gfx: the RGB565 (16-bit red, green, blue) rasteriser. See include/gfx.h. More...

#include "gfx_int.h"
#include "gfx_subpixel.h"
#include "gfx_work.h"
#include <limits.h>
#include <stdlib.h>
#include <math.h>
#include <string.h>

Data Structures
struct	span_t
	A run of pixels of one row, from `lo` up to `hi`. More...
struct	ring_cut_t
	The directions of a partial ring that need no angle worked out: the middle of its lit part, drawn in the full colour at the full coverage, and the middle of its gap, drawn not at all. More...
struct	arc_dirs_t
	The directions an arc is walked in, as arc_window() finds them: from `lo` over `span` degrees, 360 for all of them. More...

Macros
#define	GFX_INL_FORCE
#define	GFX_MIN(a, b)
#define	GFX_MAX(a, b)

Typedefs
typedef uint32_t	gfx_u32_alias

Functions
static void	fill_span (gfx_color_t *p, int n, gfx_color_t color)
gfx_color_t	gfx_lerp (gfx_color_t a, gfx_color_t b, uint8_t t)
bool	gfx_rect_intersect (gfx_rect_t a, gfx_rect_t b, gfx_rect_t *out)
void	gfx_canvas_init (gfx_canvas_t c, gfx_color_t pixels, int width, int height, int32_t stride)
bool	gfx_canvas_sub (const gfx_canvas_t src, gfx_rect_t window, gfx_canvas_t out)
void	gfx_clip_reset (gfx_canvas_t *c)
bool	gfx_clip_set (gfx_canvas_t *c, gfx_rect_t r)
bool	gfx_clip_intersect (gfx_canvas_t *c, gfx_rect_t r)
void	gfx_pixel (gfx_canvas_t *c, int x, int y, gfx_color_t color)
gfx_color_t	gfx_pixel_get (const gfx_canvas_t *c, int x, int y)
void	gfx_fill_rect (gfx_canvas_t *c, int x, int y, int w, int h, gfx_color_t color)
void	gfx_clear (gfx_canvas_t *c, gfx_color_t color)
void	gfx_hline (gfx_canvas_t *c, int x, int y, int w, gfx_color_t color)
void	gfx_vline (gfx_canvas_t *c, int x, int y, int h, gfx_color_t color)
void	gfx_draw_rect (gfx_canvas_t *c, int x, int y, int w, int h, gfx_color_t color)
void	gfx_line (gfx_canvas_t *c, int x0, int y0, int x1, int y1, gfx_color_t color)
void	gfx_thick_line (gfx_canvas_t *c, int x0, int y0, int x1, int y1, int thickness, gfx_color_t color)
	A line `thickness` px wide: a disc of half that radius stamped at each pixel of the line from (`x0`, `y0`) to (`x1`, `y1`).
void	gfx_draw_circle (gfx_canvas_t *c, int cx, int cy, int r, gfx_color_t color)
void	gfx_fill_circle (gfx_canvas_t *c, int cx, int cy, int r, gfx_color_t color)
static int	clamp_radius (int w, int h, int r)
void	gfx_fill_round_rect (gfx_canvas_t *c, int x, int y, int w, int h, int r, gfx_color_t color)
void	gfx_draw_round_rect (gfx_canvas_t *c, int x, int y, int w, int h, int r, gfx_color_t color)
static int	clamp_cut (int w, int h, int cut)
void	gfx_fill_chamfer_rect_ex (gfx_canvas_t *c, int x, int y, int w, int h, int tl, int tr, int br, int bl, gfx_color_t color)
void	gfx_fill_chamfer_rect (gfx_canvas_t *c, int x, int y, int w, int h, int cut, gfx_color_t color)
void	gfx_draw_chamfer_rect_ex (gfx_canvas_t *c, int x, int y, int w, int h, int tl, int tr, int br, int bl, gfx_color_t color)
void	gfx_draw_chamfer_rect (gfx_canvas_t *c, int x, int y, int w, int h, int cut, gfx_color_t color)
void	gfx_fill_rect_gradient (gfx_canvas_t *c, int x, int y, int w, int h, gfx_color_t a, gfx_color_t b)
void	gfx_blit (gfx_canvas_t c, int x, int y, const gfx_color_t src, int w, int h, int32_t src_stride)
void	gfx_blit_key (gfx_canvas_t c, int x, int y, const gfx_color_t src, int w, int h, int32_t src_stride, gfx_color_t key)
void	gfx_blit_1bpp (gfx_canvas_t c, int x, int y, const uint8_t bits, int w, int h, gfx_color_t fg)
