91 lines
2.4 KiB
C
91 lines
2.4 KiB
C
/*
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u8g_line.c
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Universal 8bit Graphics Library
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Copyright (c) 2012, olikraus@gmail.com
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All rights reserved.
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Redistribution and use in source and binary forms, with or without modification,
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are permitted provided that the following conditions are met:
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* Redistributions of source code must retain the above copyright notice, this list
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of conditions and the following disclaimer.
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* Redistributions in binary form must reproduce the above copyright notice, this
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list of conditions and the following disclaimer in the documentation and/or other
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materials provided with the distribution.
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THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
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CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
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INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
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MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR
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CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
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LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
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CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
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STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
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ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#include "u8g.h"
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void u8g_DrawLine(u8g_t *u8g, u8g_uint_t x1, u8g_uint_t y1, u8g_uint_t x2, u8g_uint_t y2)
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{
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u8g_uint_t tmp;
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u8g_uint_t x,y;
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u8g_uint_t dx, dy;
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u8g_int_t err;
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u8g_int_t ystep;
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uint8_t swapxy = 0;
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/* no BBX intersection check at the moment, should be added... */
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if ( x1 > x2 ) dx = x1-x2; else dx = x2-x1;
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if ( y1 > y2 ) dy = y1-y2; else dy = y2-y1;
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if ( dy > dx )
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{
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swapxy = 1;
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tmp = dx; dx =dy; dy = tmp;
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tmp = x1; x1 =y1; y1 = tmp;
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tmp = x2; x2 =y2; y2 = tmp;
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}
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if ( x1 > x2 )
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{
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tmp = x1; x1 =x2; x2 = tmp;
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tmp = y1; y1 =y2; y2 = tmp;
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}
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err = dx >> 1;
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if ( y2 > y1 ) ystep = 1; else ystep = -1;
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y = y1;
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#ifndef U8G_16BIT
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if ( x2 == 255 )
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x2--;
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#else
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if ( x2 == 0xffff )
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x2--;
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#endif
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for( x = x1; x <= x2; x++ )
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{
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if ( swapxy == 0 )
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u8g_DrawPixel(u8g, x, y);
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else
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u8g_DrawPixel(u8g, y, x);
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err -= (uint8_t)dy;
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if ( err < 0 )
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{
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y += (u8g_uint_t)ystep;
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err += (u8g_uint_t)dx;
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}
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}
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}
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