From 7218f83513cf8337a3cca24b4cf99864232a7b23 Mon Sep 17 00:00:00 2001
From: Jan Sladek <Jan.Sladek@mni.thm.de>
Date: Tue, 10 Mar 2015 16:24:00 +0100
Subject: [PATCH] Worked on #15324. Added rescale capabilities and thumbnail
field in DB
---
src/main/java/de/thm/arsnova/ImageUtils.java | 75 +++++++++++++++++++
.../java/de/thm/arsnova/dao/CouchDBDao.java | 3 +
.../java/de/thm/arsnova/entities/Answer.java | 9 +++
3 files changed, 87 insertions(+)
diff --git a/src/main/java/de/thm/arsnova/ImageUtils.java b/src/main/java/de/thm/arsnova/ImageUtils.java
index f291f8234..3c8cf374f 100644
--- a/src/main/java/de/thm/arsnova/ImageUtils.java
+++ b/src/main/java/de/thm/arsnova/ImageUtils.java
@@ -17,12 +17,16 @@
*/
package de.thm.arsnova;
+import java.awt.Graphics2D;
import java.awt.image.BufferedImage;
+import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.net.MalformedURLException;
import java.net.URL;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
import javax.imageio.ImageIO;
@@ -40,6 +44,9 @@ public class ImageUtils {
// Or whatever size you want to read in at a time.
private static final int CHUNK_SIZE = 4096;
+
+ public static final Pattern BASE64_IMAGE_PREFIX_PATTERN = Pattern.compile("data:image/(.*);base64,(.*)");
+
private ImageUtils() {
}
@@ -72,6 +79,74 @@ public class ImageUtils {
return null;
}
+
+ /**
+ * Checks if a String starts with the base 64 prefix.
+ *
+ * @param maybeImage The Image as a base64 encoded {@link String}
+ * @return true if the string is a potentially a base 64 encoded image.
+ */
+ public static boolean isBase64EncodedImage(String maybeImage) {
+ if (maybeImage == null) {
+ return false;
+ }
+ else if (maybeImage.isEmpty()) {
+ return false;
+ }
+ else
+ return BASE64_IMAGE_PREFIX_PATTERN.matcher(maybeImage).matches();
+ }
+
+ public static String rescaleImage(String originalImageString, final int width, final int height) {
+ if (!isBase64EncodedImage(originalImageString)) return null;
+ else {
+ Matcher imageMatcher = BASE64_IMAGE_PREFIX_PATTERN.matcher(originalImageString);
+ if (!imageMatcher.find()) {
+ // shouldn't ever happen, because the regex is already checked.
+ return null;
+ }
+ String extension = imageMatcher.group(1);
+ String base64String = imageMatcher.group(2);
+
+ byte[] imageData = Base64.decodeBase64(base64String);
+ try {
+ BufferedImage originalImage = ImageIO.read(new ByteArrayInputStream(imageData));
+ BufferedImage newImage = new BufferedImage(width, height, BufferedImage.TYPE_INT_ARGB);
+ Graphics2D g = newImage.createGraphics();
+
+ final double ratio = ((double) originalImage.getWidth()) / ((double) originalImage.getHeight());
+
+ int x = 0, y = 0, w = width, h = height;
+ if (originalImage.getWidth() > originalImage.getHeight()) {
+ final int newWidth = (int) Math.round((float) height * ratio);
+ x = -(newWidth - width) >> 1;
+ w = newWidth;
+ } else if (originalImage.getWidth() < originalImage.getHeight()) {
+ final int newHeight = (int) Math.round((float) width / ratio);
+ y = -(newHeight - height) >> 1;
+ h = newHeight;
+ }
+ g.drawImage(originalImage, x, y, w, h, null);
+ g.dispose();
+
+ StringBuilder result = new StringBuilder();
+ result.append("data:image/");
+ result.append(extension);
+ result.append(";base64,");
+
+ ByteArrayOutputStream output = new ByteArrayOutputStream();
+ ImageIO.write(newImage, extension, output);
+
+ output.flush();
+ output.close();
+
+ return Base64.encodeBase64String(output.toByteArray());
+ } catch (IOException e) {
+ LOGGER.error(e.getLocalizedMessage());
+ return null;
+ }
+ }
+ }
/**
* Gets the bytestream of an image url.
diff --git a/src/main/java/de/thm/arsnova/dao/CouchDBDao.java b/src/main/java/de/thm/arsnova/dao/CouchDBDao.java
index 13ad2949e..1e2b29a3a 100644
--- a/src/main/java/de/thm/arsnova/dao/CouchDBDao.java
+++ b/src/main/java/de/thm/arsnova/dao/CouchDBDao.java
@@ -1257,6 +1257,7 @@ public class CouchDBDao implements IDatabaseDao, ApplicationEventPublisherAware
a.put("piRound", answer.getPiRound());
a.put("abstention", answer.isAbstention());
a.put("answerImage", answer.getAnswerImage());
+ a.put("answerThumbnailImage", answer.getAnswerThumbnailImage());
AnswerQueueElement answerQueueElement = new AnswerQueueElement(session, question, answer, user);
this.answerQueue.offer(new AbstractMap.SimpleEntry<Document, AnswerQueueElement>(a, answerQueueElement));
return answer;
@@ -1306,6 +1307,8 @@ public class CouchDBDao implements IDatabaseDao, ApplicationEventPublisherAware
a.put("abstention", answer.isAbstention());
a.put("questionValue", answer.getQuestionValue());
a.put("answerImage", answer.getAnswerImage());
+
+ a.put("answerThumbnailImage", answer.getAnswerThumbnailImage());
database.saveDocument(a);
answer.set_rev(a.getRev());
return answer;
diff --git a/src/main/java/de/thm/arsnova/entities/Answer.java b/src/main/java/de/thm/arsnova/entities/Answer.java
index 33d5b349a..5d7023eea 100644
--- a/src/main/java/de/thm/arsnova/entities/Answer.java
+++ b/src/main/java/de/thm/arsnova/entities/Answer.java
@@ -37,6 +37,7 @@ public class Answer {
private boolean abstention;
private int abstentionCount;
private String answerImage;
+ private String answerThumbnailImage;
public Answer() {
this.type = "skill_question_answer";
@@ -121,6 +122,14 @@ public class Answer {
public void setAnswerImage(String answerImage) {
this.answerImage = answerImage;
}
+
+ public String getAnswerThumbnailImage() {
+ return answerThumbnailImage;
+ }
+
+ public void setAnswerThumbnailImage(String answerThumbnailImage) {
+ this.answerThumbnailImage = answerThumbnailImage;
+ }
public final void setUser(final String user) {
this.user = user;
--
GitLab