TweetFollow Us on Twitter

March 96 - Print Hints: QuickDraw GX Breaks the Space Hack

Print Hints: QuickDraw GX Breaks the Space Hack

Dave Polaschek

Before QuickDraw GX, when an application that generated its own PostScript(TM) code wanted to make sure the printer could print a particular font, it could send one space character in the needed font. The LaserWriter driver would check the printer to see if the font was available, and if not, the driver would send the font to the printer so that it would be available to print the space character -- and any other characters in that font that the application-generated PostScript code might require. The reason for using a space was simple: you didn't want to mark the page just to get a font to the printer, and a space wouldn't mark it. This technique, first described in "The Perils of PostScript" back in develop Issue 1, became known as the "space hack."

Unfortunately, the space hack doesn't work with QuickDraw GX. This column describes a new way for applications that generate their own PostScript code to send fonts to the printer. The code to do this is provided on this issue's CD.

QUICKDRAW GX CHANGES THE PICTURE

QuickDraw GX has a really cool imaging model, supports all kinds of whizzy features, and to top it off, introduces the long-awaited new printing architecture. But it has one snag: after all the years you've spent getting your PostScript printing tuned just the way you like it, QuickDraw GX breaks the space hack.

The space hack depends on a font's entire character set being sent to the printer in response to the need for a single character (the space character). But QuickDraw GX sends only the needed characters in a font to a printer, because it's trying to conserve memory on the printer and also because sending less data means faster transmission of that data. This isn't such a big issue with Roman fonts, where there are only 256 characters at most, but in the case of two-byte fonts such as Chinese, Japanese, and Korean fonts, where there can be tens of thousands of characters and the font can be tens of megabytes in size, sending only the required characters makes a big difference in speed.

Incidentally, with QuickDraw GX you don't need a specialized printer to print two-byte fonts. It divides fonts with more than 256 characters into several smaller fonts with new encodings containing just the characters you need, so you can print characters from the font on any PostScript printer.

THE NEW WAY TO DOWNLOAD FONTS

So QuickDraw GX has lots of advantages over QuickDraw, but the space hack is broken. What's the poor programmer to do?

You can use a new font downloading method based on calling GXFlattenFont, a handy function introduced with QuickDraw GX, to convert the font to a form that's easily sent to the printer. GXFlattenFont is intended to convert any font present on your Macintosh into the output font format of your choice. (Conversion is limited by the capabilities of the scalers present, as explained in "QuickDraw GX Font Scalers.")

    QUICKDRAW GX FONT SCALERS

    The QuickDraw GX Open Font Architecture accepts drop-in font scalers. A font scaler is a bit of code that takes a font of a given type and converts it to bitmaps for display. It also converts fonts to outline format and can optionally convert a font to another font format. QuickDraw GX includes three default scalers:

    • the bitmap scaler, which is essentially the same as in QuickDraw
    • the TrueType GX scaler, which supports the TrueType GX format
    • the Type 1 scaler, which is part of Adobe(TM) Type Manager

    All of these default scalers are capable of generating bitmaps for screen display and PostScript fonts for printing. Only the TrueType GX scaler can generate downloadable TrueType fonts.

GXFlattenFont can produce Type 1 data that's ready to be sent to your PostScript printer with no problem.

Now let's turn to the code that replaces the old space hack. The rough idea is to call GXFlattenFont on a QuickDraw font reference and a set of characters (an encoding) that you need to print, and return the result in a form that's easy to send to the printer. For simplicity, if no encoding is present, we use the standard Macintosh encoding. Listing 1 shows a font-downloading routine, FontToPict, that uses this technique if QuickDraw GX is installed. (This is a somewhat simplified version; see the CD for the full code of FontToPict and its related utility functions.)

Listing 1. FontToPict

PicHandle FontToPict(short qdFont, short qdStyle)
{
   Rect         theRect = {0, 0, 1, 1};
   PicHandle      thePict = OpenPicture(&theRect);
   const   short   kPostScriptHandle = 192;

   // If QuickDraw GX is installed, use the new method.
   if (GXInstalled()) {
      Handle            piccommentHdl;
      unsigned   short   *myEncoding = nil;
      
      MakePSHandle(qdFont, qdStyle, myEncoding, &piccommentHdl);
      PicComment(kPostScriptHandle, GetHandleSize(piccommentHdl),
          piccommentHdl);
   } else {
     // If QuickDraw GX isn't installed, use the old method.
      Point   penPoint;

      // We would normally set the clip here, but since we're just
      // drawing a space there's no need.
      GetPen(&penPoint);             // Save the pen location.
      TextFont(qdFont);
      TextFace(qdStyle);
      DrawChar(' ');
      MoveTo(penPoint.h, penPoint.v);    // Restore the pen location.
   }
   ClosePicture();
   return (thePict);
)
FontToPict starts by checking to see if QuickDraw GX is installed. If not, it uses the old hack of printing a space; otherwise, it calls MakePSHandle (Listing 2), which calls the utility function ConvertQDFontToGXFont to convert the QuickDraw font reference into a QuickDraw GX font reference. MakePSHandle then checks to see if an encoding has been passed in; if not, it builds the standard Macintosh encoding. Next it calls FontToHandle, which is just a wrapper for GXFlattenFont. GXFlattenFont converts the specified font to the Type 1 format. Error-handling and cleanup code is last. Simplicity itself! The result, whether QuickDraw GX is present or not, is a PICT that you can send to the printer by calling DrawPicture once the printer port has been opened.

