ladybird/Userland/Applications/PDFViewer/PDFViewer.h
Rodrigo Tobar e87fecf710 LibPDF: Switch to best-effort PDF rendering
The current rendering routine aborts as soon as an error is found during
rendering, which potentially severely limits the contents we show on
screen. Moreover, whenever an error happens the PDFViewer widget shows
an error dialog, and doesn't display the bitmap that has been painted so
far.

This commit improves the situation in both fronts, implementing
rendering now with a best-effort approach. Firstly, execution of
operations isn't halted after an operand results in an error, but
instead execution of all operations is always attempted, and all
collected errors are returned in bulk. Secondly, PDFViewer now always
displays the resulting bitmap, regardless of error being produced or
not. To communicate errors, an on_render_errors callback has been added
so clients can subscribe to these events and handle them as appropriate.
2022-12-16 10:04:23 +01:00

104 lines
3.1 KiB
C++

/*
* Copyright (c) 2021-2022, Matthew Olsson <mattco@serenityos.org>
* Copyright (c) 2022, the SerenityOS developers.
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#pragma once
#include <AK/HashMap.h>
#include <LibGUI/AbstractScrollableWidget.h>
#include <LibGfx/Bitmap.h>
#include <LibPDF/Document.h>
#include <LibPDF/Renderer.h>
static constexpr size_t initial_zoom_level = 8;
struct PageDimensionCache {
// Fixed for a given document
struct PageInfo {
Gfx::FloatSize size;
int rotation;
};
// Based on PageInfo, also depends on some dynamic factors like
// zoom level and app size
struct RenderInfo {
Gfx::FloatSize size;
float total_height_before_this_page;
};
Vector<PageInfo> page_info;
Vector<RenderInfo> render_info;
float max_width;
float total_height;
};
class PDFViewer : public GUI::AbstractScrollableWidget {
C_OBJECT(PDFViewer)
public:
enum class PageViewMode {
Single,
Multiple,
};
virtual ~PDFViewer() override = default;
ALWAYS_INLINE u32 current_page() const { return m_current_page_index; }
void set_current_page(u32 current_page);
ALWAYS_INLINE RefPtr<PDF::Document> const& document() const { return m_document; }
PDF::PDFErrorOr<void> set_document(RefPtr<PDF::Document>);
Function<void(u32 new_page)> on_page_change;
Function<void(u32 page, PDF::Errors const& errors)> on_render_errors;
void zoom_in();
void zoom_out();
void reset_zoom();
void rotate(int degrees);
PageViewMode page_view_mode() const { return m_page_view_mode; }
void set_page_view_mode(PageViewMode);
bool show_clipping_paths() const { return m_rendering_preferences.show_clipping_paths; }
void set_show_clipping_paths(bool);
bool show_images() const { return m_rendering_preferences.show_images; }
void set_show_images(bool);
protected:
PDFViewer();
virtual void paint_event(GUI::PaintEvent&) override;
virtual void resize_event(GUI::ResizeEvent&) override;
virtual void mousewheel_event(GUI::MouseEvent&) override;
virtual void mousedown_event(GUI::MouseEvent&) override;
virtual void mouseup_event(GUI::MouseEvent&) override;
virtual void mousemove_event(GUI::MouseEvent&) override;
virtual void timer_event(Core::TimerEvent&) override;
private:
struct RenderedPage {
NonnullRefPtr<Gfx::Bitmap> bitmap;
int rotation;
};
PDF::PDFErrorOr<NonnullRefPtr<Gfx::Bitmap>> get_rendered_page(u32 index);
PDF::PDFErrorOr<NonnullRefPtr<Gfx::Bitmap>> render_page(u32 page_index);
PDF::PDFErrorOr<void> cache_page_dimensions(bool recalculate_fixed_info = false);
void change_page(u32 new_page);
RefPtr<PDF::Document> m_document;
u32 m_current_page_index { 0 };
Vector<HashMap<u32, RenderedPage>> m_rendered_page_list;
u8 m_zoom_level { initial_zoom_level };
PageDimensionCache m_page_dimension_cache;
PageViewMode m_page_view_mode;
PDF::RenderingPreferences m_rendering_preferences;
Gfx::IntPoint m_pan_starting_position;
int m_rotations { 0 };
};