CoreTextを使用して、部分的に同様の問題を解決する例を次に示します。おそらくそれはあなたをその方向に向けるでしょう。
- (CFArrayRef)copyRectangularPathsForPath:(CGPathRef)path
height:(CGFloat)height {
CFMutableArrayRef paths = CFArrayCreateMutable(NULL, 0,
&kCFTypeArrayCallBacks);
// First, check if we're a rectangle. If so, we can skip the hard parts.
CGRect rect;
if (CGPathIsRect(path, &rect)) {
CFArrayAppendValue(paths, path);
}
else {
// Build up the boxes one line at a time. If two boxes have the
// same width and offset, then merge them.
CGRect boundingBox = CGPathGetPathBoundingBox(path);
CGRect frameRect = CGRectZero;
for (CGFloat y = CGRectGetMaxY(boundingBox) - height;
y > height; y -= height) {
CGRect lineRect =
CGRectMake(CGRectGetMinX(boundingBox), y,
CGRectGetWidth(boundingBox), height);
CGContextAddRect(UIGraphicsGetCurrentContext(), lineRect);
// Do the math with full precision so we don't drift,
// but do final render on pixel boundaries.
lineRect = CGRectIntegral(clipRectToPath(lineRect, path));
CGContextAddRect(UIGraphicsGetCurrentContext(), lineRect);
if (! CGRectIsEmpty(lineRect)) {
if (CGRectIsEmpty(frameRect)) {
frameRect = lineRect;
}
else if (frameRect.origin.x == lineRect.origin.x &&
frameRect.size.width == lineRect.size.width) {
frameRect = CGRectMake(lineRect.origin.x, lineRect.origin.y, lineRect.size.width,
CGRectGetMaxY(frameRect) - CGRectGetMinY(lineRect));
}
else {
CGMutablePathRef framePath =
CGPathCreateMutable();
CGPathAddRect(framePath, NULL, frameRect);
CFArrayAppendValue(paths, framePath);
CFRelease(framePath);
frameRect = lineRect;
}
}
}
if (! CGRectIsEmpty(frameRect)) {
CGMutablePathRef framePath = CGPathCreateMutable();
CGPathAddRect(framePath, NULL, frameRect);
CFArrayAppendValue(paths, framePath);
CFRelease(framePath);
}
}
return paths;
}