When calling MakePSHandle, you should specify an encoding array that contains the characters you intend to actually print. This prevents QuickDraw GX from sending the entire font to the printer and becomes very important when you make your application WorldScript aware. There's an #ifdef in the code on the CD that generates only the encoding array you need in order to use a portion of the font. As mentioned earlier, with Chinese, Japanese, and Korean fonts, sending only the characters you need can make the difference between sending a few kilobytes or many megabytes of data to the printer. If you don't use the entire font, remember to encode the characters that you want to draw, using the same encoding that you passed in to the MakePSHandle function.

Listing 2. MakePSHandle

OSErr MakePSHandle(short qdFont, char qdStyle,
    unsigned short *encodingArray, Handle *outputHandle)
{
   OSErr            status = noErr;
   gxFont            theFont;
   unsigned short   *myEncoding;
   Boolean         madeEncoding = false;

   // Convert to a QuickDraw GX font reference.
   theFont = ConvertQDFontToGXFont(qdFont, qdStyle);

   // If no encoding, create the standard Macintosh encoding.
   if (!encodingArray) {
      long   returnLength;

      myEncoding =
          (unsigned short *)NewPtrClear(256 * sizeof(short));
      returnLength = MakeMac8BitEncoding(theFont, myEncoding);
      if (returnLength != 256) {
         DebugStr("\pHmm. We didn't get a full encoding.");
         return (returnLength);      // Pass the error along.
      }
      madeEncoding = true;
   } else {
      myEncoding = encodingArray;
   }

   *outputHandle = FontToHandle(theFont, myEncoding);
   if (madeEncoding) DisposePtr((Ptr)myEncoding);

   status = MemError();
   if (status == noErr) {
      status = GXGetGraphicsError(nil);
      if (status != noErr) {
         DisposeHandle(*outputHandle);
         *outputHandle = nil;
      }
   }
   return (status);
}
You may want to have HandleSpoolProc (which is called by GXFlattenFont and included on the CD) spool directly to the printer via picture comments. This way you won't need memory available to hold the font data at the intermediate steps.

DOWNLOADING HAPPINESS

The new font downloading method takes a little more work but produces better results in your printer font handling. You can easily send needed fonts to the printer, either the whole font or only the characters you'll be using. As a side benefit, you get support for two-byte font systems without having to write custom code for handling the large fonts or, worse yet, having to depend on the fonts being installed on the printer in a specific manner. Even if you're not ready to add QuickDraw GX imaging to your application today, adding QuickDraw GX compatibility improves the printing experience for your customers.

DAVE POLASCHEK recently relocated to California to join Apple's Developer Technical Support group. He's been told that supporting printing leads to hair loss and insanity. Dave previously lived in beautiful sunny Minnesota, and wonders if he'll get used to the harsh San Francisco Bay Area winters before he's bald and crazy, or if it's already too late.*

Thanks to Dan Lipton for providing the idea and core code illustrating the new font downloading method, and to Pete "Luke" Alexander, Dave Hersey, and Dan Lipton for reviewing this column.*

 

Community Search:
MacTech Search:

Software Updates via MacUpdate

A beginner's guide to Spellbinders
Spellbinderslooks a heck of a lot like Clash Royale, but has an entirely different pace to it. As such, it can be difficult to adjust to. Just in case you've been playing way too much Clash Royale (and who hasn't), we've put together a bunch of... | Read more »
Camping With Grandpa (Education)
Camping With Grandpa 1.0 Device: iOS Universal Category: Education Price: $2.99, Version: 1.0 (iTunes) Description: | Read more »
Black Hole Joyrider (Games)
Black Hole Joyrider 1.0 Device: iOS Universal Category: Games Price: $2.99, Version: 1.0 (iTunes) Description: Guide your spacecraft through the gravity well of a powerful black hole using only your retro-thrusters and dwindling fuel... | Read more »
My Koi (Games)
My Koi 1.0 Device: iOS iPhone Category: Games Price: $1.99, Version: 1.0 (iTunes) Description: My Koi is a beautiful and relaxing fish pond app. Customise and name each fish. Feed them daily. Watch them grow. Collect new fish.... | Read more »
Never Gone (Games)
Never Gone 1.0.2 Device: iOS Universal Category: Games Price: $2.99, Version: 1.0.2 (iTunes) Description: ###IMPPORTANT### Never Gone's HD art resources require devices with more than 1GB RAM, so please note that iPhone 4/4s, iPad 2/... | Read more »
INKS. (Games)
INKS. 1.0 Device: iOS Universal Category: Games Price: $1.99, Version: 1.0 (iTunes) Description: From the makers of BAFTA-winning Lumino City comes INKS. INKS updates pinball for a new generation. It combines the joy of pinball with... | Read more »
How to maximise your profits in Bakery B...
Running a bakery can be an expensive venture. You’ll need to continuously upgrade your oven, your kitchen supplies, and even your ingredients to keep customers happy. Most of these renovations in Bakery Blitz cost a pretty penny, but we have a few... | Read more »
How to manage your time in Bakery Blitz
It can be tricky, especially when you risk burning your kitchen to the ground if you forget a cake in the oven, so make sure to use these time management tricks to keep your bakery running smoothly. Don’t collect the money right away [Read more] | Read more »
Model 15 (Music)
Model 15 1.0 Device: iOS iPhone Category: Music Price: $29.99, Version: 1.0 (iTunes) Description: The Moog Model 15 App is the first Moog modular synthesizer and synthesis educational tool created exclusively for iPad, iPhone and... | Read more »
How to deal with wind in Angry Birds Act...
Angry Birds Action! is a physics-based puzzler in which you're tasked with dragging and launching birds around an obstacle-littered field to achieve a set objective. It's simple enough at first, but when wind gets introduced things can get pretty... | Read more »

