backend-mupdf.c File Reference

Backend to rasterize a PDF via the muPDF library. More...

Data Structures
struct	rasterizer_info

Functions
fz_stream *	fz_open_file_ptr_no_close (fz_context *ctx, FILE *file)
static fz_stream *	mupdf_attach_stream (struct caps_rasterizer *rstr, int *rc)
static int	mupdf_init (struct caps_rasterizer *rstr)
static int	mupdf_detach (struct caps_rasterizer *rstr)
static int	mupdf_job_start (struct caps_rasterizer *rstr, unsigned *page_count)
static int	_mupdf_page_number_get (const struct rstr_print_state *state)
static int	mupdf_page_get_next (struct caps_rasterizer *rstr)
static fz_rect	caps_rect_2_fz_rec (const struct caps_rect *rect)
static fz_matrix	_fz_transform_matrix_create (struct caps_rect rect, double resx, double resy, double rotate)
static fz_rect	caps_area_2_fz_rec (const struct caps_rect *sz, const struct caps_area *area)
static int	mupdf_page_rasterize (struct caps_rasterizer *rstr, const struct caps_rstr_page *page_conf, struct raster_adapt_preparation *setup)
static int	mupdf_image_get (struct caps_rasterizer *rstr, struct caps_rstr_raster *desc)
static const void *	mupdf_line_get (struct caps_rasterizer *rstr, const struct caps_rstr_raster *desc, unsigned line_no)

Variables
const struct rstr_provider	pdf_raserizer

Detailed Description

Author

Jürgen Borleis

Copyright

GPL-2.0 or later at your opinion

Version

1.0.0

Warning

Use as experimental

Install

• libmupdf-dev
• libopenjp2-7-dev
• libjbig2dec0-dev
• libharfbuzz-dev

Provide a /usr/lib/pkgconfig/mupdf.pc:

Name: mupdf
Description: Library for rendering PDF documents
Requires.private: freetype2 jbig2dec libopenjp2 libjpeg harfbuzz
Version: 1.15.0
Libs: -L${libdir} -lmupdf
Libs.private: -lmupdf-third
Cflags: -I${includedir}

Or build the mupdf from its source repository. In this case it will be one huge monolitic block of code.

Function Documentation

fz_open_file_ptr_no_close()

fz_stream * fz_open_file_ptr_no_close	(	fz_context *	ctx,
		FILE *	file
	)

We need access to this function, even if it isn't exported via the mupdf header file.
Used in mupdf_attach_stream()

mupdf_attach_stream()

static fz_stream * mupdf_attach_stream ( struct caps_rasterizer *  rstr, int *  rc  )

static

Convert a regular file descriptor into what muPDF wants to access the document's file

Parameters

[in,out]	rstr	Our context
[out]	rc	Negative errno in case of a failure

Return values

Pointer	Stream representation for muPDF
NULL	In case of a failure. In this case *rc contains a valid negative errno

In the CAPS universe the document is already open…as a file descriptor. In order to connect muPDF to it, we need a stream. And additionally a workaround.

muPDF doesn't support using an already open stream as its document input. But it has an internal function doing so. This function isn't exported via its API header file, but it is still available to link to.

This function wraps this feature for the case in future releases fz_open_file_ptr_no_close() isn't available anymore. Or its implementation changes over releases...

According to some header comments, there should be a function called fz_open_fd() … but it isn't.

mupdf_init()

static int mupdf_init ( struct caps_rasterizer *  rstr )

static

Rasterizer specific implementation called by caps_rstr_job_attach()

Todo:

Antialiasing settings should follow INI file setting.

What are the limits of muPDF (regarding caps_rstr_page_limits)?

For coloured or grey scale it might makes sense to enable antialising. But for monochrome it doesn't make sense, it just confuses the halftone algorithms.

Note

For a halftone monochrome output, the best is to raster the image into grey scale raster with both antialising settings (text and graphics) to zero.

mupdf_detach()

static int mupdf_detach ( struct caps_rasterizer *  rstr )

static

Rasterizer specific implementation called by caps_rstr_job_detach()

This will close the still open filedescriptor.

mupdf_job_start()

static int mupdf_job_start ( struct caps_rasterizer *  rstr, unsigned *  page_count  )

static

Rasterizer specific implementation called by caps_rstr_job_attach()

_mupdf_page_number_get()

static int _mupdf_page_number_get ( const struct rstr_print_state *  state )

static

Translate the pagenumber to be rasterized from CAPS to muPDF

Parameters

[in]

state

The current page state

Returns

Page number to rasterize in muPDF counting

The muPDF API counts from page 0

Precondition

rstr_print_state::current_page must be at least '1'

mupdf_page_get_next()

static int mupdf_page_get_next ( struct caps_rasterizer *  rstr )

static

Rasterizer specific implementation called by caps_rstr_page_get_next()

Todo:

Ask libpaper for the medium format name and report its exact size instead (already done in the main library after calling this function)

caps_rect_2_fz_rec()

static fz_rect caps_rect_2_fz_rec ( const struct caps_rect *  rect )

static

_fz_transform_matrix_create()

static fz_matrix _fz_transform_matrix_create ( struct caps_rect  rect, double  resx, double  resy, double  rotate  )

static

Create a transformation matrix to convert the given rect into a raster

Parameters

[in]	rect	Source size, all units are [points]
[in]	resx	Horizontal resolution in [DPI]
[in]	resy	Vertical resolution in [DPI]
[in]	rotate	Rotation in [°]

Returns

Transformation matrix

caps_area_2_fz_rec()

static fz_rect caps_area_2_fz_rec ( const struct caps_rect *  sz, const struct caps_area *  area  )

static

Convert our CAPS area structure into the muPDF 'fz_rect'

Parameters

[in]	sz	The full size the area is in
[in]	area	The CAPS area to convert

Returns

The muPDF rectangle

The muPDF 'fz_rect' is defined as four coordinates with floats, but its 0,0 coordinate is top/left in contrast to the bottom/left of the CAPS area.

mupdf_page_rasterize()

static int mupdf_page_rasterize ( struct caps_rasterizer *  rstr, const struct caps_rstr_page *  page_conf, struct raster_adapt_preparation *  setup  )

static

Rasterizer specific implementation called by caps_rstr_page_rasterize()

Note

The info in setup->source_sz might differ from the one we reported in caps_rstr_page_desc::medium_sz. This might happen due to unifying the size and names of well known formats. Refer medium_format_name_and_size_adapt()

mupdf_image_get()

static int mupdf_image_get ( struct caps_rasterizer *  rstr, struct caps_rstr_raster *  desc  )

static

Rasterizer specific implementation called by caps_rstr_raster_get()

mupdf_line_get()

static const void * mupdf_line_get ( struct caps_rasterizer *  rstr, const struct caps_rstr_raster *  desc, unsigned  line_no  )

static

Rasterizer specific implementation called by caps_rstr_line_get()

Variable Documentation

pdf_raserizer

const struct rstr_provider pdf_raserizer

Initial value:

= {
    .name = "PDF rasterizer (muPDF)",
    .tweaks = RSTRS_INHERIT_FILEDESC,
    .init = mupdf_init,
    .job_start = mupdf_job_start,
    .page_next = mupdf_page_get_next,
    .page_render = mupdf_page_rasterize,
    .page_image_get = mupdf_image_get,
    .line_get = mupdf_line_get,
    .job_end = NULL,
    .exit = mupdf_detach,
}