IJSVG/source/IJSVGWriter.m

//
//  IJSVGWriter.m
//  IJSVGExample
//
//  Created by Curtis Hard on 21/05/2015.
//  Copyright (c) 2015 Curtis Hard. All rights reserved.
//

#import "IJSVGWriter.h"

@implementation IJSVGWriter

+ (NSString*)SVGDocumentStringForSVGGlyph:(IJSVGPath*)node
{
    NSBezierPath* path = [node path];
    // we need to flip it
    NSAffineTransform* trans = NSAffineTransform.transform;
    [trans scaleXBy:1.f yBy:-1.f];
    [trans translateXBy:0.f yBy:path.controlPointBounds.size.height];
    path = [trans transformBezierPath:path];
    return [self.class SVGDocumentStringForBezierPath:path];
}

+ (NSString*)SVGDocumentStringForBezierPath:(NSBezierPath*)path
{
    return [self.class SVGDocumentForBezierPath:path].XMLString;
}

+ (NSXMLDocument*)SVGDocumentForBezierPath:(NSBezierPath*)path
{
    NSXMLElement* root = [self.class rootElementForPath:path];

    // create the path data
    NSXMLElement* p = [[[NSXMLElement alloc] initWithName:@"path"] autorelease];

    // add the drawing command
    NSXMLNode* n = [[[NSXMLNode alloc] initWithKind:NSXMLAttributeKind] autorelease];
    [n setName:@"d"];
    [n setStringValue:[self.class SVGPathStringForBezierPath:path]];
    [p addAttribute:n];

    // add the drawing path to the root
    [root addChild:p];
    return [[[NSXMLDocument alloc] initWithRootElement:root] autorelease];
}

+ (NSXMLElement*)rootElementForPath:(NSBezierPath*)path
{
    NSXMLElement* element = [[[NSXMLElement alloc] initWithName:@"svg"] autorelease];
    NSRect bounds = path.controlPointBounds;

    // width
    NSXMLNode* att = [[[NSXMLNode alloc] initWithKind:NSXMLAttributeKind] autorelease];
    [att setName:@"width"];
    [att setStringValue:[NSString stringWithFormat:@"%f", bounds.size.width]];
    [element addAttribute:att];

    // height
    att = [[[NSXMLNode alloc] initWithKind:NSXMLAttributeKind] autorelease];
    [att setName:@"height"];
    [att setStringValue:[NSString stringWithFormat:@"%f", bounds.size.height]];
    [element addAttribute:att];

    // viewbox
    att = [[[NSXMLNode alloc] initWithKind:NSXMLAttributeKind] autorelease];
    [att setName:@"viewBox"];
    [att setStringValue:[NSString stringWithFormat:@"%f %f %f %f", bounds.origin.x, bounds.origin.y, bounds.size.width, bounds.size.height]];
    [element addAttribute:att];

    // namespace
    att = [[[NSXMLNode alloc] initWithKind:NSXMLAttributeKind] autorelease];
    [att setName:@"xmlns"];
    [att setStringValue:@"http://www.w3.org/2000/svg"];
    [element addAttribute:att];
    return element;
}

+ (NSString*)SVGPathStringForBezierPath:(NSBezierPath*)path
{
    NSMutableString* str = [[[NSMutableString alloc] init] autorelease];
    for (NSInteger i = 0; i < path.elementCount; i++) {
        NSBezierPathElement element = [path elementAtIndex:i];
        switch (element) {
        // move
        case NSMoveToBezierPathElement: {
            NSPoint points[1];
            [path elementAtIndex:i associatedPoints:points];
            [str appendFormat:@"M%f %f", points[0].x, points[0].y];
            break;
        }
        // line
        case NSLineToBezierPathElement: {
            NSPoint points[1];
            [path elementAtIndex:i associatedPoints:points];
            [str appendFormat:@"L%f %f", points[0].x, points[0].y];
            break;
        }
        // curve
        case NSCurveToBezierPathElement: {
            NSPoint points[3];
            [path elementAtIndex:i associatedPoints:points];
            [str appendFormat:@"C%f %f %f %f %f %f", points[0].x, points[0].y, points[1].x, points[1].y, points[2].x, points[2].y];
            break;
        }
        // close
        case NSClosePathBezierPathElement: {
            [str appendFormat:@"Z"];
            break;
        }
        }
    }
    return str;
}

@end