mirror of
https://github.com/storytold/pdfcraft.git
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60 lines
2.5 KiB
Rust
60 lines
2.5 KiB
Rust
//! Pictures placed on pages: added images, and the pictures of watermarks and backgrounds.
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use std::sync::Arc;
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use crate::EditError;
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/// A picture for a watermark or background (Acrobat: Source ▸ File): an image, or `page`
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/// (0-based) of a PDF.
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#[derive(Clone, Debug, PartialEq)]
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pub struct MarkFile {
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pub name: String,
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pub bytes: Arc<Vec<u8>>,
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pub page: usize,
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}
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/// Embed an image that is placed on a page, turned the way its EXIF Orientation says.
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pub(crate) fn embed_image(
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doc: &mut pdfcraft_cos::Document,
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name: &str,
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bytes: &[u8],
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) -> Result<(pdfcraft_cos::ObjRef, (f64, f64)), pdfcraft_create::CreateError> {
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pdfcraft_create::image_xobject(doc, name, bytes)
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}
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/// The largest box of `w`:`h` shape inside `rect`, centred in it: a stamp's picture keeps its
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/// shape in a box of any other shape. A box that is already that shape (to within rounding) is
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/// kept exactly, so callers that size it themselves get their box back. An empty or non-finite
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/// box, or a picture with no size, is returned as it is, for the annotation's own check to refuse.
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pub(crate) fn fit_picture(rect: [f64; 4], w: f64, h: f64) -> [f64; 4] {
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if !rect.iter().all(|v| v.is_finite()) {
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return rect;
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}
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let rect = [rect[0].min(rect[2]), rect[1].min(rect[3]), rect[0].max(rect[2]), rect[1].max(rect[3])];
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let (bw, bh) = (rect[2] - rect[0], rect[3] - rect[1]);
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let usable = |v: f64| v.is_finite() && v > 0.0;
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if !(usable(bw) && usable(bh) && usable(w) && usable(h)) {
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return rect;
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}
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let k = (bw / w).min(bh / h);
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let (fw, fh) = (w * k, h * k);
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if (fw - bw).abs() <= bw * 1e-9 && (fh - bh).abs() <= bh * 1e-9 {
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return rect;
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}
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let (cx, cy) = (rect[0] + bw / 2.0, rect[1] + bh / 2.0);
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[cx - fw / 2.0, cy - fh / 2.0, cx + fw / 2.0, cy + fh / 2.0]
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}
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/// Bring a mark's picture into `doc`: a PDF page as a form XObject, or an image.
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pub(crate) fn mark_source(doc: &mut pdfcraft_cos::Document, f: &MarkFile) -> Result<pdfcraft_edit::MarkSource, EditError> {
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let head = &f.bytes[..f.bytes.len().min(1024)];
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if head.windows(5).any(|w| w == b"%PDF-") {
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let src = pdfcraft_cos::Document::open(f.bytes.clone()).map_err(|e| EditError::Source(format!("{}: {e}", f.name)))?;
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let (xobject, size) = pdfcraft_organize::page_as_form(doc, &src, f.page)?;
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Ok(pdfcraft_edit::MarkSource { xobject, size, image: false })
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} else {
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let (xobject, size) = embed_image(doc, &f.name, &f.bytes)?;
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Ok(pdfcraft_edit::MarkSource { xobject, size, image: true })
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}
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}
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