Question

我有一张PNG图片，我想调整它的大小。我怎样才能做到这一点？虽然我已经完成this但我无法理解该片段。

Answer 1

如果您有java.awt.Image，则重新设置它不需要任何其他库。只是做：

Image newImage = yourImage.getScaledInstance(newWidth, newHeight, Image.SCALE_DEFAULT);

苛刻地，用指定图像的尺寸替换 newWidth和newHeight。
注意最后一个参数：它告诉运行时要用于调整大小的算法。

有些算法会产生非常精确的结果，但这些算法需要很长时间才能完成您可以使用以下任何算法：

Image.SCALE_DEFAULT：使用默认的图像缩放算法。
Image.SCALE_FAST：选择一种图像缩放算法，该算法比缩放图像的平滑度具有更高的缩放速度优先级。
Image.SCALE_SMOOTH：选择图像缩放算法，使图像平滑度优先于缩放速度。
Image.SCALE_AREA_AVERAGING：使用区域平均图像缩放算法。
Image.SCALE_REPLICATE：使用ReplicateScaleFilter类中包含的图像缩放算法。

有关详细信息，请参阅Javadoc。

Answer 2

我们这样做是为了创建图像的缩略图：

  BufferedImage tThumbImage = new BufferedImage( tThumbWidth, tThumbHeight, BufferedImage.TYPE_INT_RGB );
  Graphics2D tGraphics2D = tThumbImage.createGraphics(); //create a graphics object to paint to
  tGraphics2D.setBackground( Color.WHITE );
  tGraphics2D.setPaint( Color.WHITE );
  tGraphics2D.fillRect( 0, 0, tThumbWidth, tThumbHeight );
  tGraphics2D.setRenderingHint( RenderingHints.KEY_INTERPOLATION, RenderingHints.VALUE_INTERPOLATION_BILINEAR );
  tGraphics2D.drawImage( tOriginalImage, 0, 0, tThumbWidth, tThumbHeight, null ); //draw the image scaled

  ImageIO.write( tThumbImage, "JPG", tThumbnailTarget ); //write the image to a file

Answer 3

试试这个：

ImageIcon icon = new ImageIcon(UrlToPngFile);
Image scaleImage = icon.getImage().getScaledInstance(28, 28,Image.SCALE_DEFAULT);

Answer 4

高质量调整图像大小：

private static InputStream resizeImage(InputStream uploadedInputStream, String fileName, int width, int height) {

        try {
            BufferedImage image = ImageIO.read(uploadedInputStream);
            Image originalImage= image.getScaledInstance(width, height, Image.SCALE_DEFAULT);

            int type = ((image.getType() == 0) ? BufferedImage.TYPE_INT_ARGB : image.getType());
            BufferedImage resizedImage = new BufferedImage(width, height, type);

            Graphics2D g2d = resizedImage.createGraphics();
            g2d.drawImage(originalImage, 0, 0, width, height, null);
            g2d.dispose();
            g2d.setComposite(AlphaComposite.Src);
            g2d.setRenderingHint(RenderingHints.KEY_INTERPOLATION,RenderingHints.VALUE_INTERPOLATION_BILINEAR);
            g2d.setRenderingHint(RenderingHints.KEY_RENDERING,RenderingHints.VALUE_RENDER_QUALITY);
            g2d.setRenderingHint(RenderingHints.KEY_ANTIALIASING,RenderingHints.VALUE_ANTIALIAS_ON);

            ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream();

            ImageIO.write(resizedImage, fileName.split("\\.")[1], byteArrayOutputStream);
            return new ByteArrayInputStream(byteArrayOutputStream.toByteArray());
        } catch (IOException e) {
            // Something is going wrong while resizing image
            return uploadedInputStream;
        }
    }

Answer 5

Java中的简单方法

public void resize(String inputImagePath,
            String outputImagePath, int scaledWidth, int scaledHeight)
            throws IOException {
        // reads input image
        File inputFile = new File(inputImagePath);
        BufferedImage inputImage = ImageIO.read(inputFile);
 
        // creates output image
        BufferedImage outputImage = new BufferedImage(scaledWidth,
                scaledHeight, inputImage.getType());
 
        // scales the input image to the output image
        Graphics2D g2d = outputImage.createGraphics();
        g2d.drawImage(inputImage, 0, 0, scaledWidth, scaledHeight, null);
        g2d.dispose();
 
        // extracts extension of output file
        String formatName = outputImagePath.substring(outputImagePath
                .lastIndexOf(".") + 1);
 
        // writes to output file
        ImageIO.write(outputImage, formatName, new File(outputImagePath));
    }

Answer 6

            int newHeight = 150;
            int newWidth = 150; 
            holder.iv_arrow.requestLayout();
            holder.iv_arrow.getLayoutParams().height = newHeight;
            holder.iv_arrow.getLayoutParams().width = newWidth;
            holder.iv_arrow.setScaleType(ImageView.ScaleType.FIT_XY);
            holder.iv_arrow.setImageResource(R.drawable.video_menu);

在Java中调整图像大小

6 个答案: