RNVectorIconsManager.m

//
//  RNVectorIconsManager.m
//  RNVectorIconsManager
//
//  Created by Joel Arvidsson on 2015-05-29.
//  Copyright (c) 2015 Joel Arvidsson. All rights reserved.
//

#import "RNVectorIconsManager.h"
#import <CoreText/CoreText.h>
#if __has_include(<React/RCTConvert.h>)
#import <React/RCTConvert.h>
#else // Compatibility for RN version < 0.40
#import "RCTConvert.h"
#endif
#if __has_include(<React/RCTBridge.h>)
#import <React/RCTBridge.h>
#else // Compatibility for RN version < 0.40
#import "RCTBridge.h"
#endif
#if __has_include(<React/RCTUtils.h>)
#import <React/RCTUtils.h>
#else // Compatibility for RN version < 0.40
#import "RCTUtils.h"
#endif

@implementation RNVectorIconsManager

@synthesize bridge = _bridge;
RCT_EXPORT_MODULE();

- (NSString *)hexStringFromColor:(UIColor *)color {
  const CGFloat *components = CGColorGetComponents(color.CGColor);

  CGFloat r = components[0];
  CGFloat g = components[1];
  CGFloat b = components[2];

  return [NSString stringWithFormat:@"#%02lX%02lX%02lX",
          lroundf(r * 255),
          lroundf(g * 255),
          lroundf(b * 255)];
}


RCT_EXPORT_METHOD(getImageForFont:(NSString*)fontName withGlyph:(NSString*)glyph withFontSize:(CGFloat)fontSize withColor:(UIColor *)color callback:(RCTResponseSenderBlock)callback){
  CGFloat screenScale = RCTScreenScale();

  NSString *hexColor = [self hexStringFromColor:color];

  NSString *fileName = [NSString stringWithFormat:@"tmp/RNVectorIcons_%@_%hu_%.f%@@%.fx.png", fontName, [glyph characterAtIndex:0], fontSize, hexColor, screenScale];
  NSString *filePath = [NSHomeDirectory() stringByAppendingPathComponent:fileName];

  if(![[NSFileManager defaultManager] fileExistsAtPath:filePath]) {
    // No cached icon exists, we need to create it and persist to disk

    UIFont *font = [UIFont fontWithName:fontName size:fontSize];
    NSAttributedString *attributedString = [[NSAttributedString alloc] initWithString:glyph attributes:@{NSFontAttributeName: font, NSForegroundColorAttributeName: color}];

    CGSize iconSize = [attributedString size];
    UIGraphicsBeginImageContextWithOptions(iconSize, NO, 0.0);
    [attributedString drawAtPoint:CGPointMake(0, 0)];
    
    UIImage *iconImage = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();
  
    NSData *imageData = UIImagePNGRepresentation(iconImage);
    BOOL success = [imageData writeToFile:filePath atomically:YES];
    if(!success) {
      return callback(@[@"Failed to write rendered icon image"]);
    }
  }
  callback(@[[NSNull null], filePath]);
}

RCT_EXPORT_METHOD(loadFontWithFileName:(NSString *)fontFileName
                  extension:(NSString *)extension
                  resolver:(RCTPromiseResolveBlock)resolve
                  rejecter:(RCTPromiseRejectBlock)reject)
{
  NSBundle *bundle = [NSBundle bundleForClass:[self class]];
  NSURL *fontURL = [bundle URLForResource:fontFileName withExtension:extension];
  NSData *fontData = [NSData dataWithContentsOfURL:fontURL];

  CGDataProviderRef provider = CGDataProviderCreateWithCFData((CFDataRef)fontData);
  CGFontRef font = CGFontCreateWithDataProvider(provider);

  if (font) {
    CFErrorRef errorRef = NULL;
    if (CTFontManagerRegisterGraphicsFont(font, &errorRef) == NO) {
      NSError *error = (__bridge NSError *)errorRef;
      if (error.code == kCTFontManagerErrorAlreadyRegistered) {
        resolve(nil);
      } else {
        reject(@"font_load_failed", @"Font failed to load", error);
      }
    } else {
      resolve(nil);
    }

    CFRelease(font);
  }
  if (provider) {
    CFRelease(provider);
  }
}

@end