| // Copyright 2023 The Wuffs Authors. |
| // |
| // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or |
| // https://www.apache.org/licenses/LICENSE-2.0> or the MIT license |
| // <LICENSE-MIT or https://opensource.org/licenses/MIT>, at your |
| // option. This file may not be copied, modified, or distributed |
| // except according to those terms. |
| // |
| // SPDX-License-Identifier: Apache-2.0 OR MIT |
| |
| // ---------------- |
| |
| /* |
| toy-aux-image demonstrates using the wuffs_aux::DecodeImage C++ function to |
| decode an in-memory compressed image. In this example, the compressed image is |
| hard-coded to a specific image: a JPEG encoding of the first frame of the |
| test/data/muybridge.gif animated image. |
| |
| To run: |
| |
| $CXX toy-aux-image.cc && ./a.out; rm -f a.out |
| |
| for a C++ compiler $CXX, such as clang++ or g++. |
| |
| The expected output: |
| |
| @@@@@@@@@@@@@@@@@@@@@@@@@@@@@@ |
| @@@@@@@@@@@@X@@@@XX@@@@@@@@@@X |
| XXXXX@@XXX@@@@@@@II@@@X@X@@@@@ |
| XXXXX@@XX@@X@@@XO+XXX@XX@@@X@@ |
| XXXXXXXX@XX@X@XI=I@@XXI+OXX@XX |
| XXXXXXXXXXXXXXX+=+OXO+=::OXX@X |
| XXXXXXXXXXXXXXXXXX=+==:::=XXXX |
| XXXXXXXXO+:::::+OO+===+OI=+XXX |
| XXXO::=++:::==+++XI+++X@XXO@XX |
| XXXO=X@X+::=::::+O++=I@XX@XXXX |
| XXXXX@XXX=:::::::::=+@XXXX@XXX |
| XXXXXXXX@O::IXO=::::O@@XXXXXXX |
| XXXXXXXXO=X+X@@XX::O@@XXXXXXXX |
| XXXXXXXXXOO=X@X@X+OIXXXXXXXXXX |
| XXXXXXXXXXX+IIXX+X@OX@XXXXXXXX |
| XXXXXXXXX@XXOI+IIOOOXXXXXXXXXX |
| XXXXXXXXXXX@XXXXX@XXXXXXXXXXXX |
| XXXXXXXXXXXXXXXXX@XXXXXXXXXXXX |
| OOOOXXXXXXXXXXOXXXXXXXXXXXXOOO |
| =+++IIIIIIIOOOOOOOOOOIIIIIIII+ |
| */ |
| |
| // Wuffs ships as a "single file C library" or "header file library" as per |
| // https://github.com/nothings/stb/blob/master/docs/stb_howto.txt |
| // |
| // To use that single file as a "foo.c"-like implementation, instead of a |
| // "foo.h"-like header, #define WUFFS_IMPLEMENTATION before #include'ing or |
| // compiling it. |
| #define WUFFS_IMPLEMENTATION |
| |
| // Defining the WUFFS_CONFIG__STATIC_FUNCTIONS macro is optional, but when |
| // combined with WUFFS_IMPLEMENTATION, it demonstrates making all of Wuffs' |
| // functions have static storage. |
| // |
| // This can help the compiler ignore or discard unused code, which can produce |
| // faster compiles and smaller binaries. Other motivations are discussed in the |
| // "ALLOW STATIC IMPLEMENTATION" section of |
| // https://raw.githubusercontent.com/nothings/stb/master/docs/stb_howto.txt |
| #define WUFFS_CONFIG__STATIC_FUNCTIONS |
| |
| // Defining the WUFFS_CONFIG__MODULE* macros are optional, but it lets users of |
