下面列出了javax.imageio.plugins.tiff.TIFFTag#TIFF_RATIONAL 实例代码，或者点击链接到github查看源代码，也可以在右侧发表评论。
public static IIOMetadata getWriterMeta(ImageAttributes attributes, BufferedImage image,
ImageWriter writer, ImageWriteParam param) {
try {
IIOMetadata metaData;
if (attributes != null && attributes.getColorType() != null) {
ImageTypeSpecifier imageTypeSpecifier;
switch (attributes.getColorType()) {
case ARGB:
imageTypeSpecifier = ImageTypeSpecifier.createFromBufferedImageType(BufferedImage.TYPE_INT_ARGB);
break;
case RGB:
imageTypeSpecifier = ImageTypeSpecifier.createFromBufferedImageType(BufferedImage.TYPE_INT_RGB);
break;
case BINARY:
imageTypeSpecifier = ImageTypeSpecifier.createFromBufferedImageType(BufferedImage.TYPE_BYTE_BINARY);
break;
case GRAY:
imageTypeSpecifier = ImageTypeSpecifier.createFromBufferedImageType(BufferedImage.TYPE_BYTE_GRAY);
break;
default:
imageTypeSpecifier = ImageTypeSpecifier.createFromBufferedImageType(BufferedImage.TYPE_INT_RGB);
break;
}
metaData = writer.getDefaultImageMetadata(imageTypeSpecifier, param);
} else if (image != null) {
metaData = writer.getDefaultImageMetadata(new ImageTypeSpecifier(image), param);
} else {
metaData = writer.getDefaultImageMetadata(
ImageTypeSpecifier.createFromBufferedImageType(BufferedImage.TYPE_INT_ARGB), param);
}
if (metaData == null || metaData.isReadOnly() || attributes == null) {
return metaData;
}
if (attributes.getDensity() > 0) {
String nativeName = metaData.getNativeMetadataFormatName(); // javax_imageio_tiff_image_1.0
Node nativeTree = metaData.getAsTree(nativeName);
long[] xRes = new long[]{attributes.getDensity(), 1};
long[] yRes = new long[]{attributes.getDensity(), 1};
TIFFField fieldXRes = new TIFFField(
BaselineTIFFTagSet.getInstance().getTag(BaselineTIFFTagSet.TAG_X_RESOLUTION),
TIFFTag.TIFF_RATIONAL, 1, new long[][]{xRes});
TIFFField fieldYRes = new TIFFField(
BaselineTIFFTagSet.getInstance().getTag(BaselineTIFFTagSet.TAG_Y_RESOLUTION),
TIFFTag.TIFF_RATIONAL, 1, new long[][]{yRes});
nativeTree.getFirstChild().appendChild(fieldXRes.getAsNativeNode());
nativeTree.getFirstChild().appendChild(fieldYRes.getAsNativeNode());
char[] fieldUnit = new char[]{BaselineTIFFTagSet.RESOLUTION_UNIT_INCH};
TIFFField fieldResUnit = new TIFFField(
BaselineTIFFTagSet.getInstance().getTag(BaselineTIFFTagSet.TAG_RESOLUTION_UNIT),
TIFFTag.TIFF_SHORT, 1, fieldUnit);
nativeTree.getFirstChild().appendChild(fieldResUnit.getAsNativeNode());
metaData.mergeTree(nativeName, nativeTree);
}
return metaData;
} catch (Exception e) {
logger.error(e.toString());
return null;
}
}
private static void writeTIFFFieldToStream(TIFFField field,
ImageOutputStream stream)
throws IOException {
int count = field.getCount();
Object data = field.getData();
switch (field.getType()) {
case TIFFTag.TIFF_ASCII:
for (int i = 0; i < count; i++) {
String s = ((String[])data)[i];
int length = s.length();
for (int j = 0; j < length; j++) {
stream.writeByte(s.charAt(j) & 0xff);
}
stream.writeByte(0);
}
break;
case TIFFTag.TIFF_UNDEFINED:
case TIFFTag.TIFF_BYTE:
case TIFFTag.TIFF_SBYTE:
stream.write((byte[])data);
break;
case TIFFTag.TIFF_SHORT:
stream.writeChars((char[])data, 0, ((char[])data).length);
break;
case TIFFTag.TIFF_SSHORT:
stream.writeShorts((short[])data, 0, ((short[])data).length);
break;
case TIFFTag.TIFF_SLONG:
stream.writeInts((int[])data, 0, ((int[])data).length);
break;
case TIFFTag.TIFF_LONG:
for (int i = 0; i < count; i++) {
stream.writeInt((int)(((long[])data)[i]));
}
break;
case TIFFTag.TIFF_IFD_POINTER:
stream.writeInt(0); // will need to be backpatched
break;
case TIFFTag.TIFF_FLOAT:
stream.writeFloats((float[])data, 0, ((float[])data).length);
break;
case TIFFTag.TIFF_DOUBLE:
stream.writeDoubles((double[])data, 0, ((double[])data).length);
break;
case TIFFTag.TIFF_SRATIONAL:
for (int i = 0; i < count; i++) {
stream.writeInt(((int[][])data)[i][0]);
stream.writeInt(((int[][])data)[i][1]);
}
break;
case TIFFTag.TIFF_RATIONAL:
for (int i = 0; i < count; i++) {
long num = ((long[][])data)[i][0];
long den = ((long[][])data)[i][1];
stream.writeInt((int)num);
stream.writeInt((int)den);
}
break;
default:
// error
}
}
private static void writeTIFFFieldToStream(TIFFField field,
ImageOutputStream stream)
throws IOException {
int count = field.getCount();
Object data = field.getData();
switch (field.getType()) {
case TIFFTag.TIFF_ASCII:
for (int i = 0; i < count; i++) {
String s = ((String[])data)[i];
int length = s.length();
for (int j = 0; j < length; j++) {
stream.writeByte(s.charAt(j) & 0xff);
}
stream.writeByte(0);
}
break;
case TIFFTag.TIFF_UNDEFINED:
case TIFFTag.TIFF_BYTE:
case TIFFTag.TIFF_SBYTE:
stream.write((byte[])data);
break;
case TIFFTag.TIFF_SHORT:
stream.writeChars((char[])data, 0, ((char[])data).length);
break;
case TIFFTag.TIFF_SSHORT:
stream.writeShorts((short[])data, 0, ((short[])data).length);
break;
case TIFFTag.TIFF_SLONG:
stream.writeInts((int[])data, 0, ((int[])data).length);
break;
case TIFFTag.TIFF_LONG:
for (int i = 0; i < count; i++) {
stream.writeInt((int)(((long[])data)[i]));
}
break;
case TIFFTag.TIFF_IFD_POINTER:
stream.writeInt(0); // will need to be backpatched
break;
case TIFFTag.TIFF_FLOAT:
stream.writeFloats((float[])data, 0, ((float[])data).length);
break;
case TIFFTag.TIFF_DOUBLE:
stream.writeDoubles((double[])data, 0, ((double[])data).length);
break;
case TIFFTag.TIFF_SRATIONAL:
for (int i = 0; i < count; i++) {
stream.writeInt(((int[][])data)[i][0]);
stream.writeInt(((int[][])data)[i][1]);
}
break;
case TIFFTag.TIFF_RATIONAL:
for (int i = 0; i < count; i++) {
long num = ((long[][])data)[i][0];
long den = ((long[][])data)[i][1];
stream.writeInt((int)num);
stream.writeInt((int)den);
}
break;
default:
// error
}
}