NSFont - 如何获得正确的字体？

Question

I would like to make a NSFont to describe Arial, normal, 30pt in height. So far I have:

    NSNumber *weight = [NSNumber numberWithFloat:1.0];
    NSNumber *slant = [NSNumber numberWithFloat:1.0];
    NSDictionary *fontTraits = [NSDictionary dictionaryWithObjectsAndKeys: weight, NSFontWeightTrait, slant, NSFontSlantTrait, nil];
    NSDictionary *fontAttributes = [NSDictionary dictionaryWithObjectsAndKeys: @"Arial", NSFontFaceAttribute, 
                                                                               fontTraits, NSFontTraitsAttribute, nil];
    NSFontDescriptor *fontDescriptor = [NSFontDescriptor fontDescriptorWithFontAttributes: fontAttributes];
    NSFont *largeFont = [NSFont fontWithDescriptor: fontDescriptor size: 30];

but the resulting NSFont is not the right size. I can put any size I want in there and they all look the same.

Answer 1

are you writing for iOS or Mac OS X?

this works fine in my Mac App:

NSFont* font = [NSFont fontWithName:@"Arial" size:30];

UPDATE with bold and/or italic: is that enough for you ?

NSFont* font = [NSFont fontWithName:@"Arial Italic" size:30];
NSFont* font = [NSFont fontWithName:@"Arial Bold" size:30];
NSFont* font = [NSFont fontWithName:@"Arial Bold Italic" size:30];

UPDATE 2 may be take a look at NSFontManager

// convert font
NSFont* font = [NSFont fontWithName:@"Arial" size:30];
font = [[NSFontManager sharedFontManager] convertFont:font toHaveTrait:NSFontItalicTrait];

// create with traits and weight
NSFont* font = [[NSFontManager sharedFontManager]  fontWithFamily:@"Arial" traits:NSFontItalicTrait weight:2 size:30];

But with neither of those you are able to create a font with a weight of 5 and a slant of 4.

i recently talked to a designer about fonts and he told me that usually a font like Arial is actually 4 Fonts (ie Arial, Arial Italic, Arial Bold and Arial Bold Italic). those 3 other font styles (with the traits) are not generated on the fly by an algorithm.