java로 thumbnail 생성

고화질 썸네일을 찾기 위해 이것저것 테스트해 본 것이 아까워서 적어본다.

나중에 재사용할 수 있도록 ...

 

 

1. 라이브러리 추가 없이 기본으로 생성하는 방법(1)

public Bufferedimage createThumbnail(MultipartFile mfile, int thumbWidth, int thumbHeight){

      InputStream in = mfile.getInputStream();

      BufferedImage originalImage = ImageIO.read(in);

      BufferedImage thumbImage = new BufferedImage(width, height, BufferedImage.TYPE_INT_BGR);

      Graphics2D g = thumbImage.createGraphics();

      g.setBackground(Color.WHITE);

      g.drawImage(originalImage, 0, 0, width, height, null);

      g.dispose();

     //퀄리티를 높히려면 RendringHints를 적용하라고 하는데... 효과가 눈에 잘 보이지 않는다 ㅠㅠ

     //g.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
     //g.setRenderingHint(RenderingHints.KEY_INTERPOLATION, RenderingHints.VALUE_INTERPOLATION_BILINEAR);
     //g.setRenderingHint(RenderingHints.KEY_COLOR_RENDERING, RenderingHints.VALUE_COLOR_RENDER_QUALITY);
     //g.setRenderingHint(RenderingHints.KEY_DITHERING, RenderingHints.VALUE_DITHER_ENABLE);
     //g.setRenderingHint(RenderingHints.KEY_RENDERING, RenderingHints.VALUE_RENDER_QUALITY);

      in.close();

      return thumbImage;

}

 

 

2. 라이브러리 추가 없이 기본으로 생성하는 방법(2)

public Bufferedimage createThumbnail(MultipartFile mfile, int thumbWidth, int thumbHeight){

      InputStream in = mfile.getInputStream();

      Image originalImage = null;

 

      String imgOriginalName = mfile.getOriginalFilename();
      String imgSuffix = imgOriginalName.indexOf(".") > 0 ?

                                        imgOriginalName.substring(imgOriginalName.lastIndexOf(".")) : "";

 

      if(imgSuffix.equals("png") || imgSuffix.equals("gif")){

            originalImage = ImageIO.read(in);

      } else {

            originalImage = new imageIcon(IOUtils.toByteArray(in)).getImage(); 

      }

      int originalWidth = originalImage.getWidth(null);

      int originalHeight = originalImage.getHeight(null);

  

      if((originalWidth > thumbWidth) || (originalHeight > thumbHeight)){

            double deltaWidth = (originalWidth - thumbWidth) / thumbWidth;

            double deltaHeight = (originalHeight - thumbHeight) / thumbHeight;

            double scaleFactor = 1.0;

 

            if(deltaHeight > deltaWidth){

                   scaleFactor = (double) thumbHeight / (double) originalHeight;

            } else {

                   scaleFactor = (double) thumbWidth / (double) originalWidth;

            }

 

            thumbWidth = originalWidth * scaleFactor;

            thumbHeight = originalHeight * scaleFactor;

      }

 

      if(thumbWidth < 1) thumbWidth = 1;

      if(thumbHeight < 1) thumbHeight = 1;

 

      Image imgTarget = originalImage.getScaledInstance(thumbWidth, thumbHeight, Image.SCALE_SMOOTH);

      int pixels[] = new int[thumbWidth * thumbHeight];

      PixelGrabber pg = new PixelGrabber(imgTarget, 0, 0, thumbWidth, thumbHeight, pixels, 0, thumbWidth);

    

      try{

           pg.grabPixels();

      } catch (InterruptedException e){

           throw new IOException(e.getMessage());

      }

 

      BufferedImage thumbImage = new BufferedImage(thumbWidth, thumbHeight, BufferedImage.TYPE_INT_BGR);

      thumbImage.setRGB(0, 0, thumbWidth, thumbHeight, pixel, 0, thumbWidth);

      in.close();

      return thumbImage;

}

 

 

3. java-image-scaling 라이브러리 이용

*출처 : https://handcoding.tistory.com/147

*pom.xml에 dependency를 추가한다.

<dependency>
    <group>com.mortennobel</group> 
    <artifactId>java-image-scaling</artifactId> 
    <version>0.8.6</version>
</dependency>

 

public Bufferedimage createThumbnail(MultipartFile mfile, int thumbWidth, int thumbHeight){

      InputStream in = mfile.getInputStream();

      BufferedImage originalImage = ImageIO.read(in);

      MultiStepRescaleOp rescale = new MultiStepRescaleOp(thumbWidth, thumbHeight);

      rescale.setUnsharpenMask(AdvancedResizeOp.UnsharpenMask.Soft);      

      BufferedImage thumbImage = rescale.filter(originalImage, null);

      in.close();

      return thumbImage;

}

 

 

4. imagscalr 라이브러리 이용

*출처 : https://offbyone.tistory.com/114

*pom.xml에 dependency를 추가한다.

<dependency>
    <group>org.imgscalr</group> 
    <artifactId>imgscalr-lib</artifactId> 
    <version>4.2</version>
</dependency>

 

public Bufferedimage createThumbnail(MultipartFile mfile, int thumbWidth, int thumbHeight){

      InputStream in = mfile.getInputStream();

      BufferedImage originalImage = ImageIO.read(in);

      BufferedImage thumbImage = Scalr.resize(originalImage, thumbWidth, thumbHeight);

      //만약 자동 조절 기능을 사용하려면

      //가로 기준일 때, 

      // BufferedImage thumbImage = Scalr.resize(originalImage, Scalr.Method.AUTOMATIC, Scalr.Mode.FIT_TO_WIDTH, thumbWidth);

      //세로 기준일 때,

      // BufferedImage thumbImage = Scalr.resize(originalImage, Scalr.Method.AUTOMATIC, Scalr.Mode.FIT_TO_HEIGHT, thumbHeight);

      in.close();

      return thumbImage;

}

 

 

5. thumbnailator 라이브러리 이용

*출처 : https://codeday.me/ko/qa/20190321/112754.html

*pom.xml에 dependency를 추가한다.

<dependency>
    <group>net.coobird</group> 
    <artifactId>thumbnailator</artifactId> 
    <version>0.4.8</version>
</dependency>

 

public Bufferedimage createThumbnail(MultipartFile mfile, int thumbWidth, int thumbHeight){

      InputStream in = mfile.getInputStream();

      BufferedImage originalImage = ImageIO.read(in);

      BufferedImage thumbImage = Thumbnails.of(originalImage).size(width, height).asBufferedimage();

      //보다 고화질을 얻기 위해서는

      //Thumbnails.of(originalImage).size(width, height).outputQuality(1.0f).outputFormat("png").asBufferedimage();

      in.close();

      return thumbImage;

}