tsai
/
ImageSharp
mirror of https://github.com/SixLabors/ImageSharp
1
0
Fork 0
Code Issues Projects Releases Wiki Activity
Browse Source

At least render something when progressive. 

This allows parsing of the broken eof images. The non-progressive
renders perfectly, the progressive appears to not render the final
scan.... or something.
pull/85/head
James Jackson-South 9 years ago
parent
9a072b8caf
commit
d05b06bbbd
5 changed files with 174 additions and 150 deletions
Whitespace
Show all changes Ignore whitespace when comparing lines Ignore changes in amount of whitespace Ignore changes in whitespace at EOL
Split View
Diff Options
Show Stats Download Patch File Download Diff File
  1. 33
      src/ImageSharp.Formats.Jpeg/Components/Decoder/JpegScanDecoder.cs
  2. 284
      src/ImageSharp.Formats.Jpeg/JpegDecoderCore.cs
  3. 6
      tests/ImageSharp.Tests/FileTestBase.cs
  4. 1
      tests/ImageSharp.Tests/TestImages.cs
  5. BIN
      tests/ImageSharp.Tests/TestImages/Formats/Jpg/badeofprog.jpg

33
src/ImageSharp.Formats.Jpeg/Components/Decoder/JpegScanDecoder.cs
View File

@ -356,11 +356,21 @@ namespace ImageSharp.Formats.Jpg
throw new ImageFormatException("Excessive DC component");
}
int deltaDC = decoder.Bits.ReceiveExtend(value, decoder);
this.pointers.Dc[compIndex] += deltaDC;
// TODO: Handle the EOFException and piece together the final progressive scan.
try
{
int deltaDC = decoder.Bits.ReceiveExtend(value, decoder);
this.pointers.Dc[compIndex] += deltaDC;
// b[0] = dc[compIndex] << al;
Block8x8F.SetScalarAt(b, 0, this.pointers.Dc[compIndex] << this.al);
// b[0] = dc[compIndex] << al;
Block8x8F.SetScalarAt(b, 0, this.pointers.Dc[compIndex] << this.al);
}
catch (JpegDecoderCore.EOFException)
{
// Do something clever here. I'm just undoing ReceiveExtend
decoder.Bits.UnreadBits += value;
decoder.Bits.Mask >>= value;
}
}
if (zig <= this.zigEnd && this.eobRun > 0)
@ -383,7 +393,20 @@ namespace ImageSharp.Formats.Jpg
break;
}
int ac = decoder.Bits.ReceiveExtend(val1, decoder);
int ac; // = decoder.Bits.ReceiveExtend(val1, decoder);
// TODO: Handle the EOFException and piece together the final progressive scan.
try
{
ac = decoder.Bits.ReceiveExtend(val1, decoder);
}
catch (JpegDecoderCore.EOFException)
{
// Do something clever here. I'm just undoing ReceiveExtend
decoder.Bits.UnreadBits += val1;
decoder.Bits.Mask >>= val1;
break;
}
// b[Unzig[zig]] = ac << al;
Block8x8F.SetScalarAt(b, this.pointers.Unzig[zig], ac << this.al);

