Quickly hacked together capability to thumbnail animated gifs based on code snippets...

[meviz.git] / src / main / java / eu / svjatoslav / meviz / htmlindexer / Utils.java

diff --git a/src/main/java/eu/svjatoslav/meviz/htmlindexer/Utils.java b/src/main/java/eu/svjatoslav/meviz/htmlindexer/Utils.java
index 01f2d37..ba0d23c 100755 (executable)
--- a/src/main/java/eu/svjatoslav/meviz/htmlindexer/Utils.java
+++ b/src/main/java/eu/svjatoslav/meviz/htmlindexer/Utils.java
@@ -11,12 +11,20 @@ package eu.svjatoslav.meviz.htmlindexer;
 
 import eu.svjatoslav.meviz.htmlindexer.layouts.Layout;
 import eu.svjatoslav.meviz.htmlindexer.layouts.MixedLayout;
+import org.w3c.dom.NamedNodeMap;
+import org.w3c.dom.Node;
+import org.w3c.dom.NodeList;
 
+import javax.imageio.ImageReader;
+import javax.imageio.metadata.IIOMetadata;
+import javax.imageio.metadata.IIOMetadataNode;
+import java.awt.*;
 import java.awt.image.BufferedImage;
 import java.io.BufferedReader;
 import java.io.File;
 import java.io.FileReader;
 import java.io.IOException;
+import java.util.ArrayList;
 import java.util.HashSet;
 import java.util.zip.CRC32;
 
@@ -139,4 +147,111 @@ public class Utils {
 //            throw new RuntimeException(e);
 //        }
     }
+
+    public static ImageFrame[] readGIF(ImageReader reader) throws IOException {
+        ArrayList<ImageFrame> frames = new ArrayList<ImageFrame>(2);
+
+        int width = -1;
+        int height = -1;
+
+        IIOMetadata metadata = reader.getStreamMetadata();
+        if (metadata != null) {
+            IIOMetadataNode globalRoot = (IIOMetadataNode) metadata.getAsTree(metadata.getNativeMetadataFormatName());
+
+            NodeList globalScreenDescriptor = globalRoot.getElementsByTagName("LogicalScreenDescriptor");
+
+            if (globalScreenDescriptor != null && globalScreenDescriptor.getLength() > 0) {
+                IIOMetadataNode screenDescriptor = (IIOMetadataNode) globalScreenDescriptor.item(0);
+
+                if (screenDescriptor != null) {
+                    width = Integer.parseInt(screenDescriptor.getAttribute("logicalScreenWidth"));
+                    height = Integer.parseInt(screenDescriptor.getAttribute("logicalScreenHeight"));
+                }
+            }
+        }
+
+        BufferedImage master = null;
+        Graphics2D masterGraphics = null;
+
+        for (int frameIndex = 0;; frameIndex++) {
+            BufferedImage image;
+            try {
+                image = reader.read(frameIndex);
+            } catch (IndexOutOfBoundsException io) {
+                break;
+            }
+
+            if (width == -1 || height == -1) {
+                width = image.getWidth();
+                height = image.getHeight();
+            }
+
+            IIOMetadataNode root = (IIOMetadataNode) reader.getImageMetadata(frameIndex).getAsTree("javax_imageio_gif_image_1.0");
+            IIOMetadataNode gce = (IIOMetadataNode) root.getElementsByTagName("GraphicControlExtension").item(0);
+            int delay = Integer.valueOf(gce.getAttribute("delayTime"));
+            String disposal = gce.getAttribute("disposalMethod");
+
+            int x = 0;
+            int y = 0;
+
+            if (master == null) {
+                master = new BufferedImage(width, height, BufferedImage.TYPE_INT_ARGB);
+                masterGraphics = master.createGraphics();
+                masterGraphics.setBackground(new Color(0, 0, 0, 0));
+            } else {
+                NodeList children = root.getChildNodes();
+                for (int nodeIndex = 0; nodeIndex < children.getLength(); nodeIndex++) {
+                    Node nodeItem = children.item(nodeIndex);
+                    if (nodeItem.getNodeName().equals("ImageDescriptor")) {
+                        NamedNodeMap map = nodeItem.getAttributes();
+                        x = Integer.valueOf(map.getNamedItem("imageLeftPosition").getNodeValue());
+                        y = Integer.valueOf(map.getNamedItem("imageTopPosition").getNodeValue());
+                    }
+                }
+            }
+            masterGraphics.drawImage(image, x, y, null);
+
+            BufferedImage copy = new BufferedImage(master.getColorModel(), master.copyData(null), master.isAlphaPremultiplied(), null);
+            frames.add(new ImageFrame(copy, delay, disposal));
+
+            if (disposal.equals("restoreToPrevious")) {
+                BufferedImage from = null;
+                for (int i = frameIndex - 1; i >= 0; i--) {
+                    if (!frames.get(i).getDisposal().equals("restoreToPrevious") || frameIndex == 0) {
+                        from = frames.get(i).image;
+                        break;
+                    }
+                }
+
+                master = new BufferedImage(from.getColorModel(), from.copyData(null), from.isAlphaPremultiplied(), null);
+                masterGraphics = master.createGraphics();
+                masterGraphics.setBackground(new Color(0, 0, 0, 0));
+            } else if (disposal.equals("restoreToBackgroundColor")) {
+                masterGraphics.clearRect(x, y, image.getWidth(), image.getHeight());
+            }
+        }
+        reader.dispose();
+
+        return frames.toArray(new ImageFrame[frames.size()]);
+    }
+
+    public static class ImageFrame {
+        private final int delay;
+        public BufferedImage image;
+        private final String disposal;
+
+        public ImageFrame(BufferedImage image, int delay, String disposal) {
+            this.image = image;
+            this.delay = delay;
+            this.disposal = disposal;
+        }
+
+        public int getDelay() {
+            return delay;
+        }
+
+        public String getDisposal() {
+            return disposal;
+        }
+    }
 }