glib_line.c File Reference
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
"
Functions |
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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.
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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.
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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.
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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.
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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.
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Function Documentation
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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() .
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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() .