Lots of changes (#70)

Image extraction and conversion to formats 

Multi parallel file execution for all forms so you can input multiple files quickly 

Any file at all pdf using libreoffice, super powerful
Sadly makes docker image larger but worth it 

OCR PDF using ocr my pdf
Works awesomely for adding text to a image

Improved compression using ocr my pdf app

Settings page with custom download options such as 
- open in same window
- open in new window
- download
- download as zip

Update detection in settings page it should show notification if there is a update (very hidden)

UI cleanups

Add other image formats to PDF to Image

Various fies to icons, and pdf.js usage

src/main/java/stirling/software/SPDF/controller/ExtractImagesController.java

@@ -0,0 +1,129 @@
+package stirling.software.SPDF.controller;
+
+import java.awt.Graphics2D;
+import java.awt.Image;
+import java.awt.image.BufferedImage;
+import java.awt.image.RenderedImage;
+import java.io.ByteArrayOutputStream;
+import java.io.IOException;
+import java.util.zip.Deflater;
+import java.util.zip.ZipEntry;
+import java.util.zip.ZipOutputStream;
+
+import javax.imageio.ImageIO;
+
+import org.apache.pdfbox.cos.COSName;
+import org.apache.pdfbox.pdmodel.PDDocument;
+import org.apache.pdfbox.pdmodel.PDPage;
+import org.apache.pdfbox.pdmodel.graphics.image.PDImageXObject;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import org.springframework.core.io.ByteArrayResource;
+import org.springframework.core.io.Resource;
+import org.springframework.http.HttpHeaders;
+import org.springframework.http.HttpStatus;
+import org.springframework.http.MediaType;
+import org.springframework.http.ResponseEntity;
+import org.springframework.stereotype.Controller;
+import org.springframework.ui.Model;
+import org.springframework.web.bind.annotation.GetMapping;
+import org.springframework.web.bind.annotation.PostMapping;
+import org.springframework.web.bind.annotation.RequestParam;
+import org.springframework.web.multipart.MultipartFile;
+
+@Controller
+public class ExtractImagesController {
+
+    private static final Logger logger = LoggerFactory.getLogger(ExtractImagesController.class);
+
+    @GetMapping("/extract-images")
+    public String extractImagesForm(Model model) {
+        model.addAttribute("currentPage", "extract-images");
+        return "extract-images";
+    }
+
+    @PostMapping("/extract-images")
+    public ResponseEntity<Resource> extractImages(@RequestParam("fileInput") MultipartFile file, @RequestParam("format") String format) throws IOException {
+        
+        System.out.println(System.currentTimeMillis() + "file=" + file.getName() + ", format=" + format);
+        PDDocument document = PDDocument.load(file.getBytes());
+
+        // Create ByteArrayOutputStream to write zip file to byte array
+        ByteArrayOutputStream baos = new ByteArrayOutputStream();
+
+        // Create ZipOutputStream to create zip file
+        ZipOutputStream zos = new ZipOutputStream(baos);
+
+        // Set compression level
+        zos.setLevel(Deflater.BEST_COMPRESSION);
+
+        int imageIndex = 1;
+        
+        int pageNum = 1;
+        // Iterate over each page
+        for (PDPage page : document.getPages()) {
+            ++pageNum;
+            // Extract images from page
+            for (COSName name : page.getResources().getXObjectNames()) {
+                if (page.getResources().isImageXObject(name)) {
+                    PDImageXObject image = (PDImageXObject) page.getResources().getXObject(name);
+
+                    // Convert image to desired format
+                    RenderedImage renderedImage = image.getImage();
+                    BufferedImage bufferedImage = null;
+                    if (format.equalsIgnoreCase("png")) {
+                        bufferedImage = new BufferedImage(renderedImage.getWidth(), renderedImage.getHeight(),
+                                BufferedImage.TYPE_INT_ARGB);
+                    } else if (format.equalsIgnoreCase("jpeg") || format.equalsIgnoreCase("jpg")) {
+                        bufferedImage = new BufferedImage(renderedImage.getWidth(), renderedImage.getHeight(),
+                                BufferedImage.TYPE_INT_RGB);
+                    } else if (format.equalsIgnoreCase("gif")) {
+                        bufferedImage = new BufferedImage(renderedImage.getWidth(), renderedImage.getHeight(),
+                                BufferedImage.TYPE_BYTE_INDEXED);
+                    } 
+
+                    // Write image to zip file
+                    String imageName = "Image " + imageIndex + " (Page " + pageNum + ")." + format;
+                    ZipEntry zipEntry = new ZipEntry(imageName);
+                    zos.putNextEntry(zipEntry);
+                    
+                    Graphics2D g = bufferedImage.createGraphics();
+                    g.drawImage((Image) renderedImage, 0, 0, null);
+                    g.dispose();
+                    // Write image bytes to zip file
+                    ByteArrayOutputStream imageBaos = new ByteArrayOutputStream();
+                    ImageIO.write(bufferedImage, format, imageBaos);
+                    zos.write(imageBaos.toByteArray());
+                
+                    
+                    zos.closeEntry();
+                    imageIndex++;
+                }
+            }       
+        }
+
+        // Close ZipOutputStream and PDDocument
+        zos.close();
+        document.close();
+
+        // Create ByteArrayResource from byte array
+        byte[] zipContents = baos.toByteArray();
+        ByteArrayResource resource = new ByteArrayResource(zipContents);
+
+        // Set content disposition header to indicate that the response should be downloaded as a file
+        HttpHeaders headers = new HttpHeaders();
+        headers.setContentLength(zipContents.length);
+        headers.add(HttpHeaders.CONTENT_DISPOSITION, "attachment; filename=" + file.getOriginalFilename().replaceFirst("[.][^.]+$", "") + "_extracted-images.zip");
+        
+        // Return ResponseEntity with ByteArrayResource and headers
+        return ResponseEntity
+                .status(HttpStatus.OK)
+                .headers(headers)
+                
+                .header("Cache-Control", "no-cache")
+                .contentType(MediaType.APPLICATION_OCTET_STREAM)
+                .body(resource);
+    }
+    
+    
+}