lws-svg.h File Reference

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Data Structures
struct	lws_svg_render

Macros
#define	LWS_SVG_RGBA(_r, _g, _b, _a)
#define	LWS_SVG_ALPHA(_c)

Typedefs
typedef struct lws_svg	lws_svg_t
typedef int(*	lws_svg_span_cb_t) (void *user, int x0, int x1, uint32_t rgba)
typedef struct lws_svg_render	lws_svg_render_t

Enumerations
enum	lws_svg_par_t { LWS_SVG_PAR_DEFAULT , LWS_SVG_PAR_NONE }

Functions
LWS_VISIBLE LWS_EXTERN lws_svg_t *	lws_svg_new (void)
LWS_VISIBLE LWS_EXTERN void	lws_svg_free (lws_svg_t **svg)
LWS_VISIBLE LWS_EXTERN lws_stateful_ret_t	lws_svg_parse (lws_svg_t *svg, const uint8_t **buf, size_t *len, char hold_at_metadata)
LWS_VISIBLE LWS_EXTERN unsigned int	lws_svg_get_width (const lws_svg_t *svg)
LWS_VISIBLE LWS_EXTERN unsigned int	lws_svg_get_height (const lws_svg_t *svg)
LWS_VISIBLE LWS_EXTERN char	lws_svg_get_doc_complete (const lws_svg_t *svg)
LWS_VISIBLE LWS_EXTERN lws_stateful_ret_t	lws_svg_render_line (lws_svg_t *svg, const lws_svg_render_t *ri, int y, lws_svg_span_cb_t cb, void *user)

---

Data Structure Documentation

lws_svg_render

struct lws_svg_render

Definition at line 162 of file lws-svg.h.

Collaboration diagram for lws_svg_render:

Data Fields
int	w
int	h
char	aa

Macro Definition Documentation

LWS_SVG_RGBA

#define LWS_SVG_RGBA	(		_r,
			_g,
			_b,
			_a )

Value:

(uint32_t)( \
((uint32_t)(_r) & 0xff) | \
(((uint32_t)(_g) & 0xff) << 8) | \
(((uint32_t)(_b) & 0xff) << 16) | \
(((uint32_t)(_a) & 0xff) << 24))

Definition at line 44 of file lws-svg.h.

#define LWS_SVG_RGBA(_r, _g, _b, _a) (uint32_t)( \
                ((uint32_t)(_r) & 0xff) | \
                (((uint32_t)(_g) & 0xff) << 8) | \
                (((uint32_t)(_b) & 0xff) << 16) | \
                (((uint32_t)(_a) & 0xff) << 24))

LWS_SVG_ALPHA

#define LWS_SVG_ALPHA

(

_c

)

Value:

((uint32_t)(((_c) >> 24) & 0xff))

Definition at line 50 of file lws-svg.h.

Typedef Documentation

lws_svg_t

typedef struct lws_svg lws_svg_t

Definition at line 39 of file lws-svg.h.

lws_svg_span_cb_t

typedef int(* lws_svg_span_cb_t) (void *user, int x0, int x1, uint32_t rgba)

Definition at line 160 of file lws-svg.h.

lws_svg_render_t

typedef struct lws_svg_render lws_svg_render_t

Enumeration Type Documentation

lws_svg_par_t

enum lws_svg_par_t

Enumerator
LWS_SVG_PAR_DEFAULT
LWS_SVG_PAR_NONE

Definition at line 57 of file lws-svg.h.

             {
        LWS_SVG_PAR_DEFAULT,    /* xMidYMid meet */
        LWS_SVG_PAR_NONE,       /* stretch to fill */
} lws_svg_par_t;

Function Documentation

lws_svg_new()

LWS_VISIBLE LWS_EXTERN lws_svg_t * lws_svg_new

(

void

)

lws_svg_new() - create an SVG scene parse object

Returns a new SVG scene object which should be destroyed with lws_svg_free(), or NULL if OOM.

References LWS_EXTERN, and LWS_VISIBLE.

lws_svg_free()

LWS_VISIBLE LWS_EXTERN void lws_svg_free

(

lws_svg_t **

svg

)

lws_svg_free() - destroy an SVG scene object

Parameters

svg	pointer to the scene object pointer to destroy and set NULL

This also frees the retained scene and all sub-allocations.