| // release/c/etc.c choose which parts of Wuffs to build. That file contains the |
| // entire Wuffs standard library, implementing a variety of codecs and file |
| // formats. Without this macro definition, an optimizing compiler or linker may |
| // very well discard Wuffs code for unused codecs, but listing the Wuffs |
| // modules we use makes that process explicit. Preprocessing means that such |
| // code simply isn't compiled. |
| #define WUFFS_CONFIG__MODULES |
| #define WUFFS_CONFIG__MODULE__AUX__BASE |
| #define WUFFS_CONFIG__MODULE__AUX__IMAGE |
| #define WUFFS_CONFIG__MODULE__BASE |
| #define WUFFS_CONFIG__MODULE__JPEG |
| |
| // Defining the WUFFS_CONFIG__DST_PIXEL_FORMAT__ENABLE_ALLOWLIST (and the |
| // associated ETC__ALLOW_FOO) macros are optional, but can lead to smaller |
| // programs (in terms of binary size). By default (without these macros), |
| // Wuffs' standard library can decode images to a variety of pixel formats, |
| // such as BGR_565, BGRA_PREMUL or RGBA_NONPREMUL. The destination pixel format |
| // is selectable at runtime. Using these macros essentially makes the selection |
| // at compile time, by narrowing the list of supported destination pixel |
| // formats. The FOO in ETC__ALLOW_FOO should match the pixel format passed (as |
| // part of the wuffs_base__image_config argument) to the decode_frame method. |
| // |
| // If using the wuffs_aux C++ API, without overriding the SelectPixfmt method, |
| // the implicit destination pixel format is BGRA_PREMUL. |
| #define WUFFS_CONFIG__DST_PIXEL_FORMAT__ENABLE_ALLOWLIST |
| #define WUFFS_CONFIG__DST_PIXEL_FORMAT__ALLOW_BGRA_PREMUL |
| |
| // If building this program in an environment that doesn't easily accommodate |
| // relative includes, you can use the script/inline-c-relative-includes.go |
| // program to generate a stand-alone C file. |
| #include "../../release/c/wuffs-unsupported-snapshot.c" |
| |
| // g_src_array and g_src_len hold a grayscale JPEG image of a galloping horse. |
| // |
| // $ convert 'test/data/muybridge.gif[0]' -colorspace gray x.jpeg |
| // $ hd x.jpeg |
| // 00000000 ff d8 ff e0 00 10 4a 46 49 46 00 01 01 00 00 01 |......JFIF......| |
| // 00000010 00 01 00 00 ff db 00 43 00 03 02 02 02 02 02 03 |.......C........| |
| // 00000020 02 02 02 03 03 03 03 04 06 04 04 04 04 04 08 06 |................| |
| // etc |
| // 00000200 53 04 29 20 5a 26 25 41 d3 44 75 ee fa 37 07 d5 |S.) Z&%A.Du..7..| |
| // 00000210 fd 40 67 91 55 49 14 49 6c 55 53 af 14 ed e7 fd |.@g.UI.IlUS.....| |
| // 00000220 6e 3f ff d9 |n?..| |
