add extract txt with page example

examples/extract_txt_with_page.rs

@@ -0,0 +1,98 @@
+use std::{cell::RefCell, collections::HashMap, env, fmt, rc::Rc};
+
+use lopdf::Document;
+use pdf_extract::{ConvertToFmt, OutputDev, OutputError, PlainTextOutput};
+
+fn main() {
+    let file = env::args().nth(1).unwrap();
+    let doc = Document::load(file).unwrap();
+    let mut output = PagePlainTextOutput::new();
+    pdf_extract::output_doc(&doc, &mut output).unwrap();
+
+    // print the text of each page
+    for (page_num, text) in output.pages {
+        println!("Page {}: {}", page_num, text);
+    }
+}
+
+struct PagePlainTextOutput {
+    inner: PlainTextOutput<OutputWarpper>,
+    pages: HashMap<u32, String>,
+    current_page: u32,
+    reader: Rc<RefCell<String>>,
+}
+
+struct OutputWarpper(Rc<RefCell<String>>);
+
+impl std::fmt::Write for OutputWarpper {
+    fn write_str(&mut self, s: &str) -> std::fmt::Result {
+        self.0.borrow_mut().write_str(s).map_err(|_| fmt::Error)
+    }
+}
+
+impl ConvertToFmt for OutputWarpper {
+    type Writer = OutputWarpper;
+
+    fn convert(self) -> Self::Writer {
+        self
+    }
+}
+
+impl PagePlainTextOutput {
+    fn new() -> Self {
+        let s = Rc::new(RefCell::new(String::new()));
+        let writer = Rc::clone(&s);
+        Self {
+            pages: HashMap::new(),
+            current_page: 0,
+            reader: s,
+            inner: PlainTextOutput::new(OutputWarpper(writer)),
+        }
+    }
+}
+
+impl OutputDev for PagePlainTextOutput {
+    fn begin_page(
+        &mut self,
+        page_num: u32,
+        media_box: &pdf_extract::MediaBox,
+        art_box: Option<(f64, f64, f64, f64)>,
+    ) -> Result<(), OutputError> {
+        self.current_page = page_num;
+        self.inner.begin_page(page_num, media_box, art_box)
+    }
+
+    fn end_page(&mut self) -> Result<(), OutputError> {
+        self.inner.end_page()?;
+
+        let buf = self.reader.borrow().clone();
+        self.pages.insert(self.current_page, buf);
+        self.reader.borrow_mut().clear();
+
+        Ok(())
+    }
+
+    fn output_character(
+        &mut self,
+        trm: &pdf_extract::Transform,
+        width: f64,
+        spacing: f64,
+        font_size: f64,
+        char: &str,
+    ) -> Result<(), OutputError> {
+        self.inner
+            .output_character(trm, width, spacing, font_size, char)
+    }
+
+    fn begin_word(&mut self) -> Result<(), OutputError> {
+        self.inner.begin_word()
+    }
+
+    fn end_word(&mut self) -> Result<(), OutputError> {
+        self.inner.end_word()
+    }
+
+    fn end_line(&mut self) -> Result<(), OutputError> {
+        self.inner.end_line()
+    }
+}