mirror of
https://github.com/storytold/pdfcraft.git
synced 2026-10-31 13:37:35 -06:00
aiongg
77480498b2
Pages printed as pictures were drawn with everything on them, so form fields only printed the page content, and the document with stamps printed every comment. The pictures are drawn from a copy holding only what the vector print draws.
70 lines
3.7 KiB
Rust
70 lines
3.7 KiB
Rust
//! Print as image (Acrobat's Advanced Print Setup ▸ Print As Image): every page
|
|
//! sent to the printer as a picture at a chosen resolution, for printers that skip text,
|
|
//! shading or transparency. The pages are rendered the way the viewer shows them (reading
|
|
//! colours off, the print's own colours) with only what the print's content choice keeps, made
|
|
//! into an image-only document, and that document is imposed on the paper like any other. The
|
|
//! print is no longer searchable text.
|
|
|
|
use pdfcraft_cos::{SaveOptions, write_incremental};
|
|
use pdfcraft_create::ImageResolution;
|
|
use pdfcraft_print::{Content, Raster};
|
|
use pdfcraft_render::{PRINT_TAG, PageRenderer, RenderRequest};
|
|
|
|
use crate::export::encode_png;
|
|
use crate::{Document, guard};
|
|
|
|
/// `doc`'s pages `pages` (0-based, each once, in the order given) as an image-only PDF, one
|
|
/// page per entry, the size of the source page as displayed, drawing what `content` prints.
|
|
/// Pages too large for the renderer at `raster.dpi` render at the largest resolution it allows.
|
|
pub fn rasterize(doc: &Document, pages: &[usize], raster: &Raster, content: Content) -> Result<Vec<u8>, String> {
|
|
let dpi = raster.dpi.clamp(72.0, 600.0);
|
|
let src = doc.export_source();
|
|
let mut config = src.config.clone();
|
|
// The copy below holds only what prints, so the viewer's own comment hiding plays no part.
|
|
config.hide_comments = false;
|
|
let printed = guard(|| -> Result<Vec<u8>, String> {
|
|
let mut cos = pdfcraft_cos::Document::open_with_password(src.bytes.clone(), config.password.as_deref()).map_err(|e| e.to_string())?;
|
|
pdfcraft_print::keep_printed(&mut cos, content);
|
|
write_incremental(&cos, &SaveOptions::default()).map_err(|e| e.to_string())
|
|
})??;
|
|
let mut renderer = PageRenderer::new(std::sync::Arc::new(printed), config);
|
|
let mut images: Vec<(String, Vec<u8>)> = Vec::with_capacity(pages.len());
|
|
let mut used: Option<f64> = None;
|
|
for &page in pages {
|
|
let (w, h) = src.sizes.get(page).copied().ok_or_else(|| format!("page {} does not exist", page + 1))?;
|
|
let scale = pdfcraft_render::effective_scale(w, h, (dpi / 72.0) as f32);
|
|
let page_dpi = f64::from(scale) * 72.0;
|
|
// Every page of the image document shares one resolution, so its pages keep the
|
|
// source's sizes; the lowest a page needed is used for all.
|
|
used = Some(used.map_or(page_dpi, |u: f64| u.min(page_dpi)));
|
|
let r = renderer.render(RenderRequest { page, scale, tag: PRINT_TAG, ..Default::default() });
|
|
if let Some(e) = r.error {
|
|
return Err(format!("page {}: {e}", page + 1));
|
|
}
|
|
let mut rgba = r.rgba.to_vec();
|
|
over_white(&mut rgba, raster.grayscale);
|
|
images.push((format!("page-{}.png", page + 1), encode_png(r.width, r.height, &rgba)?));
|
|
}
|
|
let dpi = used.unwrap_or(dpi);
|
|
let doc = pdfcraft_create::from_images_with_resolution(&images, ImageResolution::Dpi(dpi)).map_err(|e| e.to_string())?;
|
|
pdfcraft_cos::write_full(&doc, &pdfcraft_cos::SaveOptions::default()).map_err(|e| e.to_string())
|
|
}
|
|
|
|
/// Premultiplied RGBA composed over white paper (opaque), in grey when asked (Rec. 601 luma).
|
|
fn over_white(rgba: &mut [u8], grayscale: bool) {
|
|
for px in rgba.as_chunks_mut::<4>().0 {
|
|
let gap = 255 - u32::from(px[3]);
|
|
let (r, g, b) = ((u32::from(px[0]) + gap).min(255), (u32::from(px[1]) + gap).min(255), (u32::from(px[2]) + gap).min(255));
|
|
let (r, g, b) = if grayscale {
|
|
let y = ((299 * r + 587 * g + 114 * b) / 1000).min(255);
|
|
(y, y, y)
|
|
} else {
|
|
(r, g, b)
|
|
};
|
|
px[0] = r as u8;
|
|
px[1] = g as u8;
|
|
px[2] = b as u8;
|
|
px[3] = 255;
|
|
}
|
|
}
|