/**
* 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);
}