References LWS_EXTERN, and LWS_VISIBLE.

lws_svg_parse()

LWS_VISIBLE LWS_EXTERN lws_stateful_ret_t lws_svg_parse	(	lws_svg_t *	svg,
		const uint8_t **	buf,
		size_t *	len,
		char	hold_at_metadata )

lws_svg_parse() - parse streaming SVG document input

Parameters

svg	the SVG scene object
buf	pointer to a const uint8_t array of SVG input
len	pointer to the count of bytes available at *buf
hold_at_metadata	nonzero to stop consuming once the root <svg> tag has been parsed

Makes SVG input available to the scene parser so it can build the retained vector scene. If the call consumed any input, *buf and *len are adjusted accordingly. The parser is stateful so it is not sensitive to the input chunk sizes it is fed.

If hold_at_metadata is set, parsing stops at the end of the root <svg> open tag even if further input is available at *buf, so image dimensions can be discovered before committing to retaining the whole document.

Returns LWS_SRET_OK if the document has completely parsed (ie, the root element has closed), or, when hold_at_metadata is set, as soon as the root tag parsed; LWS_SRET_WANT_INPUT if the input so far was consumed and more is needed to progress; or a return with LWS_SRET_FATAL set if the document is too broken to process. When LWS_SRET_OK is returned for the full document case, the retained scene is complete and ready for rendering; if the input ends without closing the root element, whatever parsed so far is still renderable.

References LWS_EXTERN, and LWS_VISIBLE.

lws_svg_get_width()

LWS_VISIBLE LWS_EXTERN unsigned int lws_svg_get_width

(

const lws_svg_t *

svg

)

lws_svg_get_width() - get intrinsic document width in px

Parameters

svg	the SVG scene object

Returns the intrinsic document width in px once the root tag has been parsed: the width attribute if it is in px, otherwise the viewBox width if present, otherwise the CSS default replaced element width. Returns 0 if the root tag has not been parsed yet.

References LWS_EXTERN, and LWS_VISIBLE.

lws_svg_get_height()

LWS_VISIBLE LWS_EXTERN unsigned int lws_svg_get_height

(

const lws_svg_t *

svg

)

lws_svg_get_height() - get intrinsic document height in px

Parameters

svg	the SVG scene object

As lws_svg_get_width(), but for the document height.

References LWS_EXTERN, and LWS_VISIBLE.

lws_svg_get_doc_complete()

LWS_VISIBLE LWS_EXTERN char lws_svg_get_doc_complete

(

const lws_svg_t *

svg

)

lws_svg_get_doc_complete() - has the whole document been parsed?

Parameters

svg	the SVG scene object

Returns nonzero if the root element has closed (or an unrecoverable truncated-document condition was reached), so the retained scene will not change any further.

lws_svg_render_line()

LWS_VISIBLE LWS_EXTERN lws_stateful_ret_t lws_svg_render_line	(	lws_svg_t *	svg,
		const lws_svg_render_t *	ri,
		int	y,
		lws_svg_span_cb_t	cb,
		void *	user )

lws_svg_render_line() - render a single raster line of the scene

Parameters

svg	the SVG scene object
ri	render mapping info (output raster size)
y	the output line to render, 0 .. ri->h - 1
cb	callback to receive filled spans on the line
user	opaque user pointer passed to the callback

Maps the retained user-space geometry into a ri->w x ri->h px raster according to the document's viewBox and preserveAspectRatio policy, and renders output line y of it by scanline intersection of the flattened geometry, delivering the filled spans via cb in document order.

Sample points are at pixel centres, so with the default binary coverage a pixel is either covered or not. With ri->aa set, coverage is the exact covered fraction of the pixel square, computed as the area integral of the winding function over the pixel (each band-clipped boundary edge contributes clipped-linear ramp areas, with no supersampling): corners, thin features and slivers between scanlines are handled exactly, and the span alpha carries the fractional coverage for compositing.

Lines can be rendered in any order and repeatedly; the scene is not modified except for internal scratch reallocation. Calls on the same scene object are not reentrant against each other.

Returns LWS_SRET_OK, or LWS_SRET_FATAL if an internal allocation failed.