iphone - 来自字符串的 CGPathRef

Question

请问我们怎样才能得到特定的法语字母阿拉伯语的路径？我刚刚发现 CTFontCreatePathForGlyph 会给 CGPathRef 之类的，但它会是 text 的轮廓。

我需要这个真实的文本路径来显示文本绘制动画..

请有任何帮助

Answer 1

您根本不需要将您的路径转换为 ​​NSString。

您可以按如下方式创建文本路径：

    CTFontRef font = CTFontCreateWithName(CFSTR("Helvetica-Bold"), 72.0f, NULL);
NSDictionary *attrs = [NSDictionary dictionaryWithObjectsAndKeys:
                       (id)font, kCTFontAttributeName,
                       nil];
NSAttributedString *attrString = [[NSAttributedString alloc] initWithString:@"Hello World!"
                                                                 attributes:attrs];
CTLineRef line = CTLineCreateWithAttributedString((CFAttributedStringRef)attrString);
CFArrayRef runArray = CTLineGetGlyphRuns(line);

// for each RUN
for (CFIndex runIndex = 0; runIndex < CFArrayGetCount(runArray); runIndex++)
{
    // Get FONT for this run
    CTRunRef run = (CTRunRef)CFArrayGetValueAtIndex(runArray, runIndex);
    CTFontRef runFont = CFDictionaryGetValue(CTRunGetAttributes(run), kCTFontAttributeName);

    // for each GLYPH in run
    for (CFIndex runGlyphIndex = 0; runGlyphIndex < CTRunGetGlyphCount(run); runGlyphIndex++) 
    {
        // get Glyph & Glyph-data
        CFRange thisGlyphRange = CFRangeMake(runGlyphIndex, 1);
        CGGlyph glyph;
        CGPoint position;
        CTRunGetGlyphs(run, thisGlyphRange, &glyph);
        CTRunGetPositions(run, thisGlyphRange, &position);

        // Get PATH of outline
        {
            CGPathRef letter = CTFontCreatePathForGlyph(runFont, glyph, NULL);
            CGAffineTransform t = CGAffineTransformMakeTranslation(position.x, position.y);
            CGPathAddPath(letters, &t, letter);
            CGPathRelease(letter);
        }
    }
}
CFRelease(line);

这是您创建路径的方式，示例代码请参考此链接。此代码是此示例项目的一部分。希望这可以帮助你

Answer 2

我在 Swift 中需要这个，但解决起来很痛苦。我希望这对其他人有用！我将其编写为对 String 和 NSAttributedString 的扩展，以使其更加通用。

根据您绘制路径的方式，您可能会看到这些字母是颠倒的。您可以通过在对 CTFontCreatePathForGlyph() 的调用中添加垂直翻转变换来解决此问题（垂直翻转只是 scaleY 为 -1 的 CGAffineTransform）。

public extension String {
    func path(withFont font: UIFont) -> CGPath {
        let attributedString = NSAttributedString(string: self, attributes: [.font: font])
        let path = attributedString.path()
        return path
    }
}

public extension NSAttributedString {
    func path() -> CGPath {
        let path = CGMutablePath()

        // Use CoreText to lay the string out as a line
        let line = CTLineCreateWithAttributedString(self as CFAttributedString)

        // Iterate the runs on the line
        let runArray = CTLineGetGlyphRuns(line)
        let numRuns = CFArrayGetCount(runArray)
        for runIndex in 0..<numRuns {

            // Get the font for this run
            let run = unsafeBitCast(CFArrayGetValueAtIndex(runArray, runIndex), to: CTRun.self)
            let runAttributes = CTRunGetAttributes(run) as Dictionary
            let runFont = runAttributes[kCTFontAttributeName] as! CTFont

            // Iterate the glyphs in this run
            let numGlyphs = CTRunGetGlyphCount(run)
            for glyphIndex in 0..<numGlyphs {
                let glyphRange = CFRangeMake(glyphIndex, 1)

                // Get the glyph
                var glyph : CGGlyph = 0
                withUnsafeMutablePointer(to: &glyph) { glyphPtr in
                    CTRunGetGlyphs(run, glyphRange, glyphPtr)
                }

                // Get the position
                var position : CGPoint = .zero
                withUnsafeMutablePointer(to: &position) {positionPtr in
                    CTRunGetPositions(run, glyphRange, positionPtr)
                }

                // Get a path for the glyph
                guard let glyphPath = CTFontCreatePathForGlyph(runFont, glyph, nil) else {
                    continue
                }

                // Transform the glyph as it is added to the final path
                let t = CGAffineTransform(translationX: position.x, y: position.y)
                path.addPath(glyphPath, transform: t)
            }
        }

        return path
    }
}