static void	cov_blend (gfx_canvas_t *c, int x, int y, gfx_color_t col, float cov)
	One antialiased pixel: `col` over what is there, by `cov`.
static bool	cov_box (const gfx_canvas_t c, float cx, float cy, float reach, int x0, int y0, int x1, int *y1)
static bool	span_round (float cx, float dy, float reach, span_t *sp)
	Narrow `sp` to the columns of the row `dy` from a centre at `cx` that can lie nearer the centre than `reach:` those more than a pixel further are left out, so a loop over a shape's box walks the shape's own pixels.
static bool	span_inside (float cx, float dy, float reach, span_t *sp)
	Set `sp` to columns of the row `dy` from a centre at `cx` that lie at least a pixel nearer the centre than `reach:` inside it whatever a float's rounding does to the distance.
void	gfx_fill_circle_aaf (gfx_canvas_t *c, float cx, float cy, float r, gfx_color_t col)
	A disc of radius `r` centred on (`cx`, `cy`), anti-aliased from each pixel's distance to the centre.
void	gfx_fill_circle_aa (gfx_canvas_t *c, int cx, int cy, int r, gfx_color_t col)
	gfx_fill_circle_aaf() on whole pixels.
static bool	span_capsule (float ax, float ay, float ex, float ey, float reach, float y, span_t *sp)
	Narrow `sp` to the columns of row `y` that can lie nearer than `reach` to the segment from (`ax`, `ay`) along (`ex`, `ey`): the part of the segment within a pixel more than `reach` of the row, widened by that much and a pixel either side.
void	gfx_capsule_aaf (gfx_canvas_t *c, float ax, float ay, float bx, float by, float thickness, gfx_color_t col)
	A capsule, a thick line with round ends, from (`ax`, `ay`) to (`bx`, `by`), anti-aliased from each pixel's distance to its spine.
void	gfx_capsule_aa (gfx_canvas_t *c, int ax, int ay, int bx, int by, int thickness, gfx_color_t col)
	gfx_capsule_aaf() on whole pixels.
static float	arc_depth (float ang_deg, float a0_deg, float span)
	How far into the arc from `a0_deg` over `span` degrees the direction `ang_deg` lies, in degrees: positive inside, from the nearer end; negative outside, to the nearer end.
static ring_cut_t	ring_cut (float lo, float span, float inner, float fade_deg)
	The cut of a ring from `lo` over `span` degrees whose band starts at `inner` px, fading over `fade_deg`.
void	gfx_ring_aaf (gfx_canvas_t *c, float cx, float cy, float r, float thickness, float a0_deg, float a1_deg, gfx_color_t col, gfx_color_t into, float fade_deg)
	A ring, or an arc of one, solved per pixel from its distance and direction to the centre.
static float	dir_of (int x, int y, int cx, int cy)
	The direction of (`x`, `y`) from (`cx`, `cy`), degrees, up the screen as +90, as arc_walk() places its pixels.
static bool	arc_window (const gfx_canvas_t c, int cx, int cy, float r0, float r1, arc_dirs_t out)
	Where an arc round (`cx`, `cy`) between radii `r0` and `r1` can reach the clip of `c`.
static bool	arc_dir_in (const arc_dirs_t *w, float a_deg)
	Whether the direction `a_deg` is one of `w's`.
static void	arc_walk (gfx_canvas_t *c, int cx, int cy, int r, int thickness, float a0_deg, float a1_deg, gfx_color_t col, gfx_color_t into, float fade_deg)
void	gfx_arc (gfx_canvas_t *c, int cx, int cy, int r, int thickness, float a0_deg, float a1_deg, gfx_color_t col)
void	gfx_arc_fade (gfx_canvas_t *c, int cx, int cy, int r, int thickness, float a0_deg, float a1_deg, gfx_color_t col, gfx_color_t into, float fade_deg)

Variables
int	s_trace_hold
	The fit check's hold depth: 0 reports, more holds back.

