Add option to center all text, and display encryption time by default

.gitignore

@@ -9,3 +9,4 @@
 test-output.json
 /visual-snapshots
 *.profraw
+.idea/

Cargo.toml

@@ -30,6 +30,7 @@ printpdf = { version = "0.5.3", features = ["svg"] }
 qrcode = "0.12.0"
 log = "0.4"
 env_logger = "0.10"
+chrono = "0.4.28"
 
 [dev-dependencies]
 assert_cmd = "2.0"

src/builder.rs

@@ -1,5 +1,6 @@
 //! PaperAge
 use std::io::{BufReader, Cursor};
+use chrono::Local;
 
 use printpdf::{
     Color, IndirectFontRef, Line, LineDashPattern, Mm, PdfDocument, PdfDocumentReference,
@@ -13,6 +14,9 @@ pub mod svg;
 /// PaperAge version
 pub const VERSION: Option<&str> = option_env!("CARGO_PKG_VERSION");
 
+/// Font width / height = 3 / 5
+pub const FONT_RATIO: f64 = 3.0 / 5.0;
+
 /// Container for all the data required to insert elements into the PDF
 pub struct Document {
     /// A reference to the printpdf PDF document
@@ -69,17 +73,25 @@ impl Document {
         self.doc.get_page(self.page).get_layer(self.layer)
     }
 
+    /// Calculate the left margin when text is centered
+    fn calc_center_margin(&self, font_size: f64, text_length: usize) -> Mm {
+        let text_width = font_size * FONT_RATIO * text_length as f64;
+        (self.page_size.dimensions().width - Mm::from(Pt(text_width))) / 2.0
+    }
+
     /// Insert the given title at the top of the PDF
-    pub fn insert_title_text(&self, title: String) {
+    pub fn insert_title_text(&self, title: String, center: bool) {
         debug!("Inserting title: {}", title.as_str());
 
         let current_layer = self.get_current_layer();
 
         let font_size = 14.0;
 
         // Align the title with the QR code if the title is narrower than the QR code
-        let margin = {
-            if title.len() <= 37 {
+        let left_margin = {
+            if center {
+                self.calc_center_margin(font_size, title.len())
+            } else if title.len() <= 37 {
                 self.page_size.qrcode_left_edge()
             } else {
                 self.page_size.dimensions().margin
@@ -89,7 +101,7 @@ impl Document {
         current_layer.use_text(
             title,
             font_size,
-            margin,
+            left_margin,
             self.page_size.dimensions().height
                 - self.page_size.dimensions().margin
                 - Mm::from(Pt(font_size)),
@@ -98,7 +110,7 @@ impl Document {
     }
 
     /// Insert the given PEM ciphertext in the bottom half of the page
-    pub fn insert_pem_text(&self, pem: String) {
+    pub fn insert_pem_text(&self, pem: String, center: bool) {
         debug!("Inserting PEM encoded ciphertext");
 
         let current_layer = self.get_current_layer();
@@ -123,8 +135,14 @@ impl Document {
 
         current_layer.begin_text_section();
 
+        let left_margin = if center {
+            self.calc_center_margin(font_size, 64)
+        } else {
+            self.page_size.dimensions().margin
+        };
+
         current_layer.set_text_cursor(
-            self.page_size.dimensions().margin,
+            left_margin,
             (self.page_size.dimensions().height / 2.0)
                 - Mm::from(Pt(font_size))
                 - self.page_size.dimensions().margin,
@@ -238,49 +256,70 @@ impl Document {
         current_layer.add_shape(divider);
     }
 
-    /// Insert the passphrase label and placeholder in the PDF
-    pub fn insert_passphrase(&self) {
+    /// Insert the time or passphrase field in the PDF
+    pub fn insert_time_or_passphrase(&self, passphrase_field: bool, center: bool) {
         debug!("Inserting passphrase placeholder");
 
         let current_layer = self.get_current_layer();
 
