Determine the CTLine containg specific character

Question

I am developing an Application in which I am using Core Text for layout purpose. I have used CTFrameSetter to draw the text.I have inserted a blank character '\' in my text. Now what i want is to determine the position of this blank character ie its x, y coordinates. I have not been able to find any function to determine the position of any specific character.

I tried using CTLineGetOffsetForStringIndex( CTLineRef line, CFIndex charIndex, CGFloat* secondaryOffset ); for finding the position, but I couldn't fully understand the working of this method.

Can anyone provide me some pointers on this issue?

Answer 1

you can loop all the CTLines of the current CTFrameRef, and for each ctline, get the CTRun and check if that CTRun is yours. simple code

 NSArray *lines = (NSArray*)CTFrameGetLines(workFrame);
 NSInteger count = [lines count];
 CGPoint *origins = (CGPoint*)malloc(count * sizeof(CGPoint));
 CTFrameGetLineOrigins(workFrame, CFRangeMake(0, count), origins); 

 for (int i = 0; i < lines.count; i++) {
      CTLineRef line = (CTLineRef)[lines objectAtIndex:i];
      CFRange cfRange = CTLineGetStringRange(line);//the string-range

       NSArray * runArray = (NSArray *)CTLineGetGlyphRuns(line);

        int runIndex = 0;
        for (id runObj in runArray) {
          CTRunRef run = (CTRunRef)runObj;          
          CFRange runRange = CTRunGetStringRange(run);
          CGFloat xOffset = CTLineGetOffsetForStringIndex(line, runRange.location + runRange.length, NULL);
          //checks if the crrun's text is your space
        }
   }