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

            if (!iter.hasNext()) {
                log.error("No ImageReader found.");
                return false;
            }
            ImageReader reader = (ImageReader)iter.next();
            ImageReadParam param = reader.getDefaultReadParam();
            reader.setInput(imgStream, true, false);
            BufferedImage imageData = reader.read(0, param);
            
            //Read image resolution
            IIOMetadata iiometa = reader.getImageMetadata(0);

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Examples of javax.imageio.ImageReadParam

                             If the image is very large, use subsampling anyway
                             to decrease memory consumption & speed up interactive 
                             operations. Anyway, most often user just views image 
                             at screen resolution
                             */
                            ImageReadParam param = reader.getDefaultReadParam();
                            


                            if ( minWidth * 2 < width && minHeight * 2 < height ) {
                                param.setSourceSubsampling( 2, 2, 0, 0 );
                            }
                                ri = reader.read( 0, param );
                            
                        }
                        if ( ri != null ) {

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Examples of javax.imageio.ImageReadParam

                    + reader.getThumbnailHeight( 0, 0 ) );
            image = reader.readThumbnail( 0, 0 );
            log.debug( "Read thumbnail" );
        } else {
            log.debug( "No thumbnail in original" );
            ImageReadParam param = reader.getDefaultReadParam();
            
            // Find the maximum subsampling rate we can still use for creating
            // a quality thumbnail. Some image format readers seem to have
            // problems with subsampling values (e.g. PNG sometimes crashed
            // the whole virtual machine, to for now let's do this only
            // with JPG.
            int subsampling = 1;
            if ( reader.getFormatName().equals( "JPEG" ) ) {
                int minDim = Math.min( reader.getWidth( 0 ),reader.getHeight( 0 ) );
                while ( 2 * minInstanceSide * subsampling < minDim ) {
                    subsampling *= 2;
                }
            }
            param.setSourceSubsampling( subsampling, subsampling, 0, 0 );
            image = reader.read( 0, param );
        }
        return image;
    }

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Examples of javax.imageio.ImageReadParam

    BufferedImage body;
    MediaType contentType = MediaType.IMAGE_JPEG;
    Iterator<ImageReader> imageReaders = ImageIO.getImageReadersByMIMEType(contentType.toString());
    if (imageReaders.hasNext()) {
      ImageReader imageReader = imageReaders.next();
      ImageReadParam irp = imageReader.getDefaultReadParam();
      imageReader.setInput(new MemoryCacheImageInputStream(photo), true);
      body = imageReader.read(0, irp);
    } else {
      throw new HttpMessageNotReadableException("Could not find javax.imageio.ImageReader for Content-Type ["
          + contentType + "]");

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Examples of javax.imageio.ImageReadParam

    BufferedImage body;
    MediaType contentType = MediaType.IMAGE_JPEG;
    Iterator<ImageReader> imageReaders = ImageIO.getImageReadersByMIMEType(contentType.toString());
    if (imageReaders.hasNext()) {
      ImageReader imageReader = imageReaders.next();
      ImageReadParam irp = imageReader.getDefaultReadParam();
      imageReader.setInput(new MemoryCacheImageInputStream(photo), true);
      body = imageReader.read(0, irp);
    } else {
      throw new HttpMessageNotReadableException("Could not find javax.imageio.ImageReader for Content-Type ["
          + contentType + "]");

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Examples of javax.imageio.ImageReadParam

    BufferedImage body;
    MediaType contentType = MediaType.IMAGE_JPEG;
    Iterator<ImageReader> imageReaders = ImageIO.getImageReadersByMIMEType(contentType.toString());
    if (imageReaders.hasNext()) {
      ImageReader imageReader = imageReaders.next();
      ImageReadParam irp = imageReader.getDefaultReadParam();
      imageReader.setInput(new MemoryCacheImageInputStream(photo), true);
      body = imageReader.read(0, irp);
    } else {
      throw new HttpMessageNotReadableException("Could not find javax.imageio.ImageReader for Content-Type ["
          + contentType + "]");

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Examples of javax.imageio.ImageReadParam

        if (reader.canReadRaster())
          break;
      }
    }
    reader.setInput(iis);
    Raster raster = reader.readRaster(0, new ImageReadParam());
    DataBuffer dataBuffer = raster.getDataBuffer();
    int w = raster.getWidth();
    int h = raster.getHeight();
    float[] pels = new float[w * h * 3];
    if (raster.getNumBands() == 4) {

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Examples of javax.imageio.ImageReadParam

   is = new FileInputStream(srcpath);
   Iterator<ImageReader> it = ImageIO.getImageReadersByFormatName(this.imageType);
   ImageReader reader = it.next();
   iis = ImageIO.createImageInputStream(is);
   reader.setInput(iis, true);
   ImageReadParam param = reader.getDefaultReadParam();
   Rectangle rect = new Rectangle(x, y, width, height);
   param.setSourceRegion(rect);
   BufferedImage bi = reader.read(0, param);
   ImageIO.write(bi, this.imageType, new File(subpath));
  } finally {
   if (is != null)
    is.close();

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Examples of javax.imageio.ImageReadParam

                                               DataBuffer.TYPE_BYTE));
        return l.iterator();
    }


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

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Examples of javax.imageio.ImageReadParam

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


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

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