お絵描きソフトの書いた絵の保存方法

現在javaでお絵描きソフトを勉強しているのですが、自分で描いた絵を画像として保存する機能を付けたいと思い、質問させていただきました。
まだまだプログラムには弱くどのようにすればいいのかわからないので、詳しく教えていただけると幸いです。

該当のソースコード

java
1import java.awt.BasicStroke;
2import java.awt.BorderLayout;
3import java.awt.Color;
4import java.awt.Graphics;
5import java.awt.Graphics2D;
6import java.awt.Image;
7import java.awt.Paint;
8import java.awt.RenderingHints;
9import java.awt.event.ActionEvent;
10import java.awt.event.ActionListener;
11import java.awt.event.MouseAdapter;
12import java.awt.event.MouseEvent;
13import java.awt.event.MouseMotionAdapter;
14
15import javax.swing.ButtonGroup;
16import javax.swing.JButton;
17import javax.swing.JComponent;
18import javax.swing.JFrame;
19import javax.swing.JLabel;
20import javax.swing.JPanel;
21import javax.swing.JToggleButton;
22
23public class SwingPaint extends JFrame {
24    private final DrawArea drawArea = new DrawArea();
25
26    public static void main(String[] args) {
27        new SwingPaint().setVisible(true);
28    }
29
30    private SwingPaint() {
31        super("お絵かき");
32        setSize(600, 600);
33        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
34        setLocationRelativeTo(null); // 中央表示
35        setResizable(false); // リサイズ禁止
36
37        JButton clearBtn = new JButton("Clear");
38        clearBtn.addActionListener(e -> drawArea.clear());
39        JPanel panel = new JPanel();
40        panel.add(clearBtn);
41
42        JPanel controls = new JPanel(new BorderLayout());
43        controls.add(createColorButtons(), BorderLayout.NORTH);
44        controls.add(createSizeButtons(), BorderLayout.CENTER);
45        controls.add(panel, BorderLayout.EAST);
46
47        add(controls, BorderLayout.NORTH);
48        add(drawArea, BorderLayout.CENTER);
49    }
50
51    private JPanel createColorButtons() {
52        JToggleButton green = new JToggleButton("緑");
53        JToggleButton blue = new JToggleButton("青");
54        JToggleButton black = new JToggleButton("黒", true); // 初期選択
55        JToggleButton red = new JToggleButton("赤");
56        JToggleButton magenta = new JToggleButton("マゼンタ");
57        JToggleButton white = new JToggleButton("消しゴム");
58
59        ActionListener actionListener = new ActionListener() {
60            @Override public void actionPerformed(ActionEvent e) {
61                if (e.getSource() == black) {
62                    drawArea.setStrokeColor(Color.BLACK);
63                } else if (e.getSource() == blue) {
64                    drawArea.setStrokeColor(Color.BLUE);
65                } else if (e.getSource() == green) {
66                    drawArea.setStrokeColor(Color.GREEN);
67                } else if (e.getSource() == red) {
68                    drawArea.setStrokeColor(Color.RED);
69                } else if (e.getSource() == magenta) {
70                    drawArea.setStrokeColor(Color.MAGENTA);
71                } else if (e.getSource() == white) {
72                	drawArea.setStrokeColor(Color.WHITE);
73                }
74            }
75        };
76
77        ButtonGroup group = new ButtonGroup(); // 同じグループに入れると勝手にトグルしてくれる
78        JPanel controls = new JPanel();
79        controls.add(new JLabel("Color"));
80
81        JToggleButton[] buttons = new JToggleButton[]{ green, blue, black, red, magenta,white };
82        for (JToggleButton button : buttons) {
83            button.addActionListener(actionListener);
84            group.add(button);
85            controls.add(button);
86        }
87
88        return controls;
89    }
90
91    private JPanel createSizeButtons() {
92        JToggleButton stroke1 = new JToggleButton("1", true);
93        JToggleButton stroke5 = new JToggleButton("5");
94        JToggleButton stroke10 = new JToggleButton("10");
95        JToggleButton stroke20 = new JToggleButton("20");
96
97        ActionListener actionListener = new ActionListener() {
98            @Override public void actionPerformed(ActionEvent e) {
99                if (e.getSource() == stroke1) {
100                    drawArea.setStrokeSize(1);
101                } else if (e.getSource() == stroke5) {
102                    drawArea.setStrokeSize(5);
103                } else if (e.getSource() == stroke10) {
104                    drawArea.setStrokeSize(10);
105                } else if (e.getSource() == stroke20) {
106                	drawArea.setStrokeSize(20);
107                }
108            }
109        };
110
111        ButtonGroup group = new ButtonGroup();
112        JPanel controls = new JPanel();
113        controls.add(new JLabel("Size"));
114
115        JToggleButton[] buttons = new JToggleButton[]{ stroke1, stroke5, stroke10,stroke20 };
116        for (JToggleButton button : buttons) {
117            button.addActionListener(actionListener);
118            group.add(button);
119            controls.add(button);
120        }
121
122        return controls;
123    }
124}
125
126class DrawArea extends JComponent {
127    private Image image;
128    private Graphics2D g2;
129    private int oldX, oldY;
130
131    public DrawArea() {
132        setDoubleBuffered(false);
133        addMouseListener(new MouseAdapter() {
134            @Override public void mousePressed(MouseEvent e) {
135                oldX = e.getX();
136                oldY = e.getY();
137            }
138        });
139
140        addMouseMotionListener(new MouseMotionAdapter() {
141            @Override public void mouseDragged(MouseEvent e) {
142                int currentX = e.getX();
143                int currentY = e.getY();
144
145                g2.drawLine(oldX, oldY, currentX, currentY);
146                repaint();
147
148                oldX = currentX;
149                oldY = currentY;
150            }
151        });
152    }
153
154    protected void paintComponent(Graphics g) {
155        if (image == null) {
156            image = createImage(getWidth(), getHeight());
157            g2 = (Graphics2D) image.getGraphics();
158            g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
159            clear();
160        }
161
162        g.drawImage(image, 0, 0, null);
163    }
164
165    public void clear() {
166        Paint p = g2.getPaint(); // 元の色
167        g2.setPaint(Color.WHITE);
168        g2.fillRect(0, 0, getWidth(), getHeight());
169        g2.setPaint(p); // 元の色に戻す
170        repaint();
171    }
172
173    public void setStrokeColor(Color color) { g2.setPaint(color); }
174
175    public void setStrokeSize(int size) {
176//        g2.setStroke(new BasicStroke(size)); // だけだとギザギザが汚い
177        g2.setStroke(new BasicStroke(size, BasicStroke.CAP_ROUND, BasicStroke.JOIN_ROUND));
178    }
179

