void readPng() throws IOException {
for (int i = 0; i < PNGID.length; i++) {
if (PNGID[i] != is.read()) {
throw new IOException("File is not a valid PNG.");
}
}
byte buffer[] = new byte[TRANSFERSIZE];
while (true) {
int len = getInt(is);
String marker = getString(is);
if (len < 0 || !checkMarker(marker)) throw new IOException("Corrupted PNG file.");
if (IDAT.equals(marker)) {
int size;
while (len != 0) {
size = is.read(buffer, 0, Math.min(len, TRANSFERSIZE));
if (size < 0) return;
idat.write(buffer, 0, size);
len -= size;
}
} else if (tRNS.equals(marker)) {
switch (colorType) {
case 0:
if (len >= 2) {
len -= 2;
int gray = getWord(is);
if (bitDepth == 16) transRedGray = gray;
else additional.put(PdfName.MASK, new PdfLiteral("[" + gray + " " + gray + "]"));
}
break;
case 2:
if (len >= 6) {
len -= 6;
int red = getWord(is);
int green = getWord(is);
int blue = getWord(is);
if (bitDepth == 16) {
transRedGray = red;
transGreen = green;
transBlue = blue;
} else
additional.put(
PdfName.MASK,
new PdfLiteral(
"[" + red + " " + red + " " + green + " " + green + " " + blue + " " + blue
+ "]"));
}
break;
case 3:
if (len > 0) {
trans = new byte[len];
for (int k = 0; k < len; ++k) trans[k] = (byte) is.read();
len = 0;
}
break;
}
Utilities.skip(is, len);
} else if (IHDR.equals(marker)) {
width = getInt(is);
height = getInt(is);
bitDepth = is.read();
colorType = is.read();
compressionMethod = is.read();
filterMethod = is.read();
interlaceMethod = is.read();
} else if (PLTE.equals(marker)) {
if (colorType == 3) {
PdfArray colorspace = new PdfArray();
colorspace.add(PdfName.INDEXED);
colorspace.add(getColorspace());
colorspace.add(new PdfNumber(len / 3 - 1));
ByteBuffer colortable = new ByteBuffer();
while ((len--) > 0) {
colortable.append_i(is.read());
}
colorspace.add(new PdfString(colorTable = colortable.toByteArray()));
additional.put(PdfName.COLORSPACE, colorspace);
} else {
Utilities.skip(is, len);
}
} else if (pHYs.equals(marker)) {
int dx = getInt(is);
int dy = getInt(is);
int unit = is.read();
if (unit == 1) {
dpiX = (int) ((float) dx * 0.0254f + 0.5f);
dpiY = (int) ((float) dy * 0.0254f + 0.5f);
} else {
if (dy != 0) XYRatio = (float) dx / (float) dy;
}
} else if (cHRM.equals(marker)) {
xW = (float) getInt(is) / 100000f;
yW = (float) getInt(is) / 100000f;
xR = (float) getInt(is) / 100000f;
yR = (float) getInt(is) / 100000f;
xG = (float) getInt(is) / 100000f;
yG = (float) getInt(is) / 100000f;
xB = (float) getInt(is) / 100000f;
yB = (float) getInt(is) / 100000f;
hasCHRM =
!(Math.abs(xW) < 0.0001f
|| Math.abs(yW) < 0.0001f
|| Math.abs(xR) < 0.0001f
|| Math.abs(yR) < 0.0001f
|| Math.abs(xG) < 0.0001f
|| Math.abs(yG) < 0.0001f
|| Math.abs(xB) < 0.0001f
|| Math.abs(yB) < 0.0001f);
} else if (sRGB.equals(marker)) {
int ri = is.read();
intent = intents[ri];
gamma = 2.2f;
xW = 0.3127f;
yW = 0.329f;
xR = 0.64f;
yR = 0.33f;
xG = 0.3f;
yG = 0.6f;
xB = 0.15f;
yB = 0.06f;
hasCHRM = true;
} else if (gAMA.equals(marker)) {
int gm = getInt(is);
if (gm != 0) {
gamma = 100000f / (float) gm;
if (!hasCHRM) {
xW = 0.3127f;
yW = 0.329f;
xR = 0.64f;
yR = 0.33f;
xG = 0.3f;
yG = 0.6f;
xB = 0.15f;
yB = 0.06f;
hasCHRM = true;
}
}
} else if (iCCP.equals(marker)) {
do {
--len;
} while (is.read() != 0);
is.read();
--len;
byte icccom[] = new byte[len];
int p = 0;
while (len > 0) {
int r = is.read(icccom, p, len);
if (r < 0) throw new IOException("Premature end of file.");
p += r;
len -= r;
}
byte iccp[] = PdfReader.FlateDecode(icccom, true);
icccom = null;
// try {
// icc_profile = ICC_Profile.getInstance(iccp);
// }
// catch (Exception e) {
icc_profile = null;
// }
} else if (IEND.equals(marker)) {
break;
} else {
Utilities.skip(is, len);
}
Utilities.skip(is, 4);
}
}
