Suggestion: "Text Rendering Mode" options

[DIV]

Hi, PDF-XChange staff.

I have a suggestion for the options listed in the drop-down menu for "Text Rendering Mode", which are respectively

• Auto
• Bitmap Always
• Bitmap for Embedded Fonts
• Outline Always
• Outline for Embedded Fonts

While I realise that you can define these options to mean whatever you want, I don't think the meaning of "Auto" is at all intuitive.
When I see "Auto", I assume it means: "Let the software choose automatically from one of the options listed below".
However, as seen in another topic, "Auto" actually means something that is not covered by any of the other four options. A better name for it could be "Embed available fonts in datastream" or "Send available fonts to printer" or "Preserve text information" or whatever other wording that would be more descriptive of what it actually does.
This will also help avoid the potential misapprehension that "Outline" options refer to the original font outlines (which would be a natural — albeit incorrect — conclusion based on some conventions regarding the term "outline"). Actually the "Outline" options refer rather to ad hoc SVG approximations (as distinct from raster approximations, in the case of the "Bitmap" options).

Regards,
David

[Timur Born]

I stumbled over the same roadblock several months ago, especially since the default setting is not "Auto" but "Outline".

[DIV]

One further thought:
I wonder what happens with fonts that aren't available.
The "Auto" setting could send fonts that were embedded in the PDF and/or installed on the user's computer, but what about fonts 'marked' in the PDF but not embedded nor installed?
I haven't investigated this, with "Auto" selected, but I guess the possibilities would be:

• respect the idea of treating the writing as text rather than graphics, and therefore send an 'equivalent' font to the printer
• fall back on SVG "outline" graphics (but based on what shape definition?)
• fall back on raster bitmap graphics (but based on what shape definition?)

To obtain an 'equivalent' font I can think of two potential possibilities:
1. if a meaningful font name is stored in the PDF, search somewhere (within a small local database for common fonts, or online for less common [but not 'rare'] fonts) to discover its basic characteristics; then substitute a suitable font from a local lookup table and/or by checking basic characteristics of each installed font.
2. if the basic font characteristics are stored within the PDF itself, then substitute a suitable font from a local lookup table and/or by checking basic characteristics of each installed font.

By "basic font characteristics" I am talking about the 'header' information in most modern computer fonts that specifies characteristic properties such as whether the font is categorised as "serif" or "sans serif", using the PANOSE system. Possibly some other header information such as glyph bounding box dimensions could be relevant, but this is getting further outside my area of expertise.

With "lookup table" I mean that the software could specify something like:
* if the missing font is a "serif" style, then try to find "Times" on the user's system; if that's missing then try the following ...
* if the missing font is a "sans serif" style, then try to find "Helvetica" on the user's system; if that's missing then try the following ...

—David

P.S. Timur, I saw a few of your earlier posts, and you've definitely looked into quite a few of those details before me....

[Tracker Supp-Stefan]

Hi David,

When a font is used inside a PDF file but is not embedded nor installed on the machine - we will indeed use a substitute font for displaying that part of the PDF page content.
You are quite right that a more generic serif and non serif fonts are chosen and used, and while I've not tested that for printing - I would assume that the same substitute font will be used for the printing process as well - so it will be sent straight out from the Windows\Fonts to the printer - and any such fonts will therefore effectively behave as other non embedded fonts for which you have a copy of the font installed locally.

Regards,
Stefan