ios - CoreText 和右对齐

Question

我正在编写一个生成 PDF 的类，我将在完成时发布！

我无法使用 CTParagraphStyle 将文本向右对齐，文本始终在左侧。怎么可能？我错了什么？

- (void)addText:(NSString *)text color:(UIColor *)color fontSize:(CGFloat)size floating:(BOOL)floating {
CGContextSaveGState(pdfContext);

// Prepare font
CTFontRef font = CTFontCreateWithName(CFSTR("Verdana"), size, NULL);

// Font color
CGColorRef fontColor = [color CGColor];

// Paragraph
CTTextAlignment alignment = kCTRightTextAlignment;

CTParagraphStyleSetting settings[] = {
    {kCTParagraphStyleSpecifierAlignment, sizeof(alignment), &alignment}
};

CTParagraphStyleRef paragraphStyle = CTParagraphStyleCreate(settings, sizeof(settings) / sizeof(settings[0]));

// Create an attributed string
CFStringRef keys[] = { kCTFontAttributeName , kCTParagraphStyleAttributeName, kCTForegroundColorAttributeName};
CFTypeRef values[] = { font, paragraphStyle, fontColor};
CFDictionaryRef attr = CFDictionaryCreate(NULL, (const void **)&keys, (const void **)&values,
                                          sizeof(keys) / sizeof(keys[0]), &kCFTypeDictionaryKeyCallBacks, &kCFTypeDictionaryValueCallBacks);
CFAttributedStringRef attrString = CFAttributedStringCreate(NULL, (CFStringRef)text, attr);

CFRelease(paragraphStyle);
CFRelease(attr);

// Draw the string
CTLineRef line = CTLineCreateWithAttributedString(attrString);

CGContextSetTextPosition(pdfContext, xPadding, [self relativeHeight:currentHeight+size]);


CTLineDraw(line, pdfContext);

// Clean up
CFRelease(line);
CFRelease(attrString);
CFRelease(font);

CGContextRestoreGState(pdfContext);

if(floating == NO) {
    currentHeight += size;
}

}

Answer 1

删除CTLineDraw()及其相关代码并使用CTFrameDraw().

尝试这个：

// Create the Core Text framesetter using the attributed string.
CTFramesetterRef framesetter = CTFramesetterCreateWithAttributedString((CFAttributedStringRef)attrString);

// Create the Core Text frame using our current view rect bounds.
UIBezierPath *path = [UIBezierPath bezierPathWithRect:self.bounds];
CTFrameRef frame =  CTFramesetterCreateFrame(framesetter, CFRangeMake(0, 0), [path CGPath], NULL);
CTFrameDraw(frame, pdfContext);