mirror of
https://github.com/qpdf/qpdf.git
synced 2024-09-22 10:09:06 +00:00
69 lines
2.9 KiB
C++
69 lines
2.9 KiB
C++
// Copyright (c) 2005-2023 Jay Berkenbilt
|
|
//
|
|
// This file is part of qpdf.
|
|
//
|
|
// Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except
|
|
// in compliance with the License. You may obtain a copy of the License at
|
|
//
|
|
// http://www.apache.org/licenses/LICENSE-2.0
|
|
//
|
|
// Unless required by applicable law or agreed to in writing, software distributed under the License
|
|
// is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express
|
|
// or implied. See the License for the specific language governing permissions and limitations under
|
|
// the License.
|
|
//
|
|
// Versions of qpdf prior to version 7 were released under the terms of version 2.0 of the Artistic
|
|
// License. At your option, you may continue to consider qpdf to be licensed under those terms.
|
|
// Please see the manual for additional information.
|
|
|
|
#ifndef QPDFSTREAMFILTER_HH
|
|
#define QPDFSTREAMFILTER_HH
|
|
|
|
#include <qpdf/DLL.h>
|
|
#include <qpdf/Pipeline.hh>
|
|
#include <qpdf/QPDFObjectHandle.hh>
|
|
|
|
class QPDF_DLL_CLASS QPDFStreamFilter
|
|
{
|
|
public:
|
|
QPDF_DLL
|
|
QPDFStreamFilter() = default;
|
|
|
|
QPDF_DLL
|
|
virtual ~QPDFStreamFilter() = default;
|
|
|
|
// A QPDFStreamFilter class must implement, at a minimum, setDecodeParms() and
|
|
// getDecodePipeline(). QPDF will always call setDecodeParms() before calling
|
|
// getDecodePipeline(). It is expected that you will store any needed information from
|
|
// decode_parms (or the decode_parms object itself) in your instance so that it can be used to
|
|
// construct the decode pipeline.
|
|
|
|
// Return a boolean indicating whether your filter can proceed with the given /DecodeParms. The
|
|
// default implementation accepts a null object and rejects everything else.
|
|
QPDF_DLL
|
|
virtual bool setDecodeParms(QPDFObjectHandle decode_parms);
|
|
|
|
// Return a pipeline that will decode data encoded with your filter. Your implementation must
|
|
// ensure that the pipeline is deleted when the instance of your class is destroyed.
|
|
QPDF_DLL
|
|
virtual Pipeline* getDecodePipeline(Pipeline* next) = 0;
|
|
|
|
// If your filter implements "specialized" compression or lossy compression, override one or
|
|
// both of these methods. The default implementations return false. See comments in QPDFWriter
|
|
// for details. QPDF defines specialized compression as non-lossy compression not intended for
|
|
// general-purpose data. qpdf, by default, doesn't mess with streams that are compressed with
|
|
// specialized compression, the idea being that the decision to use that compression scheme
|
|
// would fall outside of what QPDFWriter would know anything about, so any attempt to decode and
|
|
// re-encode would probably be undesirable.
|
|
QPDF_DLL
|
|
virtual bool isSpecializedCompression();
|
|
QPDF_DLL
|
|
virtual bool isLossyCompression();
|
|
|
|
private:
|
|
QPDFStreamFilter(QPDFStreamFilter const&) = delete;
|
|
QPDFStreamFilter& operator=(QPDFStreamFilter const&) = delete;
|
|
};
|
|
|
|
#endif // QPDFSTREAMFILTER_HH
|