Detailed Description

gfx: the RGB565 (16-bit red, green, blue) rasteriser. See include/gfx.h.

SPDX-License-Identifier: MIT

Macro Definition Documentation

◆ GFX_MAX

#define GFX_MAX	(		a,
			b )

Value:

((a) > (b) ? (a) : (b))

◆ GFX_MIN

#define GFX_MIN	(		a,
			b )

Value:

((a) < (b) ? (a) : (b))

Function Documentation

◆ arc_depth()

float arc_depth	(	float	ang_deg,
		float	a0_deg,
		float	span )

static

How far into the arc from a0_deg over span degrees the direction ang_deg lies, in degrees: positive inside, from the nearer end; negative outside, to the nearer end.

Parameters

ang_deg	the pixel's direction, -180 to 180deg
a0_deg	where the arc starts
span	its length, 0 to 360deg

Returns: the signed distance in degrees

◆ arc_dir_in()

bool arc_dir_in	(	const arc_dirs_t *	w,
		float	a_deg )

static

Whether the direction a_deg is one of w's.

Parameters

w	the directions
a_deg	the direction, degrees, any turn

Returns: true when it is

◆ arc_window()

bool arc_window	(	const gfx_canvas_t *	c,
		int	cx,
		int	cy,
		float	r0,
		float	r1,
		arc_dirs_t *	out )

static

Where an arc round (cx, cy) between radii r0 and r1 can reach the clip of c.

A pixel arc_walk() lays lies within 1.5px of its step's point on the ray: its coordinates are truncated, not rounded, on the negative side. So a clip wholly nearer the centre than r0 - 3 or wholly further than r1 + 2 gets nothing, and a clip off the centre is reached only from the directions of its corners, widened by 3px of arc at r0 - 1. A repaint clipped to a box beside a dial walks the part of the dial's arc that passes the box, not all of it.

Parameters

c	the canvas
cx	the centre's column, px
cy	its row, px
r0	the inner radius, px
r1	the outer radius, px
out	the directions to walk, when the clip can be reached

Returns: false when no pixel of the arc can land in the clip

◆ cov_blend()

void cov_blend	(	gfx_canvas_t *	c,
		int	x,
		int	y,
		gfx_color_t	col,
		float	cov )

static

One antialiased pixel: col over what is there, by cov.

Not reported to the damage record pixel by pixel: each caller reports the row's span once (GFX_DAMAGE), which in NORMAL saves a test per pixel.

Parameters

c	the canvas
x	the pixel's column
y	its row
col	the colour
cov	the coverage, 0 to 1; 1 and above writes `col`

◆ gfx_blit()

void gfx_blit	(	gfx_canvas_t *	c,
		int	x,
		int	y,
		const gfx_color_t *	src,
		int	w,
		int	h,
		int32_t	src_stride )

Copy a rectangular block of pixels. src_stride is in pixels.

◆ gfx_blit_1bpp()

void gfx_blit_1bpp	(	gfx_canvas_t *	c,
		int	x,
		int	y,
		const uint8_t *	bits,
		int	w,
		int	h,
		gfx_color_t	fg )

Expand a 1-bit-per-pixel mask (most significant bit first, rows padded to whole bytes).

◆ gfx_blit_key()

void gfx_blit_key	(	gfx_canvas_t *	c,
		int	x,
		int	y,
		const gfx_color_t *	src,
		int	w,
		int	h,
		int32_t	src_stride,
		gfx_color_t	key )

As gfx_blit(), but pixels equal to key are left untouched.

◆ gfx_canvas_init()

void gfx_canvas_init	(	gfx_canvas_t *	c,
		gfx_color_t *	pixels,
		int	width,
		int	height,
		int32_t	stride )

Bind a canvas to a pixel buffer. stride is in pixels; pass 0 to mean "tightly packed" (stride == width).

