* *
* The header of a PGM and PPM file stores a maximum sample value * (such a value is not stored for PBM, where the maximum value is always 1). * When in binary mode, PGM and PPM typically have a maximum sample value of 255, * which makes PGM 8 bits per pixel and PPM 24 bits per pixel large. * One sample will be stored as a single byte. * However, there also exist binary PGM files with a maximum sample value larger than * 255 and smaller than 65536. * These files use two bytes per sample, in network byte order (big endian). * I have yet to see PPM files with that property, but they are of course imagineable. * 16 bpp *
* *
* PNMCodec codec = new PNMCodec();
* codec.setFile("test.ppm", CodecMode.LOAD);
* codec.process();
* codec.close();
* PixelImage image = codec.getImage();
*
*
*
* PNMCodec codec = new PNMCodec();
* BilevelImage myFax = ...; // initialize
* codec.setImage(myFax);
* codec.setFile("out.pbm", CodecMode.SAVE);
* codec.process();
* codec.close();
*
*
* @author Marco Schmidt
*/
public class PNMCodec extends ImageCodec
{
/**
* Image type constant for images of unknown type.
*/
public static final int IMAGE_TYPE_UNKNOWN = -1;
/**
* Image type constant for bilevel images, stored in PBM files.
*/
public static final int IMAGE_TYPE_BILEVEL = 0;
/**
* Image type constant for grayscale images, stored in PGM files.
*/
public static final int IMAGE_TYPE_GRAY = 1;
/**
* Image type constant for RGB truecolor images, stored in PPM files.
*/
public static final int IMAGE_TYPE_COLOR = 2;
private static final String[] IMAGE_TYPE_FILE_EXTENSIONS =
{".pbm", ".pgm", ".ppm"};
private Boolean ascii;
private int columns;
private int imageType;
private PushbackInputStream in;
private DataOutput out;
private int height;
private int maxSample;
private int width;
/**
* Attempts to find the appropriate image type by looking at a file's name.
* Ignores case when comparing.
* Returns {@link #IMAGE_TYPE_BILEVEL} for .pbm,
* {@link #IMAGE_TYPE_GRAY} for .pgm and
* {@link #IMAGE_TYPE_COLOR} for .ppm.
* Otherwise, {@link #IMAGE_TYPE_UNKNOWN} is returned.
* To get a file extension given that you have an image type, use
* {@link #getTypicalFileExtension}.
*
* @param fileName the file name to be examined
* @return one of the IMAGE_TYPE_xxx constants of this class
*/
public static int determineImageTypeFromFileName(String fileName)
{
if (fileName == null || fileName.length() < 4)
{
return IMAGE_TYPE_UNKNOWN;
}
String ext = fileName.substring(fileName.length() - 3);
ext = ext.toLowerCase();
for (int i = 0; i < IMAGE_TYPE_FILE_EXTENSIONS.length; i++)
{
if (IMAGE_TYPE_FILE_EXTENSIONS[i].equals(ext))
{
return i;
}
}
return IMAGE_TYPE_UNKNOWN;
}
/**
* Returns if ASCII mode was used for loading an image or will
* be used to store an image.
* @return true for ASCII mode, false for binary mode, null if that information is not available
* @see #setAscii
*/
public Boolean getAscii()
{
return ascii;
}
public String getFormatName()
{
return "Portable Anymap (PBM, PGM, PPM)";
}
public String[] getMimeTypes()
{
return new String[] {"image/x-ppm", "image/x-pgm", "image/x-pbm", "image/x-pnm",
"image/x-portable-pixmap", "image/x-portable-bitmap", "image/x-portable-graymap",
"image/x-portable-anymap"};
}
/**
* Returns the typical file extension (including leading dot) for an
* image type.
* Returns null for {@link #IMAGE_TYPE_UNKNOWN}.
* To get the image type given that you have a file name, use
* {@link #determineImageTypeFromFileName}.
*
* @param imageType the image type for which the extension is required
* @return the file extension or null
*/
public static String getTypicalFileExtension(int imageType)
{
if (imageType >= 0 && imageType < IMAGE_TYPE_FILE_EXTENSIONS.length)
{
return IMAGE_TYPE_FILE_EXTENSIONS[imageType];
}
else
{
return null;
}
}
public boolean isLoadingSupported()
{
return true;
}
public boolean isSavingSupported()
{
return true;
}
/**
* Loads an image from a PNM input stream.
* It is assumed that a stream was given to this codec using {@link #setInputStream(InputStream)}.
*
* @return the image as an instance of a class that implements {@link IntegerImage}
* @throws InvalidFileStructureException if the input stream is not a valid PNM stream (or unsupported)
* @throws java.io.IOException if there were problems reading from the input stream
*/
private void load() throws
InvalidFileStructureException,
IOException,
MissingParameterException,
UnsupportedTypeException,
WrongFileFormatException,
WrongParameterException
{
InputStream is = getInputStream();
if (is != null)
{
if (is instanceof PushbackInputStream)
{
in = (PushbackInputStream)is;
}
else
{
in = new PushbackInputStream(is);
}
}
else
{
throw new MissingParameterException("InputStream object required for loading.");
}
loadType();
String resolutionLine = loadTextLine();
setResolution(resolutionLine);
setBoundsIfNecessary(width, height);
if (imageType == IMAGE_TYPE_BILEVEL)
{
maxSample = 1;
}
else
{
// load maximum value
String maxSampleLine = loadTextLine();
setMaximumSample(maxSampleLine);
}
if (maxSample > 65535)
{
throw new UnsupportedTypeException("Cannot deal with samples larger than 65535.");
}
checkImageResolution();
switch (imageType)
{
case(IMAGE_TYPE_BILEVEL):
{
loadBilevelImage();
break;
}
case(IMAGE_TYPE_COLOR):
{
loadColorImage();
break;
}
case(IMAGE_TYPE_GRAY):
{
loadGrayImage();
break;
}
default:
{
throw new UnsupportedTypeException("Cannot deal with image type.");
}
}
}
private int loadAsciiNumber() throws
InvalidFileStructureException,
IOException
{
boolean hasDigit = false;
int result = -1;
do
{
int b = in.read();
if (b >= 48 && b <= 57)
{
// decimal digit
if (hasDigit)
{
result = result * 10 + (b - 48);
}
else
{
hasDigit = true;
result = b - 48;
}
}
else
if (b == 32 || b == 10 || b == 13 || b == 9)
{
// whitespace
if (hasDigit)
{
if (result > maxSample)
{
throw new InvalidFileStructureException("Read number " +
"from PNM stream that is larger than allowed " +
"maximum sample value " + maxSample + " (" + result + ").");
}
return result;
}
// ignore whitespace
}
else
if (b == 35)
{
// the # character, indicating a comment row
if (hasDigit)
{
in.unread(b);
if (result > maxSample)
{
throw new InvalidFileStructureException("Read " +
"number from PNM stream that is larger than " +
"allowed maximum sample value " + maxSample +
" (" + result + ").");
}
return result;
}
do
{
b = in.read();
}
while (b != -1 && b != 10 && b != 13);
if (b == 13)
{
}
// put it into the comment list
}
else
if (b == -1)
{
// the end of file character
if (hasDigit)
{
if (result > maxSample)
{
throw new InvalidFileStructureException("Read number from PNM stream that is larger than allowed maximum sample value " +
maxSample + " (" + result + ")");
}
return result;
}
throw new InvalidFileStructureException("Unexpected end of file while reading ASCII number from PNM stream.");
}
else
{
throw new InvalidFileStructureException("Read invalid character from PNM stream: " + b +
" dec.");
}
}
while(true);
}
private void loadBilevelImage() throws
InvalidFileStructureException,
IOException,
