/** * Reads image meta data. * * @param oimage * @return */ public static Map<String, String> readImageData(IIOImage oimage) { Map<String, String> dict = new HashMap<String, String>(); IIOMetadata imageMetadata = oimage.getMetadata(); if (imageMetadata != null) { IIOMetadataNode dimNode = (IIOMetadataNode) imageMetadata.getAsTree("javax_imageio_1.0"); NodeList nodes = dimNode.getElementsByTagName("HorizontalPixelSize"); int dpiX; if (nodes.getLength() > 0) { float dpcWidth = Float.parseFloat(nodes.item(0).getAttributes().item(0).getNodeValue()); dpiX = (int) Math.round(25.4f / dpcWidth); } else { dpiX = Toolkit.getDefaultToolkit().getScreenResolution(); } dict.put("dpiX", String.valueOf(dpiX)); nodes = dimNode.getElementsByTagName("VerticalPixelSize"); int dpiY; if (nodes.getLength() > 0) { float dpcHeight = Float.parseFloat(nodes.item(0).getAttributes().item(0).getNodeValue()); dpiY = (int) Math.round(25.4f / dpcHeight); } else { dpiY = Toolkit.getDefaultToolkit().getScreenResolution(); } dict.put("dpiY", String.valueOf(dpiY)); } return dict; }
/** * Writes any extension blocks, the Image Descriptor, and the image data * * @param iioimage The image and image metadata. * @param param The write parameters. * @param globalColorTable The Global Color Table. * @param sourceBounds The source region. * @param destSize The destination dimensions. */ private void writeImage( RenderedImage image, GIFWritableImageMetadata imageMetadata, ImageWriteParam param, byte[] globalColorTable, Rectangle sourceBounds, Dimension destSize) throws IOException { ColorModel colorModel = image.getColorModel(); SampleModel sampleModel = image.getSampleModel(); boolean writeGraphicsControlExtension; if (imageMetadata == null) { // Create default metadata. imageMetadata = (GIFWritableImageMetadata) getDefaultImageMetadata(new ImageTypeSpecifier(image), param); // Set GraphicControlExtension flag only if there is // transparency. writeGraphicsControlExtension = imageMetadata.transparentColorFlag; } else { // Check for GraphicControlExtension element. NodeList list = null; try { IIOMetadataNode root = (IIOMetadataNode) imageMetadata.getAsTree(IMAGE_METADATA_NAME); list = root.getElementsByTagName("GraphicControlExtension"); } catch (IllegalArgumentException iae) { // Should never happen. } // Set GraphicControlExtension flag if element present. writeGraphicsControlExtension = list != null && list.getLength() > 0; // If progressive mode is not MODE_COPY_FROM_METADATA, ensure // the interlacing is set per the ImageWriteParam mode setting. if (param != null && param.canWriteProgressive()) { if (param.getProgressiveMode() == ImageWriteParam.MODE_DISABLED) { imageMetadata.interlaceFlag = false; } else if (param.getProgressiveMode() == ImageWriteParam.MODE_DEFAULT) { imageMetadata.interlaceFlag = true; } } } // Unset local color table if equal to global color table. if (Arrays.equals(globalColorTable, imageMetadata.localColorTable)) { imageMetadata.localColorTable = null; } // Override dimensions imageMetadata.imageWidth = destSize.width; imageMetadata.imageHeight = destSize.height; // Write Graphics Control Extension. if (writeGraphicsControlExtension) { writeGraphicControlExtension(imageMetadata); } // Write extension blocks. writePlainTextExtension(imageMetadata); writeApplicationExtension(imageMetadata); writeCommentExtension(imageMetadata); // Write Image Descriptor int bitsPerPixel = getNumBits( imageMetadata.localColorTable == null ? (globalColorTable == null ? sampleModel.getSampleSize(0) : globalColorTable.length / 3) : imageMetadata.localColorTable.length / 3); writeImageDescriptor(imageMetadata, bitsPerPixel); // Write image data writeRasterData(image, sourceBounds, destSize, param, imageMetadata.interlaceFlag); }