UTFT_Geometry.cpp

/*
  UTFT_Geometry.cpp - Add-on Library for UTFT: Geometric functions
  Copyright (C)2015-02018 Rinky-Dink Electronics, Henning Karlsen. All right reserved
  
  This library adds some geometric functions to UTFT which are not
  included in the main library.

  You can find the latest version of the library at 
  http://www.RinkyDinkElectronics.com/

  This library is free software; you can redistribute it and/or
  modify it under the terms of the CC BY-NC-SA 3.0 license.
  Please see the included documents for further information.

  Commercial use of this library requires you to buy a license that
  will allow commercial use. This includes using the library,
  modified or not, as a tool to sell products.

  The license applies to all part of the library including the 
  examples and tools supplied with the library.
*/

#include "UTFT_Geometry.h"
#include <UTFT.h>

#define swap(a, b) { int16_t t = a; a = b; b = t; }

UTFT_Geometry::UTFT_Geometry(UTFT *ptrUTFT)
{
	_UTFT = ptrUTFT;
}

void UTFT_Geometry::drawTriangle(int x1, int y1, int x2, int y2, int x3, int y3)
{
	_UTFT->drawLine(x1, y1, x2, y2);
	_UTFT->drawLine(x2, y2, x3, y3);
	_UTFT->drawLine(x3, y3, x1, y1);
}

void UTFT_Geometry::fillTriangle(int32_t x1, int32_t y1, int32_t x2, int32_t y2, int32_t x3, int32_t y3)
{
	int32_t xs, xe;
	int16_t y, ly;

	if (y1 > y2)
	{
		swap(y1, y2); 
		swap(x1, x2);
	}
	if (y2 > y3)
	{
		swap(y3, y2);
		swap(x3, x2);
	}
	if (y1 > y2)
	{
		swap(y1, y2);
		swap(x1, x2);
	}
	
	if(y1 == y3)	// Single line triangles
	{
		xs = xe = x1;
		if(x2 < xs)			xs = x2;
		else if(x2 > xe)	xe = x2;
		if(x3 < xs)			xs = x3;
		else if(x3 > xe)	xe = x3;
		_UTFT->drawHLine(xs, y1, xe-xs);
		return;
	}
	
	// Upper part
	if (y2 == y3) ly = y2;
	else          ly = y2-1;
	
	for(y=y1; y<=ly; y++)
	{
		xs = x1 + (x2 - x1) * (y - y1) / (y2 - y1);
		xe = x1 + (x3 - x1) * (y - y1) / (y3 - y1);
		_UTFT->drawHLine(xs, y, xe-xs);
	}
	
	// Lower part
	for(; y<=y3; y++)
	{
		xs = x2 + (x3 - x2) * (y - y2) / (y3 - y2);
		xe = x1 + (x3 - x1) * (y - y1) / (y3 - y1);
		_UTFT->drawHLine(xs, y, xe-xs);
	}
}

void UTFT_Geometry::drawArc(int x, int y, int r, int startAngle, int endAngle, int thickness)
{
	int rDelta = -(thickness/2);
	int px, py, cx, cy;

	startAngle -= 90;
	endAngle   -= 90;
	
	if (startAngle!=endAngle)
	{
		for (int i=0; i<thickness; i++)
		{
			px = x + cos((startAngle*3.14)/180) * (r+rDelta+i);
			py = y + sin((startAngle*3.14)/180) * (r+rDelta+i);
			for (int d=startAngle+1; d<endAngle+1; d++)
			{
				cx = x + cos((d*3.14)/180) * (r+rDelta+i);
				cy = y + sin((d*3.14)/180) * (r+rDelta+i);
				_UTFT->drawLine(px, py, cx, cy);
				px = cx;
				py = cy;
			}
		}
	}
	else
	{
		px = x + cos((startAngle*3.14)/180) * (r+rDelta);
		py = y + sin((startAngle*3.14)/180) * (r+rDelta);
		cx = x + cos((startAngle*3.14)/180) * (r-rDelta);
		cy = y + sin((startAngle*3.14)/180) * (r-rDelta);
		_UTFT->drawLine(px, py, cx, cy);
	}
}

void UTFT_Geometry::drawPie(int x, int y, int r, int startAngle, int endAngle)
{
	int px, py, cx, cy;

	startAngle -= 90;
	endAngle   -= 90;
	if (startAngle>endAngle)
		startAngle -= 360;
	
	px = x + cos((startAngle*3.14)/180) * r;
	py = y + sin((startAngle*3.14)/180) * r;
	_UTFT->drawLine(x, y, px, py);
	for (int d=startAngle+1; d<endAngle+1; d++)
	{
		cx = x + cos((d*3.14)/180) * r;
		cy = y + sin((d*3.14)/180) * r;
		_UTFT->drawLine(px, py, cx, cy);
		px = cx;
		py = cy;
	}
	_UTFT->drawLine(x, y, px, py);
}