A graphic drawing algorithms. More...

Functions
void	gp_blit_xyxy (const gp_pixmap src, gp_coord x0, gp_coord y0, gp_coord x1, gp_coord y1, gp_pixmap dst, gp_coord x2, gp_coord y2)
	Blits a rectangle from src into a dst.

void	gp_blit_xywh (const gp_pixmap src, gp_coord x0, gp_coord y0, gp_size w0, gp_size h0, gp_pixmap dst, gp_coord x1, gp_coord y1)
	Blits a rectangle from src into a dst.

static void	gp_blit (const gp_pixmap src, gp_coord x0, gp_coord y0, gp_size w0, gp_size h0, gp_pixmap dst, gp_coord x1, gp_coord y1)
	Blits a rectangle from src into a dst.

void	gp_fill (gp_pixmap *pixmap, gp_pixel val)
	Fills pixmap with given pixel value.

gp_pixel	gp_getpixel (const gp_pixmap *pixmap, gp_coord x, gp_coord y)
	Gets a pixel value.

static gp_pixel	gp_getpixel_raw (const gp_pixmap *pixmap, gp_coord x, gp_coord y)
	Gets a pixel value.

void	gp_putpixel (gp_pixmap *pixmap, gp_coord x, gp_coord y, gp_pixel p)
	Puts a pixel value.

static void	gp_putpixel_raw (gp_pixmap *pixmap, gp_coord x, gp_coord y, gp_pixel p)
	Puts a pixel value.

void	gp_circle (gp_pixmap *pixmap, gp_coord xcenter, gp_coord ycenter, gp_size r, gp_pixel pixel)
	Draws a circle.

void	gp_fill_circle (gp_pixmap *pixmap, gp_coord xcenter, gp_coord ycenter, gp_size r, gp_pixel pixel)
	Draws a filled circle.

void	gp_ring (gp_pixmap *pixmap, gp_coord xcenter, gp_coord ycenter, gp_size r1, gp_size r2, gp_pixel pixel)
	Draws a ring.

void	gp_fill_ring (gp_pixmap *pixmap, gp_coord xcenter, gp_coord ycenter, gp_size r1, gp_size r2, gp_pixel pixel)
	Draws a filled ring.

void	gp_circle_seg (gp_pixmap *pixmap, gp_coord xcenter, gp_coord ycenter, gp_size r, uint8_t seg_flag, gp_pixel pixel)
	Draws a circle segment.

void	gp_fill_circle_seg (gp_pixmap *pixmap, gp_coord xcenter, gp_coord ycenter, gp_size r, uint8_t seg_flag, gp_pixel pixel)
	Draws a filled circle segment.

void	gp_fill_ring_seg (gp_pixmap *pixmap, gp_coord xcenter, gp_coord ycenter, gp_size r1, gp_size r2, uint8_t seg_flag, gp_pixel pixel)
	Draws a filled ring segment.

void	gp_hline_xxy (gp_pixmap *pixmap, gp_coord x0, gp_coord x1, gp_coord y, gp_pixel pixel)
	Horizontal line drawing algorithm.

void	gp_hline_xyw (gp_pixmap *pixmap, gp_coord x, gp_coord y, gp_size w, gp_pixel pixel)
	Horizontal line drawing algorithm.

static void	gp_hline (gp_pixmap *pixmap, gp_coord x0, gp_coord x1, gp_coord y, gp_pixel p)
	Horizontal line drawing algorithm.

void	gp_line (gp_pixmap *pixmap, gp_coord x0, gp_coord y0, gp_coord x1, gp_coord y1, gp_pixel pixel)
	Classical Bresenham line drawing algorithm.

void	gp_line_th (gp_pixmap *pixmap, gp_coord x0, gp_coord y0, gp_coord x1, gp_coord y1, gp_size r, gp_pixel pixel)
	Murphy thick line drawing algorithm.

void	gp_polygon (gp_pixmap pixmap, gp_coord x_off, gp_coord y_off, unsigned int vertex_count, const gp_coord xy, gp_pixel pixel)
	Draws a polygon outline.

void	gp_polygon_th (gp_pixmap pixmap, gp_coord x_off, gp_coord y_off, unsigned int vertex_count, const gp_coord xy, gp_size r, gp_pixel pixel)
	Draws a thick polygon outline.

void	gp_fill_polygon (gp_pixmap pixmap, gp_coord x_off, gp_coord y_off, unsigned int vertex_count, const gp_coord xy, gp_pixel pixel)
	Fills a polygon.

void	gp_vline_xyy (gp_pixmap *pixmap, gp_coord x, gp_coord y0, gp_coord y1, gp_pixel pixel)
	Vertical line drawing algorithm.

void	gp_vline_xyh (gp_pixmap *pixmap, gp_coord x, gp_coord y, gp_size h, gp_pixel pixel)
	Vertical line drawing algorithm.

static void	gp_vline (gp_pixmap *pixmap, gp_coord x, gp_coord y0, gp_coord y1, gp_pixel pixel)
	Horizontal line drawing algorithm.

