objective-c - 如何使用 CTFontRef 获取 FontFormat

Question

有旧的碳代码使用 FMGetFontFormat 来确定字体是否为“True Type”。由于该 API 已弃用，有没有办法使用 CTFontRef 找到相同的 API。我使用了 CTFontCopyAttribute，但它返回 CTTypeRef 并且我无法获取该值？有什么建议吗？

Answer 1

CTTypeRef 是通用类型。如果您阅读 kCTFontFormatAttribute 常量的文档，它们会指出:

The value associated with this key is an integer represented as a CFNumberRef object containing one of the constants in “Font Format Constants.”

这意味着您需要将该属性视为数字，然后可以将其转换为 short 并根据 CTFontFormat 的已知值进行检查:

//get an array of all the available font names
CFArrayRef fontFamilies = CTFontManagerCopyAvailableFontFamilyNames();

//loop through the array
for(CFIndex i = 0; i < CFArrayGetCount(fontFamilies); i++)
{
    //get the current name
    CFStringRef fontName = CFArrayGetValueAtIndex(fontFamilies, i);

    //create a CTFont with the current font name
    CTFontRef font = CTFontCreateWithName(fontName, 12.0, NULL);

    //ask it for its font format attribute
    CFNumberRef fontFormat = CTFontCopyAttribute(font, kCTFontFormatAttribute);

    //release the font because we're done with it
    CFRelease(font);

    //if there is no format attribute just skip this one
    if(fontFormat == NULL)
    {
        NSLog(@"Could not determine the font format for font named %@.", fontName);
        continue;
    }

    //get the font format as a short
    SInt16 format;
    CFNumberGetValue(fontFormat, kCFNumberSInt16Type, &format);

    //release the number because we're done with it
    CFRelease(fontFormat);

    //create a human-readable string based on the format of the font
    NSString* formatName = nil;
    switch (format) {
        case kCTFontFormatOpenTypePostScript:
            formatName = @"OpenType PostScript";
            break;
        case kCTFontFormatOpenTypeTrueType:
            formatName = @"OpenType TrueType";
            break;
        case kCTFontFormatTrueType:
            formatName = @"TrueType";
            break;
        case kCTFontFormatPostScript:
            formatName = @"PostScript";
            break;
        case kCTFontFormatBitmap:
            formatName = @"Bitmap";
            break;
        case kCTFontFormatUnrecognized:
        default:
            formatName = @"Unrecognized";
            break;
    }
    NSLog(@"Font: '%@' Format: '%@'", fontName, formatName);
}