どうかお願いします。

m.ts10806

2021/01/26 06:25

今何がどこまでできていて何が起きてるのでしょうか。「質問した」と書いてあるだけで質問になっていませんし、要件だけでしたら調べて何も出ないように思えません（要は丸投げです）

行動規範の内容に同意します

回答2件

ベストアンサー

imageはBufferedImageにキャストできます。
こんなメソッドをボタンなりなんなりから呼び出せばいいでしょう。

Java
1public void save() {
2    JFileChooser fileChooser = new JFileChooser(); // ファイルダイアログ
3    fileChooser.setFileFilter(new FileNameExtensionFilter("pngファイル", "png")); // ファイルの種類設定
4    if (fileChooser.showSaveDialog(this) != JFileChooser.APPROVE_OPTION) return; // OKじゃなければ何もせず抜ける
5
6    File file = fileChooser.getSelectedFile(); // 新しいファイルもしくは選択したファイル
7    String filePath = file.getPath();
8    if (!filePath.toLowerCase().endsWith(".png")) // 拡張子の確認
9        file = new File(filePath + ".png"); // 付いてなければ付ける
10
11    try {
12        ImageIO.write((BufferedImage) image, "png", file); // imageを指定フォーマットで指定パスに保存
13    } catch (Exception e) {
14        e.printStackTrace();
15    }
16}

