Question

The code below is from iOS dev center: http://developer.apple.com/library/ios/#documentation/2ddrawing/conceptual/drawingprintingios/GeneratingPDF/GeneratingPDF.html

Problem is, the thing seems to be a mess. For example, it references “Context” and “currentRange” before it declares such parameters. Can anyone make heads or tails out of this? Maybe I am supposed to declare those somewhere else, like in the “UIGraphicsBeginPDFPage” function? I do know that you need to have “#import ” in your .m file.

- (CFRange)renderPage:(NSInteger)pageNum withTextRange:(CFRange)currentRangeandFramesetter:(CTFramesetterRef)framesetter
{
// Get the graphics context.
CGContextRef    currentContext = UIGraphicsGetCurrentContext();

// Put the text matrix into a known state. This ensures
// that no old scaling factors are left in place.
CGContextSetTextMatrix(Context, CGAffineTransformIdentity);

// Create a path object to enclose the text. Use 72 point
// margins all around the text.
CGRect    frameRect = CGRectMake(72, 72, 468, 648);
CGMutablePathRef framePath = CGPathCreateMutable();
CGPathAddRect(framePath, NULL, frameRect);

// Get the frame that will do the rendering.
// The currentRange variable specifies only the starting point. The framesetter
// lays out as much text as will fit into the frame.
CTFrameRef frameRef = CTFramesetterCreateFrame(framesetter, currentRange, framePath, NULL);
CGPathRelease(framePath);

// Core Text draws from the bottom-left corner up, so flip
// the current transform prior to drawing.
CGContextTranslateCTM(currentContext, 0, 792);
CGContextScaleCTM(currentContext, 1.0, -1.0);

// Draw the frame.
CTFrameDraw(frameRef, currentContext);

// Update the current range based on what was drawn.
currentRange = CTFrameGetVisibleStringRange(frameRef);
currentRange.location += currentRange.length;
currentRange.length = 0;
CFRelease(frameRef);

return currentRange;
}

- (void)drawPageNumber:(NSInteger)pageNum
{
NSString* pageString = [NSString stringWithFormat:@"Page %d", pageNum];
UIFont* theFont = [UIFont systemFontOfSize:12];
CGSize maxSize = CGSizeMake(612, 72);

CGSize pageStringSize = [pageString sizeWithFont:theFont
                               constrainedToSize:maxSize
                                   lineBreakMode:UILineBreakModeClip];
CGRect stringRect = CGRectMake(((612.0 - pageStringSize.width) / 2.0),
                               720.0 + ((72.0 - pageStringSize.height) / 2.0) ,
                               pageStringSize.width,
                               pageStringSize.height);

[pageString drawInRect:stringRect withFont:theFont];
}

Answer 1

currentRange is an argument to the method. It looks like you’ve lost a space there: currentRangeandFramesetter should be currentRange andFramesetter

Context is a typo which should be currentContext. Other than that the code compiles.