-        let baseline =
-            self.page_size.dimensions().height / 2.0 + self.page_size.dimensions().margin;
+        let font_size = 13.0;
+        let baseline = self.page_size.dimensions().height / 2.0 + self.page_size.dimensions().margin;
+        let text = if passphrase_field { "Passphrase: ".to_string() } else {
+            Local::now()
+                .format("Encrypted at %Y-%m-%d %H:%M:%S")
+                .to_string()
+        };
+
+        let left_margin = if center && !passphrase_field {
+            self.calc_center_margin(font_size, text.len())
+        } else {
+            self.page_size.qrcode_left_edge()
+        };
 
         current_layer.use_text(
-            "Passphrase: ",
-            13.0,
-            self.page_size.qrcode_left_edge(),
+            text,
+            font_size,
+            left_margin,
             baseline,
             &self.title_font,
         );
 
-        self.draw_line(
-            vec![
-                Point::new(
-                    self.page_size.qrcode_left_edge() + Mm(30.0),
-                    baseline - Mm(1.0),
-                ),
-                Point::new(
-                    self.page_size.qrcode_left_edge() + self.page_size.qrcode_size(),
-                    baseline - Mm(1.0),
-                ),
-            ],
-            1.0,
-            LineDashPattern::default(),
-        )
+        if passphrase_field {
+            self.draw_line(
+                vec![
+                    Point::new(
+                        self.page_size.qrcode_left_edge() + Mm(30.0),
+                        baseline - Mm(1.0),
+                    ),
+                    Point::new(
+                        self.page_size.qrcode_left_edge() + self.page_size.qrcode_size(),
+                        baseline - Mm(1.0),
+                    ),
+                ],
+                1.0,
+                LineDashPattern::default(),
+            )
+        }
     }
 
     /// Add the footer at the bottom of the page
-    pub fn insert_footer(&self) {
+    pub fn insert_footer(&self, center: bool) {
         debug!("Inserting footer");
 
         let current_layer = self.get_current_layer();
+        let text = "Scan QR code and decrypt using Age <https://age-encryption.org>";
+        let font_size = 13.0;
+
+        let left_margin = if center {
+            self.calc_center_margin(font_size, text.len())
+        } else {
+            self.page_size.dimensions().margin
+        };
 
         current_layer.use_text(
-            "Scan QR code and decrypt using Age <https://age-encryption.org>",
-            13.0,
-            self.page_size.dimensions().margin,
+            text,
+            font_size,
+            left_margin,
             self.page_size.dimensions().margin,
             &self.title_font,
         );

src/cli.rs

@@ -22,6 +22,14 @@ pub struct Args {
     #[arg(short = 's', long, default_value_t = PageSize::A4)]
     pub page_size: PageSize,
 
+    /// Center all text
+    #[arg(short, long, default_value_t = false)]
+    pub center: bool,
+
+    /// Display passphrase field instead of time
+    #[arg(short = 'P', long, default_value_t = false)]
+    pub passphrase_field: bool,
+
     /// Overwrite the output file if it already exists
     #[arg(short, long, default_value_t = false)]
     pub force: bool,

src/main.rs

@@ -94,7 +94,7 @@ fn main() -> Result<(), Box<dyn std::error::Error>> {
         pdf.draw_grid();
     }
 
-    pdf.insert_title_text(args.title);
+    pdf.insert_title_text(args.title, args.center);
 
     match pdf.insert_qr_code(encrypted.clone()) {
         Ok(()) => (),
@@ -109,7 +109,7 @@ fn main() -> Result<(), Box<dyn std::error::Error>> {
         }
     }
 
-    pdf.insert_passphrase();
+    pdf.insert_time_or_passphrase(args.passphrase_field, args.center);
 
     pdf.draw_line(
         vec![
@@ -123,9 +123,9 @@ fn main() -> Result<(), Box<dyn std::error::Error>> {
         },
     );
 
-    pdf.insert_pem_text(encrypted);
+    pdf.insert_pem_text(encrypted, args.center);
 
-    pdf.insert_footer();
+    pdf.insert_footer(args.center);
 
     if output == PathBuf::from("-") {
         debug!("Writing to STDOUT");