284
src/ImageSharp.Formats.Jpeg/JpegDecoderCore.cs
View File

@ -186,164 +186,162 @@ namespace ImageSharp.Formats
throw new ImageFormatException("Missing SOI marker.");
}
// Process the remaining segments until the End Of Image marker.
bool processBytes = true;
// we can't currently short circute progressive images so don't try.
while (processBytes)
while (true)
{
this.ReadFull(this.Temp, 0, 2);
while (this.Temp[0] != 0xff)
try
{
// Strictly speaking, this is a format error. However, libjpeg is
// liberal in what it accepts. As of version 9, next_marker in
// jdmarker.c treats this as a warning (JWRN_EXTRANEOUS_DATA) and
// continues to decode the stream. Even before next_marker sees
// extraneous data, jpeg_fill_bit_buffer in jdhuff.c reads as many
// bytes as it can, possibly past the end of a scan's data. It
// effectively puts back any markers that it overscanned (e.g. an
// "\xff\xd9" EOI marker), but it does not put back non-marker data,
// and thus it can silently ignore a small number of extraneous
// non-marker bytes before next_marker has a chance to see them (and
// print a warning).
// We are therefore also liberal in what we accept. Extraneous data
// is silently ignore
// This is similar to, but not exactly the same as, the restart
// mechanism within a scan (the RST[0-7] markers).
// Note that extraneous 0xff bytes in e.g. SOS data are escaped as
// "\xff\x00", and so are detected a little further down below.
this.Temp[0] = this.Temp[1];
this.Temp[1] = this.ReadByte();
}
this.ReadFull(this.Temp, 0, 2);
while (this.Temp[0] != 0xff)
{
// Strictly speaking, this is a format error. However, libjpeg is
// liberal in what it accepts. As of version 9, next_marker in
// jdmarker.c treats this as a warning (JWRN_EXTRANEOUS_DATA) and
// continues to decode the stream. Even before next_marker sees
// extraneous data, jpeg_fill_bit_buffer in jdhuff.c reads as many
// bytes as it can, possibly past the end of a scan's data. It
// effectively puts back any markers that it overscanned (e.g. an
// "\xff\xd9" EOI marker), but it does not put back non-marker data,
// and thus it can silently ignore a small number of extraneous
// non-marker bytes before next_marker has a chance to see them (and
// print a warning).
// We are therefore also liberal in what we accept. Extraneous data
// is silently ignore
// This is similar to, but not exactly the same as, the restart
// mechanism within a scan (the RST[0-7] markers).
// Note that extraneous 0xff bytes in e.g. SOS data are escaped as
// "\xff\x00", and so are detected a little further down below.
this.Temp[0] = this.Temp[1];
this.Temp[1] = this.ReadByte();
}
byte marker = this.Temp[1];
if (marker == 0)
{
// Treat "\xff\x00" as extraneous data.
continue;
}
byte marker = this.Temp[1];
if (marker == 0)
{
// Treat "\xff\x00" as extraneous data.
continue;
}
while (marker == 0xff)
{
// Section B.1.1.2 says, "Any marker may optionally be preceded by any
// number of fill bytes, which are bytes assigned code X'FF'".
marker = this.ReadByte();
}
while (marker == 0xff)
{
// Section B.1.1.2 says, "Any marker may optionally be preceded by any
// number of fill bytes, which are bytes assigned code X'FF'".
marker = this.ReadByte();
}
// End Of Image.
if (marker == JpegConstants.Markers.EOI)
{
break;
}
// End Of Image.
if (marker == JpegConstants.Markers.EOI)
{
break;
}
if (marker >= JpegConstants.Markers.RST0 && marker <= JpegConstants.Markers.RST7)
{
// Figures B.2 and B.16 of the specification suggest that restart markers should
// only occur between Entropy Coded Segments and not after the final ECS.
// However, some encoders may generate incorrect JPEGs with a final restart
// marker. That restart marker will be seen here instead of inside the ProcessSOS
// method, and is ignored as a harmless error. Restart markers have no extra data,
// so we check for this before we read the 16-bit length of the segment.
continue;
}
if (marker >= JpegConstants.Markers.RST0 && marker <= JpegConstants.Markers.RST7)
{
// Figures B.2 and B.16 of the specification suggest that restart markers should
// only occur between Entropy Coded Segments and not after the final ECS.
// However, some encoders may generate incorrect JPEGs with a final restart
// marker. That restart marker will be seen here instead of inside the ProcessSOS
// method, and is ignored as a harmless error. Restart markers have no extra data,
// so we check for this before we read the 16-bit length of the segment.
continue;
}
// Read the 16-bit length of the segment. The value includes the 2 bytes for the
// length itself, so we subtract 2 to get the number of remaining bytes.
this.ReadFull(this.Temp, 0, 2);
int remaining = (this.Temp[0] << 8) + this.Temp[1] - 2;
if (remaining < 0)
{
throw new ImageFormatException("Short segment length.");
}
// Read the 16-bit length of the segment. The value includes the 2 bytes for the
// length itself, so we subtract 2 to get the number of remaining bytes.
this.ReadFull(this.Temp, 0, 2);
int remaining = (this.Temp[0] << 8) + this.Temp[1] - 2;
if (remaining < 0)
{
throw new ImageFormatException("Short segment length.");
}
switch (marker)
{
case JpegConstants.Markers.SOF0:
case JpegConstants.Markers.SOF1:
case JpegConstants.Markers.SOF2:
this.IsProgressive = marker == JpegConstants.Markers.SOF2;
this.ProcessStartOfFrameMarker(remaining);
if (configOnly && this.isJfif)
{
return;
}
switch (marker)
{
case JpegConstants.Markers.SOF0:
case JpegConstants.Markers.SOF1:
case JpegConstants.Markers.SOF2:
this.IsProgressive = marker == JpegConstants.Markers.SOF2;
this.ProcessStartOfFrameMarker(remaining);
if (configOnly && this.isJfif)
{
return;
}
break;
case JpegConstants.Markers.DHT:
if (configOnly)
{
this.Skip(remaining);
}
else
{
this.ProcessDefineHuffmanTablesMarker(remaining);
}
break;
case JpegConstants.Markers.DHT:
if (configOnly)
{
this.Skip(remaining);
}
else
{
this.ProcessDefineHuffmanTablesMarker(remaining);
}
break;
case JpegConstants.Markers.DQT:
if (configOnly)
{
this.Skip(remaining);
}
else
{
this.ProcessDqt(remaining);
}
break;
case JpegConstants.Markers.DQT:
if (configOnly)
{
this.Skip(remaining);
}
else
{
this.ProcessDqt(remaining);
}
break;
case JpegConstants.Markers.SOS:
if (configOnly)
{
return;
}
break;
case JpegConstants.Markers.SOS:
if (configOnly)
{
return;
}
// when this is a progressive image this gets called a number of times
// need to know how many times this should be called in total.
this.ProcessStartOfScan(remaining);
if (!this.IsProgressive)
{
// if this is not a progressive image we can stop processing bytes as we now have the image data.
processBytes = false;
}
this.ProcessStartOfScan(remaining);
break;
case JpegConstants.Markers.DRI:
if (configOnly)
{
this.Skip(remaining);
}
else
{
this.ProcessDefineRestartIntervalMarker(remaining);
}
break;
case JpegConstants.Markers.DRI:
if (configOnly)
{
this.Skip(remaining);
}
else
{
this.ProcessDefineRestartIntervalMarker(remaining);
}
break;
case JpegConstants.Markers.APP0:
this.ProcessApplicationHeader(remaining);
break;
case JpegConstants.Markers.APP1:
this.ProcessApp1Marker(remaining, image);
break;
case JpegConstants.Markers.APP14:
this.ProcessApp14Marker(remaining);
break;
default:
if ((marker >= JpegConstants.Markers.APP0 && marker <= JpegConstants.Markers.APP15)
|| marker == JpegConstants.Markers.COM)
{
this.Skip(remaining);
}
else if (marker < JpegConstants.Markers.SOF0)
{
// See Table B.1 "Marker code assignments".
throw new ImageFormatException("Unknown marker");
}
else
{
throw new ImageFormatException("Unknown marker");
}
break;
case JpegConstants.Markers.APP0:
this.ProcessApplicationHeader(remaining);
break;
case JpegConstants.Markers.APP1:
this.ProcessApp1Marker(remaining, image);
break;
case JpegConstants.Markers.APP14:
this.ProcessApp14Marker(remaining);
break;
default:
if ((marker >= JpegConstants.Markers.APP0 && marker <= JpegConstants.Markers.APP15)
|| marker == JpegConstants.Markers.COM)
{
this.Skip(remaining);
}
else if (marker < JpegConstants.Markers.SOF0)
{
// See Table B.1 "Marker code assignments".
throw new ImageFormatException("Unknown marker");
}
else
{
throw new ImageFormatException("Unknown marker");
}
break;
break;
}
}
catch (EOFException)
{
// For non-progressive images this is a simple way to handle a missing EOI
// TODO: For progressive we still have to handle the exception within JpegScanDecoder to include last scan
break;
}
}

