package myGraphics.Perspective;

import myGraphics.VectorGrafix.Vector;
import myGraphics.VectorGrafix.Vector2d;

public class Viewport {	
	public int hPix;					/* Width of viewport in pixels */
	public int vPix;					/* Heigth of viewport in pixels */
	public double pixPerUnit = 20.0;	/* Window to viewport scale factor */
	
	public Viewport() {
		hPix = 250;
		vPix = 250;
		pixPerUnit = 20.0;
	}
	
	public Viewport(int width, int height) {
		hPix = width;
		vPix = height;
		pixPerUnit = 20.0;
	}
	
	public Viewport(int width, int height, double thePixPerUnit) {
		hPix = width;
		vPix = height;
		pixPerUnit = thePixPerUnit;
	}
	
	public Vector2d window2viewport(Vector2d thePoint)  {
		/*
		 *	Given a point projected on the image plane, this method translates
		 *	that point to a pixel on the viewport.
		 */
		 
		return new Vector2d((double) hPix / 2.0 + pixPerUnit * thePoint.x(),
							(double) vPix / 2.0 - pixPerUnit * thePoint.y());  
	}
	
	public double fitImagePlane(double imageWidth, double imageHeight)  {
		/*
		 *	This method will typically be called once, when the initial size of 
		 *	the viewport is set.  It probably ought not to be called when the
		 *	user resizes the viewport, unless the user intends the image size
		 *	to grow and shrink with the window.
		 */
		 
		if (imageHeight / (double) vPix > imageWidth / (double) hPix)  {	
			/* taller image: make fit vertically */
			pixPerUnit = (double) vPix / imageHeight;
				
		} else {
			/* wider (or equivalently proportioned) image: make fit horizontally */
			pixPerUnit = (double) hPix / imageWidth;
		}
		return pixPerUnit;
	}
}