Drawing

Collaboration diagram for Drawing:

Functions
void	bj_draw_line (bj_bitmap *p_bitmap, int x0, int y0, int x1, int y1, uint32_t pixel)
void	bj_draw_rectangle (bj_bitmap *p_bitmap, const bj_rect *p_area, uint32_t pixel)
void	bj_draw_filled_rectangle (bj_bitmap *p_bitmap, const bj_rect *p_area, uint32_t pixel)
void	bj_draw_triangle (bj_bitmap *p_bitmap, int x0, int y0, int x1, int y1, int x2, int y2, uint32_t color)
void	bj_draw_circle (bj_bitmap *p_bitmap, int cx, int cy, int radius, uint32_t color)
void	bj_draw_filled_circle (bj_bitmap *p_bitmap, int cx, int cy, int radius, uint32_t color)
void	bj_draw_polyline (bj_bitmap *p_bitmap, size_t count, const int *x, const int *y, bj_bool loop, uint32_t color)

Detailed Description

2D drawing facilities

Function Documentation

bj_draw_circle()

void bj_draw_circle	(	bj_bitmap *	p_bitmap,
		int	cx,
		int	cy,
		int	radius,
		uint32_t	color )

Draw the outline of a circle onto a bitmap.

Uses the midpoint circle algorithm (integer arithmetic).

Parameters

p_bitmap	Target bitmap (must not be NULL).
cx	X-coordinate of circle center (pixels).
cy	Y-coordinate of circle center (pixels).
radius	Circle radius in pixels (>= 0).
color	Pixel color in 0xAARRGGBB format.

bj_draw_filled_circle()

void bj_draw_filled_circle	(	bj_bitmap *	p_bitmap,
		int	cx,
		int	cy,
		int	radius,
		uint32_t	color )

Draw a filled circle onto a bitmap.

Fills all pixels within radius distance from (cx, cy).

Parameters

p_bitmap	Target bitmap (must not be NULL).
cx	X-coordinate of circle center (pixels).
cy	Y-coordinate of circle center (pixels).
radius	Circle radius in pixels (>= 0).
color	Pixel color in 0xAARRGGBB format.

bj_draw_filled_rectangle()

void bj_draw_filled_rectangle	(	bj_bitmap *	p_bitmap,
		const bj_rect *	p_area,
		uint32_t	pixel )

Draws a filled rectangle in the given bitmap.

The function draws an filled rectangle by filling all pixels within p_area.

Parameters

p_bitmap	The bitmap object.
p_area	The rectangle to draw.
pixel	The line pixel value.

Memory Safety

This function does not perform any bound checking on the pixel coordinates. It is up to you to ensure the coordinates lie between [0, bj_bitmap->width * bj_bitmap->height]. Writing outside of these bounds will result in undefined behavior or corrupted memory access.

bj_draw_line()

void bj_draw_line	(	bj_bitmap *	p_bitmap,
		int	x0,
		int	y0,
		int	x1,
		int	y1,
		uint32_t	pixel )

Draws a line of pixels in the given bitmap.

The line is drawn for each pixel between p0 and p1.

Parameters

p_bitmap	The bitmap object.
x0	The X coordinate of the first point in the line.
y0	The Y coordinate of the first point in the line.
x1	The X coordinate of the second point in the line.
y1	The Y coordinate of the second point in the line.
pixel	The line pixel value.

Memory Safety

This function does not perform any bound checking on the pixel coordinates. It is up to you to ensure the coordinates lie between [0, bj_bitmap->width * bj_bitmap->height]. Writing outside of these bounds will result in undefined behavior or corrupted memory access.

bj_draw_polyline()

void bj_draw_polyline	(	bj_bitmap *	p_bitmap,
		size_t	count,
		const int *	x,
		const int *	y,
		bj_bool	loop,
		uint32_t	color )

Draw a polyline from C-style coordinate arrays.

Draws line segments between successive vertex pairs (x[i], y[i]) -> (x[i+1], y[i+1]). If loop != 0 and count >= 2, an extra segment connects the last vertex to the first.

Parameters

p_bitmap	Target bitmap.
x	Pointer to array of x coordinates (length >= count).
y	Pointer to array of y coordinates (length >= count).
count	Number of vertices. Segments drawn for i = 0..count-2.
color	Pixel color in 0xAARRGGBB format.
loop	Nonzero to close the polyline.

bj_draw_rectangle()

void bj_draw_rectangle	(	bj_bitmap *	p_bitmap,
		const bj_rect *	p_area,
		uint32_t	pixel )

Draws a rectangle in the given bitmap.

The function draws an rectangle outline using 4 consecutive calls to bj_draw_line.

Parameters

p_bitmap	The bitmap object.
p_area	The rectangle to draw.
pixel	The line pixel value.

Memory Safety

This function does not perform any bound checking on the pixel coordinates. It is up to you to ensure the coordinates lie between [0, bj_bitmap->width * bj_bitmap->height]. Writing outside of these bounds will result in undefined behavior or corrupted memory access.

bj_draw_triangle()

void bj_draw_triangle	(	bj_bitmap *	p_bitmap,
		int	x0,
		int	y0,
		int	x1,
		int	y1,
		int	x2,
		int	y2,
		uint32_t	color )

Draws the edges of a triangle given its 3 corners.

Parameters

p_bitmap	The bitmap object.
x0	The X coordinate of the first triangle vertex.
y0	The Y coordinate of the first triangle vertex.
x1	The X coordinate of the second triangle vertex.
y1	The Y coordinate of the second triangle vertex.
x2	The X coordinate of the third triangle vertex.
y2	The Y coordinate of the third triangle vertex.
color	The line color.

Memory Safety

This function does not perform any bound checking on the pixel coordinates. It is up to you to ensure the coordinates lie between [0, bj_bitmap->width * bj_bitmap->height]. Writing outside of these bounds will result in undefined behavior or corrupted memory access.