Emulate the unsupported colour formats and restore the raster. More...

Macros
#define	MONOCHROME0_WHITE 0xff

#define	MONOCHROME1_WHITE 0x00

#define	LUMINANCE_WHITE 0xff

#define	RGB_WHITE 0xff

#define	CMYK_WHITE 0x00

Functions
static void	monochome_dots_wipe_out_left (size_t cnt, struct caps_dot_monochrome *buf, uint8_t nodot)

static void	monochome_dots_wipe_out_right (size_t cnt, struct caps_dot_monochrome *buf, uint8_t nodot)

static void	grey_dots_wipe_out (size_t cnt, struct caps_dot_grey buf[cnt])

static void	rgb_dots_wipe_out (size_t cnt, struct caps_dot_rgb *buf)

static void	cmyk_dots_wipe_out (size_t cnt, struct caps_dot_cmyk *buf)

static void *	empty_line (size_t dots_per_line, void *buf, enum caps_colour_format cf)

static void *	line_buffer_allocate (void *buf, unsigned dots_per_line, enum caps_colour_format cf)

static void	line_buffer_poisoning (void *buf, enum caps_colour_format cf, unsigned dot_cnt)

const void *	caps_drv_raw_raster_line_get (struct caps_drv *cdrv, unsigned line_no)

void *	caps_drv_raster_line_copy_get (struct caps_drv cdrv, void line_buf, unsigned line_no)

void	caps_drv_emulation_stop (struct caps_drv *cdrv)

static void	alloc_monochrome_buffer (struct caps_drv *cdrv)

static void	read_and_store (struct caps_dot_monochrome buf, struct drv_halftone_converter htc, unsigned ll, unsigned no, unsigned expected_width, enum caps_colour_format cf)

static void	monochrome_buffer_convert (struct caps_drv cdrv, struct drv_halftone_converter htc)

static void	tweak_monochrome_position (struct caps_rstr_raster *desc)

int	caps_drv_emulation_setup (struct caps_drv *cdrv)

Detailed Description

Copyright: GNU General Public License 2 or later

Author: Jürgen Borleis

Warning: Use as experimental

Drivers rely on the fact, they get a ready-to-use raster to convert and send it to the printer. But sometimes libcapsraster hasn't support for the requested colour format for example. Or the source (the document) hasn't the same format as the target medium.

Both adaptions shouldn't be done by the driver itself. That's the job of the framework.

This file provides the corresponding routines.

Macro Definition Documentation

◆ MONOCHROME0_WHITE

#define MONOCHROME0_WHITE 0xff

No-dot value for CAPS_CF_MONOCHROME0

◆ MONOCHROME1_WHITE

#define MONOCHROME1_WHITE 0x00

No-dot value for CAPS_CF_MONOCHROME1

◆ LUMINANCE_WHITE

#define LUMINANCE_WHITE 0xff

No-dot value for CAPS_CF_GREY

Luminance=0xff => white, e.g. no dot

◆ RGB_WHITE

#define RGB_WHITE 0xff

No-dot value for CAPS_CF_RGB

Red=0xff, Green=0xff, Blue=0xff => white, e.g. no dot

◆ CMYK_WHITE

#define CMYK_WHITE 0x00

No-dot value for CAPS_CF_CMYK

Cyan=0, Mangenta=0, Yellow=0, Key=0 => white, e.g. no dot

Function Documentation

◆ monochome_dots_wipe_out_left()

static void monochome_dots_wipe_out_left	(	size_t	cnt,
		struct caps_dot_monochrome *	buf,
		uint8_t	nodot
	)

static

Wipe-out an amount of monochrome dots beginning at the given buffer

Parameters

[in]	cnt	Amount of dots to wipe-out
[in,out]	buf	Where to start changing dots
[in]	nodot	Wipe-out value (0xff or 0x00)

For CAPS_CF_MONOCHROME0 let val = 0xff, for CAPS_CF_MONOCHROME1 let val = 0x00

Precondition: Bit 7 in each byte is the leftmost dot on the paper

Note: This only handles monochrome modes (e.g. one bit per dot)

◆ monochome_dots_wipe_out_right()

static void monochome_dots_wipe_out_right	(	size_t	cnt,
		struct caps_dot_monochrome *	buf,
		uint8_t	nodot
	)

static

Wipe-out an amount of dots in the given buffer from right to left

Parameters

[in]	cnt	Amount of dots to wipe-out
[in,out]	buf	Where to stop changing dots (e.g. last byte in the buffer)
[in]	nodot	Wipe-out value (0xff or 0x00)

For CAPS_CF_MONOCHROME0 let val = 0xff, for CAPS_CF_MONOCHROME1 let val = 0x00

Precondition: Bit 7 in each byte is the leftmost dot on the paper

Attention: The dot count must always start at the right most dot, e.g. bit 0 in *buf

Note: This only handles monochrome modes (e.g. one bit per dot)

◆ grey_dots_wipe_out()

static void grey_dots_wipe_out	(	size_t	cnt,
		struct caps_dot_grey	buf[cnt]
	)

static

Wipe-out an amount of grey dots beginning at the given buffer

Parameters

[in]	cnt	Amount of dots to wipe-out
[in,out]	buf	Where to start changing dots

Uses LUMINANCE_WHITE for each dot

◆ rgb_dots_wipe_out()

static void rgb_dots_wipe_out	(	size_t	cnt,
		struct caps_dot_rgb *	buf
	)

static

Wipe-out an amount of RGB dots beginning at the given buffer

Parameters

[in]	cnt	Amount of dots to wipe-out
[in,out]	buf	Where to start changing dots

Uses RGB_WHITE for all three colour components for each dot

◆ cmyk_dots_wipe_out()

static void cmyk_dots_wipe_out	(	size_t	cnt,
		struct caps_dot_cmyk *	buf
	)

static

Wipe-out an amount of CMYK dots beginning at the given buffer

Parameters

[in,out]	buf	Where to start changing dots
[in]	cnt	Amount of dots to wipe-out

Used CMYK_WHITE for all four colour components for each dot

◆ empty_line()

static void * empty_line	(	size_t	dots_per_line,
		void *	buf,
		enum caps_colour_format	cf
	)

static

Provide an empty line in the corresponding colour format

Parameters

[in]	dots_per_line	Dots in the line in the corresponding colour format
[in,out]	buf	Where the line to be wiped-out starts
[in]	cf	Colour format

