gfx_damage.c File Reference

Damage: the part of one frame buffer the rasteriser wrote, as 16-row bands. See include/gfx_damage.h. More...

#include "gfx_damage.h"
#include <stddef.h>

Functions
void	gfx_damage_init (gfx_damage_t *d, const gfx_canvas_t *root)
	Bind d to the buffer under root, empty.
void	gfx_damage_reset (gfx_damage_t *d)
	Forget what d holds: nothing written.
void	gfx_damage_all (gfx_damage_t *d)
	Count the whole buffer as written.
static bool	place (gfx_damage_t *d, const gfx_canvas_t *c, int *x, int *y)
	Where c's top-left pixel lies in d's buffer.
void	gfx_damage_mark (gfx_damage_t *d, const gfx_canvas_t *c, int x, int y, int w, int h)
	Count a rectangle written through c as written.
bool	gfx_damage_empty (const gfx_damage_t *d)
	Whether d holds no write.
static long	area (gfx_rect_t r)
	A rectangle's area, pixels.
static gfx_rect_t	bound (gfx_rect_t a, gfx_rect_t b)
	The smallest rectangle round a and b.
int	gfx_damage_rects (const gfx_damage_t *d, gfx_rect_t *out, int max)
	The written area as at most max rectangles, top to bottom.
gfx_rect_t	gfx_damage_turn (gfx_rect_t r, int width, int height)
	Where r lies in a width x height buffer turned by 180°.
void	gfx_damage_attach (gfx_damage_t *d)
	Report the primitives' writes to d, or to nothing.

Variables
gfx_damage_t *	gfx_damage_sink
	The record the primitives report to, or NULL; gfx_damage.c.

Detailed Description

Damage: the part of one frame buffer the rasteriser wrote, as 16-row bands. See include/gfx_damage.h.

SPDX-License-Identifier: MIT

Function Documentation

gfx_damage_all()

void gfx_damage_all

(

gfx_damage_t *

d

)

Count the whole buffer as written.

Parameters

d	the record

gfx_damage_attach()

void gfx_damage_attach

(

gfx_damage_t *

d

)

Report the primitives' writes to d, or to nothing.

Parameters

d	the record, or NULL to stop counting

gfx_damage_empty()

bool gfx_damage_empty

(

const gfx_damage_t *

d

)

Whether d holds no write.

Parameters

d	the record

Returns

true when nothing was written since the last reset

gfx_damage_init()

void gfx_damage_init	(	gfx_damage_t *	d,
		const gfx_canvas_t *	root )

Bind d to the buffer under root, empty.

Parameters

d	the record
root	a canvas whose pixels are the buffer's first pixel and whose width, height and stride are the buffer's

gfx_damage_mark()

void gfx_damage_mark	(	gfx_damage_t *	d,
		const gfx_canvas_t *	c,
		int	x,
		int	y,
		int	w,
		int	h )

Count a rectangle written through c as written.

Nothing when c's pixels lie outside d's buffer. A canvas inside it with another stride counts the whole buffer.

Parameters

d	the record
c	the canvas written through
x	the rectangle's left edge, in c's coordinates
y	its top edge
w	its width, already clipped to c
h	its height, already clipped

gfx_damage_rects()

int gfx_damage_rects	(	const gfx_damage_t *	d,
		gfx_rect_t *	out,
		int	max )

The written area as at most max rectangles, top to bottom.

Each band's span is one rectangle; neighbouring bands then merge, the pair that adds the fewest unwritten pixels first, while a merge adds none or more than max are left. Every written pixel lies in one of the rectangles; a rectangle may hold unwritten pixels.

Parameters

d	the record
out	the rectangles, in buffer coordinates
max	room in out, 1 or more

Returns

the rectangles written to out, 0 when nothing was written

gfx_damage_reset()

void gfx_damage_reset

(

gfx_damage_t *

d

)

Forget what d holds: nothing written.

Parameters

d	the record

gfx_damage_turn()

gfx_rect_t gfx_damage_turn	(	gfx_rect_t	r,
		int	width,
		int	height )

Where r lies in a width x height buffer turned by 180°.

Parameters

r	a rectangle inside the buffer
width	the buffer's width, pixels
height	its height, rows

Returns

the turned rectangle, of the same size

place()

bool place ( gfx_damage_t * d, const gfx_canvas_t * c, int * x, int * y )

static

Where c's top-left pixel lies in d's buffer.

Parameters

d	the record
c	the canvas
x	its left edge in the buffer, set when it lies inside
y	its top edge, set when it lies inside

Returns

true when c's pixels lie inside the buffer with its stride