fix(render): emit clip-only text (7 Tr) to devices for text extraction (#3109)

This commit is contained in:
jonathanwxh-cell
2026-10-18 08:16:58 +08:00
parent 3f5a784c2c
commit d7b4d576a1
2 changed files with 74 additions and 0 deletions
+64
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@@ -1740,6 +1740,70 @@ mod tests {
}
}
/// Issue #3109: text drawn in clipping mode (`7 Tr`) sets the clip for a subsequent fill,
/// shading or image without painting the glyphs directly, and must still reach `TextDevice`
/// with the same boxes and search ranges as modes 0–6.
#[test]
fn clipping_mode_text_is_extracted_and_searchable_like_other_rendering_modes() {
let fill_through = " 0 0 1 rg 0 0 300 300 re f";
let mut pages: Vec<String> =
(0..=7).map(|mode| format!("q BT /F1 24 Tf {mode} Tr 72 150 Td () Tj [(Hello) -200 (World)] TJ ET{fill_through} Q")).collect();
// Page 8: /ActualText wrapping 7 Tr clip-only text.
pages.push(format!("q /Span <</ActualText (Hello World)>> BDC BT /F1 24 Tf 7 Tr 72 150 Td (Glyphs) Tj ET EMC{fill_through} Q"));
// Page 9: 0 Tr underpainting followed by 7 Tr at the same position (outline/gradient overlay) deduplicates.
pages.push(format!("BT /F1 24 Tf 0 Tr 72 150 Td (Hello World) Tj ET q BT /F1 24 Tf 7 Tr 72 150 Td (Hello World) Tj ET{fill_through} Q"));
// Page 10: 90° turned 7 Tr text.
pages.push(format!("q BT /F1 24 Tf 7 Tr 0 1 -1 0 150 100 Tm (Hello World) Tj ET{fill_through} Q"));
// Page 11: 7 Tr without any fill-through (visually blank, still extractable).
pages.push("BT /F1 24 Tf 7 Tr 72 150 Td (Hello World) Tj ET".into());
let refs: Vec<&str> = pages.iter().map(String::as_str).collect();
let pdf = marked_pages(&refs);
let control = marked_text(&pdf, 0);
assert_eq!(control.plain_text(), "Hello World");
let control_rects = control.line_rects(0..5);
assert_eq!(control_rects.len(), 1);
for mode in 0..=7 {
let text = marked_text(&pdf, mode);
assert_eq!(text.plain_text(), "Hello World", "mode {mode} Tr");
assert_eq!(text.find("hello"), vec![0..5], "mode {mode} Tr");
assert_eq!(text.find_opts("Hello", true, true), vec![0..5], "mode {mode} Tr");
assert_eq!(
text.find_with(|chars| chars.starts_with(&['H', 'e', 'l', 'l', 'o']).then_some(0..5).into_iter().collect()),
vec![0..5],
"mode {mode} Tr"
);
assert_eq!(text.line_rects(0..5), control_rects, "mode {mode} Tr");
assert_eq!(text.glyphs, control.glyphs, "mode {mode} Tr");
}
let actual = marked_text(&pdf, 8);
assert_eq!(actual.plain_text(), "Hello World");
assert_eq!(actual.find("Hello"), vec![0..1]);
let deduped = marked_text(&pdf, 9);
assert_eq!(deduped.plain_text(), "Hello World");
let turned = marked_text(&pdf, 10);
assert_eq!(turned.plain_text(), "Hello World");
assert_eq!(turned.find("World"), vec![6..11]);
let unfilled = marked_text(&pdf, 11);
assert_eq!(unfilled.plain_text(), "Hello World");
// Visual check: page 7 (`7 Tr` + blue fill-through) paints blue only inside the clipped
// glyph outlines, whereas page 11 (`7 Tr` alone) paints no ink at all.
let mut renderer = crate::PageRenderer::new(std::sync::Arc::new(pdf.data().as_ref().to_vec()), crate::RenderConfig::default());
let filled_px = renderer.render(crate::RenderRequest { page: 7, kind: crate::RequestKind::Pixels, scale: 1.0, ..Default::default() });
assert!(filled_px.error.is_none());
let blue_pixels = filled_px.rgba.as_chunks::<4>().0.iter().filter(|p| p[0] < 32 && p[1] < 32 && p[2] > 200).count();
let white_pixels = filled_px.rgba.as_chunks::<4>().0.iter().filter(|p| p[..3] == [255, 255, 255]).count();
assert!(blue_pixels > 50 && white_pixels > 80_000, "blue={blue_pixels}, white={white_pixels}");
let unfilled_px = renderer.render(crate::RenderRequest { page: 11, kind: crate::RequestKind::Pixels, scale: 1.0, ..Default::default() });
assert!(unfilled_px.error.is_none());
assert!(unfilled_px.rgba.as_chunks::<4>().0.iter().all(|p| p[..3] == [255, 255, 255]));
}
/// One page per `(encoding, content)`, in Helvetica (`/F1`).
fn encoded_pages(pages: &[(lopdf::Object, &[u8])]) -> Pdf {
use lopdf::{Document, Object, Stream, dictionary};
+10
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@@ -126,6 +126,16 @@ pub(crate) fn show_glyph<'a>(
}
TextRenderingMode::Clip => {
clip_glyph(ctx, glyph, glyph_transform);
// PdfCraft patch: still call draw_glyph for clip-only text (`7 Tr`), as mode 3 does,
// so text extraction, search and search-redaction see text that is filled through its
// clipping path without rendering devices drawing it directly.
device.draw_glyph(
glyph,
ctx.get().ctm,
glyph_transform,
&get_paint(ctx, false),
&GlyphDrawMode::Invisible,
);
}
TextRenderingMode::FillAndClip => {
clip_glyph(ctx, glyph, glyph_transform);