Mac Forum / Programming / Mac Programming / October 2004

(Sorry for the cross-post, I realized after posting that c.s.m.p.misc
was probably not the best place for this... also, I'm using CW 9.3 on OS
10.3.5, if that makes any difference.)

I am writing the Mac OS side of a Windows/Mac application, and I'm
having a major issue with font spacing.  It's critical that this program
prints exactly the same, regardless of which platform it's running on.  
For the most part, all is well, but several of the fonts that we're
printing are SLIGHTLY different on the two platforms.

The fonts are printing fine on Windows, they're slightly expanded when
printed on the Mac.  Basically, they need to be 10 characters per inch,
and they're coming out a little wider than that.  Right now, I'm
printing with QuickDraw, so it seems that my options of printing these
items is limited.  My testers indicate that printing out of TextEdit (or
SimpleEdit, or something like that) has the same results as my program,
while printing out of Microsoft Word for OS X is perfect (10 characters
per inch.)

(As an aside, printing in "condense" style results in the characters
being too close together.)

So, question one is whether there's any way to adjust font kerning or
spacing when using Quickdraw.

Okay, going under the assumption that that wouldn't be an option, I went
to look into Quartz and ATSU.  Sure enough, there's a handy method for
adjusting kerning.  Unfortunately, I can't seem to get it working.  
Here's some code:

The two snippets below call the functions which follow them.  The only
thing different is the last bit of the "MakeATSUIStyle" call, which
leaves kerning alone in the first iteration, says to inhibit it by half
in the second.

When printed, these two text strings are exactly the same length,
leading me to believe that my kerning call is doing absolutely nothing.

Any help would be appreciated -- I'm really in uncharted waters with
these font issues!

  iErr = MakeATSUIStyle(0, normal, 12, &theStyle, X2Frac(0));
  CFStringRef ourString = CFStringCreateWithPascalString(NULL, "\pThis
is a test", kCFStringEncodingMacRoman);
  iErr = RenderCFString(context, ourString, theStyle, thePoint.h, 0 -
thePoint.v);
  CFRelease((CFTypeRef)ourString);
  thePoint.v += 20;

  iErr = MakeATSUIStyle(0, normal, 12, &theStyle2, X2Frac(0.5));
  ourString = CFStringCreateWithPascalString(NULL, "\pThis is a test",
kCFStringEncodingMacRoman);
  iErr = RenderCFString(context, ourString, theStyle2, thePoint.h, 0 -
thePoint.v);
  CFRelease((CFTypeRef)ourString);

static OSStatus MakeATSUIStyle(short fontFamily, Style fontStyle, short
fontSize, ATSUStyle *theStyle, Fract kerningInhibitFactor)
{
   OSStatus err;
   ATSUStyle localStyle;
   ATSUFontID atsuFont;
   Fixed atsuSize;
   short atsuOrientation;
   Boolean trueVar = true, falseVar = false;

       /* Three parrallel arrays for setting up attributes. */
   ATSUAttributeTag theTags[] = {
           kATSUFontTag, kATSUSizeTag, kATSUVerticalCharacterTag,
           kATSUQDBoldfaceTag, kATSUQDItalicTag, kATSUQDUnderlineTag,
           kATSUQDCondensedTag, kATSUQDExtendedTag
       };
   ByteCount theSizes[] = {
           sizeof(ATSUFontID), sizeof(Fixed), sizeof(UInt16),
           sizeof(Boolean), sizeof(Boolean), sizeof(Boolean),
           sizeof(Boolean), sizeof(Boolean)
       };
   ATSUAttributeValuePtr theValues[] = {
           NULL, NULL, NULL, NULL,
           NULL, NULL, NULL, NULL
       };

       /* set up locals */
   localStyle = NULL;
   atsuFont = 0;
   atsuSize = FixRatio(fontSize, 1);
   atsuOrientation = kATSUStronglyHorizontal;
   /* or atsuOrientation = kATSUStronglyVertical */

