下列字體亦可依照 app 需求安裝(Apps can download the following fonts if necessary)?

在設計iOS app時，常需要用到一些字型
這時候就可以參考一下font list
但是讓我疑惑的是，

下列字體亦可依照 app 需求安裝

是要如何安裝。
後來在apple上，發現這個sample

convert color code to UIColor

+ (UIColor*)colorWithColorCode:(NSString*)hex
{
    NSString *cString = [[hex stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceAndNewlineCharacterSet]] uppercaseString];
    
    // String should be 6 or 8 or 10 characters
    if ([cString length] < 6) return [UIColor grayColor];
    
    // strip 0X if it appears
    if ([cString hasPrefix:@"0X"]) cString = [cString substringFromIndex:2];
    
    if ([cString length] != 6 && [cString length] != 8) return  [UIColor grayColor];
    
    // Separate into r, g, b substrings
    NSRange range;
    range.location = 0;
    range.length = 2;
    NSString *rString = [cString substringWithRange:range];
    
    range.location = 2;
    NSString *gString = [cString substringWithRange:range];
    
    range.location = 4;
    NSString *bString = [cString substringWithRange:range];
    
    NSString *aString = @"FF";
    range.location = 6;
    if ([cString length] == 8)
        aString = [cString substringWithRange:range];
    
    // Scan values
    unsigned int r, g, b, a;
    [[NSScanner scannerWithString:rString] scanHexInt:&r];
    [[NSScanner scannerWithString:gString] scanHexInt:&g];
    [[NSScanner scannerWithString:bString] scanHexInt:&b];
    [[NSScanner scannerWithString:aString] scanHexInt:&a];
    
    return [UIColor colorWithRed:((float) r / 255.0f)
                           green:((float) g / 255.0f)
                            blue:((float) b / 255.0f)
                           alpha:((float) a / 255.0f)];
}

參考

white line on iOS7

今天突然發現我的元件上有一條白線，
不管是用path或讀圖畫出來的都後。
而且iOS6，還沒事。
google後，才發現是antialias搞。
CGContextSetShouldAntialias(context, NO); 參考