使用CGPath绘制到SVG输出

你可以从在GitHub上查看这个文件开始.它有一个例程将CGPathRef转换为SVG路径的d属性.我写的.

类方法的签名是+(NSString*)svgPathFromCGPath:(CGPathRef)aPath; [更新:在下面添加了代码段]

#import "SVGPathGenerator.h"

...

CGMutablePathRef pathToBuild = CGPathCreateMutable();
CGPathMoveToPoint(pathToBuild, nil, 10, 10);
CGPathAddQuadCurveToPoint(pathToBuild, nil, 20, 0, 30, 40);
CGPathAddCurveToPoint(pathToBuild, nil, 20, 40, 40, 30, 100, 90);
CGPathAddLineToPoint(pathToBuild, nil, 50, 100);

NSString* aDAttribute =  [SVGPathGenerator svgPathFromCGPath:pathToBuild];
NSLog(@"%@",aDAttribute);

输出:M10.0 10.0Q20.0 0.0 30.0 40.0C20.0 40.0 40.0 30.0 100.0 90.0L50.0 100.0

注意,如果添加弧,输出将没有紧密的对应关系,因为SVG中的弧和Quartz中的弧的描述完全不同.

如果你想将它输出到一个简单的SVG文件,那么你可以做类似的事情:

 CGRect boundingBox = CGPathGetPathBoundingBox(pathToBuild);

NSString* svgAsString = [NSString stringWithFormat:@" <?xml version=\"1.0\" encoding=\"UTF-8\"?> \
                         <!DOCTYPE svg PUBLIC \"-//W3C//DTD SVG 1.1//EN\" \"http://www.w3.org/Graphics/SVG/1.1/DTD/svg11.dtd\"> \
                         <svg  xmlns=\"http://www.w3.org/2000/svg\" xmlns:xlink=\"http://www.w3.org/1999/xlink\" viewport-fill=\"none\" viewBox=\"%lf, %lf, %lf, %lf\" version=\"1.1\" %lf\" %lf\" > \
                         <path fill=\"none\" stroke=\"green\" d=\"%@\" /> \
                         </svg>",
                         boundingBox.origin.x, boundingBox.origin.y, boundingBox.size.width, boundingBox.size.height, boundingBox.size.height, boundingBox.size.width, aDAttribute
                         ];

NSData* utf8Data = [svgAsString dataUsingEncoding:NSUTF8StringEncoding];
[utf8Data writeToFile:pathToFile atomically:YES];

(我没有编译这段代码).