PLUGINS in Font

Generator Data Matrix 2d barcode in Font PLUGINS

CHAPTER 11 PLUGINS
Data Matrix ECC200 Encoder In None
Using Barcode creation for Font Control to generate, create Data Matrix ECC200 image in Font applications.
www.OnBarcode.com
Printing Barcode In None
Using Barcode drawer for Font Control to generate, create Barcode image in Font applications.
www.OnBarcode.com
ment is the class name with all characters in lowercase, whereas the second argument is the actual class name. The macro tells Qt that this class is the interface to the plugin. Each plugin can have only one interface, so this macro must be used exactly one time per plugin. Listing 11-5. Exporting the class as a plugin Q_EXPORT_PLUGIN2( textimageplugin, TextImagePlugin )
UCC.EAN - 128 Generation In None
Using Barcode encoder for Font Control to generate, create UCC.EAN - 128 image in Font applications.
www.OnBarcode.com
Painting European Article Number 13 In None
Using Barcode generation for Font Control to generate, create European Article Number 13 image in Font applications.
www.OnBarcode.com
Reading and Writing Images
Create Barcode In None
Using Barcode generator for Font Control to generate, create Barcode image in Font applications.
www.OnBarcode.com
PDF 417 Printer In None
Using Barcode generator for Font Control to generate, create PDF-417 2d barcode image in Font applications.
www.OnBarcode.com
The TextImagePlugin makes up one-half of the plugin. The other half consists of the TextImageHandler class, which is the class that performs all the heavy lifting reading and writing images to and from devices. Let s start by having a look at the class declaration in Listing 11-6. The class inherits the QImageIOHandler class and implements the methods read, write, and two variations of canRead. The read and write methods are pretty self-explanatory, but the two canRead versions need a bit of explanation. The nonstatic version simply calls the static version. The reason for having a static version is that it is easier to use from the capabilities method in the TextImagePlugin class (refer to Listing 11-2). From Qt s point of view, the static version is not required. Listing 11-6. The class declaration of the image IO handler class TextImageHandler : public QImageIOHandler { public: TextImageHandler(); ~TextImageHandler(); bool read( QImage *image ); bool write( const QImage &image ); bool canRead() const; static bool canRead( QIODevice *device ); }; The simplest of the more complex methods is the write method, shown in Listing 11-7. It needs very little error checking and just streams the parts of the image to a QTextStream writing to the device specified. The device method returns the same device as is set using setDevice in the create method of TextImagePlugin (refer to Listing 11-4). It is used when creating the text stream stream. When the stream is set up, a prefix is written to the file. All ASCII art images start with a line reading TEXT. Then the dimensions are written as width x height, where the x serves as a separator character. You get the dimensions from the image given as an argument to the method. The prefix and dimensions make up the header; the rest is the image data.
QR Code Maker In None
Using Barcode printer for Font Control to generate, create QR image in Font applications.
www.OnBarcode.com
ANSI/AIM Code 93 Generator In None
Using Barcode creator for Font Control to generate, create Code 9/3 image in Font applications.
www.OnBarcode.com
CHAPTER 11 PLUGINS
Scan Data Matrix In C#.NET
Using Barcode decoder for .NET Control to read, scan read, scan image in .NET framework applications.
www.OnBarcode.com
Data Matrix ECC200 Creator In Visual C#.NET
Using Barcode maker for VS .NET Control to generate, create Data Matrix 2d barcode image in Visual Studio .NET applications.
www.OnBarcode.com
The image data is calculated by converting the red, green, and blue values of each pixel to an average gray scale value. The value is then shifted down and masked to three bits, giving the value range 0 7. This value corresponds to the darkness of each pixel and is used to look up a character in the map string. The map variable is a char* initialized to .:ilNAM (including an initial space). The characters in the map string have been picked so that the lowest value is white, and each character gets darker and darker as the index increases. The source image and the resulting ASCII art can be seen in Figure 11-3. The ASCII art is shown in a word processor using a monospace font set to a very small size. When all image data is written to the stream, the stream s good status is ensured before true is returned for a successful write operation. Listing 11-7. Writing the image to a device bool TextImageHandler::write( const QImage &image ) { QTextStream stream( device() ); stream << "TEXT\n"; stream << image.width() << "x" << image.height() << "\n"; for( int y=0; y<image.height(); ++y ) { for( int x=0; x<image.width(); ++x ) { QRgb rgb = image.pixel( x, y ); int r = rgb & 0xff; int g = (rgb >> 8) & 0xff; int b = (rgb >> 16) & 0xff; stream << map[ 7 - (((r+g+b)/3)>>5) & 0x7 ]; } stream << "\n"; } if( stream.status() != QTextStream::Ok ) return false; return true; } Most fonts today are not monospace, which means that the width of a character depends on the character; an i requires less space than an M. Another problem is that most fonts are higher than they are wide. The ASCII art image plugin does not take this into account, so even if a monospace font is used, the result appears to be stretched. It s hard to compensate for this in the write method because you never know which font the user will use to view the image. All in all, the results are not perfect, but you can still tell what the image shows.
Recognize QR Code In VS .NET
Using Barcode scanner for Visual Studio .NET Control to read, scan read, scan image in .NET applications.
www.OnBarcode.com
Code-128 Decoder In .NET Framework
Using Barcode decoder for .NET Control to read, scan read, scan image in Visual Studio .NET applications.
www.OnBarcode.com
PDF 417 Drawer In None
Using Barcode drawer for Excel Control to generate, create PDF 417 image in Office Excel applications.
www.OnBarcode.com
QR Drawer In None
Using Barcode maker for Microsoft Word Control to generate, create QR-Code image in Microsoft Word applications.
www.OnBarcode.com
Encode Code-39 In None
Using Barcode creation for Online Control to generate, create Code 3/9 image in Online applications.
www.OnBarcode.com
Barcode Encoder In None
Using Barcode generation for Microsoft Word Control to generate, create Barcode image in Office Word applications.
www.OnBarcode.com
Generating ECC200 In Java
Using Barcode drawer for Java Control to generate, create ECC200 image in Java applications.
www.OnBarcode.com
Quick Response Code Generation In None
Using Barcode maker for Software Control to generate, create QR Code JIS X 0510 image in Software applications.
www.OnBarcode.com
UCC - 12 Printer In Java
Using Barcode printer for Java Control to generate, create EAN 128 image in Java applications.
www.OnBarcode.com
Reading DataMatrix In VB.NET
Using Barcode recognizer for Visual Studio .NET Control to read, scan read, scan image in VS .NET applications.
www.OnBarcode.com
Copyright © OnBarcode.com . All rights reserved.