Detailed Description

A graphic drawing algorithms.

Function Documentation

◆ gp_blit()

static void gp_blit	(	const gp_pixmap *	src,
		gp_coord	x0,
		gp_coord	y0,
		gp_size	w0,
		gp_size	h0,
		gp_pixmap *	dst,
		gp_coord	x1,
		gp_coord	y1
	)

inlinestatic

Blits a rectangle from src into a dst.

An alias for gp_blit_xywh().

Definition at line 90 of file gp_blit.h.

References gp_blit_xywh().

◆ gp_blit_xywh()

void gp_blit_xywh	(	const gp_pixmap *	src,
		gp_coord	x0,
		gp_coord	y0,
		gp_size	w0,
		gp_size	h0,
		gp_pixmap *	dst,
		gp_coord	x1,
		gp_coord	y1
	)

Blits a rectangle from src into a dst.

This blit automatically converts between different gp_pixel_type, however they operate on a single pixel value at a time, if you are converting from a higher bit depths the results are suboptimal, expecially conversions to 1bpp does not end up as a recognizable image. In these cases an error distribution dithering gp_dither_type should be used instead.

Blits rectangle from src defined by x0, y0, x1, y1 (x1, y1 included) to dst starting on x2, y2.

Parameters

src	A source pixmap.
x0	A left rectangle corner coordinate in src.
y0	A top rectangle corner coordinate in src.
w0	A rectangle width.
h0	A rectangle height.
dst	A destination pixmap.
x1	A left rectangle corner coordinate in dst.
y1	A top rectangle corner coordinate in dst.

Referenced by gp_blit().

◆ gp_blit_xyxy()

void gp_blit_xyxy	(	const gp_pixmap *	src,
		gp_coord	x0,
		gp_coord	y0,
		gp_coord	x1,
		gp_coord	y1,
		gp_pixmap *	dst,
		gp_coord	x2,
		gp_coord	y2
	)

Blits a rectangle from src into a dst.

This blit automatically converts between different gp_pixel_type, however they operate on a single pixel value at a time, if you are converting from a higher bit depths the results are suboptimal, expecially conversions to 1bpp does not end up as a recognizable image. In these cases an error distribution dithering gp_dither_type should be used instead.

Blits rectangle from src defined by x0, y0, x1, y1 (x1, y1 included) to dst starting on x2, y2.

Parameters

src	A source pixmap.
x0	A left rectangle corner coordinate in src.
y0	A top rectangle corner coordinate in src.
x1	A right rectangle corner coordinate in src.
y1	A bottom rectangle corner coordinate in src.
dst	A destination pixmap.
x2	A left rectangle corner coordinate in dst.
y2	A top rectangle corner coordinate in dst.

◆ gp_circle()

void gp_circle	(	gp_pixmap *	pixmap,
		gp_coord	xcenter,
		gp_coord	ycenter,
		gp_size	r,
		gp_pixel	pixel
	)

Draws a circle.

Parameters

pixmap	A pixmap to draw into.
xcenter	A circle center coordinate.
ycenter	A circle center coordinate.
r	A circle radius, r=0 draws a single pixel.
pixel	A pixel value to be used for the drawing.

◆ gp_circle_seg()

void gp_circle_seg	(	gp_pixmap *	pixmap,
		gp_coord	xcenter,
		gp_coord	ycenter,
		gp_size	r,
		uint8_t	seg_flag,
		gp_pixel	pixel
	)

Draws a circle segment.

Parameters

pixmap	A pixmap to draw into.
xcenter	A circle center coordinate.
ycenter	A circle center coordinate.
r	A circle radius, r=0 draws a single pixel.
seg_flag	A bitmask of circle segments to draw.
pixel	A pixel value to be used for the drawing.

◆ gp_fill()

void gp_fill	(	gp_pixmap *	pixmap,
		gp_pixel	val
	)

Fills pixmap with given pixel value.

