Mouse cursor

package com.betalord.sgx.core;

import java.awt.Toolkit;

import com.badlogic.gdx.Gdx;
import com.badlogic.gdx.graphics.Pixmap;
import com.badlogic.gdx.graphics.Texture;
import com.badlogic.gdx.graphics.TextureData;
import com.badlogic.gdx.graphics.Pixmap.Format;
import com.badlogic.gdx.graphics.g2d.TextureRegion;
import com.badlogic.gdx.graphics.glutils.PixmapTextureData;
import com.badlogic.gdx.scenes.scene2d.utils.Drawable;
import com.badlogic.gdx.scenes.scene2d.utils.TextureRegionDrawable;
import com.badlogic.gdx.utils.Disposable;

/**
 * Class that contains all of the logic to load and set mouse cursor image.
 * 
 * @author Betalord
 */
 public class MouseCursor {
	/**
	 * Note: we don't statically load cursor data since we must not do that on Android.
	 * This is why we load it on {@link MouseCursor#init()}, which should get invoked on desktop only.
	 */
	public static enum MouseCursorSize {
		/** 24x24 pixels */
		P24(24),
		/** 32x32 pixels */
		P32(32),
		/** 40x40 pixels */
		P40(40),
		/** 48x48 pixels */
		P48(48),
		/** 56x56 pixels */
		P56(56),
		/** 64x64 pixels */
		P64(64);
		
		/** Size in pixels (n x n pixels). Note that cursor image itself is padded to power of two sized image, however the cursor image itself may be smaller. */
		private int pixels;
		private MouseCursorData data;
		
		MouseCursorSize(int pixels) {
			this.pixels = pixels;
		}
		
		public int getPixels() {
			return pixels;
		}
		
		public MouseCursorData getData() {
			return data;
		}
		
		@Override
		public String toString() {
			return pixels + " x " + pixels;
		}
		
		public static MouseCursorSize getClosest(int pixels) {
			MouseCursorSize value = null;
			int diff = Integer.MAX_VALUE;
			for (MouseCursorSize size : MouseCursorSize.values())
				if (Math.abs(pixels-size.pixels) <= diff) {
					diff = Math.abs(pixels-size.pixels);
					value = size;
				}
			return value;
		}
		
		private MouseCursorData load() {
			MouseCursorData data = new MouseCursorData();
			
			// create a 1x1 white pixel texture:
			data.pixmap = new Pixmap(Gdx.files.internal("gfx/mouse_" + pixels + ".png"));
			TextureData texData = new PixmapTextureData(data.pixmap, Format.RGBA8888, false, false, false);
			data.texture = new Texture(texData);
			data.drawable = new TextureRegionDrawable(new TextureRegion(data.texture));
			
			return data;
		}
	}

	public static class MouseCursorData implements Disposable {
		public Pixmap pixmap;
		public Texture texture;
		public Drawable drawable;
		
		@Override
		public void dispose() {
			pixmap.dispose();
			texture.dispose();
		}
	}
	
	/**
	 * Loads cursors of all sizes and creates textures for them.
	 * Should be called on desktop only (Android doesn't have mouse and hence does not use mouse cursors).
	 */
	public static void init() {
		for (MouseCursorSize size : MouseCursorSize.values())
			size.data = size.load();
	}
	
	/**
	 * Will determine best mouse cursor image size (based on monitor's PPI value).
	 */
	public static MouseCursorSize determineClosest() {
		float ppi = Toolkit.getDefaultToolkit().getScreenResolution();
		float start = 96; // PPI value for which we use the smallest cursor, 24x24 pixels
		int pixels = Math.round(24 * (ppi/start));
		return MouseCursorSize.getClosest(pixels);
	}
}