3 * Copyright © 2014 František Kučera (frantovo.cz)
5 * This program is free software: you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License as published by
7 * the Free Software Foundation, either version 3 of the License, or
8 * (at your option) any later version.
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 * GNU General Public License for more details.
15 * You should have received a copy of the GNU General Public License
16 * along with this program. If not, see <http://www.gnu.org/licenses/>.
18 package cz.frantovo.copyImageResizer;
20 import java.awt.Graphics2D;
21 import java.awt.image.BufferedImage;
22 import java.io.IOException;
23 import java.io.InputStream;
24 import java.io.OutputStream;
25 import java.util.logging.Level;
26 import java.util.logging.Logger;
27 import java.util.regex.Pattern;
28 import javax.imageio.ImageIO;
32 * @author Ing. František Kučera (frantovo.cz)
34 public class SingleImageResizer {
36 private static final Logger log = Logger.getLogger(SingleImageResizer.class.getName());
44 * @return whether image was resized → if false, you should just copy the image after calling
45 * this method. Image is resized if larger than requested size or if {@linkplain SizeSpecification#isResizeSmaller()
47 * @throws ResizeException
49 public boolean resize(InputStream input, OutputStream output, SizeSpecification size, ImageFormat outputFormat) throws ResizeException {
51 BufferedImage image = readImage(input);
52 if (shouldResize(image, size)) {
53 BufferedImage resized = resize(image, size.getWidth(), size.getHeight(), image.getType());
54 ImageIO.write(resized, outputFormat.getFormat(), output);
59 } catch (IOException e) {
60 throw new ResizeException("Error while resizing image", e);
64 private BufferedImage resize(BufferedImage original, int maxWidth, int maxHeight, int type) {
68 float aspectRatio = (float) original.getWidth() / (float) original.getHeight();
70 if (aspectRatio > 1) {
72 height = Math.max(Math.round(maxWidth / aspectRatio), 1);
74 width = Math.max(Math.round(maxHeight * aspectRatio), 1);
78 if (type == BufferedImage.TYPE_CUSTOM) {
79 log.log(Level.FINER, "Setting default image type: from TYPE_CUSTOM to TYPE_INT_ARGB");
80 type = BufferedImage.TYPE_INT_ARGB;
83 BufferedImage resized = new BufferedImage(width, height, type);
84 Graphics2D g = resized.createGraphics();
85 g.drawImage(original, 0, 0, width, height, null);
91 private static BufferedImage readImage(InputStream input) throws ResizeException {
93 return ImageIO.read(input);
94 } catch (IOException e) {
95 throw new ResizeException("Unable to read image from stream", e);
99 private static boolean shouldResize(BufferedImage input, SizeSpecification requested) {
100 if (requested.isResizeSmaller()) {
101 return input.getHeight() != requested.getHeight() || input.getWidth() != requested.getWidth();
103 return input.getHeight() > requested.getHeight() || input.getWidth() > requested.getWidth();
107 public static enum ImageFormat {
109 JPEG("jpg", Pattern.compile(".*\\.(jpg|jpeg)$", Pattern.CASE_INSENSITIVE)),
110 PNG("png", Pattern.compile(".*\\.png$", Pattern.CASE_INSENSITIVE)),
111 GIF("gif", Pattern.compile(".*\\.gif$", Pattern.CASE_INSENSITIVE));
113 private final String format;
114 private final Pattern regex;
116 private ImageFormat(String format, Pattern regex) {
117 this.format = format;
122 * @return format name for {@linkplain ImageIO#write(java.awt.image.RenderedImage, java.lang.String, java.io.File)
124 public String getFormat() {
128 public static ImageFormat getMatching(String fileName) {
129 for (ImageFormat type : values()) {
130 if (type.regex.matcher(fileName).matches()) {