//
//  IJSVGGradientLayer.m
//  IJSVGExample
//
//  Created by Curtis Hard on 29/12/2016.
//  Copyright © 2016 Curtis Hard. All rights reserved.
//

#import "IJSVGGradientLayer.h"

@implementation IJSVGGradientLayer

@synthesize viewBox;
@synthesize gradient;
@synthesize absoluteTransform;
@synthesize objectRect;

- (void)dealloc
{
    [gradient release], gradient = nil;
    [super dealloc];
}

- (id)init
{
    if((self = [super init]) != nil) {
        self.requiresBackingScaleHelp = YES;
        self.shouldRasterize = YES;
    }
    return self;
}

- (void)setGradient:(IJSVGGradient *)newGradient
{
    if(gradient != nil) {
        [gradient release], gradient = nil;
    }
    gradient = [newGradient retain];
    
    // lets check its alpha properties on the colors
    BOOL hasAlphaChannel = NO;
    NSInteger stops = gradient.gradient.numberOfColorStops;
    for(NSInteger i = 0; i < stops; i++) {
        NSColor * color = nil;
        [gradient.gradient getColor:&color
                           location:NULL
                            atIndex:i];
        if(color.alphaComponent != 1.f) {
            hasAlphaChannel = YES;
            break;
        }
    }
    self.opaque = hasAlphaChannel == NO;
}

- (void)setOpacity:(float)opacity
{
    if(opacity != 1.f) {
        self.opaque = NO;
    }
    [super setOpacity:opacity];
}

- (void)setBackingScaleFactor:(CGFloat)backingScaleFactor
{
    switch (self.renderQuality) {
        case IJSVGRenderQualityOptimized: {
            backingScaleFactor = .35f;
            break;
        }
        case IJSVGRenderQualityLow: {
            backingScaleFactor = .05f;
            break;
        }
        default: {
            break;
        }
    }
    [super setBackingScaleFactor:backingScaleFactor];
}

- (void)drawInContext:(CGContextRef)ctx
{
    [super drawInContext:ctx];
 
    // nothing to do :(
    if(self.gradient == nil) {
        return;
    }
    
    // draw the gradient
    CGAffineTransform trans = CGAffineTransformMakeTranslation(-CGRectGetMinX(objectRect),
                                                               -CGRectGetMinY(objectRect));
    CGAffineTransform transform = CGAffineTransformConcat(absoluteTransform,trans);
    CGContextSaveGState(ctx);
    [self.gradient drawInContextRef:ctx
                         objectRect:objectRect
                  absoluteTransform:transform
                           viewPort:self.viewBox];
    CGContextRestoreGState(ctx);
}

@end