Setting default font & size while loading HTML into NSTextView - cocoa

Question

I'm loading a simple HTML into NSTextView. I have already set the font attributes for NSTextView but the loading of HTML ignore these fonts and defaults always to 'Times-Roman 12 size'. Currently I'm enumerating through the attributes and setting the font size. But it seems expensive to do this just for changing the size. Is this the only way to do it? Is there a better way?
HTML:
<p>This is just a <b>title</b></p>
Loading HTML into NSTextView & subsequent change of fontsize:
NSData *valueInDataFormat = [bodyContent dataUsingEncoding:NSUTF8StringEncoding];
NSAttributedString *textToBeInserted = [[NSAttributedString alloc] initWithHTML:valueInDataFormat documentAttributes:nil];
NSDictionary *rtfTextAttributes = [self defaultTextAttributesFor:RTFText];
//inserttext mimic what user do; so it takes the typingattributes
//ref: http://www.cocoabuilder.com/archive/cocoa/113938-setting-default-font-of-an-nstextview.html#114071
[entryContent setString:#""];
[entryContent setTypingAttributes:rtfTextAttributes];
[entryContent insertText:textToBeInserted];
//now change font size
NSTextStorage *content = [entryContent textStorage];
[content beginEditing];
NSRange totalRange = NSMakeRange (0, content.length);
[content enumerateAttributesInRange: totalRange
options: 0
usingBlock: ^(NSDictionary *attributes, NSRange range, BOOL *stop) {
NSLog (#"range: %# attributes: %#",
NSStringFromRange(range), attributes);
NSFont *font = [attributes objectForKey:NSFontAttributeName];
if (font){
[content removeAttribute:NSFontAttributeName range:range];
font = [[NSFontManager sharedFontManager] convertFont:font toSize:[font pointSize] + 3];
[content addAttribute:NSFontAttributeName value:font range:range];
}
}];
[content endEditing];
[entryContent didChangeText];

Answer 1

Came across this problem recently, in the end I found it was possible to use a <style> block at the front of the HTML content and set the font-family to the system default. This works well and allows the HTML to describe all the bold and italic attributes whilst using the system font.
NSString* bodyContent = #"<p>This is just a <b>title</b></p>";
NSMutableString *htmlContent = [NSMutableString string];
[html appendString: #"<style>body { font-family: "];
[html appendString: [[NSFont systemFontOfSize: 12] fontName]];
[html appendString: #"; }</style>"];
[html appendString: bodyContent];
NSData *htmlData = [htmlContent dataUsingEncoding:NSUTF8StringEncoding];
NSAttributedString *html = [[NSAttributedString alloc] initWithHTML: htmlDescriptionData baseURL: NULL documentAttributes: NULL];
There might be a more elegant solution to this, but I have not found it yet.

Answer 2

You can use a WebPreferences object to control the font used when creating an attributed string from HTML.
The method -initWithHTML:options:documentAttributes: takes an options dictionary. One of the recognized keys for that dictionary is NSWebPreferencesDocumentOption. The value is a WebPreferences instance to be used when interpreting the HTML.
A WebPreferences instance has several font family settings. The one which is used when no other font attributes have been specified in the HTML is -standardFontFamily. If the HTML specifies a font class (such as "sans-serif") but no specific font, then the settings for that font class (such as -sansSerifFontFamily) is used.
WebPreferences also has settings for the font size.
For example:
WebPreferences *webPreferences = [[WebPreferences alloc] initWithIdentifier:#"com.company.app.something"];
webPreferences.standardFontFamily = [someFont familyName]; // or a hard-coded family name like #"Helvetica Neue"
webPreferences.defaultFontSize = [NSFont systemFontSize];
...
[[NSAttributedString alloc] initWithHTML:htmlData
options:#{NSWebPreferencesDocumentOption : webPreferences}
documentAttributes:NULL];
There's a caveat: the system font is of a family which is hidden from WebPreferences/NSAttributedString. On Mavericks, its name is ".Lucida Grande UI"; on Yosemite, its name is ".Helvetica Neue UI". For some reason, these can't be used when converting HTML to an attributed string using a WebPreferences object. My best guess is that it's because they aren't listed in [[NSFontManager sharedFontManager] availableFontFamilies]. When you try to use such a font family, the system defaults to Times (yuck!).