WrongParameterException
{
PixelImage image = getImage();
if (image == null)
{
setImage(new MemoryBilevelImage(getBoundsWidth(), getBoundsHeight()));
}
else
{
if (!(image instanceof BilevelImage))
{
throw new WrongParameterException("Specified input image must implement BilevelImage for this image type.");
}
}
if (getAscii().booleanValue())
{
loadBilevelImageAscii();
}
else
{
loadBilevelImageBinary();
}
}
private void loadBilevelImageAscii() throws
InvalidFileStructureException,
IOException
{
BilevelImage image = (BilevelImage)getImage();
// skip the pixels of the first getBoundsY1() rows
int pixelsToSkip = width * getBoundsY1();
for (int i = 0; i < pixelsToSkip; i++)
{
loadAsciiNumber();
}
final int NUM_ROWS = getBoundsHeight();
final int COLUMNS = getBoundsWidth();
final int X1 = getBoundsX1();
int[] row = new int[width];
// now read and store getBoundsHeight() rows
for (int y = 0; y < NUM_ROWS; y++)
{
for (int x = 0; x < width; x++)
{
int value = loadAsciiNumber();
if (value == 0)
{
row[x] = BilevelImage.WHITE;
}
else
if (value == 1)
{
row[x] = BilevelImage.BLACK;
}
else
{
throw new InvalidFileStructureException("Loaded " +
"number for position x=" + x + ", y=" + (y + getBoundsY1()) +
" is neither 0 nor 1 in PBM stream: " + value);
}
}
image.putSamples(0, 0, y, COLUMNS, 1, row, X1);
setProgress(y, NUM_ROWS);
}
}
private void loadBilevelImageBinary() throws
InvalidFileStructureException,
IOException
{
BilevelImage image = (BilevelImage)getImage();
int bytesPerRow = (width + 7) / 8;
// skip the first getBoundsY1() rows
long bytesToSkip = (long)getBoundsY1() * (long)bytesPerRow;
// Note:
// removed in.skip(bytesToSkip) because that was only available in Java 1.2
// instead the following while loop is used
while (bytesToSkip-- > 0)
{
in.read();
}
// allocate buffer large enough for a complete row
byte[] row = new byte[bytesPerRow];
final int numRows = getBoundsHeight();
// read and store the next getBoundsHeight() rows
for (int y = 0; y < numRows; y++)
{
// read bytesPerRow bytes into row
int bytesToRead = bytesPerRow;
int index = 0;
while (bytesToRead > 0)
{
int result = in.read(row, index, bytesToRead);
if (result >= 0)
{
index += result;
bytesToRead -= result;
}
else
{
throw new InvalidFileStructureException("Unexpected end of input stream while reading.");
}
}
// invert values
for (int x = 0; x < row.length; x++)
{
row[x] = (byte)~row[x];
}
//image.putPackedBytes(0, y, bytesPerRow, buffer, 0);
if (isRowRequired(y))
{
image.putPackedBytes(0, y - getBoundsY1(), getBoundsWidth(), row, getBoundsX1() >> 3, getBoundsX1() & 7);
}
setProgress(y, numRows);
}
}
private void loadColorImage() throws InvalidFileStructureException, IOException
{
RGBIntegerImage image = null;
RGB24Image image24 = null;
if (maxSample <= 255)
{
image24 = new MemoryRGB24Image(width, height);
image = image24;
setImage(image);
}
else
{
image = new MemoryRGB48Image(width, height);
setImage(image);
}
for (int y = 0, destY = - getBoundsY1(); y < height; y++, destY++)
{
if (getAscii().booleanValue())
{
for (int x = 0; x < width; x++)
{
int red = loadAsciiNumber();
if (red < 0 || red > maxSample)
{
throw new InvalidFileStructureException("Invalid " +
"sample value " + red + " for red sample at " +
"(x=" + x + ", y=" + y + ").");
}
image.putSample(RGBIndex.INDEX_RED, x, y, red);
int green = loadAsciiNumber();
if (green < 0 || green > maxSample)
{
throw new InvalidFileStructureException("Invalid " +
"sample value " + green + " for green sample at " +
"(x=" + x + ", y=" + y + ").");
}
image.putSample(RGBIndex.INDEX_GREEN, x, y, green);
int blue = loadAsciiNumber();