Parameters

pixmap	A pixmap to be filled.
val	A pixel value to fill the pixmap with.

◆ gp_fill_circle()

void gp_fill_circle	(	gp_pixmap *	pixmap,
		gp_coord	xcenter,
		gp_coord	ycenter,
		gp_size	r,
		gp_pixel	pixel
	)

Draws a filled circle.

Parameters

pixmap	A pixmap to draw into.
xcenter	A circle center coordinate.
ycenter	A circle center coordinate.
r	A circle radius, r=0 draws a single pixel.
pixel	A pixel value to be used for the drawing.

◆ gp_fill_circle_seg()

void gp_fill_circle_seg	(	gp_pixmap *	pixmap,
		gp_coord	xcenter,
		gp_coord	ycenter,
		gp_size	r,
		uint8_t	seg_flag,
		gp_pixel	pixel
	)

Draws a filled circle segment.

Parameters

pixmap	A pixmap to draw into.
xcenter	A circle center coordinate.
ycenter	A circle center coordinate.
r	A circle radius, r=0 draws a single pixel.
seg_flag	A bitmask of circle segments to draw.
pixel	A pixel value to be used for the drawing.

◆ gp_fill_polygon()

void gp_fill_polygon	(	gp_pixmap *	pixmap,
		gp_coord	x_off,
		gp_coord	y_off,
		unsigned int	vertex_count,
		const gp_coord *	xy,
		gp_pixel	pixel
	)

Fills a polygon.

Parameters

pixmap	A pixmap to draw the polygon into.
x_off	A x offset to draw the polygon at.
y_off	A y offset to draw the polygon at.
vertex_count	The number of coordinates in the xy array.
xy	An array of a 2 * vertex_count numbers in the [x0, y0, ..., xn, yn] format.
pixel	A pixel value to be used to draw the polygon.

◆ gp_fill_ring()

void gp_fill_ring	(	gp_pixmap *	pixmap,
		gp_coord	xcenter,
		gp_coord	ycenter,
		gp_size	r1,
		gp_size	r2,
		gp_pixel	pixel
	)

Draws a filled ring.

Parameters

pixmap	A pixmap to draw into.
xcenter	A circle center coordinate.
ycenter	A circle center coordinate.
r1	A first circle radius, r=0 draws a single pixel.
r2	A second circle radius, r=0 draws a single pixel.
pixel	A pixel value to be used for the drawing.

◆ gp_fill_ring_seg()

void gp_fill_ring_seg	(	gp_pixmap *	pixmap,
		gp_coord	xcenter,
		gp_coord	ycenter,
		gp_size	r1,
		gp_size	r2,
		uint8_t	seg_flag,
		gp_pixel	pixel
	)

Draws a filled ring segment.

Parameters

pixmap	A pixmap to draw into.
xcenter	A circle center coordinate.
ycenter	A circle center coordinate.
r1	A first circle radius, r=0 draws a single pixel.
r2	A second circle radius, r=0 draws a single pixel.
seg_flag	A bitmask of circle segments to draw.
pixel	A pixel value to be used for the drawing.

◆ gp_getpixel()

gp_pixel gp_getpixel	(	const gp_pixmap *	pixmap,
		gp_coord	x,
		gp_coord	y
	)

Gets a pixel value.

This is a safe and slow function that does coordinate transformations (see GP_TRANSFORM_POINT) and clipping, i.e. reads outside of the gp_pixmap::pixels return 0.

Parameters

pixmap	A pixmap to get the pixel from.
x	A x coordinate to get the pixel from.
y	A y coordinate to get the pixel from.

Returns: A pixel value at give coordinates or 0 for pixels outside bitmap.

◆ gp_getpixel_raw()

static gp_pixel gp_getpixel_raw	(	const gp_pixmap *	pixmap,
		gp_coord	x,
		gp_coord	y
	)

inlinestatic

Gets a pixel value.

Version of gp_getpixel() without transformations nor border checking. This is faster than the non-raw variant but stil somewhat slow since the function has to handle different types of gp_pixel_pack. If you are going for speed use the pixel pack specific function e.g. gp_getpixel_raw_32BPP().

Warning: If x or y are outside of gp_pixmap::pixels the function will read ouside of the buffer.

Parameters

pixmap	A pixmap to put the pixel into.
x	A x coordinate to put the pixel at.
y	A y coordinate to put the pixel at.

Returns: A pixel value.

Definition at line 52 of file gp_get_put_pixel.h.

References gp_getpixel_raw().

Referenced by gp_getpixel_raw().