一応全文

Java
1import java.awt.BasicStroke;
2import java.awt.BorderLayout;
3import java.awt.Color;
4import java.awt.Graphics;
5import java.awt.Graphics2D;
6import java.awt.Image;
7import java.awt.Paint;
8import java.awt.RenderingHints;
9import java.awt.event.ActionEvent;
10import java.awt.event.ActionListener;
11import java.awt.event.MouseAdapter;
12import java.awt.event.MouseEvent;
13import java.awt.event.MouseMotionAdapter;
14import java.awt.image.BufferedImage;
15import java.io.File;
16import javax.imageio.ImageIO;
17import javax.swing.ButtonGroup;
18import javax.swing.JButton;
19import javax.swing.JComponent;
20import javax.swing.JFileChooser;
21import javax.swing.JFrame;
22import javax.swing.JLabel;
23import javax.swing.JPanel;
24import javax.swing.JToggleButton;
25import javax.swing.filechooser.FileNameExtensionFilter;
26
27public class SwingPaint extends JFrame {
28    private final DrawArea drawArea = new DrawArea();
29
30    public static void main(String[] args) {
31        new SwingPaint().setVisible(true);
32    }
33
34    private SwingPaint() {
35        super("お絵かき");
36        setSize(600, 600);
37        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
38        setLocationRelativeTo(null);
39        setResizable(false);
40
41        JPanel panel = new JPanel();
42        JButton clearBtn = new JButton("Clear");
43        clearBtn.addActionListener(e -> drawArea.clear());
44        panel.add(clearBtn);
45
46        JButton saveBtn = new JButton("Save...");
47        saveBtn.addActionListener(e -> drawArea.save());
48        panel.add(saveBtn);
49
50        JPanel controls = new JPanel(new BorderLayout());
51        controls.add(createColorButtons(), BorderLayout.NORTH);
52        controls.add(createSizeButtons(), BorderLayout.CENTER);
53        controls.add(panel, BorderLayout.EAST);
54
55        add(controls, BorderLayout.NORTH);
56        add(drawArea, BorderLayout.CENTER);
57    }
58
59    private JPanel createColorButtons() {
60        JToggleButton green = new JToggleButton("緑");
61        JToggleButton blue = new JToggleButton("青");
62        JToggleButton black = new JToggleButton("黒", true);
63        JToggleButton red = new JToggleButton("赤");
64        JToggleButton magenta = new JToggleButton("マゼンタ");
65        JToggleButton white = new JToggleButton("消しゴム");
66
67        ActionListener actionListener = new ActionListener() {
68            @Override public void actionPerformed(ActionEvent e) {
69                if (e.getSource() == black) {
70                    drawArea.setStrokeColor(Color.BLACK);
71                } else if (e.getSource() == blue) {
72                    drawArea.setStrokeColor(Color.BLUE);
73                } else if (e.getSource() == green) {
74                    drawArea.setStrokeColor(Color.GREEN);
75                } else if (e.getSource() == red) {
76                    drawArea.setStrokeColor(Color.RED);
77                } else if (e.getSource() == magenta) {
78                    drawArea.setStrokeColor(Color.MAGENTA);
79                } else if (e.getSource() == white) {
80                    drawArea.setStrokeColor(Color.WHITE);
81                }
82            }
83        };
84
85        ButtonGroup group = new ButtonGroup();
86        JPanel controls = new JPanel();
87        controls.add(new JLabel("Color"));
88
89        JToggleButton[] buttons = new JToggleButton[]{ green, blue, black, red, magenta, white };
90        for (JToggleButton button : buttons) {
91            button.addActionListener(actionListener);
92            group.add(button);
93            controls.add(button);
94        }
95
96        return controls;
97    }
98
99    private JPanel createSizeButtons() {
100        JToggleButton stroke1 = new JToggleButton("1", true);
101        JToggleButton stroke5 = new JToggleButton("5");
102        JToggleButton stroke10 = new JToggleButton("10");
103        JToggleButton stroke20 = new JToggleButton("20");
104
105        ActionListener actionListener = new ActionListener() {
106            @Override public void actionPerformed(ActionEvent e) {
