2 Copyright (C) 2014-2021 Carl Hetherington <cth@carlh.net>
4 This file is part of DCP-o-matic.
6 DCP-o-matic is free software; you can redistribute it and/or modify
7 it under the terms of the GNU General Public License as published by
8 the Free Software Foundation; either version 2 of the License, or
9 (at your option) any later version.
11 DCP-o-matic is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 GNU General Public License for more details.
16 You should have received a copy of the GNU General Public License
17 along with DCP-o-matic. If not, see <http://www.gnu.org/licenses/>.
22 #ifndef DCPOMATIC_IMAGE_PROXY_H
23 #define DCPOMATIC_IMAGE_PROXY_H
26 /** @file src/lib/image_proxy.h
27 * @brief ImageProxy and subclasses.
33 #include <libavutil/pixfmt.h>
35 #include <dcp/types.h>
36 #include <boost/optional.hpp>
37 #include <boost/utility.hpp>
53 * @brief A class which holds an Image, and can produce it on request.
55 * This is so that decoding of source images can be postponed until
56 * the encoder thread, where multi-threading is happening, instead
57 * of happening in a single-threaded decoder.
59 * For example, large TIFFs are slow to decode, so this class will keep
60 * the TIFF data compressed until the decompressed image is needed.
61 * At this point, the class decodes the TIFF to an Image.
67 virtual ~ImageProxy () {}
69 ImageProxy (ImageProxy const&) = delete;
70 ImageProxy& operator= (ImageProxy const&) = delete;
73 Result (std::shared_ptr<const Image> image_, int log2_scaling_)
75 , log2_scaling (log2_scaling_)
79 Result (std::shared_ptr<Image> image_, int log2_scaling_, bool error_)
81 , log2_scaling (log2_scaling_)
85 std::shared_ptr<const Image> image;
86 /** log2 of any scaling down that has already been applied to the image;
87 * e.g. if the image is already half the size of the original, this value
91 /** true if there was an error during image decoding, otherwise false */
95 /** @param log Log to write to, or 0.
96 * @param size Size that the returned image will be scaled to, in case this
97 * can be used as an optimisation.
99 virtual Result image (
100 Image::Alignment alignment,
101 boost::optional<dcp::Size> size = boost::optional<dcp::Size> ()
104 virtual void add_metadata (xmlpp::Node *) const = 0;
105 virtual void write_to_socket (std::shared_ptr<Socket>) const = 0;
106 /** @return true if our image is definitely the same as another, false if it is probably not */
107 virtual bool same (std::shared_ptr<const ImageProxy>) const = 0;
108 /** Do any useful work that would speed up a subsequent call to ::image().
109 * This method may be called in a different thread to image().
110 * @return log2 of any scaling down that will be applied to the image.
112 virtual int prepare (Image::Alignment, boost::optional<dcp::Size> = boost::optional<dcp::Size>()) const { return 0; }
113 virtual size_t memory_used () const = 0;
117 std::shared_ptr<ImageProxy> image_proxy_factory (std::shared_ptr<cxml::Node> xml, std::shared_ptr<Socket> socket);