Lines

Functions
void	dog_draw_line (uint8_t x1, uint8_t y1, uint8_t x2, uint8_t y2, uint8_t size, char mode)
void	dog_draw_h_line (uint8_t x1, uint8_t x2, uint8_t y, uint8_t size, char mode)
void	dog_draw_v_line (uint8_t x, uint8_t y1, uint8_t y2, uint8_t size, char mode)

Detailed Description

This header file contains function prototypes for drawing lines on the EA DOGM128. It includes a generic line-drawing function prototype which works for lines of all slopes as well as fast line-drawing function prototypes for horizontal and vertical lines.

Function Documentation

void dog_draw_h_line	(	uint8_t	x1,
		uint8_t	x2,
		uint8_t	y,
		uint8_t	size,
		char	mode
	)

This function is used to draw exclusively horizontal lines to the screen buffer. It should be used in place of dog_draw_line() whenever possible to conserve resources.

Parameters

• x1 = X coordinate of line end point(x1,y) in the set of [0,127].
• x2 = X coordinate of line end point(x2,y) in the set of [0,127].
• y = Y coordinate of line in the set of [0,63]. Since a horizontal line maintains a constant Y value, we only need one Y parameter.
• size = Thickness of the line in the set [0,1].
• mode = 'c' to clear the line, 's' to set the line.

Algorithm

The function begins by checking the parameter ranges, then swaps the x1 and x2 if needed. Finally, it loops through, setting or clearing every pixel between x1 and x2.

Assumptions

• none

void dog_draw_line	(	uint8_t	x1,
		uint8_t	y1,
		uint8_t	x2,
		uint8_t	y2,
		uint8_t	size,
		char	mode
	)

This function is used to draw generic lines of any slope to the screen buffer. If the user is only drawing horizontal or vertical lines, it is advised to use one of the two other functions in this file to conserve system resources.

Parameters

• x1 = X coordinate of line end point(x1,y1) in the set of [0,127].
• y1 = Y coordinate of line end point(x1,y1) in the set of [0,63].
• x2 = X coordinate of line end point(x2,y2) in the set of [0,127].
• y2 = Y coordinate of line end point(x2,y2) in the set of [0,63].
• size = Thickness of the line in the set [0,1].
• mode = 'c' to clear the line, 's' to set the line.

Algorithm

The function begins by checking parameter ranges, then computes point placement using Bresenham's Line Algorithm.

Assumptions

• none

void dog_draw_v_line	(	uint8_t	x,
		uint8_t	y1,
		uint8_t	y2,
		uint8_t	size,
		char	mode
	)

This function is used to draw exclusively vertical lines to the screen buffer. It should be used in place of dog_draw_line() whenever possible to conserve resources.

Parameters

• x = X coordinate of line in the set of [0,127]. Since a vertical line maintains a constant X value, we only need one X parameter.
• y1 = Y coordinate of line end point(x,y1) in the set of [0,63].
• y2 = Y coordinate of line end point(x,y2) in the set of [0,63].
• size = Thickness of the line in the set [0,1].
• mode = 'c' to clear the line, 's' to set the line.

Algorithm

The function begins by checking the parameter ranges, then swaps the y1 and y2 if needed. Finally, it loops through, setting or clearing every pixel between y1 and y2.

Assumptions

• none