glib_line.c File Reference

Detailed Description

Silicon Labs Graphics Library: Line Drawing Routines.

License

Copyright 2015 Silicon Labs, http://www.silabs.com

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"

Go to the source code of this file.

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. More...
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. More...
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. More...
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. More...
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. More...

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 217 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 175 of file glib_line.c.

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

Referenced by GLIB_clipLine().