if (blue < 0 || blue > maxSample)
{
throw new InvalidFileStructureException("Invalid " +
"sample value " + blue + " for blue sample at " +
"(x=" + x + ", y=" + y + ").");
}
image.putSample(RGBIndex.INDEX_BLUE, x, y, blue);
}
}
else
{
if (image24 != null)
{
for (int x = 0; x < width; x++)
{
int red = in.read();
if (red == -1)
{
throw new InvalidFileStructureException("Unexpected " +
"end of file while reading red sample for pixel " +
"x=" + x + ", y=" + y + ".");
}
image24.putByteSample(RGBIndex.INDEX_RED, x, y, (byte)(red & 0xff));
int green = in.read();
if (green == -1)
{
throw new InvalidFileStructureException("Unexpected " +
"end of file while reading green sample for pixel " +
"x=" + x + ", y=" + y + ".");
}
image24.putByteSample(RGBIndex.INDEX_GREEN, x, y, (byte)(green & 0xff));
int blue = in.read();
if (blue == -1)
{
throw new InvalidFileStructureException("Unexpected " +
"end of file while reading blue sample for pixel " +
"x=" + x + ", y=" + y + ".");
}
image24.putByteSample(RGBIndex.INDEX_BLUE, x, y, (byte)(blue & 0xff));
}
}
}
setProgress(y, getBoundsHeight());
}
}
private void loadGrayImage() throws InvalidFileStructureException, IOException, UnsupportedTypeException
{
final int WIDTH = getBoundsWidth();
final int HEIGHT = getBoundsHeight();
PixelImage pimage = getImage();
if (pimage == null)
{
if (maxSample < 256)
{
pimage = new MemoryGray8Image(WIDTH, HEIGHT);
}
else
if (maxSample < 65536)
{
pimage = new MemoryGray16Image(WIDTH, HEIGHT);
}
else
{
throw new UnsupportedTypeException("Gray images with more than 16 bits per pixel are not supported.");
}
setImage(pimage);
}
else
{
}
GrayIntegerImage image = (GrayIntegerImage)pimage;
int[] buffer = new int[width];
for (int y = 0, destY = -getBoundsY1(); destY < getBoundsHeight(); y++, destY++)
{
if (getAscii().booleanValue())
{
for (int x = 0; x < width; x++)
{
buffer[x] = loadAsciiNumber();
}
}
else
{
if (maxSample < 256)
{
for (int x = 0; x < width; x++)
{
buffer[x] = in.read();
}
}
else
{
for (int x = 0; x < width; x++)
{
int msb = in.read();
int lsb = in.read();
buffer[x] = (msb << 8) | lsb;
}
}
}
if (destY >= 0 && destY < getBoundsHeight())
{
image.putSamples(0, 0, destY, getBoundsWidth(), 1, buffer, getBoundsX1());
}
setProgress(y, getBoundsY2() + 1);
}
}
private String loadTextLine() throws InvalidFileStructureException, IOException
{
// load text lines until
// 1) a normal text line is found
// 2) an error occurs
// any comment lines starting with # are added to the
// comments Vector
boolean isComment;
StringBuffer sb;
do
{
sb = new StringBuffer();
int b;
boolean crOrLf;
do
{
b = in.read();
if (b == -1)
{
throw new InvalidFileStructureException("Unexpected end of file in PNM stream.");
}
crOrLf = (b == 0x0a || b == 0x0d);
if (!crOrLf)
{
sb.append((char)b);
}
}
while (!crOrLf);
if (b == 0x0d)
{
b = in.read();
if (b != 0x0a)
{
throw new InvalidFileStructureException("Unexpected end of file in PNM stream.");
}
}
isComment = (sb.length() > 0 && sb.charAt(0) == '#');
if (isComment)
{
//sb.deleteCharAt(0);
//sb.delete(0, 1);
StringBuffer result = new StringBuffer(sb.length() - 1);
int i = 1;
while (i < sb.length())
{
result.append(sb.charAt(i++));
}
appendComment(result.toString());
}
}
while (isComment);
return sb.toString();
}
/**
* Loads the first two characters (which are expected to be a capital P
* followed by a decimal digit between 1 and 6, inclusively) and skips
* following LF and CR characters.
* This method not only checks the two bytes, it also initializes internal fields
* for storage mode (ASCII or binary) and image type.
