Camera.java

package ca.cmput301f13t03.adventure_datetime.view.treeView;

import android.graphics.*;

class Camera
{
	// these will be overwritten early on
	private static final float DEFAULT_WIDTH = 500;
	private static final float DEFAULT_HEIGHT = 1000;
	
	// x, y position of the top left of the screen in world coordinates
	private float x = 0;
	private float y = 0;
	
	// size of the view
	private float m_viewWidth = DEFAULT_WIDTH;
	private float m_viewHeight = DEFAULT_HEIGHT;
	
	// coords we want to keep centered
	private float m_xTarget = 0 - m_viewWidth / 2;
	private float m_yTarget = 0 - m_viewWidth / 2;
	
	private float m_zoomLevel = 1.0f;
	
	private Matrix m_transform = null;
	private Matrix m_inverse = null;
	
	private Object m_syncLock = new Object();
	
	public void DrawLocal(Canvas canvas, Paint paint, Path p)
	{
		synchronized (m_syncLock) 
		{
			p.transform(this.GetTransform());
			canvas.drawPath(p, paint);
			p.transform(this.GetInverseTransform());
		}
	}
	
	public void DrawLocal(Canvas canvas, Paint paint, Bitmap image, int x, int y)
	{
		synchronized (m_syncLock) 
		{
			Matrix trans = new Matrix(GetTransform());
			trans.setTranslate(x - this.x, y - this.y);
			canvas.drawBitmap(image, trans, paint);
		}
	}
	
	public void DrawLocal(Canvas canvas, Paint paint, String text, int centerX, int centerY)
	{
		synchronized (m_syncLock) 
		{
			float points[] = { centerX, centerY };
			this.GetTransform().mapPoints(points);
			canvas.drawText(text, points[0], points[1], paint);
		}
	}
	
	private Matrix GetTransform()
	{
		Matrix result = null;
		
		synchronized (m_syncLock) 
		{
			if(m_transform == null)
			{
				m_transform = new Matrix();
				m_transform.setScale(m_zoomLevel, m_zoomLevel);
				m_transform.setTranslate(-this.x, -this.y);
			}
			
			result = m_transform;
		}
		
		return result;
	}
	
	private Matrix GetInverseTransform()
	{
		Matrix result = null;
		
		synchronized (m_syncLock) 
		{
			if(m_inverse == null)
			{
				m_inverse = new Matrix();
				m_inverse.setScale(1.0f / m_zoomLevel, 1.0f / m_zoomLevel);
				m_inverse.setTranslate(this.x, this.y);
			}
			
			result = m_inverse;
		}
		
		return result;
	}
	
	public float GetXTarget()
	{
		return m_xTarget;
	}
	
	public float GetYTarget()
	{
		return m_yTarget;
	}
	
	public void ResizeView(float width, float height)
	{
		synchronized (m_syncLock) 
		{
			m_viewWidth = width;
			m_viewHeight = height;
			
			m_inverse = null;
			m_transform = null;
		}
		
		LookAt(m_xTarget, m_yTarget);
	}
	
	public void LookAt(float x, float y)
	{
		synchronized (m_syncLock) 
		{
			m_xTarget = x;
			m_yTarget = y;
			
			this.x = m_xTarget - m_viewWidth / 2;
			this.y = m_yTarget - m_viewHeight / 2;
			
			m_inverse = null;
			m_transform = null;
		}
	}
	
	public void ScreenCordsToWorldCords(float[] screenCords)
	{
		synchronized (m_syncLock) 
		{
			GetInverseTransform().mapPoints(screenCords);
		}
	}
}