IJSVG/source/IJSVGShapeLayer.m

//
//  IJSVGShapeLayer.m
//  IJSVGExample
//
//  Created by Curtis Hard on 07/01/2017.
//  Copyright © 2017 Curtis Hard. All rights reserved.
//

#import "IJSVGShapeLayer.h"
#import "IJSVGGroupLayer.h"

@implementation IJSVGShapeLayer

@synthesize gradientFillLayer;
@synthesize patternFillLayer;
@synthesize gradientStrokeLayer;
@synthesize patternStrokeLayer;
@synthesize strokeLayer;
@synthesize requiresBackingScaleHelp;
@synthesize backingScaleFactor;
@synthesize blendingMode;
@synthesize convertMasksToPaths;
@synthesize originalPathOrigin;

- (void)dealloc
{
    IJSVGBeginTransactionLock();
    [_maskingLayer release], _maskingLayer = nil;
    [super dealloc];
    IJSVGEndTransactionLock();
}

- (void)addSublayer:(CALayer *)layer {
    if([layer isKindOfClass:[IJSVGLayer class]] == NO &&
       [layer isKindOfClass:[IJSVGShapeLayer class]] == NO) {
        NSString * r = [NSString stringWithFormat:@"The layer must be an instance of IJSVGLayer, %@ given.",
                        [layer class]];
        NSException * exception = [NSException exceptionWithName:@"IJSVGInvalidSublayerException"
                                                          reason:r
                                                        userInfo:nil];
        @throw exception;
    }
    [super addSublayer:layer];
}

- (void)setBackingScaleFactor:(CGFloat)newFactor
{
    if(self.backingScaleFactor == newFactor) {
        return;
    }
    backingScaleFactor = newFactor;
    self.contentsScale = newFactor;
    self.rasterizationScale = newFactor;
    [self setNeedsDisplay];
}

- (void)_customRenderInContext:(CGContextRef)ctx
{
    if(self.convertMasksToPaths == YES && _maskingLayer != nil) {
        CGContextSaveGState(ctx);
        [self applySublayerMaskToContext:ctx
                             forSublayer:(IJSVGLayer *)self
                              withOffset:CGPointZero];
        [super renderInContext:ctx];
        CGContextRestoreGState(ctx);
        return;
    }
    [super renderInContext:ctx];
}

- (void)setConvertMasksToPaths:(BOOL)flag
{
    if(convertMasksToPaths == flag) {
        return;
    }
    convertMasksToPaths = flag;
    if(flag == YES) {
        if(_maskingLayer != nil) {
            [_maskingLayer release], _maskingLayer = nil;
        }
        _maskingLayer = [(IJSVGLayer *)self.mask retain];
        self.mask = nil;
    } else {
        self.mask = _maskingLayer;
        [_maskingLayer release], _maskingLayer = nil;
    }
}

- (void)applySublayerMaskToContext:(CGContextRef)context
                       forSublayer:(IJSVGLayer *)sublayer
                        withOffset:(CGPoint)offset
{
    // apply any transforms needed
    CGPoint layerOffset = offset;
    CGAffineTransform sublayerTransform = CATransform3DGetAffineTransform(sublayer.transform);
    CGContextConcatCTM( context, CGAffineTransformInvert(sublayerTransform) );
    
    // walk up the superlayer chain
    CALayer * superlayer = self.superlayer;
    if (IJSVGIsSVGLayer(superlayer) == YES) {
        [(IJSVGLayer *)superlayer applySublayerMaskToContext:context
                                                 forSublayer:(IJSVGLayer *)self
                                                  withOffset:layerOffset];
    }
    
    // grab the masking layer
    IJSVGShapeLayer * maskingLayer = [self maskingLayer];
    
    // if its a group we need to get the lowest level children
    // and walk up the chain again
    if([maskingLayer isKindOfClass:[IJSVGGroupLayer class]]) {
        NSArray * subs = [IJSVGLayer deepestSublayersOfLayer:maskingLayer];
        for(IJSVGLayer * subLayer in subs) {
            [subLayer applySublayerMaskToContext:context
                                     forSublayer:(IJSVGLayer *)self
                                      withOffset:layerOffset];
        }
    } else if ([maskingLayer isKindOfClass:[IJSVGShapeLayer class]]) {
        // is a shape, go for it!
        CGPathRef maskPath = maskingLayer.path;
        CGContextTranslateCTM(context, -layerOffset.x, -layerOffset.y);
        CGContextAddPath(context, maskPath);
        CGContextClip(context);
        CGContextTranslateCTM(context, layerOffset.x, layerOffset.y);
    }
    CGContextConcatCTM(context, sublayerTransform);
}

- (IJSVGShapeLayer *)maskingLayer
{
    return (IJSVGShapeLayer *)_maskingLayer ?: nil;
}

- (void)renderInContext:(CGContextRef)ctx
{
    if(self.blendingMode != kCGBlendModeNormal) {
        CGContextSaveGState(ctx);
        CGContextSetBlendMode(ctx, self.blendingMode);
        [self _customRenderInContext:ctx];
        CGContextRestoreGState(ctx);
        return;
    }
    [self _customRenderInContext:ctx];
}

- (CGPoint)absoluteOrigin
{
    CGPoint point = CGPointZero;
    CALayer * pLayer = self;
    while(pLayer != nil) {
        point.x += pLayer.frame.origin.x;
        point.y += pLayer.frame.origin.y;
        pLayer = pLayer.superlayer;
    }
    return point;
}

@end