Examples of ImageReadParam

ae.javax.imageio.ImageReadParam
A class describing how a stream is to be decoded. Instances of this class or its subclasses are used to supply prescriptive "how-to" information to instances of ImageReader.
An image encoded as part of a file or stream may be thought of extending out in multiple dimensions: the spatial dimensions of width and height, a number of bands, and a number of progressive decoding passes. This class allows a contiguous (hyper)rectangular subarea of the image in all of these dimensions to be selected for decoding. Additionally, the spatial dimensions may be subsampled discontinuously. Finally, color and format conversions may be specified by controlling the ColorModel and SampleModel of the destination image, either by providing a BufferedImage or by using an ImageTypeSpecifier.
An ImageReadParam object is used to specify how an image, or a set of images, will be converted on input from a stream in the context of the Java Image I/O framework. A plug-in for a specific image format will return instances of ImageReadParam from the getDefaultReadParam method of its ImageReader implementation.
The state maintained by an instance of ImageReadParam is independent of any particular image being decoded. When actual decoding takes place, the values set in the read param are combined with the actual properties of the image being decoded from the stream and the destination BufferedImage that will receive the decoded pixel data. For example, the source region set using setSourceRegion will first be intersected with the actual valid source area. The result will be translated by the value returned by getDestinationOffset, and the resulting rectangle intersected with the actual valid destination area to yield the destination area that will be written.
The parameters specified by an ImageReadParam are applied to an image as follows. First, if a rendering size has been set by setSourceRenderSize, the entire decoded image is rendered at the size given by getSourceRenderSize. Otherwise, the image has its natural size given by ImageReader.getWidth and ImageReader.getHeight.
Next, the image is clipped against the source region specified by getSourceXOffset, getSourceYOffset, getSourceWidth, and getSourceHeight.
The resulting region is then subsampled according to the factors given in {@link IIOParam#setSourceSubsampling IIOParam.setSourceSubsampling}. The first pixel, the number of pixels per row, and the number of rows all depend on the subsampling settings. Call the minimum X and Y coordinates of the resulting rectangle (minX, minY), its width w and its height h.
This rectangle is offset by (getDestinationOffset().x, getDestinationOffset().y) and clipped against the destination bounds. If no destination image has been set, the destination is defined to have a width of getDestinationOffset().x + w, and a height of getDestinationOffset().y + h so that all pixels of the source region may be written to the destination.
Pixels that land, after subsampling, within the destination image, and that are written in one of the progressive passes specified by getSourceMinProgressivePass and getSourceNumProgressivePasses are passed along to the next step.
Finally, the source samples of each pixel are mapped into destination bands according to the algorithm described in the comment for setDestinationBands.
Plug-in writers may extend the functionality of ImageReadParam by providing a subclass that implements additional, plug-in specific interfaces. It is up to the plug-in to document what interfaces are available and how they are to be used. Readers will silently ignore any extended features of an ImageReadParam subclass of which they are not aware. Also, they may ignore any optional features that they normally disable when creating their own ImageReadParam instances via getDefaultReadParam.
Note that unless a query method exists for a capability, it must be supported by all ImageReader implementations (e.g. source render size is optional, but subsampling must be supported). @see ImageReader @see ImageWriter @see ImageWriteParam
com.google.code.appengine.imageio.ImageReadParam
@author Sergey I. Salishev
javax.imageio.ImageReadParam
A class describing how a stream is to be decoded. Instances of this class or its subclasses are used to supply prescriptive "how-to" information to instances of ImageReader.
An image encoded as part of a file or stream may be thought of extending out in multiple dimensions: the spatial dimensions of width and height, a number of bands, and a number of progressive decoding passes. This class allows a contiguous (hyper)rectangular subarea of the image in all of these dimensions to be selected for decoding. Additionally, the spatial dimensions may be subsampled discontinuously. Finally, color and format conversions may be specified by controlling the ColorModel and SampleModel of the destination image, either by providing a BufferedImage or by using an ImageTypeSpecifier.
An ImageReadParam object is used to specify how an image, or a set of images, will be converted on input from a stream in the context of the Java Image I/O framework. A plug-in for a specific image format will return instances of ImageReadParam from the getDefaultReadParam method of its ImageReader implementation.
The state maintained by an instance of ImageReadParam is independent of any particular image being decoded. When actual decoding takes place, the values set in the read param are combined with the actual properties of the image being decoded from the stream and the destination BufferedImage that will receive the decoded pixel data. For example, the source region set using setSourceRegion will first be intersected with the actual valid source area. The result will be translated by the value returned by getDestinationOffset, and the resulting rectangle intersected with the actual valid destination area to yield the destination area that will be written.
The parameters specified by an ImageReadParam are applied to an image as follows. First, if a rendering size has been set by setSourceRenderSize, the entire decoded image is rendered at the size given by getSourceRenderSize. Otherwise, the image has its natural size given by ImageReader.getWidth and ImageReader.getHeight.
Next, the image is clipped against the source region specified by getSourceXOffset, getSourceYOffset, getSourceWidth, and getSourceHeight.
The resulting region is then subsampled according to the factors given in {@link IIOParam#setSourceSubsampling IIOParam.setSourceSubsampling}. The first pixel, the number of pixels per row, and the number of rows all depend on the subsampling settings. Call the minimum X and Y coordinates of the resulting rectangle (minX, minY), its width w and its height h.
This rectangle is offset by (getDestinationOffset().x, getDestinationOffset().y) and clipped against the destination bounds. If no destination image has been set, the destination is defined to have a width of getDestinationOffset().x + w, and a height of getDestinationOffset().y + h so that all pixels of the source region may be written to the destination.
Pixels that land, after subsampling, within the destination image, and that are written in one of the progressive passes specified by getSourceMinProgressivePass and getSourceNumProgressivePasses are passed along to the next step.
Finally, the source samples of each pixel are mapped into destination bands according to the algorithm described in the comment for setDestinationBands.
Plug-in writers may extend the functionality of ImageReadParam by providing a subclass that implements additional, plug-in specific interfaces. It is up to the plug-in to document what interfaces are available and how they are to be used. Readers will silently ignore any extended features of an ImageReadParam subclass of which they are not aware. Also, they may ignore any optional features that they normally disable when creating their own ImageReadParam instances via getDefaultReadParam.
Note that unless a query method exists for a capability, it must be supported by all ImageReader implementations (e.g. source render size is optional, but subsampling must be supported). @see ImageReader @see ImageWriter @see ImageWriteParam

