ios - 获取 UIBezierpath 的中心点

Question

我能够使用任何选定的字体和大小生成字符的 UIBezierPath。现在我想在贝塞尔曲线路径之间制作一条 eclipse 刻线。我可以得到贝塞尔路径的中心点吗？或者我可以制作中心虚线并沿着那条路径走的任何其他方式？

下面是我的代码

Reference Link. I want something like this. :

 UIBezierPath *path = [UIBezierPath bezierPathWithRoundedRect:CGRectMake(0, 0, 568, 568) cornerRadius:0];
UIBezierPath *circlePath = [self createArcPath];
[path appendPath:circlePath];
[path setUsesEvenOddFillRule:YES];





shapeView = [CAShapeLayer layer];
shapeView.geometryFlipped = false;
shapeView.path = path.CGPath;
shapeView.fillRule = kCAFillRuleEvenOdd;
shapeView.fillColor = [UIColor grayColor].CGColor;
shapeView.opacity = 1.0;
shapeView.lineDashPattern = @[@2, @3];
[self.view.layer addSublayer:shapeView];

CGFloat dashes[] = {2, 3};
[path setLineDash:dashes count:2 phase:0];


- (UIBezierPath *)createArcPath
{
// Create path from text
// See: http://www.codeproject.com/KB/iPhone/Glyph.aspx
// License: The Code Project Open License (CPOL) 1.02 http://www.codeproject.com/info/cpol10.aspx
letters = CGPathCreateMutable();

CTFontRef font = CTFontCreateWithName(CFSTR("Helvetica-Bold"),80, NULL);
NSDictionary *attrs = [NSDictionary dictionaryWithObjectsAndKeys:
                       (__bridge id)font, kCTFontAttributeName,//د
                       nil];//ج
NSAttributedString *attrString = [[NSAttributedString alloc] initWithString:@"H"
                                                                 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+200, position.y+80);
            CGPathAddPath(letters, &t, letter);
            CGPathRelease(letter);
        }
    }
}
CFRelease(line);

self.path = [UIBezierPath bezierPath];
[self.path appendPath:[UIBezierPath bezierPathWithCGPath:letters]];

return self.path;


}

Answer 1

Can I get the center points of the bezier path along? Or any other way that I can make the center dotted line and follow that path?

要知道用户的手指是否沿着路径移动，您必须路径上的命中检测。

To determine whether a touch event occurred on the filled portion of a path, you can use the containsPoint: method of UIBezierPath. This method tests the specified point against all closed subpaths in the path object and returns YES if it lies on or inside any of those subpaths.

If you want to do hit-testing on the stroked portion of the path (instead of the fill area), you must use Core Graphics. The CGContextPathContainsPoint function lets you test points on either the fill or stroke portion of the path currently assigned to the graphics context.

下面的方法测试指定的点是否与指定的路径相交。 inFill 参数让调用者指定是否应针对路径的填充部分或描边部分测试该点。调用者传入的路径必须包含一个或多个闭合的子路径，命中检测才能成功。

针对路径对象的测试点。

- (BOOL)containsPoint:(CGPoint)point onPath:(UIBezierPath *)path inFillArea:(BOOL)inFill
{
   CGContextRef context = UIGraphicsGetCurrentContext();
   CGPathRef cgPath = path.CGPath;
   BOOL    isHit = NO;

   // Determine the drawing mode to use. Default to
   // detecting hits on the stroked portion of the path.
   CGPathDrawingMode mode = kCGPathStroke;
   if (inFill)
   {
      // Look for hits in the fill area of the path instead.
      if (path.usesEvenOddFillRule)
         mode = kCGPathEOFill;
      else
         mode = kCGPathFill;
   }

   // Save the graphics state so that the path can be removed later.
   CGContextSaveGState(context);
   CGContextAddPath(context, cgPath);

   // Do the hit detection.
   isHit = CGContextPathContainsPoint(context, point, mode);

   CGContextRestoreGState(context);

   return isHit;
}

查看此链接以了解更多关于 Hit-Detection on a Path 的信息

获取路径中心

您可以获得路径的宽度作为 myPath.bounds.size.width; 并获得路径的中心只需将宽度除以 2。

并绘制虚线检查此 answer

在任何 UIBezierPath 上制作虚线为:

CGFloat dashes[] = {2, 3};
//passing an array with the values {2,3} sets a dash pattern that alternates between a 2 space-unit-long painted segment and a 3 space-unit-long unpainted segment.
UIBezierPath *path = [UIBezierPath bezierPath];
[path setLineDash:dashes count:2 phase:0];

并在 CAShapeLayer 上划线使用属性 lineDashPattern 作为:

shapeView.lineDashPattern = @[@2, @3];