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extern crate thiserror; use self::thiserror::Error; use std::ffi::CString; use std::ffi::NulError; use std::str; pub mod plumbing; #[derive(Debug, Error)] pub enum InitializeError { #[error("Conversion to CString failed")] CStringError(#[from] NulError), #[error("TessBaseApi failed to initialize")] TessBaseAPIInitError(#[from] plumbing::TessBaseAPIInitError), } #[derive(Debug, Error)] pub enum SetImageError { #[error("Conversion to CString failed")] CStringError(#[from] NulError), #[error("Failed to read image")] PixReadError(#[from] plumbing::PixReadError), } #[derive(Debug, Error)] pub enum SetVariableError { #[error("Conversion to CString failed")] CStringError(#[from] NulError), #[error("TessBaseApi failed to set variable")] TessBaseAPISetVariableError(#[from] plumbing::TessBaseAPISetVariableError), } #[derive(Debug, Error)] pub enum TesseractError { #[error("Failed to set language")] InitializeError(#[from] InitializeError), #[error("Failed to set image")] SetImageError(#[from] SetImageError), #[error("Errored whilst recognizing")] RecognizeError(#[from] plumbing::TessBaseAPIRecogniseError), #[error("Errored whilst getting text")] GetTextError(#[from] plumbing::TessBaseAPIGetUTF8TextError), #[error("Errored whilst setting frame")] SetFrameError(#[from] plumbing::TessBaseAPISetImageSafetyError), #[error("Errored whilst setting image from mem")] SetImgFromMemError(#[from] plumbing::PixReadMemError), #[error("Errored whilst setting variable")] SetVariableError(#[from] SetVariableError), } pub struct Tesseract(plumbing::TessBaseAPI); impl Tesseract { pub fn new(datapath: Option<&str>, language: Option<&str>) -> Result<Self, InitializeError> { let mut tess = Tesseract(plumbing::TessBaseAPI::new()); let datapath = match datapath { Some(i) => Some(CString::new(i)?), None => None, }; let language = match language { Some(i) => Some(CString::new(i)?), None => None, }; tess.0.init_2(datapath.as_deref(), language.as_deref())?; Ok(tess) } pub fn set_image(mut self, filename: &str) -> Result<Self, SetImageError> { let pix = plumbing::Pix::read(&CString::new(filename)?)?; self.0.set_image_2(&pix); Ok(self) } pub fn set_frame( mut self, frame_data: &[u8], width: i32, height: i32, bytes_per_pixel: i32, bytes_per_line: i32, ) -> Result<Self, plumbing::TessBaseAPISetImageSafetyError> { self.0 .set_image_1(frame_data, width, height, bytes_per_pixel, bytes_per_line)?; Ok(self) } pub fn set_image_from_mem(mut self, img: &[u8]) -> Result<Self, plumbing::PixReadMemError> { let pix = plumbing::Pix::read_mem(img)?; self.0.set_image_2(&pix); Ok(self) } pub fn set_source_resolution(mut self, ppi: i32) -> Self { self.0.set_source_resolution(ppi); self } pub fn set_variable(mut self, name: &str, value: &str) -> Result<Self, SetVariableError> { self.0 .set_variable(&CString::new(name)?, &CString::new(value)?)?; Ok(self) } pub fn recognize(mut self) -> Result<Self, plumbing::TessBaseAPIRecogniseError> { self.0.recognize()?; Ok(self) } pub fn get_text(&mut self) -> Result<String, plumbing::TessBaseAPIGetUTF8TextError> { Ok(self .0 .get_utf8_text()? .as_ref() .to_string_lossy() .into_owned()) } } pub fn ocr(filename: &str, language: &str) -> Result<String, TesseractError> { Ok(Tesseract::new(None, Some(language))? .set_image(filename)? .recognize()? .get_text()?) } pub fn ocr_from_frame( frame_data: &[u8], width: i32, height: i32, bytes_per_pixel: i32, bytes_per_line: i32, language: &str, ) -> Result<String, TesseractError> { Ok(Tesseract::new(None, Some(language))? .set_frame(frame_data, width, height, bytes_per_pixel, bytes_per_line)? .recognize()? .get_text()?) } #[test] fn ocr_test() -> Result<(), TesseractError> { assert_eq!( ocr("img.png", "eng")?, include_str!("../img.txt").to_string() ); Ok(()) } #[test] fn ocr_from_frame_test() -> Result<(), TesseractError> { assert_eq!( ocr_from_frame(include_bytes!("../img.tiff"), 2256, 324, 3, 2256 * 3, "eng")?, include_str!("../img.txt").to_string() ); Ok(()) } #[test] fn ocr_from_mem_with_ppi() -> Result<(), TesseractError> { let mut cube = Tesseract::new(None, Some("eng"))? .set_image_from_mem(include_bytes!("../img.tiff"))? .set_source_resolution(70); assert_eq!(&cube.get_text()?, include_str!("../img.txt")); Ok(()) } #[test] fn expanded_test() -> Result<(), TesseractError> { let mut cube = Tesseract::new(None, Some("eng"))? .set_image("img.png")? .set_variable("tessedit_char_blacklist", "z")? .recognize()?; assert_eq!(&cube.get_text()?, include_str!("../img.txt")); Ok(()) }