       /* set the values array to point to our locals */
   theValues[0] = &atsuFont;
   theValues[1] = &atsuSize;
   theValues[2] = &atsuOrientation;
   theValues[3] = ((fontStyle & bold) != 0 ? &trueVar : &falseVar);
   theValues[4] = ((fontStyle & italic) != 0 ? &trueVar : &falseVar);
   theValues[5] = ((fontStyle & underline) != 0 ? &trueVar : &falseVar);
   theValues[6] = ((fontStyle & condense) != 0 ? &trueVar : &falseVar);
   theValues[7] = ((fontStyle & extend) != 0 ? &trueVar : &falseVar);

   err = ATSUFONDtoFontID( fontFamily, fontStyle, &atsuFont);
   if (err != noErr) goto bail;

       /* create a style */
   err = ATSUCreateStyle(&localStyle);
   if (err != noErr) goto bail;

       /* set the style attributes */
   err = ATSUSetAttributes( localStyle,
       sizeof(theTags)/sizeof(theTags[0]),
       theTags, theSizes, theValues );
   if (err != noErr) goto bail;
   
   if (kerningInhibitFactor)
   {
     OSStatus status = noErr;
     ATSUAttributeTag theTag;
     ByteCount theSize;
     ATSUAttributeValuePtr theValue;

     theTag = kATSUKerningInhibitFactorTag;
     theSize = (ByteCount) sizeof(Fract);
     theValue = (ATSUAttributeValuePtr) &kerningInhibitFactor;

     status = ATSUSetAttributes(localStyle, 1, &theTag, &theSize,
&theValue);
   }

       /* store the new style for the caller */
   *theStyle = localStyle;
   return noErr;
bail:
   if (localStyle != NULL) ATSUDisposeStyle(localStyle);
   return err;
}

static OSStatus RenderCFString(CGContextRef ctx, CFStringRef theString,  
            ATSUStyle theStyle, short h, short v)
{
   ATSUTextLayout theLayout = NULL;
   CFIndex textLength;
   OSStatus err = noErr;
   UniChar *uniBuffer;
   CFRange uniRange;
   
   /* set up our locals, verify parameters... */
   if (theString == NULL || theStyle == NULL) return paramErr;
   uniBuffer = NULL;
   textLength = CFStringGetLength(theString);
   if (textLength == 0) return noErr;
   
   /* get our data */
   uniRange = CFRangeMake(0, textLength);
   uniBuffer = (UniChar *) NewPtr( textLength * sizeof(UniChar) );
   if (uniBuffer == NULL) { err = memFullErr; goto bail; }
   CFStringGetCharacters( theString,  uniRange, uniBuffer);

   /* create the ATSUI layout */
   err = ATSUCreateTextLayoutWithTextPtr( uniBuffer, 0,
       textLength, textLength, 1,
       (unsigned long *) &textLength, &theStyle,
       &theLayout);
   if (err != noErr) goto bail;

   if(!err)
   {
       // Assign the CGContext to the layout
       // so the text is imaged into the CG Context supplied
       ByteCount iSize = sizeof(CGContextRef);
       ATSUAttributeTag iTag = kATSUCGContextTag;
       ATSUAttributeValuePtr iValuePtr=&ctx;
       ATSUSetLayoutControls( theLayout, 1, &iTag, &iSize, &iValuePtr );
   }

   /* draw the text */
   err = ATSUDrawText(theLayout, 0, textLength,//
kATSUUseGrafPortPenLoc, kATSUUseGrafPortPenLoc);
           FixRatio(h, 1), FixRatio(v, 1));
   if (err != noErr) goto bail;

   /* clean up */
bail:
   if (uniBuffer != NULL) DisposePtr((Ptr) uniBuffer);
   if (theLayout != NULL) ATSUDisposeTextLayout(theLayout);
   return err;
}