◆ gfx_canvas_sub()

bool gfx_canvas_sub	(	const gfx_canvas_t *	src,
		gfx_rect_t	window,
		gfx_canvas_t *	out )

Carve a sub-canvas out of src. Returns false if the window is empty.

◆ gfx_capsule_aa()

void gfx_capsule_aa	(	gfx_canvas_t *	c,
		int	ax,
		int	ay,
		int	bx,
		int	by,
		int	thickness,
		gfx_color_t	col )

gfx_capsule_aaf() on whole pixels.

Parameters

c	the canvas
ax	one end's column, px
ay	its row, px
bx	the other end's column, px
by	its row, px
thickness	the width, px; 0 or less draws nothing
col	the colour

◆ gfx_capsule_aaf()

void gfx_capsule_aaf	(	gfx_canvas_t *	c,
		float	ax,
		float	ay,
		float	bx,
		float	by,
		float	thickness,
		gfx_color_t	col )

A capsule, a thick line with round ends, from (ax, ay) to (bx, by), anti-aliased from each pixel's distance to its spine.

Parameters

c	the canvas
ax	one end's column, px
ay	its row, px
bx	the other end's column, px
by	its row, px
thickness	the width, px; 0 or less draws nothing
col	the colour

◆ gfx_clip_intersect()

bool gfx_clip_intersect	(	gfx_canvas_t *	c,
		gfx_rect_t	r )

Restrict further, relative to the current clip. False if empty.

◆ gfx_clip_set()

bool gfx_clip_set	(	gfx_canvas_t *	c,
		gfx_rect_t	r )

Restrict drawing to r (intersected with the canvas). False if empty.

◆ gfx_fill_circle_aa()

void gfx_fill_circle_aa	(	gfx_canvas_t *	c,
		int	cx,
		int	cy,
		int	r,
		gfx_color_t	col )

gfx_fill_circle_aaf() on whole pixels.

Parameters

c	the canvas
cx	the centre's column, px
cy	the centre's row, px
r	the radius, px; 0 or less draws nothing
col	the colour

◆ gfx_fill_circle_aaf()

void gfx_fill_circle_aaf	(	gfx_canvas_t *	c,
		float	cx,
		float	cy,
		float	r,
		gfx_color_t	col )

A disc of radius r centred on (cx, cy), anti-aliased from each pixel's distance to the centre.

Parameters

c	the canvas
cx	the centre's column, px
cy	the centre's row, px
r	the radius, px; 0 or less draws nothing
col	the colour

◆ gfx_fill_rect_gradient()

void gfx_fill_rect_gradient	(	gfx_canvas_t *	c,
		int	x,
		int	y,
		int	w,
		int	h,
		gfx_color_t	a,
		gfx_color_t	b )

Vertical gradient fill, top colour a to bottom colour b.

◆ gfx_lerp()

gfx_color_t gfx_lerp	(	gfx_color_t	a,
		gfx_color_t	b,
		uint8_t	t )

Linear blend of two colours, t in [0,255] where 0 == a and 255 == b.

◆ gfx_pixel_get()

gfx_color_t gfx_pixel_get	(	const gfx_canvas_t *	c,
		int	x,
		int	y )

Reads back a pixel; returns 0 when (x,y) is outside the canvas.

◆ gfx_rect_intersect()

bool gfx_rect_intersect	(	gfx_rect_t	a,
		gfx_rect_t	b,
		gfx_rect_t *	out )

Intersect two rects. Returns false (and zeroes *out) when they miss.

◆ gfx_ring_aaf()

void gfx_ring_aaf	(	gfx_canvas_t *	c,
		float	cx,
		float	cy,
		float	r,
		float	thickness,
		float	a0_deg,
		float	a1_deg,
		gfx_color_t	col,
		gfx_color_t	into,
		float	fade_deg )

A ring, or an arc of one, solved per pixel from its distance and direction to the centre.

gfx_arc_fade() walks its arc and rounds each step to a pixel. This one blends the band's two edges and the arc's two ends over half a pixel either side, the ends measured along the arc at each pixel's radius. A span of 360deg or more is the whole ring. A pixel whose centre lies half a pixel or more beyond the band or past an end is not touched.

