel; class MapItemWidget : public QWidget { Q_OBJECT public: explicit MapItemWidget(QWidget *parent = 0); ~MapItemWidget(); QSize sizeHint(); QSizePolicy sizePolicy(); void setModel(QAbstractItemModel* model); public slots: void itemsChanged(const QModelIndex& topLeft, const QModelIndex & bottomRight ); void itemsReset(); protected: void paintEvent(QPaintEvent *event); void resizeEvent(QResizeEvent *event); private: void initMap(); void initMarkers(); QPoint geoToWidgetCoords(qreal lat, qreal lon); QPixmap mMap; QSize mMapSize; QList< QPair<QPoint, int> > mMarkers; QAbstractItemModel* mModel; Q_DISABLE_COPY(MapItemWidget) };
Draw Barcode In None
Using Barcode creation for Office Excel Control to generate, create Barcode image in Office Excel applications.
www.OnBarcode.com
Scanning QR In .NET Framework
Using Barcode reader for .NET Control to read, scan read, scan image in .NET applications.
www.OnBarcode.com
MOBILE DIGITAL CARTOGRAPHY
As we suggest, our goals here are to provide a glanceable view of where earthquakes occurred, and provide you with a digestable example that demonstrates how to create your own widget. The MapItemWidget is admittedly anemic if you re interested in presenting large-scale real cartographic data, or even in providing such basic operations as panning and zooming. If you need to show real data on real maps, what are your choices First, future versions of Qt Mobility will provide a maps and navigation API, letting device manufacturers provide plug-in map providers. Using the API, on devices with appropriate server applications, you can
CHAPTER 5: Doing More with Qt
embed maps in your application, providing the full digital mapping experience found with the native hosting application. For many applications, this may be ideal, but does require that the application you re writing run on devices that have software serving maps to the Qt Mobility Layer. Another option is to go with web-based maps like Open Street Maps or Google Maps. One solution would be to embed a QWebView within your application that displays a web-hosted map, using the Qt-JavaScript bindings to move information like the location of map markers from your application s data model to the JavaScript layer, thereby putting C++ objects directly on a map from the Web. Either way you go, there s still substantial work, and most of that work is with the interfaces of a specific map provider, rather than what we want to show you here: how to create a custom widget. For more information about Qt Mobility s upcoming support for map rendering, see http://developer.qt.nokia.com/wiki/MapsNavigationAPI. We can divide the widget s functionality into three broad areas: providing size hints to the containing widget, handling the drawing and placement of map markers, and map rendering. Listing 5 15 shows the code that provides the desired size hints for the widget.
Listing 5 15. Providing default size hints const int kMinWidth = 320; const int kMinHeight = 240; QSize MapItemWidget::sizeHint() { return QSize(kMinWidth, kMinHeight); } QSizePolicy MapItemWidget::sizePolicy() { return QSizePolicy(QSizePolicy::MinimumExpanding, QSizePolicy::MinimumExpanding); }
Maps are useless when they re too small, so we provide a fairly large minimum size, indicate that our policy is to disallow anything smaller than that default, and grow to accept as much size as the layout will provide. The map rendering and marker handling are closely related and also coupled with resizing the widget. This is because resizing the map involves redrawing the base map and relocating all of the map markers before redrawing them as well. For a given widget size, the map keeps two pieces of data to speed rendering: a pixmap containing the base map, an image of a map of the Earth in Mercator projection we found at WikiCommons (http://en.wikipedia.org/wiki/File:Mercator-projection.jpg), and the location and relative size of each map marker in widget coordinates. The location and size information is kept as a QPair, rather than a separate class; there s no reason not to use a separate class in this case, except that it makes the code longer, and QPair works just as well. The base map and marker cache are all initialized whenever the widget resizes. This occurs when the widget is placed in a containing widget, as well as if the widget changes sizes (say, because the screen orientation changes). Listing 5 16 shows the initialization code, starting when the widget receives the resize event.
Copyright © OnBarcode.com . All rights reserved.