print: Adjust 100% to SVG physical dimensions

Some SVGs store there size in cm or inch. With this change, the 100% in
the print dialog is calculated according to that physical size.

Closes #141

src/decoder/formats/mod.rs

@@ -25,7 +25,7 @@ use super::{DecoderUpdate, UpdateSender};
 
 #[derive(Clone, Debug, Default)]
 pub enum ImageDimensionDetails {
-    Svg(String),
+    Svg(String, Option<(f64, f64)>),
     #[default]
     None,
 }

src/decoder/formats/svg.rs

@@ -83,7 +83,10 @@ impl Svg {
             let image = image_request.request().await?;
 
             let dimensions = if let Some(string) = image.info().dimensions_text.as_ref() {
-                ImageDimensionDetails::Svg(string.to_string())
+                ImageDimensionDetails::Svg(
+                    string.to_string(),
+                    image.info().dimensions_inch.clone().into(),
+                )
             } else {
                 ImageDimensionDetails::None
             };