Diff: u8g_line.c

Revision:

0:972874f31c98

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/u8g_line.c	Wed Mar 07 12:49:14 2018 +0000
@@ -0,0 +1,82 @@
+/*
+
+  u8g_line.h
+  
+  Universal 8bit Graphics Library
+  
+  Copyright (c) 2012, olikraus@gmail.com
+  All rights reserved.
+
+  Redistribution and use in source and binary forms, with or without modification, 
+  are permitted provided that the following conditions are met:
+
+  * Redistributions of source code must retain the above copyright notice, this list 
+    of conditions and the following disclaimer.
+    
+  * Redistributions in binary form must reproduce the above copyright notice, this 
+    list of conditions and the following disclaimer in the documentation and/or other 
+    materials provided with the distribution.
+
+  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND 
+  CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, 
+  INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF 
+  MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE 
+  DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR 
+  CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 
+  SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 
+  NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; 
+  LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER 
+  CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, 
+  STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 
+  ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF 
+  ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.  
+  
+*/
+
+#include "u8g.h"
+
+void u8g_DrawLine(u8g_t *u8g, u8g_uint_t x1, u8g_uint_t y1, u8g_uint_t x2, u8g_uint_t y2)
+{
+  u8g_uint_t tmp;
+  u8g_uint_t x,y;
+  u8g_uint_t dx, dy;
+  u8g_int_t err;
+  u8g_int_t ystep;
+
+  uint8_t swapxy = 0;
+  
+  /* no BBX intersection check at the moment, should be added... */
+
+  if ( x1 > x2 ) dx = x1-x2; else dx = x2-x1;
+  if ( y1 > y2 ) dy = y1-y2; else dy = y2-y1;
+
+  if ( dy > dx ) 
+  {
+    swapxy = 1;
+    tmp = dx; dx =dy; dy = tmp;
+    tmp = x1; x1 =y1; y1 = tmp;
+    tmp = x2; x2 =y2; y2 = tmp;
+  }
+  if ( x1 > x2 ) 
+  {
+    tmp = x1; x1 =x2; x2 = tmp;
+    tmp = y1; y1 =y2; y2 = tmp;
+  }
+  err = dx >> 1;
+  if ( y2 > y1 ) ystep = 1; else ystep = -1;
+  y = y1;
+  for( x = x1; x <= x2; x++ )
+  {
+    if ( swapxy == 0 ) 
+      u8g_DrawPixel(u8g, x, y); 
+    else 
+      u8g_DrawPixel(u8g, y, x); 
+    err -= (uint8_t)dy;
+    if ( err < 0 ) 
+    {
+      y += (u8g_uint_t)ystep;
+      err += (u8g_uint_t)dx;
+    }
+  }
+}
+