Parameters

c	the canvas
cx	the centre's column, px
cy	the centre's row, px
r	the band's middle radius, px
thickness	the band's width, px
a0_deg	one end, degrees counter-clockwise from +x (90 is up)
a1_deg	the other end, degrees
col	the colour
into	the colour each end fades from over `fade_deg`
fade_deg	the fade's length, degrees; 0 for none

◆ gfx_thick_line()

void gfx_thick_line	(	gfx_canvas_t *	c,
		int	x0,
		int	y0,
		int	x1,
		int	y1,
		int	thickness,
		gfx_color_t	color )

A line thickness px wide: a disc of half that radius stamped at each pixel of the line from (x0, y0) to (x1, y1).

Parameters

c	the canvas
x0	one end's column, px
y0	its row, px
x1	the other end's column, px
y1	its row, px
thickness	the width, px; 1 or less is gfx_line()
color	the colour

◆ ring_cut()

ring_cut_t ring_cut	(	float	lo,
		float	span,
		float	inner,
		float	fade_deg )

static

The cut of a ring from lo over span degrees whose band starts at inner px, fading over fade_deg.

Parameters

lo	the arc's first direction, degrees
span	its length, under 360 degrees
inner	the band's inner edge, px
fade_deg	the fade at each end, degrees, 0 for none

Returns: the cut; neither part when inner is under a pixel

◆ span_capsule()

bool span_capsule	(	float	ax,
		float	ay,
		float	ex,
		float	ey,
		float	reach,
		float	y,
		span_t *	sp )

static

Narrow sp to the columns of row y that can lie nearer than reach to the segment from (ax, ay) along (ex, ey): the part of the segment within a pixel more than reach of the row, widened by that much and a pixel either side.

Parameters

ax	the segment's start column, px
ay	its start row, px
ex	its run in columns, px
ey	its run in rows, px
reach	the distance, px
y	the row, px
sp	the run, narrowed in place

Returns: false when nothing of the row is left

◆ span_inside()

bool span_inside	(	float	cx,
		float	dy,
		float	reach,
		span_t *	sp )

static

Set sp to columns of the row dy from a centre at cx that lie at least a pixel nearer the centre than reach: inside it whatever a float's rounding does to the distance.

Parameters

cx	the centre's column, px
dy	the row's distance from the centre's row, px
reach	the distance, px
sp	the run: left empty, at `sp->hi`, when there is none; kept within the columns it held

Returns: true when the run holds a column

◆ span_round()

bool span_round	(	float	cx,
		float	dy,
		float	reach,
		span_t *	sp )

static

Narrow sp to the columns of the row dy from a centre at cx that can lie nearer the centre than reach: those more than a pixel further are left out, so a loop over a shape's box walks the shape's own pixels.

Parameters

cx	the centre's column, px
dy	the row's distance from the centre's row, px
reach	the distance, px
sp	the run, narrowed in place

Returns: false when nothing of the row is left

Data Structures

Macros

Typedefs

Functions

Variables

Detailed Description

Macro Definition Documentation

◆ GFX_MAX

◆ GFX_MIN

Function Documentation

◆ arc_depth()

◆ arc_dir_in()

◆ arc_window()

◆ cov_blend()

◆ gfx_blit()

◆ gfx_blit_1bpp()

◆ gfx_blit_key()

◆ gfx_canvas_init()

◆ gfx_canvas_sub()

◆ gfx_capsule_aa()

◆ gfx_capsule_aaf()

◆ gfx_clip_intersect()

◆ gfx_clip_set()

◆ gfx_fill_circle_aa()

◆ gfx_fill_circle_aaf()

◆ gfx_fill_rect_gradient()

◆ gfx_lerp()

◆ gfx_pixel_get()

◆ gfx_rect_intersect()

◆ gfx_ring_aaf()

◆ gfx_thick_line()

◆ ring_cut()

◆ span_capsule()

◆ span_inside()

◆ span_round()