◆ gp_hline()

static void gp_hline	(	gp_pixmap *	pixmap,
		gp_coord	x0,
		gp_coord	x1,
		gp_coord	y,
		gp_pixel	p
	)

inlinestatic

Horizontal line drawing algorithm.

An alias for gp_hline_xxy().

Definition at line 64 of file gp_hline.h.

References gp_hline_xxy().

◆ gp_hline_xxy()

void gp_hline_xxy	(	gp_pixmap *	pixmap,
		gp_coord	x0,
		gp_coord	x1,
		gp_coord	y,
		gp_pixel	pixel
	)

Horizontal line drawing algorithm.

Parameters

pixmap	A pixmap to draw into.
x0	A starting point x coordinate.
x1	An ending point x coordinate.
y	A y coordinate.
pixel	A pixel value to be used for the drawing.

Referenced by gp_hline().

◆ gp_hline_xyw()

void gp_hline_xyw	(	gp_pixmap *	pixmap,
		gp_coord	x,
		gp_coord	y,
		gp_size	w,
		gp_pixel	pixel
	)

Horizontal line drawing algorithm.

Parameters

pixmap	A pixmap to draw into.
x	A starting point x coordinate.
w	A line width, a lenght of the line.
y	A y coordinate.
pixel	A pixel value to be used for the drawing.

◆ gp_line()

void gp_line	(	gp_pixmap *	pixmap,
		gp_coord	x0,
		gp_coord	y0,
		gp_coord	x1,
		gp_coord	y1,
		gp_pixel	pixel
	)

Classical Bresenham line drawing algorithm.

Classical Bresenham with a nice little trick on the top of the original algorithm, we only track half of the line and paint it from both sides at the same time.

Draws a line from (x0, y0) to (x1, y1), inclusive. The starting and ending point can be specified in any order (the implementation guarantees that exactly the same set of pixels will be drawn in both cases).

Parameters

pixmap	A pixmap to draw into.
x0	A starting point x coordinate.
y0	A starting point y coordinate.
x1	An ending point x coordinate.
y1	An ending point y coordinate.
pixel	A pixel value to be used for the drawing.

◆ gp_line_th()

void gp_line_th	(	gp_pixmap *	pixmap,
		gp_coord	x0,
		gp_coord	y0,
		gp_coord	x1,
		gp_coord	y1,
		gp_size	r,
		gp_pixel	pixel
	)

Murphy thick line drawing algorithm.

This is a modified Bresenham, we run two Bresenham line algorithms, outher one that track the line and inner one that draws lines perpendicular to the line we track. The outher Bresenham also tracks initial errors for the inner one.

We do a nice little trick on the top of the original algorithm, we only track half of the line and paint it from both sides at the same time.

Draws a line from (x0, y0) to (x1, y1), inclusive. The starting and ending point can be specified in any order (the implementation guarantees that exactly the same set of pixels will be drawn in both cases).

Parameters

pixmap	A pixmap to draw into.
x0	A starting point x coordinate.
y0	A starting point y coordinate.
x1	An ending point x coordinate.
y1	An ending point y coordinate.
r	A radius, r=0 is single pixel line.
pixel	A pixel value to be used for the drawing.

◆ gp_polygon()

void gp_polygon	(	gp_pixmap *	pixmap,
		gp_coord	x_off,
		gp_coord	y_off,
		unsigned int	vertex_count,
		const gp_coord *	xy,
		gp_pixel	pixel
	)

Draws a polygon outline.

Traces a polygon by drawing lines between subsequent coordinates with gp_line().

Parameters

pixmap	A pixmap to draw the polygon into.
x_off	A x offset to draw the polygon at.
y_off	A y offset to draw the polygon at.
vertex_count	The number of coordinates in the xy array.
xy	An array of a 2 * vertex_count numbers in the [x0, y0, ..., xn, yn] format.
pixel	A pixel value to be used to draw the polygon.

◆ gp_polygon_th()

void gp_polygon_th	(	gp_pixmap *	pixmap,
		gp_coord	x_off,
		gp_coord	y_off,
		unsigned int	vertex_count,
		const gp_coord *	xy,
		gp_size	r,
		gp_pixel	pixel
	)

Draws a thick polygon outline.

Traces a polygon by drawing lines between subsequent coordinates with gp_line_th().

