saveNSStringAsImg

gistfile1.m

- (void)saveMessageAsImg: (NSString *)comment fileName:(NSString *) filePath
{

    UIFont *font = [UIFont fontWithName:@"HiraKakuProN-W3" size:60];
    CGSize size = [comment sizeWithFont: font];


    UIGraphicsBeginImageContextWithOptions(CGSizeMake(size.width, size.height), NO, [[UIScreen mainScreen] scale]);
    CGContextRef ctx = UIGraphicsGetCurrentContext();
    CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB();
    CGContextSetFillColorSpace(ctx, colorSpace);
    CGColorSpaceRelease(colorSpace);

    CGContextSetAllowsAntialiasing(ctx, YES);
    CGContextSetAllowsFontSmoothing(ctx, YES);
    CGContextSetShouldAntialias(ctx, YES);
    CGContextSetShouldSmoothFonts(ctx, YES);
    CGContextSetRGBFillColor(ctx, 0.0, 0.0, 0.0, 1.0);
    CGContextFillRect(ctx, CGRectMake(0.0, 0.0, size.width, size.height)); // Background

    CGContextSetRGBFillColor(ctx, 1.0, 1.0, 1.0, 1.0);
    [comment drawInRect:CGRectMake(0, 0, size.width, size.height) withFont:font];

    CGImageRef imageRef = CGBitmapContextCreateImage(ctx);
    UIImage *image = [UIImage imageWithCGImage:imageRef];
    NSData *pngData = UIImagePNGRepresentation(image);
    [pngData writeToFile:filePath atomically:NO];
    
    CGImageRelease(imageRef);

    LOG(@"save comment: %@", filePath);
    UIGraphicsEndImageContext();
}