6
tests/ImageSharp.Tests/FileTestBase.cs
View File

@ -22,9 +22,11 @@ namespace ImageSharp.Tests
// TestFile.Create(TestImages.Png.Pd), // Perf: Enable for local testing only
// TestFile.Create(TestImages.Jpeg.Floorplan), // Perf: Enable for local testing only
TestFile.Create(TestImages.Jpeg.Calliphora),
// TestFile.Create(TestImages.Jpeg.BadEOF), // Perf: Enable for local testing only
// TestFile.Create(TestImages.Jpeg.BadEOFProgressive),
// TestFile.Create(TestImages.Jpeg.Ycck), // Perf: Enable for local testing only
// TestFile.Create(TestImages.Jpeg.Cmyk), // Perf: Enable for local testing only
TestFile.Create(TestImages.Jpeg.Turtle),
// TestFile.Create(TestImages.Jpeg.Turtle), // Perf: Enable for local testing only
// TestFile.Create(TestImages.Jpeg.Fb), // Perf: Enable for local testing only
// TestFile.Create(TestImages.Jpeg.Progress), // Perf: Enable for local testing only
// TestFile.Create(TestImages.Jpeg.GammaDalaiLamaGray), // Perf: Enable for local testing only
@ -33,7 +35,7 @@ namespace ImageSharp.Tests
// TestFile.Create(TestImages.Png.Blur), // Perf: Enable for local testing only
// TestFile.Create(TestImages.Png.Indexed), // Perf: Enable for local testing only
TestFile.Create(TestImages.Png.Splash),
TestFile.Create(TestImages.Png.Powerpoint),
// TestFile.Create(TestImages.Png.Powerpoint), // Perf: Enable for local testing only
// TestFile.Create(TestImages.Png.SplashInterlaced), // Perf: Enable for local testing only
// TestFile.Create(TestImages.Png.Interlaced), // Perf: Enable for local testing only
// TestFile.Create(TestImages.Png.Filter0), // Perf: Enable for local testing only

1
tests/ImageSharp.Tests/TestImages.cs
View File

@ -52,6 +52,7 @@ namespace ImageSharp.Tests
public const string Hiyamugi = "Jpg/Hiyamugi.jpg";
public const string BadEOF = "Jpg/badeof.jpg";
public const string BadEOFProgressive = "Jpg/badeofprog.jpg";
public const string Snake = "Jpg/Snake.jpg";
public const string Lake = "Jpg/Lake.jpg";

BIN
tests/ImageSharp.Tests/TestImages/Formats/Jpg/badeofprog.jpg
View File

Binary file not shown.
Side by Side

After

Width:  |  Height:  |  Size: 66 KiB

Write Preview
Loading…
Cancel
Save