Price Scanner via MacPrices.net

Hybrid Tablets Meet Rising Demand for a Singl...
Rising demand for a new breed of hybrid tablets — 2 in 1 devices that function as either a laptop or a tablet — is shaking up the tablet market and contributing to a shift in the way owners are... Read more
Bausch + Lomb and IBM Collaborate on iPhone...
Global eye health company Bausch + Lomb, and IBM on Thursday announced a collaboration to develop the first app of its kind for iPhone and iPad for surgeons who perform cataract surgery. The... Read more
Apple & SAP Partner to Deliver New iOS Ap...
Apple and Walldorf, Germany based SAP have announced a partnership to revolutionize the mobile work experience for enterprise customers of all sizes, combining powerful native apps for iPhone and... Read more
New 12-inch 1.1GHz Rose Gold Retina MacBook o...
B&H Photo has the new 2016 12″ 1.1GHz/256GB Rose Gold Retina MacBook (sku MMGL2LL/A) on sale for $1199 including free shipping plus NY tax only. Their price is $100 off MSRP, and it’s the lowest... Read more
12-inch 128GB iPad Pros on sale for up to $10...
B&H Photo has 12″ 128GB WiFi iPad Pros on sale for up to $100 off MSRP, each including free shipping. B&H charges sales tax in NY only: - 12″ Space Gray 128GB WiFi iPad Pro: $899 $50 off MSRP... Read more
Global Tablet Sales Slump Continues, iPad’s F...
Another miserable showing for the global slate tablet category in calendar Q1/16, with global tablet shipments falling another 1ten percent to 46.5 million units during the according to Strategy... Read more
Revel Systems to Showcase iPad POS Platform w...
Revel Systems, specialists in iPad Point of Sale management solution for brick-and-mortar retail, food businesses and more, today announced that it will showcase its innovative iPad Point of Sale... Read more
13-inch 2.5GHz MacBook Pro on sale for $999,...
B&H Photo has the 13″ 2.5GHz MacBook Pro on sale for $999 including free shipping plus NY sales tax only. Their price is $100 off MSRP. Read more
Apple refurbished 2015 iMacs available for up...
Apple now has a full line of Certified Refurbished 2015 21″ & 27″ iMacs available for up to $350 off MSRP. Apple’s one-year warranty is standard, and shipping is free. The following models are... Read more
Indian Smartphone Market Grows Annually by 12...
India’s smartphone market grew by 12 percent year-over-year, with 24.4 million units shipping in Q1 2016. The top five vendors stayed the same, with Samsung in the lead, followed by Micromax, Intex... Read more

Jobs Board

*Apple* Support Technician II - Worldventure...
…global, fast growing member based travel company, is currently sourcing for an Apple Support Technician II to be based in our Plano headquarters. WorldVentures is Read more
*Apple* Retail - Multiple Positions (US) - A...
Job Description: Sales Specialist - Retail Customer Service and Sales Transform Apple Store visitors into loyal Apple customers. When customers enter the store, Read more
Restaurant Manager (Neighborhood Captain) - A...
…in every aspect of daily operation. WHY YOU'LL LIKE IT: You'll be the Big Apple . You'll solve problems. You'll get to show your ability to handle the stress and Read more
Automotive Sales Consultant - Apple Ford Linc...
…you. The best candidates are smart, technologically savvy and are customer focused. Apple Ford Lincoln Apple Valley is different, because: $30,000 annual salary Read more
Restaurant Manager (Neighborhood Captain) - A...
…in every aspect of daily operation. WHY YOU'LL LIKE IT: You'll be the Big Apple . You'll solve problems. You'll get to show your ability to handle the stress and Read more
All contents are Copyright 1984-2011 by Xplain Corporation. All rights reserved. Theme designed by Icreon.