Return the svg document including the svg data and the range covered.

Closes #108

examples/font2svg.rs

@@ -156,7 +156,7 @@ fn process(args: Args) -> Result<(), Box<dyn std::error::Error>> {
                 buf.extend_from_slice(b"data:image/svg+xml;base64, ");
 
                 let mut enc = base64::write::EncoderWriter::new(buf, base64::STANDARD);
-                enc.write_all(img).unwrap();
+                enc.write_all(img.data).unwrap();
                 enc.finish().unwrap();
             });
             svg.end_element();

src/lib.rs

@@ -2057,7 +2057,7 @@ impl<'a> Face<'a> {
     /// Also, a font can contain both: images and outlines. So when this method returns `None`
     /// you should also try `outline_glyph()` afterwards.
     #[inline]
-    pub fn glyph_svg_image(&self, glyph_id: GlyphId) -> Option<&'a [u8]> {
+    pub fn glyph_svg_image(&self, glyph_id: GlyphId) -> Option<svg::SvgDocument<'a>> {
         self.tables.svg.and_then(|svg| svg.documents.find(glyph_id))
     }
 

src/tables/svg.rs

@@ -3,6 +3,17 @@
 use crate::parser::{FromData, LazyArray16, NumFrom, Offset, Offset32, Stream};
 use crate::GlyphId;
 
+#[derive(Debug, Clone, Copy)]
+/// An SvgDocument can include multi glyphs
+pub struct SvgDocument<'a> {
+    /// The SVG document data.The detail of data can see https://learn.microsoft.com/en-us/typography/opentype/spec/svg#svg-document-list
+    pub data: &'a [u8],
+    /// The first glyph ID for the range covered by this record.
+    pub start_glyph_id: GlyphId,
+    /// The last glyph ID for the range covered by this record.
+    pub end_glyph_id: GlyphId,
+}
+
 #[derive(Clone, Copy)]
 struct SvgDocumentRecord {
     start_glyph_id: GlyphId,
@@ -39,16 +50,21 @@ impl<'a> SvgDocumentsList<'a> {
     ///
     /// `index` is not a GlyphId. You should use [`find()`](SvgDocumentsList::find) instead.
     #[inline]
-    pub fn get(&self, index: u16) -> Option<&'a [u8]> {
+    pub fn get(&self, index: u16) -> Option<SvgDocument<'a>> {
         let record = self.records.get(index)?;
         let offset = record.svg_doc_offset?.to_usize();
         self.data
             .get(offset..offset + usize::num_from(record.svg_doc_length))
+            .map(|data| SvgDocument {
+                data,
+                start_glyph_id: record.start_glyph_id,
+                end_glyph_id: record.end_glyph_id,
+            })
     }
 
     /// Returns a SVG document data by glyph ID.
     #[inline]
-    pub fn find(&self, glyph_id: GlyphId) -> Option<&'a [u8]> {
+    pub fn find(&self, glyph_id: GlyphId) -> Option<SvgDocument<'a>> {
         let index = self
             .records
             .into_iter()
@@ -74,7 +90,7 @@ impl core::fmt::Debug for SvgDocumentsList<'_> {
 }
 
 impl<'a> IntoIterator for SvgDocumentsList<'a> {
-    type Item = &'a [u8];
+    type Item = SvgDocument<'a>;
     type IntoIter = SvgDocumentsListIter<'a>;
 
     #[inline]
@@ -95,7 +111,7 @@ pub struct SvgDocumentsListIter<'a> {
 }
 
 impl<'a> Iterator for SvgDocumentsListIter<'a> {
-    type Item = &'a [u8];
+    type Item = SvgDocument<'a>;
 
     #[inline]
     fn next(&mut self) -> Option<Self::Item> {