107                if (e.getSource() == stroke1) {
108                    drawArea.setStrokeSize(1);
109                } else if (e.getSource() == stroke5) {
110                    drawArea.setStrokeSize(5);
111                } else if (e.getSource() == stroke10) {
112                    drawArea.setStrokeSize(10);
113                } else if (e.getSource() == stroke20) {
114                    drawArea.setStrokeSize(20);
115                }
116            }
117        };
118
119        ButtonGroup group = new ButtonGroup();
120        JPanel controls = new JPanel();
121        controls.add(new JLabel("Size"));
122
123        JToggleButton[] buttons = new JToggleButton[]{ stroke1, stroke5, stroke10, stroke20 };
124        for (JToggleButton button : buttons) {
125            button.addActionListener(actionListener);
126            group.add(button);
127            controls.add(button);
128        }
129
130        return controls;
131    }
132}
133
134class DrawArea extends JComponent {
135    private Image image;
136    private Graphics2D g2;
137    private int oldX, oldY;
138
139    public DrawArea() {
140        setDoubleBuffered(false);
141        addMouseListener(new MouseAdapter() {
142            @Override public void mousePressed(MouseEvent e) {
143                oldX = e.getX();
144                oldY = e.getY();
145            }
146        });
147
148        addMouseMotionListener(new MouseMotionAdapter() {
149            @Override public void mouseDragged(MouseEvent e) {
150                int currentX = e.getX();
151                int currentY = e.getY();
152
153                g2.drawLine(oldX, oldY, currentX, currentY);
154                repaint();
155
156                oldX = currentX;
157                oldY = currentY;
158            }
159        });
160    }
161
162    protected void paintComponent(Graphics g) {
163        if (image == null) {
164            image = createImage(getWidth(), getHeight());
165            g2 = (Graphics2D) image.getGraphics();
166            g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
167            clear();
168        }
169
170        g.drawImage(image, 0, 0, null);
171    }
172
173    public void clear() {
174        Paint p = g2.getPaint();
175        g2.setPaint(Color.WHITE);
176        g2.fillRect(0, 0, getWidth(), getHeight());
177        g2.setPaint(p);
178        repaint();
179    }
180
181    public void save() {
182        JFileChooser fileChooser = new JFileChooser(); // ファイルダイアログ
183        fileChooser.setFileFilter(new FileNameExtensionFilter("pngファイル", "png")); // ファイルの種類設定
184        if (fileChooser.showSaveDialog(this) != JFileChooser.APPROVE_OPTION) return; // OKじゃなければ何もせず抜ける
185
186        File file = fileChooser.getSelectedFile(); // 新しいファイルもしくは選択したファイル
187        String filePath = file.getPath();
188        if (!filePath.toLowerCase().endsWith(".png")) // 拡張子の確認
189            file = new File(filePath + ".png"); // 付いてなければ付ける
190
191        try {
192            ImageIO.write((BufferedImage) image, "png", file); // imageを指定フォーマットで指定パスに保存
193        } catch (Exception e) {
194            e.printStackTrace();
195        }
196    }
197
198    public void setStrokeColor(Color color) { g2.setPaint(color); }
199
200    public void setStrokeSize(int size) {
201        g2.setStroke(new BasicStroke(size, BasicStroke.CAP_ROUND, BasicStroke.JOIN_ROUND));
202    }
203}

投稿2021/01/26 09:31

TN8001

総合スコア8868

see: https://docs.oracle.com/javase/jp/8/docs/api/javax/imageio/ImageIO.html

java
1import javax.imageio.ImageIO;
2import java.awt.*;
3import java.awt.image.BufferedImage;
4import java.io.File;
5
6public class xxHoge {
7  public static final void main(final String[] args) throws Exception {
8    final BufferedImage image = new BufferedImage(100, 200, BufferedImage.TYPE_INT_ARGB);
9    final Graphics2D g = (Graphics2D) image.getGraphics();
10    g.setColor(Color.RED);
11    g.fill(new Rectangle(10, 20, 40, 50));
12    ImageIO.write(image, "png", new File("/tmp/xx.png"));
13  }
14}