Struct InterpreterSettings

pub struct InterpreterSettings {
    pub font_resolver: FontResolverFn,
    pub warning_sink: WarningSinkFn,
}

Settings that should be applied during the interpretation process.

Fields

font_resolver: FontResolverFn

Nearly every PDF contains text. In most cases, PDF files embed the fonts they use, and hayro can therefore read the font files and do all the processing needed. However, there are two problems:

• Fonts don’t have to be embedded, it’s possible that the PDF file only defines the basic metadata of the font, like its name, but relies on the PDF processor to find that font in its environment.
• The PDF specification requires a list of 14 fonts that should always be available to a PDF processor. These include:
  • Times New Roman (Normal, Bold, Italic, BoldItalic)
  • Courier (Normal, Bold, Italic, BoldItalic)
  • Helvetica (Normal, Bold, Italic, BoldItalic)
  • ZapfDingBats
  • Symbol

Because of this, if any of the above situations occurs, this callback will be called, which expects the data of an appropriate font to be returned, if available. If no such font is provided, the text will most likely fail to render.

For the font data, there are two different formats that are accepted:

• Any valid TTF/OTF font.
• A valid CFF font program.

The following recommendations are given for the implementation of this callback function.

For the standard fonts, in case the original fonts are available on the system, you should just return those. Otherwise, for Helvetica, Courier and Times New Roman, the best alternative are the corresponding fonts of the Liberation font family. If you prefer smaller fonts, you can use the Foxit CFF fonts, which are much smaller but are missing glyphs for certain scripts.

For the Symbol and ZapfDingBats fonts, you should also prefer the system fonts, and if not available to you, you can, similarly to above, use the corresponding fonts from Foxit.

warning_sink: WarningSinkFn

In certain cases, hayro will emit a warning in case an issue was encountered while interpreting the PDF file. Providing a callback allows you to catch those warnings and handle them, if desired.

Trait Implementations

impl Clone for InterpreterSettings

fn clone(&self) -> InterpreterSettings

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Default for InterpreterSettings

fn default() -> Self

Returns the “default value” for a type.