diff options
Diffstat (limited to 'src/lib.rs')
| -rw-r--r-- | src/lib.rs | 185 |
1 files changed, 164 insertions, 21 deletions
@@ -13,6 +13,7 @@ use std::str; use bitflags::_core::str::from_utf8; +use lopdf::content::{Content, Operation}; use lopdf::{Document, Object, ObjectId, StringFormat}; use crate::utils::*; @@ -135,18 +136,31 @@ impl Form { Self::load_doc(doc) } - fn load_doc(doc: Document) -> Result<Self, LoadError> { + fn load_doc(mut doc: Document) -> Result<Self, LoadError> { let mut form_ids = Vec::new(); let mut queue = VecDeque::new(); // Block so borrow of doc ends before doc is moved into the result { - // Get the form's top level fields - let catalog = doc.trailer.get(b"Root")?.deref(&doc)?.as_dict()?; - let acroform = catalog.get(b"AcroForm")?.deref(&doc)?.as_dict()?; - let fields_list = acroform - .get(b"Fields")? - // .deref(&doc)? - .as_array()?; + doc.decompress(); + + let acroform = doc + .objects + .get_mut( + &doc.trailer + .get(b"Root")? + .deref(&doc)? + .as_dict()? + .get(b"AcroForm")? + .as_reference()?, + ) + .ok_or(LoadError::NotAReference)? + .as_dict_mut()?; + + // Sets the NeedAppearances option to true into "AcroForm" in order + // to render fields correctly + // acroform.set("NeedAppearances", Object::Boolean(true)); + + let fields_list = acroform.get(b"Fields")?.as_array()?; queue.append(&mut VecDeque::from(fields_list.clone())); // Iterate over the fields @@ -423,8 +437,10 @@ impl Form { .as_dict_mut() .unwrap(); - field.set("V", Object::String(s.into_bytes(), StringFormat::Literal)); - field.remove(b"AP"); + field.set("V", Object::string_literal(s.into_bytes())); + + // Regenerate text appearance confoming the new text but ignore the result + let _ = self.regenerate_text_appearance(n); Ok(()) } @@ -432,6 +448,137 @@ impl Form { } } + /// Regenerates the appearance for the field at index `n` due to an alteration of the + /// original TextField value, the AP will be updated accordingly. + /// + /// # Incomplete + /// This function is not exhaustive as not parse the original TextField orientation + /// or the text alignment and other kind of enrichments, also doesn't discover for + /// the global document DA. + /// + /// A more sophisticated parser is needed here + fn regenerate_text_appearance(&mut self, n: usize) -> Result<(), lopdf::Error> { + let field = { + self.doc + .objects + .get(&self.form_ids[n]) + .unwrap() + .as_dict() + .unwrap() + }; + + // The value of the object (should be a string) + let value = field.get(b"V")?.to_owned(); + + // The default appearance of the object (should be a string) + let da = field.get(b"DA")?.to_owned(); + + // The default appearance of the object (should be a string) + let rect = field + .get(b"Rect")? + .as_array()? + .iter() + .map(|object| { + object + .as_f64() + .unwrap_or(object.as_i64().unwrap_or(0) as f64) + }) + .collect::<Vec<_>>(); + + // Gets the object stream + let object_id = field.get(b"AP")?.as_dict()?.get(b"N")?.as_reference()?; + let stream = self.doc.get_object_mut(object_id)?.as_stream_mut()?; + + // Decode and get the content, even if is compressed + let mut content = { + if let Ok(content) = stream.decompressed_content() { + Content::decode(&content)? + } else { + Content::decode(&stream.content)? + } + }; + + // Ignored operators + let ignored_operators = vec![ + "bt", "tc", "tw", "tz", "g", "tr", "tf", "tj", "et", "q", "bmc", "emc", + ]; + + // Remove these ignored operators as we have to generate the text and fonts again + content.operations.retain(|operation| { + !ignored_operators.contains(&operation.operator.to_lowercase().as_str()) + }); + + // Let's construct the text widget + content.operations.append(&mut vec![ + Operation::new("BMC", vec!["Tx".into()]), + Operation::new("q", vec![]), + Operation::new("BT", vec![]), + ]); + + // The default font object (/Helv 12 Tf 0 g) + let default_font = ("Helv", 12, 0, "g"); + + // Build the font basing on the default appearance, if exists, if not, + // assume a default font (surely to be improved!) + let font = match da { + Object::String(ref bytes, _) => { + let values = from_utf8(bytes)? + .trim_start_matches('/') + .split(' ') + .collect::<Vec<_>>(); + + if values.len() != 5 { + default_font + } else { + ( + values[0], + values[1].parse::<i32>().unwrap_or(0), + values[3].parse::<i32>().unwrap_or(0), + values[4], + ) + } + } + _ => default_font, + }; + + // Define some helping font variables + let font_name = font.0; + let font_size = font.1; + let font_color = (font.2, font.3); + + // Set the font type and size and color + content.operations.append(&mut vec![ + Operation::new("Tf", vec![font_name.into(), font_size.into()]), + Operation::new(font_color.1, vec![font_color.0.into()]), + ]); + + // Calcolate the text offset + let x = 3.0; // Suppose this fixed offset as we should have known the border here + let y = 0.5 * (rect[3] - rect[1]) - 0.4 * font_size as f64; // Formula picked up from Poppler + + // Set the text bounds, first are fixed at "1 0 0 1" and then the calculated x,y + content.operations.append(&mut vec![Operation::new( + "Tm", + vec![1.into(), 0.into(), 0.into(), 1.into(), x.into(), y.into()], + )]); + + // Set the text value and some finalizing operations + content.operations.append(&mut vec![ + Operation::new("Tj", vec![value]), + Operation::new("ET", vec![]), + Operation::new("Q", vec![]), + Operation::new("EMC", vec![]), + ]); + + // Set the new content to the original stream and compress it + if let Ok(encoded_content) = content.encode() { + stream.set_plain_content(encoded_content); + let _ = stream.compress(); + } + + Ok(()) + } + /// If the field at index `n` is a checkbox field, toggles the check box based on the value /// `is_checked`. /// If it is not a checkbox field, returns ValueError @@ -441,17 +588,6 @@ impl Form { pub fn set_check_box(&mut self, n: usize, is_checked: bool) -> Result<(), ValueError> { match self.get_state(n) { FieldState::CheckBox { .. } => { - let state = Object::Name( - { - if is_checked { - "Yes" - } else { - "Off" - } - } - .to_owned() - .into_bytes(), - ); let field = self .doc .objects @@ -460,6 +596,13 @@ impl Form { .as_dict_mut() .unwrap(); + let on = get_on_value(field); + let state = Object::Name( + if is_checked { on.as_str() } else { "Off" } + .to_owned() + .into_bytes(), + ); + field.set("V", state.clone()); field.set("AS", state); |