Julian Mutter
78bc8b1e64
Improve performance by not caching pages which would have to be removed from cache anyways
74 lines
2.3 KiB
Rust
74 lines
2.3 KiB
Rust
use std::rc::Rc;
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use cairo::{Context, ImageSurface};
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use glib::Bytes;
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use gtk::gdk::Texture;
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use log::debug;
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use poppler::Page;
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pub fn draw_pages_to_texture(pages: &[Rc<Page>], area_height: i32) -> Texture {
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let area_height = i32::max(100, area_height);
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let total_width_normalized: f64 = pages
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.iter()
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.map(|page| page.size())
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.map(|(w, h)| w / h)
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.sum();
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let area_width = (total_width_normalized * area_height as f64 + 0.5) as i32;
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let surface = ImageSurface::create(cairo::Format::Rgb24, area_width, area_height).unwrap();
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let context = Context::new(&surface).unwrap();
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draw_pages(pages, &context, area_width, area_height);
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let mut stream: Vec<u8> = Vec::new();
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surface.write_to_png(&mut stream).unwrap();
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Texture::from_bytes(&Bytes::from(&stream)).unwrap()
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}
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fn draw_pages(pages: &[Rc<Page>], context: &Context, area_width: i32, area_height: i32) {
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if pages.is_empty() {
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return;
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}
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let area_width = area_width as f64;
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let area_height = area_height as f64;
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// Total width if height of every page was 1
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let total_width_normalized: f64 = pages
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.iter()
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.map(|page| page.size())
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.map(|(w, h)| w / h)
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.sum();
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// let height_to_scale_to = f64::min(area_width / total_width_normalized, area_height);
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let height_to_scale_to = area_height;
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let total_width = total_width_normalized * height_to_scale_to;
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context.set_source_rgba(1.0, 1.0, 1.0, 1.0);
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context.translate(
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(area_width - total_width) / 2.0,
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(area_height - height_to_scale_to) / 2.0,
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);
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context.save().unwrap();
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for page in pages {
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let (page_width, page_height) = page.size();
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let scale = height_to_scale_to / page_height;
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let scaled_width = page_width * scale;
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debug!(
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"drawing with size: {}, {}",
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scaled_width, height_to_scale_to
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);
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// context.translate(total_width_of_rendered_pages, 0.0);
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// Poppler sometimes crops white border, draw it manually
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context.rectangle(0.0, 0.0, scaled_width, height_to_scale_to);
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context.fill().unwrap();
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context.scale(scale, scale);
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page.render(context);
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context.restore().unwrap();
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context.translate(scaled_width, 0.0);
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context.save().unwrap();
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}
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}
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