react-native-svg/ios/Text/RNSVGText.m

/**
 * Copyright (c) 2015-present, Horcrux.
 * All rights reserved.
 *
 * This source code is licensed under the MIT-style license found in the
 * LICENSE file in the root directory of this source tree.
 */

#import "RNSVGText.h"
#import "RNSVGTextPath.h"
#import <React/RCTFont.h>
#import <CoreText/CoreText.h>
#import "RNSVGGlyphContext.h"
#import "RNSVGTextProperties.h"

@implementation RNSVGText
{
    RNSVGGlyphContext *_glyphContext;
}

- (void)invalidate
{
    [super invalidate];
    [self releaseCachedPath];
}

- (void)renderLayerTo:(CGContextRef)context rect:(CGRect)rect
{
    [self clip:context];
    CGContextSaveGState(context);
    [self setupGlyphContext:context];

    CGPathRef path = [self getGroupPath:context];
    [self renderGroupTo:context rect:rect];
    CGContextRestoreGState(context);

    CGPathRef transformedPath = CGPathCreateCopyByTransformingPath(path, &CGAffineTransformIdentity);
    [self setHitArea:transformedPath];
    CGPathRelease(transformedPath);
}

- (void)setupGlyphContext:(CGContextRef)context
{
    _glyphContext = [[RNSVGGlyphContext alloc] initWithScale:1 width:[self getContextWidth]
                                                   height:[self getContextHeight]];
}

// release the cached CGPathRef for RNSVGTSpan
- (void)releaseCachedPath
{
    [self traverseSubviews:^BOOL(__kindof RNSVGNode *node) {
        RNSVGText *text = node;
        [text releaseCachedPath];
        return YES;
    }];
}

- (CGPathRef)getGroupPath:(CGContextRef)context
{
    [self pushGlyphContext];
    CGPathRef groupPath = [super getPath:context];
    [self popGlyphContext];

    return groupPath;
}

- (CGPathRef)getPath:(CGContextRef)context
{
    [self setupGlyphContext:context];
    CGPathRef groupPath = [self getGroupPath:context];

    return (CGPathRef)CFAutorelease(CGPathCreateCopyByTransformingPath(groupPath, &CGAffineTransformIdentity));
}

- (void)renderGroupTo:(CGContextRef)context rect:(CGRect)rect
{
    [self pushGlyphContext];
    [super renderGroupTo:context rect:rect];
    [self popGlyphContext];
}

// TODO: Optimisation required
- (RNSVGText *)textRoot
{
    RNSVGText *root = self;
    while (root && [root class] != [RNSVGText class]) {
        if (![root isKindOfClass:[RNSVGText class]]) {
            //todo: throw exception here
            break;
        }
        root = (RNSVGText*)[root superview];
    }

    return root;
}

- (NSString *)alignmentBaseline
{
    if (_alignmentBaseline != nil) {
        return _alignmentBaseline;
    }

    UIView* parent = self.superview;
    while (parent != nil) {
        if ([parent isKindOfClass:[RNSVGText class]]) {
            RNSVGText* node = (RNSVGText*)parent;
            NSString* baseline = node.alignmentBaseline;
            if (baseline != nil) {
                _alignmentBaseline = baseline;
                return baseline;
            }
        }
        parent = [parent superview];
    }

    if (_alignmentBaseline == nil) {
        _alignmentBaseline = RNSVGAlignmentBaselineStrings[0];
    }
    return _alignmentBaseline;
}

- (NSString *)baselineShift
{
    if (_baselineShift != nil) {
        return _baselineShift;
    }

    UIView* parent = [self superview];
    while (parent != nil) {
        if ([parent isKindOfClass:[RNSVGText class]]) {
            RNSVGText* node = (RNSVGText*)parent;
            NSString* baselineShift = node.baselineShift;
            if (baselineShift != nil) {
                _baselineShift = baselineShift;
                return baselineShift;
            }
        }
        parent = [parent superview];
    }

    // set default value
    _baselineShift = @"";

    return _baselineShift;
}

- (RNSVGGlyphContext *)getGlyphContext
{
    return _glyphContext;
}

- (void)pushGlyphContext
{
    [[self.textRoot getGlyphContext] pushContext:self
                                            font:self.font
                                               x:self.positionX
                                               y:self.positionY
                                          deltaX:self.deltaX
                                          deltaY:self.deltaY
                                          rotate:self.rotate];
}

- (void)popGlyphContext
{
    [[self.textRoot getGlyphContext] popContext];
}

- (CTFontRef)getFontFromContext
{
    return [[self.textRoot getGlyphContext] getGlyphFont];
}

@end