SquirrelJME/SquirrelJME

// -*- Mode: Java; indent-tabs-mode: t; tab-width: 4 -*-
// ---------------------------------------------------------------------------
// SquirrelJME
//     Copyright (C) Stephanie Gawroriski <xer@multiphasicapps.net>
// ---------------------------------------------------------------------------
// SquirrelJME is under the Mozilla Public License Version 2.0.
// See license.mkd for licensing and copyright information.
// ---------------------------------------------------------------------------

package cc.squirreljme.emulator.uiform;

import cc.squirreljme.jvm.mle.brackets.UIDrawableBracket;
import cc.squirreljme.jvm.mle.callbacks.UIDrawableCallback;
import cc.squirreljme.jvm.mle.callbacks.UIFormCallback;
import cc.squirreljme.jvm.mle.constants.UIPixelFormat;
import java.awt.AlphaComposite;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.image.BufferedImage;
import java.awt.image.DataBufferInt;
import java.lang.ref.Reference;
import java.lang.ref.WeakReference;
import java.util.Arrays;
import javax.swing.JPanel;

/**
 * Panel used for painting graphics.
 *
 * @since 2020/09/20
 */
class __PaintingPanel__
    extends JPanel
{
    /** The display to draw on. */
    protected final Reference<SwingDisplay> displayRef;
    
    /** The item to check callbacks on. */
    protected final Reference<SwingItem> itemRef;
    
    /** The pixel image for drawing. */
    private BufferedImage _pixelImage;
    
    /**
     * Initializes the painting panel, with no linked item.
     * 
     * @param __display The display to paint on.
     * @throws NullPointerException On null arguments.
     * @since 2023/01/14
     */
    __PaintingPanel__(SwingDisplay __display)
        throws NullPointerException
    {
        if (__display == null)
            throw new NullPointerException("NARG");
        
        this.displayRef = new WeakReference<>(__display);
        this.itemRef = null;
    }
    
    /**
     * Initializes the painting panel.
     * 
     * @param __item The item owning this.
     * @throws NullPointerException On null arguments.
     * @since 2020/09/20
     */
    __PaintingPanel__(SwingItem __item)
        throws NullPointerException
    {
        if (__item == null)
            throw new NullPointerException("NARG");
        
        this.displayRef = null;
        this.itemRef = new WeakReference<>(__item);
    }
    
    /**
     * {@inheritDoc}
     * @since 2020/09/20
     */
    @Override
    protected void paintComponent(Graphics __g)
    {
        // Must always be called to perform other operations
        super.paintComponent(__g);
        
        // We always want to overwrite the alpha values and do no blending
        Graphics2D gt = ((__g instanceof Graphics2D) ? (Graphics2D)__g : null);
        if (gt != null)
            gt.setComposite(AlphaComposite.SrcOver);
        
        // Get the panel size, used for drawing and such
        int pW = this.getWidth();
        int pH = this.getHeight();
        
        // Did the framebuffer need to be recreated?
        BufferedImage pixelImage = this._pixelImage;
        if (pixelImage == null || pW != pixelImage.getWidth() ||
            pH != pixelImage.getHeight())
        {
            // Set base image
            this._pixelImage = (pixelImage = new BufferedImage(pW, pH,
                BufferedImage.TYPE_INT_RGB));
            
            // Fill the entire buffer with nothing
            int[] buffer = ((DataBufferInt)pixelImage.getRaster()
                .getDataBuffer()).getData();
            
            Arrays.fill(buffer, 0xFF_000000);
        }
        
        // Determine which callback is to be called
        UIDrawableCallback callback = null;
        UIDrawableBracket callbackItem = null;
        if (this.itemRef != null)
        {
            SwingItem item = this.itemRef.get();
            if (item != null)
            {
                SwingForm form = item._form;
                if (form != null)
                    callback = form.callback();
                
                // Use for the callback
                callbackItem = item;
            }
        }
        
        // Is a display?
        else if (this.displayRef != null)
        {
            SwingDisplay display = this.displayRef.get();
            if (display != null)
            {
                callback = display.callback();
                callbackItem = display;
            }    
        }
        
        // Send to callback
        if (callback != null)
            callback.paint(callbackItem, UIPixelFormat.INT_RGB888,
                pW, pH, ((DataBufferInt)pixelImage.getRaster()
                    .getDataBuffer()).getData(), 0,
                    null, 0, 0, pW, pH, 0);
        
        // Draw the buffer directly onto the panel
        __g.drawImage(pixelImage, 0, 0, pW, pH,
            0, 0, pW, pH, null);
    }
}