*
* @throws WrongFileFormatException if the input stream is not a PNM stream
* @throws InvalidFileStructureException if the format that
* is described above was not encountered
* @throws java.io.IOException if there were errors reading data
* @throws java.lang.IllegalArgumentException if the input stream was not given to this codec
*/
private void loadType() throws InvalidFileStructureException, IOException, WrongFileFormatException
{
// read two bytes
int v1 = in.read();
int v2 = in.read();
// check if first byte is P
if (v1 != 0x50)
{
throw new WrongFileFormatException("Not a PNM stream. First byte " +
"in PNM stream is expected to be 0x50 ('P'); found: " +
v1 + " (dec).");
}
// check if second byte is ASCII of digit from 1 to 6
if (v2 < 0x31 || v2 > 0x36)
{
throw new WrongFileFormatException("Not a PNM stream. Second byte " +
"in PNM stream is expected to be the ASCII value of decimal " +
"digit between 1 and 6 (49 dec to 54 dec); found " +
v2 + " dec.");
}
// determine mode (ASCII or binary) from second byte
ascii = new Boolean(v2 < 0x34);
// determine image type from second byte
v2 = v2 - 0x30;
imageType = (v2 - 1) % 3;
// skip LF and CR
int b;
do
{
b = in.read();
}
while (b == 0x0a || b == 0x0d || b == ' ');
if (b == -1)
{
throw new InvalidFileStructureException("Read type (" +
v2 + "). Unexpected end of file in input PNM stream.");
}
in.unread(b);
}
public void process() throws
MissingParameterException,
OperationFailedException
{
initModeFromIOObjects();
try
{
if (getMode() == CodecMode.LOAD)
{
load();
}
else
{
save();
}
}
catch (IOException ioe)
{
throw new OperationFailedException("I/O error: " + ioe.toString());
}
}
private void save() throws
IOException,
MissingParameterException,
WrongParameterException
{
out = getOutputAsDataOutput();
if (out == null)
{
throw new WrongParameterException("Cannot get a DataOutput object to use for saving.");
}
PixelImage pi = getImage();
if (pi == null)
{
throw new MissingParameterException("Input image missing.");
}
if (!(pi instanceof IntegerImage))
{
throw new WrongParameterException("Input image must implement IntegerImage.");
}
IntegerImage image = (IntegerImage)pi;
width = image.getWidth();
height = image.getHeight();
setBoundsIfNecessary(width, height);
if (image instanceof RGB24Image)
{
imageType = IMAGE_TYPE_COLOR;
maxSample = 255;
save((RGB24Image)image);
}
else
if (image instanceof RGB48Image)
{
imageType = IMAGE_TYPE_COLOR;
maxSample = 65535;
save((RGB48Image)image);
}
else
if (image instanceof BilevelImage)
{
imageType = IMAGE_TYPE_BILEVEL;
maxSample = 1;
save((BilevelImage)image);
}
else
if (image instanceof Gray8Image)
{
imageType = IMAGE_TYPE_GRAY;
maxSample = 255;
save((Gray8Image)image);
}
else
if (image instanceof Gray16Image)
{
imageType = IMAGE_TYPE_GRAY;
maxSample = 65535;
save((Gray16Image)image);
}
else
{
throw new WrongParameterException("Unsupported input image type: " +
image.getClass().getName());
}
close();
}
private void save(BilevelImage image) throws IOException
{
saveHeader();
final int WIDTH = getBoundsWidth();
final int HEIGHT = getBoundsHeight();
final int BYTES_PER_ROW = (WIDTH + 7) / 8;
byte[] buffer = new byte[BYTES_PER_ROW];
for (int y = 0, srcY = getBoundsY1(); y < HEIGHT; y++, srcY++)
{
if (getAscii().booleanValue())
{
for (int x = 0, srcX = getBoundsX1(); x < WIDTH; x++, srcX++)
{
if (image.isBlack(srcX, srcY))
{
