// Last edited on 2000-09-05 04:03:19 by stolfi

import java.awt.Point;
import java.awt.Rectangle;
import Ponto;
import Retangulo;
import Escala;

public class EscalaImpl extends Escala
  {
    private double minX; // X do mapa que corresponde a abcissa 0 da tela
    private double maxY; // Y do mapa que corresponde a ordenada 0 da tela
    private double tamPixel;  // em unidades do mapa

    // Construtor
    
    public void define(Rectangle tR, Retangulo mR)
      {
        // Calcula os parâmetros da conversão de modo a garantir
        // escalas iguais em X e em Y.

        double mDX = mR.xMax - mR.xMin;
        double mDY = mR.yMax - mR.yMin;

        double escalaX = mDX / (double) tR.width; 
        double escalaY = mDY / (double) tR.height;
        double escala = (escalaX > escalaY ? escalaX : escalaY);
        double hX = (escala/escalaX-1)/2; double hY = (escala/escalaY-1)/2;

        minX = mR.xMin - mDX*hX; 
        maxY = mR.yMax + mDY*hY;
        tamPixel = escala;
      }

    public void mapaParaTela(Ponto mP, Point tP) 
      {
        tP.x = (int)((mP.x - minX) / tamPixel + 0.5);
        tP.y = (int)((maxY - mP.y) / tamPixel + 0.5);
      }

    public void mapaParaTela(Retangulo mR, Rectangle tR)
      { 
        tR.x = (int)((mR.xMin - minX) / tamPixel + 0.5);
        tR.y = (int)((maxY - mR.yMax) / tamPixel + 0.5);
        tR.width  = (int)((mR.xMax - mR.xMin) / tamPixel + 0.5);
        tR.height = (int)((mR.yMax - mR.yMin) / tamPixel + 0.5);
      }

    public void telaParaMapa(Point tP, Ponto mP)
      {
        mP.x = ((double)tP.x) * tamPixel + minX;
        mP.y = maxY - ((double)tP.y) * tamPixel;
      }

    public void telaParaMapa(Rectangle tR, Retangulo mR)
      {
        mR.xMin = ((double)tR.x) * tamPixel + minX;
        mR.xMax = ((double)(tR.x + tR.width)) * tamPixel + minX;
        mR.yMin = maxY - ((double)(tR.y + tR.height)) * tamPixel;
        mR.yMax = maxY - ((double)tR.y) * tamPixel;
      }
      
    public final double unidadesPorPixel()
      { 
        return tamPixel;
      }
  }