Silicon Labs Graphics Library: Line Drawing Routines.

License

This file is licensensed under the Silabs License Agreement. See the file "Silabs_License_Agreement.txt" for details. Before using this software for any purpose, you must agree to the terms of that agreement.

Definition in file glib_line.c .


       #include <stdint.h>


       #include <stdbool.h>


       #include "em_types.h"


       #include "
       
        glib.h
       
       "

Functions
static bool	GLIB_clipLine ( GLIB_Context_t pContext, int32_t pX1, int32_t pY1, int32_t pX2, int32_t *pY2)
	Clips the line if necessary, using the Cohen-Sutherland algorithm for clipping lines. See Wikipedia for algorithm.

EMSTATUS	GLIB_drawLine ( GLIB_Context_t *pContext, int32_t x1, int32_t y1, int32_t x2, int32_t y2)
	Draws a line from x1,y1 to x2, y2.

EMSTATUS	GLIB_drawLineH ( GLIB_Context_t *pContext, int32_t x1, int32_t y1, int32_t x2)
	Draws a horizontal line from x1, y1 to x2, y2.

EMSTATUS	GLIB_drawLineV ( GLIB_Context_t *pContext, int32_t x1, int32_t y1, int32_t y2)
	Draws a vertical line from x1, y1 to x1, y2.

static uint8_t	GLIB_getClipCode ( GLIB_Context_t *pContext, int32_t x, int32_t y)
	Gets the clip code for the point that is used by Cohen-Sutherland algorithm.

Function Documentation

static bool GLIB_clipLine	(	GLIB_Context_t *	`pContext,`
		int32_t *	`pX1,`
		int32_t *	`pY1,`
		int32_t *	`pX2,`
		int32_t *	`pY2`
	)

static

Clips the line if necessary, using the Cohen-Sutherland algorithm for clipping lines. See Wikipedia for algorithm.

The points are moved using the linear equations: y=y0+slope*(x-x0),x=x0+(1/slope)*(y-y0)

Parameters

`pContext`	Pointer to the GLIB_Context_t which holds the clipping region
`pX1`	Pointer to the start x-coordinate
`pY1`	Pointer to the start y-coordinate
`pX2`	Pointer to the end-x coordinate
`pY2`	Pointer to the end-y coordinate

Returns: Returns true if the line is inside, or crosses into, the clipping region, otherwise return false

Definition at line 244 of file glib_line.c .

References __GLIB_Context_t::clippingRegion , GLIB_getClipCode() , __GLIB_Rectangle_t::xMax , __GLIB_Rectangle_t::xMin , __GLIB_Rectangle_t::yMax , and __GLIB_Rectangle_t::yMin .

Referenced by GLIB_drawLine() .

static uint8_t GLIB_getClipCode	(	GLIB_Context_t *	`pContext,`
		int32_t	`x,`
		int32_t	`y`
	)

static

Gets the clip code for the point that is used by Cohen-Sutherland algorithm.

Parameters

`pContext`	Pointer to the GLIB_Context_t which holds the clipping region
`x`	Start x-coordinate
`y`	Start y-coordinate

Returns: Returns the 4-bit clip code

Definition at line 194 of file glib_line.c .

References __GLIB_Context_t::clippingRegion , __GLIB_Rectangle_t::xMax , and __GLIB_Rectangle_t::yMax .

Referenced by GLIB_clipLine() .

glib_line.c File Reference

License

Functions

Function Documentation