Parameters

pixmap	A pixmap to draw the polygon into.
x_off	A x offset to draw the polygon at.
y_off	A y offset to draw the polygon at.
vertex_count	The number of coordinates in the xy array.
xy	An array of a 2 * vertex_count numbers in the [x0, y0, ..., xn, yn] format.
r	A radius, r=0 is single pixel line.
pixel	A pixel value to be used to draw the polygon.

◆ gp_putpixel()

void gp_putpixel	(	gp_pixmap *	pixmap,
		gp_coord	x,
		gp_coord	y,
		gp_pixel	p
	)

Puts a pixel value.

This is a safe and slow function that does coordinate transformations (see GP_TRANSFORM_POINT) and clipping i.e. writes outside of the gp_pixmap::pixels are ignored.

If you are going to loop over all pixels in a pixmap you should use gp_putpixel_raw() variant that is not clipped nor transformed.

Parameters

pixmap	A pixmap to put the pixel into.
x	A x coordinate to put the pixel at.
y	A y coordinate to put the pixel at.
p	A pixel value.

◆ gp_putpixel_raw()

static void gp_putpixel_raw	(	gp_pixmap *	pixmap,
		gp_coord	x,
		gp_coord	y,
		gp_pixel	p
	)

inlinestatic

Puts a pixel value.

Version of gp_putpixel() without transformations nor border checking. This is faster than the non-raw variant but stil somewhat slow since the function has to handle all different types of gp_pixel_pack. If you are going for speed use the pixel pack specific function e.g. gp_putpixel_raw_32BPP().

Warning: If x or y are outside of gp_pixmap::pixels the function will write ouside of the buffer.

Parameters

pixmap	A pixmap to put the pixel into.
x	A x coordinate to put the pixel at.
y	A y coordinate to put the pixel at.
p	A pixel value.

Definition at line 107 of file gp_get_put_pixel.h.

References gp_putpixel_raw().

Referenced by gp_putpixel_raw().

◆ gp_ring()

void gp_ring	(	gp_pixmap *	pixmap,
		gp_coord	xcenter,
		gp_coord	ycenter,
		gp_size	r1,
		gp_size	r2,
		gp_pixel	pixel
	)

Draws a ring.

Parameters

pixmap	A pixmap to draw into.
xcenter	A circle center coordinate.
ycenter	A circle center coordinate.
r1	A first circle radius, r=0 draws a single pixel.
r2	A second circle radius, r=0 draws a single pixel.
pixel	A pixel value to be used for the drawing.

◆ gp_vline()

static void gp_vline	(	gp_pixmap *	pixmap,
		gp_coord	x,
		gp_coord	y0,
		gp_coord	y1,
		gp_pixel	pixel
	)

inlinestatic

Horizontal line drawing algorithm.

An alias for gp_hline_xyy().

Definition at line 57 of file gp_vline.h.

References gp_vline_xyy().

◆ gp_vline_xyh()

void gp_vline_xyh	(	gp_pixmap *	pixmap,
		gp_coord	x,
		gp_coord	y,
		gp_size	h,
		gp_pixel	pixel
	)

Vertical line drawing algorithm.

Parameters

pixmap	A pixmap to draw into.
x	A x coordinate.
y	A starting point y coordinate.
h	A line height, a lenght of the line.
pixel	A pixel value to be used for the drawing.

◆ gp_vline_xyy()

void gp_vline_xyy	(	gp_pixmap *	pixmap,
		gp_coord	x,
		gp_coord	y0,
		gp_coord	y1,
		gp_pixel	pixel
	)

Vertical line drawing algorithm.

Parameters

pixmap	A pixmap to draw into.
x	A x coordinate.
y0	A starting point y coordinate.
y1	An ending point y coordinate.
pixel	A pixel value to be used for the drawing.

Referenced by gp_vline().

Functions

Detailed Description

Function Documentation

◆ gp_blit()

◆ gp_blit_xywh()

◆ gp_blit_xyxy()

◆ gp_circle()

◆ gp_circle_seg()

◆ gp_fill()

◆ gp_fill_circle()

◆ gp_fill_circle_seg()

◆ gp_fill_polygon()

◆ gp_fill_ring()

◆ gp_fill_ring_seg()

◆ gp_getpixel()

◆ gp_getpixel_raw()

◆ gp_hline()

◆ gp_hline_xxy()

◆ gp_hline_xyw()

◆ gp_line()

◆ gp_line_th()

◆ gp_polygon()

◆ gp_polygon_th()

◆ gp_putpixel()

◆ gp_putpixel_raw()

◆ gp_ring()

◆ gp_vline()

◆ gp_vline_xyh()

◆ gp_vline_xyy()