在看以下这个开源组件的时候，发现一个非常棒的方法，能够将文字生成path，这样就能够作出用笔写字的效果了。
关键代码：
-(CGPathRef)pathRefFromText
NSAttributedString *attributed = self.attributedText;
CGMutablePathRef letters = CGPathCreateMutable();
CTLineRef line = CTLineCreateWithAttributedString((__bridge CFAttributedStringRef)attributed);
CFArrayRef runArray = CTLineGetGlyphRuns(line);
for (CFIndex runIndex = 0; runIndex < CFArrayGetCount(runArray); runIndex++)
CTRunRef run = (CTRunRef)CFArrayGetValueAtIndex(runArray, runIndex);
CTFontRef runFont = CFDictionaryGetValue(CTRunGetAttributes(run), kCTFontAttributeName);
for (CFIndex runGlyphIndex = 0; runGlyphIndex < CTRunGetGlyphCount(run); runGlyphIndex++)
CFRange thisGlyphRange = CFRangeMake(runGlyphIndex, 1);
CGGlyph glyph;
CGPoint position;
CTRunGetGlyphs(run, thisGlyphRange, &glyph);
CTRunGetPositions(run, thisGlyphRange, &position);
CGPathRef letter = CTFontCreatePathForGlyph(runFont, glyph, NULL);
CGAffineTransform t = CGAffineTransformMakeTranslation(position.x, position.y);
CGPathAddPath(letters, &t, letter);
CGPathRelease(letter);
UIBezierPath *path = [UIBezierPath bezierPathWithCGPath:letters];
CGRect boundingBox = CGPathGetBoundingBox(letters);
CGPathRelease(letters);
CFRelease(line);
[path applyTransform:CGAffineTransformMakeScale(1.0, -1.0)];
[path applyTransform:CGAffineTransformMakeTranslation(0.0, boundingBox.size.height)];
if (self.reversedAnimation) {
return [[path bezierPathByReversingPath] CGPath];
return [path CGPath];