Returns: buf

Todo:: Should be optimzed and only wiped out if not already done. Lines at high resolutions can be large! But the driver can modify the data, it is free to do so!

◆ line_buffer_allocate()

static void * line_buffer_allocate	(	void *	buf,
		unsigned	dots_per_line,
		enum caps_colour_format	cf
	)

static

Allocate a line buffer on demand for the emulated colour format

Parameters

[in]	buf	The current buffer pointer (can be NULL)
[in]	dots_per_line	Dot count of one line
[in]	cf	The colour format of the dots to emulate

Return values

buf	If a buffer is already available
Pointer	A line buffer of the correct length

If buf is NULL a correct sized buffer is returned. This buffer can be used on further calls as buf again.

◆ line_buffer_poisoning()

static void line_buffer_poisoning	(	void *	buf,
		enum caps_colour_format	cf,
		unsigned	dot_cnt
	)

static

Poison the line buffer to discover bad margin/offset handling

This is only made when DEBUG is enabled. Let the compiler sort it out if not used

◆ caps_drv_emulation_stop()

void caps_drv_emulation_stop ( struct caps_drv * cdrv )

Clean up the emulated data

◆ alloc_monochrome_buffer()

static void alloc_monochrome_buffer ( struct caps_drv * cdrv )

static

Allocate once per page a buffer for the halftone raster

Unless the buffer is freed, no new buffer is allocated, instead the existing one from the previous page is re-used.

Precondition: caps_drv::raster_desc must be valid

Postcondition: caps_drv_emulation_stop() frees the buffer at the end of the job; The halftone raster has the dimension of the source raster from the rasterizer (regarding dots)

◆ read_and_store()

static void read_and_store	(	struct caps_dot_monochrome *	buf,
		struct drv_halftone_converter *	htc,
		unsigned	ll,
		unsigned	no,
		unsigned	expected_width,
		enum caps_colour_format	cf
	)

static

Read one line from a halftone converter and store it into the emulation raster buffer

Parameters

[in,out]	buf	The emulation buffer to store the line to (its base address)
[in]	htc	The halftone converter to read a line from
[in]	ll	Full line length in `buf`
[in]	no	Line number in `buf` to write the line to
[in]	expected_width	Expected width in pixel per line (e.g. <= `ll`) for error cecking
[in]	cf	Colour format in which the line should be stored in `buf`

Precondition: buf is expected to have the size to store an ll long line at line no.

◆ monochrome_buffer_convert()

static void monochrome_buffer_convert	(	struct caps_drv *	cdrv,
		struct drv_halftone_converter *	htc
	)

static

Dither the input grey scale raster with the given halftone converter

Parameters

[in,out]	cdrv	libcapsdriver handle
[in]	htc	Halftone converter to use for the conversion

Precondition: Input raster must be in format grey scale

When the routine returns, there is a second raster buffer with the requested monochrome data format in caps_drv::mono_buf. It is used as long caps_drv::emulate is one of the monochrome pixel formats instead of CAPS_CF_NONE.

This buffer is created when the first page of a document should be converted and re-used on every next page if possible and freed at the end when emulation is stopped (caps_drv_emulation_stop())

◆ tweak_monochrome_position()

static void tweak_monochrome_position ( struct caps_rstr_raster * desc )

static

Tweak the horizontal position of the monochrome raster

Parameters

[in,out] desc The raster description to tweak

When we copy the monochrome line into the full line buffer in caps_drv_raster_line_copy_get() we have a little problem with positions which aren't a multiple of eight. Due to the implementation in caps_drv_raster_line_copy_get() the start of the line is exact or up to 7 bits left. These up to 7 bits must be added at the right border to wipe them out.

◆ caps_drv_emulation_setup()

int caps_drv_emulation_setup ( struct caps_drv * cdrv )

Convert the rasterized image on demand

Return values

0 Always

For the case, we need to emulate some colour format, we do it here

Note: This increases the amount of required memory, since the raw raster and the emulated raster exists at the same time.

Precondition: caps_drv::raster_desc must be valid

Todo:: Think about to free the raw raster, when the emulated raster has been created. This might conflict with printing more than one copies of the current page!

Macros

Functions

Detailed Description

Macro Definition Documentation

◆ MONOCHROME0_WHITE

◆ MONOCHROME1_WHITE

◆ LUMINANCE_WHITE

◆ RGB_WHITE

◆ CMYK_WHITE

Function Documentation

◆ monochome_dots_wipe_out_left()

◆ monochome_dots_wipe_out_right()

◆ grey_dots_wipe_out()

◆ rgb_dots_wipe_out()

◆ cmyk_dots_wipe_out()

◆ empty_line()

◆ line_buffer_allocate()

◆ line_buffer_poisoning()

◆ caps_drv_emulation_stop()

◆ alloc_monochrome_buffer()

◆ read_and_store()

◆ monochrome_buffer_convert()

◆ tweak_monochrome_position()

◆ caps_drv_emulation_setup()