如何获取 Quartz 用来描边 NSBezierPath 的路径

Question

我正在使用此代码用一条宽的黑色虚线描边 NSBezierPath。

（c 和 strForBezier 在其他地方定义）

NSGlyph glyph;
for(n = 0; n < len; n++) {
    glyph = [font glyphWithName: [strForBezier substringWithRange:NSMakeRange(n, 1)]];
    [path appendBezierPathWithGlyph: glyph inFont: font];
}

CGFloat pattern2[4]; pattern2[0]=5*c; pattern2[1]=2*c; pattern2[2]=2*c; pattern2[3]=2*c;
[path setLineDash:pattern2 count:4 phase:0];

[path setLineWidth:c];
[path stroke];
[[NSColor blueColor] set ];
[path fill];

我怎样才能得到黑色的 NSBezierPath ？我假设 NSBezierPath 已构建并填充以描边初始曲线。

Answer 1

您可以通过划线和抚摸现有路径来创建路径，但这需要使用CGPathRef 而不是NSBezierPath。

CGMutablePathRef path0 = CGPathCreateMutable();
CGAffineTransform transform = CGAffineTransformMakeTranslation(20, 20);
// initial position is {20, 20}

CGGlyph glyph;
for(n = 0; n < len; n++)
{
    glyph = [font glyphWithName: [strForBezier substringWithRange:NSMakeRange(n, 1)]];
    CGPathRef glyphPath = CTFontCreatePathForGlyph((__bridge CTFontRef) font, glyph, NULL);
    CGPathAddPath(path0, &transform, glyphPath);
    CGPathRelease(glyphPath);

    // append the glyph advance to the transform
    CGSize advance;
    CTFontGetAdvancesForGlyphs((__bridge CTFontRef) font, kCTFontDefaultOrientation, &glyph, &advance, 1);
    transform.tx += advance.width;
    transform.ty += advance.height;
}

CGFloat pattern2[4]; pattern2[0]=5*c; pattern2[1]=2*c; pattern2[2]=2*c; pattern2[3]=2*c;
CGPathRef path1 = CGPathCreateCopyByDashingPath(path0, NULL, 0, pattern2, 4);
CGPathRef path2 = CGPathCreateCopyByStrokingPath(path1, NULL, c, kCGLineCapButt, kCGLineJoinMiter, CGFLOAT_MAX);

CGContextRef context = [NSGraphicsContext currentContext].graphicsPort;
CGContextAddPath(context, path2);
CGContextDrawPath(context, kCGPathFill);

CGPathRelease(path0);
CGPathRelease(path1);
CGPathRelease(path2);

如果您对CGPathRef 不满意，您可以创建一个NSBezierPath，然后使用Apple 文档Building a CGPathRef From a NSBezierPath Object 中描述的方法将其转换为CGPathRef（也可以反过来）。