Silicon Labs Graphics Library: Line Drawing Routines.

License

The licensor of this software is Silicon Laboratories Inc. Your use of this software is governed by the terms of Silicon Labs Master Software License Agreement (MSLA) available at www.silabs.com/about-us/legal/master-software-license-agreement. This software is distributed to you in Source Code format and is governed by the sections of the MSLA applicable to Source Code.

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 247 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 197 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