Examples of javax.imageio.ImageReadParam

            try {
                ImageInputStream imageInputStream =
                    ImageIO.createImageInputStream(inputStream);


                try {
                    ImageReadParam param = imageReader.getDefaultReadParam();
                    imageReader.setInput(imageInputStream, true, true);
                    BufferedImage bufferedImage =
                        imageReader.read(imageReader.getMinIndex(), param);
                    if (bufferedImage != null) {
                        return bufferedImage;

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Examples of javax.imageio.ImageReadParam

        iis = (ImageInputStream) input;
    }


    @Override
    public ImageReadParam getDefaultReadParam() {
        return new ImageReadParam();
    }

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Examples of javax.imageio.ImageReadParam

      {
         return;
      }


      ImageReader reader = (ImageReader) iter.next();
      ImageReadParam param = reader.getDefaultReadParam();
      reader.setInput(stream, true, true);
      String type = reader.getFormatName();
      setContentType(Type.getTypeByFormatName(type));
      bufferedImage = reader.read(0, param);
      stream.close();

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Examples of javax.imageio.ImageReadParam

       * 描述如何对流进行解码的类
       * <p>
       * .用于指定如何在输入时从 Java Image I/O 框架的上下文中的流转换一幅图像或一组图像。用于特定图像格式的插件 将从其
       * ImageReader 实现的 getDefaultReadParam 方法中返回 ImageReadParam 的实例。
       */
      ImageReadParam param = reader.getDefaultReadParam();
      /**
       * 图片裁剪区域。Rectangle 指定了坐标空间中的一个区域，通过 Rectangle 对象
       * 的左上顶点的坐标（x，y）、宽度和高度可以定义这个区域。
       */
      Rectangle rect = new Rectangle(intX, intY, intWidth, intHeight);
      // 提供一个 BufferedImage，将其用作解码像素数据的目标。
      param.setSourceRegion(rect);
      /**
       * 使用所提供的 ImageReadParam 读取通过索引 imageIndex 指定的对象，并将 它作为一个完整的
       * BufferedImage 返回。
       */
      BufferedImage bi = reader.read(0, param);

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Examples of javax.imageio.ImageReadParam

            try {
                ImageInputStream imageInputStream =
                    ImageIO.createImageInputStream(inputStream);


                try {
                    ImageReadParam param = imageReader.getDefaultReadParam();
                    imageReader.setInput(imageInputStream, true, true);
                    BufferedImage bufferedImage =
                        imageReader.read(imageReader.getMinIndex(), param);
                    if (bufferedImage != null) {
                        return bufferedImage;

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Examples of javax.imageio.ImageReadParam

        } while (types.hasNext());
        return raw;
    }


    public ImageReadParam getDefaultReadParam() {
        return new ImageReadParam();
    }

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Examples of javax.imageio.ImageReadParam

      {
         return;
      }


      ImageReader reader = (ImageReader) iter.next();
      ImageReadParam param = reader.getDefaultReadParam();
      reader.setInput(stream, true, true);
      String type = reader.getFormatName();
      setContentType(Type.getTypeByFormatName(type));
      bufferedImage = reader.read(0, param);
      stream.close();

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Examples of javax.imageio.ImageReadParam

        image = null;
    }


    @Override
    public ImageReadParam getDefaultReadParam() {
        return new ImageReadParam();
    }

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Examples of javax.imageio.ImageReadParam

      imageInputStream = createImageInputStream(inputMessage.getBody());
      MediaType contentType = inputMessage.getHeaders().getContentType();
      Iterator<ImageReader> imageReaders = ImageIO.getImageReadersByMIMEType(contentType.toString());
      if (imageReaders.hasNext()) {
        imageReader = imageReaders.next();
        ImageReadParam irp = imageReader.getDefaultReadParam();
        process(irp);
        imageReader.setInput(imageInputStream, true);
        return imageReader.read(0, irp);
      }
      else {

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Examples of javax.imageio.ImageReadParam

            Iterator iter = ImageIO.getImageReaders(imgStream);
            while (iter.hasNext()) {
                ImageReader reader = (ImageReader)iter.next();
                try {
                    imgStream.mark();
                    ImageReadParam param = reader.getDefaultReadParam();
                    reader.setInput(imgStream, false, ignoreMetadata);
                    final int pageIndex = ImageUtil.needPageIndexFromURI(info.getOriginalURI());
                    try {
                        if (ImageFlavor.BUFFERED_IMAGE.equals(this.targetFlavor)) {
                            imageData = reader.read(pageIndex, param);

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