IJSVG/source/IJSVGRadialGradient.m

//
//  IJSVGRadialGradient.m
//  IJSVGExample
//
//  Created by Curtis Hard on 03/09/2014.
//  Copyright (c) 2014 Curtis Hard. All rights reserved.
//

#import "IJSVGRadialGradient.h"

@implementation IJSVGRadialGradient

@synthesize cx;
@synthesize cy;
@synthesize fx;
@synthesize fy;
@synthesize radius;

- (void)dealloc
{
    [cx release], cx = nil;
    [cy release], cy = nil;
    [fx release], fx = nil;
    [fy release], fy = nil;
    [radius release], radius = nil;
    [super dealloc];
}

- (id)copyWithZone:(NSZone *)zone
{
    IJSVGRadialGradient * grad = [super copyWithZone:zone];
    grad.fx = self.fx;
    grad.fy = self.fy;
    grad.cx = self.cx;
    grad.cy = self.cy;
    grad.radius = self.radius;
    return grad;
}


+ (NSGradient *)parseGradient:(NSXMLElement *)element
                     gradient:(IJSVGRadialGradient *)gradient
{
    // cx defaults to 50% if not specified
    NSDictionary * kv = @{@"cx":@"cx",
                          @"cy":@"cy",
                          @"r":@"radius"};
    
    for(NSString * key in kv.allKeys) {
        NSString * str = [element attributeForName:key].stringValue;
        IJSVGUnitLength * unit = nil;
        if(str != nil) {
            unit = [IJSVGUnitLength unitWithString:str];
        } else {
            unit = [IJSVGUnitLength unitWithPercentageFloat:.5f];
        }
        [gradient setValue:unit
                    forKey:kv[key]];
    }
    
    gradient.fx = gradient.cx;
    gradient.fy = gradient.cy;
    
    // needs fixing
    NSString * fx = [element attributeForName:@"fx"].stringValue;
    if(fx != nil) {
        if(fx.floatValue < 1.f) {
            gradient.fx = [IJSVGUnitLength unitWithPercentageString:fx];
        } else {
            gradient.fx = [IJSVGUnitLength unitWithString:fx];
        }
    }
    
    NSString * fy = [element attributeForName:@"fy"].stringValue;
    if(fx != nil) {
        if(fx.floatValue < 1.f) {
            gradient.fy = [IJSVGUnitLength unitWithPercentageString:fy];
        } else {
            gradient.fy = [IJSVGUnitLength unitWithString:fy];
        }
    }
  
    if( gradient.gradient != nil ) {
        return nil;
    }
    
    NSArray * colors = nil;
    CGFloat * colorStops = [[self class] computeColorStopsFromString:element colors:&colors];
    NSGradient * ret = [[[NSGradient alloc] initWithColors:colors
                                               atLocations:colorStops
                                                colorSpace:IJSVGColor.defaultColorSpace] autorelease];
    free(colorStops);
    return ret;
}

- (void)drawInContextRef:(CGContextRef)ctx
              objectRect:(NSRect)objectRect
       absoluteTransform:(CGAffineTransform)absoluteTransform
                viewPort:(CGRect)viewBox
{
    BOOL inUserSpace = self.units == IJSVGUnitUserSpaceOnUse;
    CGFloat radius = self.radius.value;
    CGPoint startPoint = CGPointZero;
    CGPoint gradientStartPoint = CGPointZero;
    CGPoint gradientEndPoint = CGPointZero;
    
    // transforms
    CGAffineTransform selfTransform = IJSVGConcatTransforms(self.transforms);
    
#pragma mark User Space On Use
    if(inUserSpace == YES) {
        CGFloat rad = radius*2.f;
        startPoint = CGPointMake(self.cx.value, self.cy.value);
        
        // work out the new radius
        CGRect rect = CGRectMake(startPoint.x, startPoint.y, rad, rad);
        rect = CGRectApplyAffineTransform(rect, selfTransform);
        rect = CGRectApplyAffineTransform(rect, absoluteTransform);
        radius = CGRectGetHeight(rect)/2.f;
        
        gradientStartPoint = startPoint;
        gradientEndPoint = CGPointMake(self.fx.value, self.fy.value);
        
        // apply the absolute position
        CGContextConcatCTM(ctx, absoluteTransform);
    } else {
#pragma mark Object Bounding Box
        // compute size based on percentages
        CGFloat x = [self.cx computeValue:CGRectGetWidth(objectRect)];
        CGFloat y = [self.cy computeValue:CGRectGetHeight(objectRect)];
        startPoint = CGPointMake(x, y);
        CGFloat val = MIN(CGRectGetWidth(objectRect), CGRectGetHeight(objectRect));
        radius = [self.radius computeValue:val];
        
        CGFloat ex = [self.fx computeValue:CGRectGetWidth(objectRect)];
        CGFloat ey = [self.fy computeValue:CGRectGetHeight(objectRect)];
        
        gradientEndPoint = CGPointMake(ex, ey);
        gradientStartPoint = startPoint;
        
        // transform if width or height is not equal
        if(CGRectGetWidth(objectRect) != CGRectGetHeight(objectRect)) {
            CGAffineTransform tr = CGAffineTransformMakeTranslation(gradientStartPoint.x,
                                                                    gradientStartPoint.y);
            if(CGRectGetWidth(objectRect) > CGRectGetHeight(objectRect)) {
                tr = CGAffineTransformScale(tr, CGRectGetWidth(objectRect)/CGRectGetHeight(objectRect), 1);
            } else {
                tr = CGAffineTransformScale(tr, 1.f, CGRectGetHeight(objectRect)/CGRectGetWidth(objectRect));
            }
            tr = CGAffineTransformTranslate(tr, -gradientStartPoint.x, -gradientStartPoint.y);
            selfTransform = CGAffineTransformConcat(tr, selfTransform);
        }
    }

#pragma mark Default drawing
    // transform the context
    CGContextConcatCTM(ctx, selfTransform);

    // draw the gradient
    CGGradientDrawingOptions options = kCGGradientDrawsBeforeStartLocation|
        kCGGradientDrawsAfterEndLocation;
    CGContextDrawRadialGradient(ctx, self.CGGradient,
                                gradientEndPoint, 0, gradientStartPoint,
                                radius, options);
}

@end