biskuteri-cafe-JKomasto2/ImageWindow.java

/* copyright

This file is part of JKomasto2.
Written in 2022 by Usawashi <usawashi16@yahoo.co.jp>

This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program.  If not, see <https://www.gnu.org/licenses/>.

copyright */

import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JButton;
import javax.swing.ImageIcon;
import java.awt.Graphics;
import java.awt.Image;
import java.awt.Dimension;
import java.awt.FontMetrics;
import java.awt.BorderLayout;
import java.awt.event.ActionListener;
import java.awt.event.ActionEvent;
import java.awt.event.MouseListener;
import java.awt.event.MouseMotionListener;
import java.awt.event.MouseEvent;
import java.awt.event.MouseWheelListener;
import java.awt.event.MouseWheelEvent;
import java.awt.Image;
import java.net.URL;
import java.net.MalformedURLException;

class
ImageWindow extends JFrame {

    private Attachment[]
    attachments;

    private int
    offset;

//     -    -%-     -

    private ImageComponent
    display;

//    ---%-@-%---

    public synchronized void
    showAttachments(Attachment[] attachments)
    {
        this.attachments = attachments;

        if (attachments.length == 0) {
            display.setImage(null);
            display.setNext(null);
            display.setPrev(null);
            display.repaint();
            return;
        }

        toImage(offset = 0);
    }

    public void
    toNextImage()
    {
        if (attachments.length == 0) return;
        assert offset < attachments.length - 1;
        toImage(++offset);
    }

    public void
    toPrevImage()
    {
        if (attachments.length == 0) return;
        assert offset > 0;
        toImage(--offset);
    }

//     -    -%-     -

    private synchronized void
    toImage(int offset)
    {
        int last = attachments.length  - 1;
        assert offset >= 0;
        assert offset < attachments.length;

        Attachment prev, curr, next;
        curr = attachments[offset];
        next = offset < last ? attachments[offset + 1] : null;
        prev = offset > 0 ? attachments[offset - 1] : null;

        display.setImage(curr.image);
        display.setNext(next != null ? next.image : null);
        display.setPrev(prev != null ? prev.image : null);

        if (!curr.type.equals("image"))
            display.setToolTipText(
                display.getToolTipText()
                + "\n(Media is of type '" + curr.type + "')"
            );

        repaint();
    }

//    ---%-@-%---

    ImageWindow()
    {
        setDefaultCloseOperation(DISPOSE_ON_CLOSE);
        setSize(600, 600);

        display = new ImageComponent(this);
        showAttachments(new Attachment[0]);
        setContentPane(display);
    }

}

class
ImageComponent extends JPanel
implements
    ActionListener,
    MouseListener, MouseMotionListener, MouseWheelListener {

    private ImageWindow
    primaire;

//     -    -%-     -

    private Image
    image, prevImage, nextImage;

    private JPanel
    buttonArea;

    private JButton
    prev, next, toggle;

    private boolean
    scaleImage;

    private int
    xOffset, yOffset, zoomLevel;

    private int
    dragX, dragY, xPOffset, yPOffset;

//    ---%-@-%---

    public void
    setImage(Image image)
    {
        this.image = image;
        if (image != null) {
            Object p = image.getProperty("comment", this);
            String desc = p instanceof String ? (String)p : null;
            setToolTipText(desc);
        }
        xOffset = yOffset = xPOffset = yPOffset = 0;
        zoomLevel = 100;
    }

    public void
    setPrev(Image image)
    {
        prev.setEnabled(image != null);
        prev.setText(image == null ? "<" : "");
        prev.setIcon(toIcon(image));
    }

    public void
    setNext(Image image)
    {
        next.setEnabled(image != null);
        next.setText(image == null ? ">" : "");
        next.setIcon(toIcon(image));
    }

//     -    -%-     -

    public void
    actionPerformed(ActionEvent eA)
    {
        if (eA.getSource() == prev) primaire.toPrevImage();
        if (eA.getSource() == next) primaire.toNextImage();
        if (eA.getSource() == toggle) {
            scaleImage = !scaleImage;
            if (scaleImage) toggle.setText("Show unscaled");
            else toggle.setText("Show scaled to window");
            setImage(this.image);
            repaint();
        }
    }



    public void
    mousePressed(MouseEvent eM)
    {
        dragX = eM.getX();
        dragY = eM.getY();
    }

    public void
    mouseDragged(MouseEvent eM)
    {
        int dx = eM.getX() - dragX;
        int dy = eM.getY() - dragY;
        xPOffset = dx;
        yPOffset = dy;
        repaint();
    }

    public void
    mouseReleased(MouseEvent eM)
    {
        xOffset += xPOffset;
        yOffset += yPOffset;
        xPOffset = yPOffset = 0;
    }

    public void
    mouseWheelMoved(MouseWheelEvent eMw)
    {
        zoomLevel += 10 * -eMw.getUnitsToScroll();
        if (zoomLevel < 50) zoomLevel = 50;
        if (zoomLevel > 400) zoomLevel = 400;
        repaint();
    }


    public void
    mouseEntered(MouseEvent eM) { }

    public void
    mouseExited(MouseEvent eM) { }

    public void
    mouseClicked(MouseEvent eM) { }

    public void
    mouseMoved(MouseEvent eM) { }

//     -    -%-     -

    private static ImageIcon
    toIcon(Image image)
    {
        if (image == null) return null;
        return new ImageIcon(image);
    }

//    ---%-@-%---

    private class
    Painter extends JPanel {

        protected void
        paintComponent(Graphics g)
        {
            if (image == null)
            {
                String str =
                    "(There are no images being displayed.)";
                FontMetrics fm = g.getFontMetrics();
                int x = (getWidth() - fm.stringWidth(str)) / 2;
                int y = (getHeight() + fm.getHeight()) / 2;
                g.drawString(str, x, y);
                return;
            }
            int wo = image.getWidth(this);
            int ho = image.getHeight(this);
            int wn, hn;
            if (wo > ho) {
                wn = scaleImage ? getWidth() : wo;
                hn = ho * wn / wo;
            }
            else {
                hn = scaleImage ? getHeight() : ho;
                wn = wo * hn / ho;
            }
            wn = wn * zoomLevel / 100;
            hn = hn * zoomLevel / 100;
            int x = (getWidth() - wn) / 2;
            int y = (getHeight() - hn) / 2;
            x += xOffset + xPOffset;
            y += yOffset + yPOffset;
            g.drawImage(image, x, y, wn, hn, this);
        }

    }

//    ---%-@-%---

    ImageComponent(ImageWindow primaire)
    {
        this.primaire = primaire;

        Dimension BUTTON_SIZE = new Dimension(48, 48);

        setOpaque(false);
        scaleImage = true;
        zoomLevel = 100;

        prev = new JButton();
        toggle = new JButton("Show unscaled");
        next = new JButton();
        prev.setPreferredSize(BUTTON_SIZE);
        next.setPreferredSize(BUTTON_SIZE);
        prev.addActionListener(this);
        toggle.addActionListener(this);
        next.addActionListener(this);

        buttonArea = new JPanel();
        buttonArea.setOpaque(false);
        buttonArea.add(prev);
        buttonArea.add(toggle);
        buttonArea.add(next);

        setPrev(null);
        setNext(null);

        setLayout(new BorderLayout());
        add(buttonArea, BorderLayout.SOUTH);
        add(new Painter(), BorderLayout.CENTER);

        addMouseListener(this);
        addMouseMotionListener(this);
        addMouseWheelListener(this);
    }

}