out.write(49); // 1
}
else
{
out.write(48); // 0
}
columns ++;
if (columns > 70)
{
columns = 0;
out.write(10);
}
else
{
out.write(32);
columns++;
}
}
}
else
{
image.getPackedBytes(getBoundsX1(), srcY, WIDTH, buffer, 0, 0);
for (int x = 0; x < buffer.length; x++)
{
buffer[x] = (byte)(~buffer[x]);
}
out.write(buffer);
}
setProgress(y, HEIGHT);
}
}
private void save(Gray8Image image) throws IOException
{
saveHeader();
final int HEIGHT = getBoundsHeight();
final int WIDTH = getBoundsWidth();
final int X1 = getBoundsX1();
System.out.println(WIDTH + " " + HEIGHT + " " + X1);
byte[] buffer = new byte[WIDTH];
for (int y = 0, srcY = getBoundsY1(); y < HEIGHT; y++, srcY++)
{
image.getByteSamples(0, X1, srcY, WIDTH, 1, buffer, 0);
if (getAscii().booleanValue())
{
for (int x = 0; x < WIDTH; x++)
{
saveAsciiNumber(buffer[x] & 0xff);
out.write(32);
columns += 2;
if (columns > 70)
{
columns = 0;
out.write(10);
}
else
{
out.write(32);
columns++;
}
}
}
else
{
out.write(buffer);
}
setProgress(y, HEIGHT);
}
}
private void save(Gray16Image image) throws IOException
{
saveHeader();
final int HEIGHT = getBoundsHeight();
final int WIDTH = getBoundsWidth();
final int X1 = getBoundsX1();
short[] buffer = new short[WIDTH];
for (int y = 0, srcY = getBoundsY1(); y < HEIGHT; y++, srcY++)
{
image.getShortSamples(0, X1, srcY, WIDTH, 1, buffer, 0);
if (getAscii().booleanValue())
{
for (int x = 0; x < WIDTH; x++)
{
saveAsciiNumber(buffer[x] & 0xffff);
out.write(32);
columns += 4;
if (columns > 70)
{
columns = 0;
out.write(10);
}
else
{
out.write(32);
columns++;
}
}
}
else
{
for (int x = 0; x < WIDTH; x++)
{
int sample = buffer[x] & 0xffff;
out.write((sample >> 8) & 0xff);
out.write(sample & 0xff);
}
}
setProgress(y, HEIGHT);
}
}
private void save(RGB24Image image) throws IOException
{
saveHeader();
final int WIDTH = getBoundsWidth();
final int HEIGHT = getBoundsHeight();
for (int y = 0, srcY = getBoundsY1(); y < HEIGHT; y++, srcY++)
{
if (getAscii().booleanValue())
{
for (int x = 0, srcX = getBoundsX1(); x < WIDTH; x++, srcX++)
{
int red = image.getSample(RGBIndex.INDEX_RED, srcX, srcY);
int green = image.getSample(RGBIndex.INDEX_GREEN, srcX, srcY);
int blue = image.getSample(RGBIndex.INDEX_BLUE, srcX, srcY);
saveAsciiNumber(red);
out.write(32);
saveAsciiNumber(green);
out.write(32);
saveAsciiNumber(blue);
columns += 11;
if (columns > 80)
{
columns = 0;
out.write(10);
}
else
{
out.write(32);
columns++;
}
}
}
else
{
for (int x = 0, srcX = getBoundsX1(); x < WIDTH; x++, srcX++)
{
out.write(image.getSample(RGBIndex.INDEX_RED, srcX, srcY));
out.write(image.getSample(RGBIndex.INDEX_GREEN, srcX, srcY));
out.write(image.getSample(RGBIndex.INDEX_BLUE, srcX, srcY));
}
}
setProgress(y, HEIGHT);
}
}
private void save(RGB48Image image) throws IOException
{
saveHeader();
final int WIDTH = getBoundsWidth();
final int HEIGHT = getBoundsHeight();
for (int y = 0, srcY = getBoundsY1(); y < HEIGHT; y++, srcY++)
{
if (getAscii().booleanValue())
{
for (int x = 0, srcX = getBoundsX1(); x < WIDTH; x++, srcX++)
{
int red = image.getSample(RGBIndex.INDEX_RED, srcX, srcY);
int green = image.getSample(RGBIndex.INDEX_GREEN, srcX, srcY);
int blue = image.getSample(RGBIndex.INDEX_BLUE, srcX, srcY);
saveAsciiNumber(red);
out.write(32);
saveAsciiNumber(green);
out.write(32);
saveAsciiNumber(blue);
columns += 13;
if (columns > 80)
{
columns = 0;
out.write(10);
}
else
{
out.write(32);
