If I use truetype font, Does it mean i need a higher-level layout engine to layout the font? I know that there are OpenType tables (GPOS and GSUB) to handle the shape and combine for complex scripts. But Is the OpenType tables support truetype font? I even don't know the difference between the truetype font and opentype font. Thanks!
On Tue, Sep 6, 2011 at 1:53 PM, Philippe Verdy <[email protected]> wrote: > Devanagari, not Decanagrari I suppose... Starts by looking at the > TrueType and OpenType specifications: > http://www.microsoft.com/typography/SpecificationsOverview.mspx > Then look at the details of the OpenType features needed for > Devanagari and Thai. > > You'll immediately see that Thai is much less complex than Devanagari > to implement. > > There are other competing technologies, base on TrueType (AAT for > MacOS, Graphite portable across platforms, but not very well supported > in applications). > > SVG fonts for now cannot support these scripts very well due to the > impossibility to map precisely the contextual forms that are unified > in Unicode (for Thai, well it could work with modern texts, but for > Devanagari, it's impossible without additional data for mapping the > contextual glyphs): there's still no specification in SVG fonts for > "features" like in OpenType, AAT and Graphite. In addition, the DOM > API for SVG fonts is not accessible in a documented way (only "opaque" > interfaces are available; you have to rely to the XML DOM instead). > > There are tricks to support Devanagari with Type1 fonts, but this > requires integratinf additional Postscript routines, specific to the > PostScript engine, to keep context variables in some accessible global > directory, such as the device context, normally not made for that, or > by self modifying the font's directory (such trick is used to generate > some Barcode fonts; font tools generally provide no help to integrate > those routines). > > But you may want to create a composite font, in which case a SVG font > can be built that combines two existing OpenType fonts (without > modifying them and without importing or converting their glyph > definitions), grouped under a single family-name and usable on the web > for CSS. Of you can do that with CSS "@font{ ...}", for later use of > the new family in a stylesheet or in HTML. > > -- Philippe -- > > 2011/9/6 li bo <[email protected]>: > > I'd like to implement the combination of thai and decanagrari scripts > using > > vector font. But I have no idea about it. How do i adjust the position > of > > the combined glyph? Could anyone give some advices or references? Thanks > a > > lot! > > >
