Closes #215: handle pptx files

docs-core/src/main/java/com/sismics/docs/core/util/format/FormatHandlerUtil.java

@@ -15,6 +15,7 @@ public class FormatHandlerUtil {
      */
     private static final List<Class<? extends FormatHandler>> FORMAT_HANDLERS = Lists.newArrayList(
             DocxFormatHandler.class,
+            PptxFormatHandler.class,
             OdtFormatHandler.class,
             VideoFormatHandler.class,
             PdfFormatHandler.class,

docs-core/src/main/java/com/sismics/docs/core/util/format/PptxFormatHandler.java

@@ -0,0 +1,97 @@
+package com.sismics.docs.core.util.format;
+
+import com.google.common.io.Closer;
+import com.sismics.util.mime.MimeType;
+import org.apache.pdfbox.io.MemoryUsageSetting;
+import org.apache.pdfbox.pdmodel.PDDocument;
+import org.apache.pdfbox.pdmodel.PDPage;
+import org.apache.pdfbox.pdmodel.PDPageContentStream;
+import org.apache.pdfbox.pdmodel.common.PDRectangle;
+import org.apache.pdfbox.pdmodel.graphics.image.LosslessFactory;
+import org.apache.pdfbox.pdmodel.graphics.image.PDImageXObject;
+import org.apache.poi.xslf.extractor.XSLFPowerPointExtractor;
+import org.apache.poi.xslf.usermodel.XMLSlideShow;
+import org.apache.poi.xslf.usermodel.XSLFSlide;
+
+import java.awt.*;
+import java.awt.geom.Rectangle2D;
+import java.awt.image.BufferedImage;
+import java.io.InputStream;
+import java.nio.file.Files;
+import java.nio.file.Path;
+
+/**
+ * PPTX format handler.
+ *
+ * @author bgamard
+ */
+public class PptxFormatHandler implements FormatHandler {
+    /**
+     * Cached PPTX loaded file.
+     */
+    private XMLSlideShow slideShow;
+
+    @Override
+    public boolean accept(String mimeType) {
+        return MimeType.OFFICE_PRESENTATION.equals(mimeType);
+    }
+
+    @Override
+    public BufferedImage generateThumbnail(Path file) throws Exception {
+        XMLSlideShow pptx = loadPPtxFile(file);
+        if (pptx.getSlides().length > 0) {
+            return generateImageFromSlide(pptx, 0);
+        }
+
+        return null;
+    }
+
+    @Override
+    public String extractContent(String language, Path file) throws Exception {
+        XMLSlideShow pptx = loadPPtxFile(file);
+        return new XSLFPowerPointExtractor(pptx).getText();
+    }
+
+    @Override
+    public void appendToPdf(Path file, PDDocument doc, boolean fitImageToPage, int margin, MemoryUsageSetting memUsageSettings, Closer closer) throws Exception {
+        XMLSlideShow pptx = loadPPtxFile(file);
+        XSLFSlide[] slides = pptx.getSlides();
+        Dimension pgsize = pptx.getPageSize();
+        for (int slideIndex = 0; slideIndex < slides.length; slideIndex++) {
+            // One PDF page per slide
+            PDPage page = new PDPage(new PDRectangle(pgsize.width, pgsize.height));
+            try (PDPageContentStream contentStream = new PDPageContentStream(doc, page)) {
+                BufferedImage bim = generateImageFromSlide(pptx, slideIndex);
+                PDImageXObject pdImage = LosslessFactory.createFromImage(doc, bim);
+                contentStream.drawImage(pdImage, 0, page.getMediaBox().getHeight() - pdImage.getHeight());
+            }
+            doc.addPage(page);
+        }
+    }
+
+    private XMLSlideShow loadPPtxFile(Path file) throws Exception {
+        if (slideShow == null) {
+            try (InputStream inputStream = Files.newInputStream(file)) {
+                slideShow = new XMLSlideShow(inputStream);
+            }
+        }
+        return slideShow;
+    }
+
+    /**
+     * Generate an image from a PPTX slide.
+     *
+     * @param pptx PPTX
+     * @param slideIndex Slide index
+     * @return Image
+     */
+    private BufferedImage generateImageFromSlide(XMLSlideShow pptx, int slideIndex) {
+        Dimension pgsize = pptx.getPageSize();
+        BufferedImage img = new BufferedImage(pgsize.width, pgsize.height,BufferedImage.TYPE_INT_RGB);
+        Graphics2D graphics = img.createGraphics();
+        graphics.setPaint(Color.white);
+        graphics.fill(new Rectangle2D.Float(0, 0, pgsize.width, pgsize.height));
+        pptx.getSlides()[slideIndex].draw(graphics);
+        return img;
+    }
+}

docs-core/src/main/java/com/sismics/util/mime/MimeType.java

@@ -20,6 +20,10 @@ public class MimeType {
     
     public static final String OFFICE_DOCUMENT = "application/vnd.openxmlformats-officedocument.wordprocessingml.document";
 
+    public static final String OFFICE_PRESENTATION = "application/vnd.openxmlformats-officedocument.presentationml.presentation";
+
+    public static final String OFFICE_SHEET = "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet";
+
     public static final String TEXT_PLAIN = "text/plain";
 
     public static final String TEXT_CSV = "text/csv";

docs-core/src/main/java/com/sismics/util/mime/MimeTypeUtil.java

@@ -145,6 +145,9 @@ public class MimeTypeUtil {
                     if (content.contains(MimeType.OFFICE_DOCUMENT)) {
                         mimeType =  MimeType.OFFICE_DOCUMENT;
                         break;
+                    } else if (content.contains(MimeType.OFFICE_PRESENTATION)) {
+                        mimeType = MimeType.OFFICE_PRESENTATION;
+                        break;
                     }
                 }