columns++;
}
}
}
else
{
/*
for (int x = 0, srcX = getBoundsX1(); x < WIDTH; x++, srcX++)
{
out.write(image.getSample(RGBIndex.INDEX_RED, srcX, srcY));
out.write(image.getSample(RGBIndex.INDEX_GREEN, srcX, srcY));
out.write(image.getSample(RGBIndex.INDEX_BLUE, srcX, srcY));
}
*/
}
setProgress(y, HEIGHT);
}
}
private void saveAsciiNumber(int number) throws
IOException
{
String s = Integer.toString(number);
for (int i = 0; i < s.length(); i++)
{
char c = s.charAt(i);
out.write(c);
}
columns += s.length();
}
private void saveHeader() throws IOException
{
out.write(80); // 'P'
int pnmType = 49 + imageType;
if (getAscii() == null)
{
setAscii(maxSample > 255);
}
if (!getAscii().booleanValue())
{
pnmType += 3;
}
out.write(pnmType); // '1' .. '6'
out.write(10); // line feed
saveAsciiNumber(getBoundsWidth());
out.write(32); // space
saveAsciiNumber(getBoundsHeight());
out.write(10); // line feed
if (imageType != IMAGE_TYPE_BILEVEL)
{
// bilevel max sample is always 1 and MUST NOT be saved
saveAsciiNumber(maxSample);
out.write(10);// line feed
}
}
/**
* Specify whether ASCII mode is to be used when saving an image.
* Default is binary mode.
* @param asciiMode if true, ASCII mode is used, binary mode otherwise
*/
public void setAscii(boolean asciiMode)
{
ascii = new Boolean(asciiMode);
}
private void setMaximumSample(String line) throws InvalidFileStructureException
{
line = line.trim();
try
{
maxSample = Integer.parseInt(line);
}
catch (NumberFormatException nfe)
{
throw new InvalidFileStructureException("Not a valid value for the maximum sample: " + line);
}
if (maxSample < 0)
{
throw new InvalidFileStructureException("The value for the maximum sample must not be negative; found " + maxSample);
}
}
/*
* Reads resolution from argument String and sets private variables
* width and height.
*/
private void setResolution(String line) throws InvalidFileStructureException
{
line = line.trim();
StringTokenizer st = new StringTokenizer(line, " ");
try
{
if (!st.hasMoreTokens())
{
throw new InvalidFileStructureException("No width value found in line \"" +
line + "\".");
}
String number = st.nextToken();
try
{
width = Integer.parseInt(number);
}
catch (NumberFormatException nfe)
{
throw new InvalidFileStructureException("Not a valid int value for width: " +
number);
}
if (width < 1)
{
throw new InvalidFileStructureException("The width value must be larger than " +
"zero; found " + width + ".");
}
if (!st.hasMoreTokens())
{
throw new InvalidFileStructureException("No height value found in line \"" +
line + "\".");
}
number = st.nextToken();
try
{
height = Integer.parseInt(number);
}
catch (NumberFormatException nfe)
{
throw new InvalidFileStructureException("Not a valid int value for height: " +
number);
}
if (height < 1)
{
throw new InvalidFileStructureException("The height value must be larger than " +
"zero; found " + width + ".");
}
}
catch (NoSuchElementException nsee)
{
// should not happen because we always check if there is a token
}
}
public String suggestFileExtension(PixelImage image)
{
if (image == null)
{
return null;
}
if (image instanceof BilevelImage)
{
return IMAGE_TYPE_FILE_EXTENSIONS[IMAGE_TYPE_BILEVEL];
}
else
if (image instanceof GrayImage)
{
return IMAGE_TYPE_FILE_EXTENSIONS[IMAGE_TYPE_GRAY];
}
else
if (image instanceof RGB24Image)
{
return IMAGE_TYPE_FILE_EXTENSIONS[IMAGE_TYPE_COLOR];
}
return null;
}
}