| // 00000224 |
| uint8_t g_src_array[] = { |
| 0xff, 0xd8, 0xff, 0xe0, 0x00, 0x10, 0x4a, 0x46, 0x49, 0x46, 0x00, 0x01, |
| 0x01, 0x00, 0x00, 0x01, 0x00, 0x01, 0x00, 0x00, 0xff, 0xdb, 0x00, 0x43, |
| 0x00, 0x03, 0x02, 0x02, 0x02, 0x02, 0x02, 0x03, 0x02, 0x02, 0x02, 0x03, |
| 0x03, 0x03, 0x03, 0x04, 0x06, 0x04, 0x04, 0x04, 0x04, 0x04, 0x08, 0x06, |
| 0x06, 0x05, 0x06, 0x09, 0x08, 0x0a, 0x0a, 0x09, 0x08, 0x09, 0x09, 0x0a, |
| 0x0c, 0x0f, 0x0c, 0x0a, 0x0b, 0x0e, 0x0b, 0x09, 0x09, 0x0d, 0x11, 0x0d, |
| 0x0e, 0x0f, 0x10, 0x10, 0x11, 0x10, 0x0a, 0x0c, 0x12, 0x13, 0x12, 0x10, |
| 0x13, 0x0f, 0x10, 0x10, 0x10, 0xff, 0xc0, 0x00, 0x0b, 0x08, 0x00, 0x14, |
| 0x00, 0x1e, 0x01, 0x01, 0x11, 0x00, 0xff, 0xc4, 0x00, 0x18, 0x00, 0x01, |
| 0x01, 0x00, 0x03, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, |
| 0x00, 0x00, 0x00, 0x07, 0x08, 0x03, 0x05, 0x06, 0xff, 0xc4, 0x00, 0x2e, |
| 0x10, 0x00, 0x02, 0x01, 0x04, 0x00, 0x05, 0x01, 0x05, 0x09, 0x00, 0x00, |
| 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x11, |
| 0x00, 0x07, 0x08, 0x12, 0x21, 0x13, 0x22, 0x31, 0x41, 0x51, 0x61, 0x14, |
| 0x17, 0x23, 0x32, 0x42, 0x52, 0x71, 0x81, 0x91, 0xff, 0xda, 0x00, 0x08, |
| 0x01, 0x01, 0x00, 0x00, 0x3f, 0x00, 0xbd, 0x63, 0xbc, 0x2a, 0x15, 0x49, |
| 0x6a, 0x02, 0xbb, 0x0d, 0x80, 0xcc, 0x01, 0x3f, 0x5d, 0x71, 0xc7, 0x5f, |
| 0x3a, 0x80, 0xe5, 0x85, 0x92, 0x5a, 0xeb, 0x5a, 0xf3, 0x0b, 0x18, 0x9a, |
| 0xf7, 0x48, 0x1a, 0x35, 0xb5, 0xc9, 0x7c, 0xa5, 0x82, 0x67, 0x9f, 0x5e, |
| 0xcc, 0x47, 0xbd, 0xc0, 0x52, 0x4e, 0x87, 0x9f, 0x77, 0x06, 0xb5, 0xbd, |
| 0x58, 0x47, 0x80, 0xd9, 0x5a, 0xd5, 0x96, 0x50, 0x5d, 0x2f, 0x59, 0xf5, |
| 0x45, 0x63, 0x16, 0xc7, 0x2d, 0xd0, 0x89, 0x7e, 0xcd, 0xea, 0x76, 0xb4, |
| 0x50, 0xc7, 0x34, 0x60, 0xa4, 0x88, 0x11, 0x97, 0x4c, 0x0b, 0x31, 0x25, |
| 0x87, 0xc3, 0x41, 0x87, 0x97, 0xfc, 0xce, 0xb3, 0xf3, 0x27, 0x16, 0xa5, |
| 0xca, 0x6c, 0x8d, 0x50, 0x91, 0xcc, 0x5a, 0x29, 0xe9, 0xaa, 0x17, 0xb2, |
| 0x7a, 0x49, 0xd7, 0xc4, 0x90, 0xca, 0x9f, 0xa5, 0xd4, 0xf8, 0x23, 0xf8, |
| 0x23, 0x60, 0x83, 0xc6, 0xb2, 0xed, 0xcb, 0xbc, 0x07, 0x30, 0xba, 0xd0, |
| 0xdf, 0xb2, 0xbc, 0x46, 0xd7, 0x78, 0xae, 0xb7, 0x43, 0x24, 0x14, 0x72, |
| 0xd7, 0x53, 0xac, 0xe2, 0x04, 0x90, 0xa9, 0x7e, 0xd5, 0x6d, 0xa8, 0x27, |
| 0xb4, 0x7b, 0x5a, 0xd8, 0xf3, 0xa3, 0xe4, 0xf1, 0x26, 0xd6, 0xf4, 0x6d, |
| 0x8b, 0xfd, 0xe3, 0x65, 0x32, 0x64, 0xd9, 0xc5, 0xeb, 0x0b, 0xa3, 0xb9, |
| 0x91, 0x57, 0x61, 0x92, 0x19, 0x51, 0xe0, 0x49, 0xe5, 0x96, 0x50, 0xca, |
| 0xd3, 0xb0, 0x1e, 0xaa, 0x84, 0x8d, 0x1b, 0xb1, 0xbd, 0x36, 0x1e, 0xb0, |
| 0x50, 0x58, 0xaf, 0x73, 0x24, 0x74, 0xbd, 0xca, 0xac, 0xaa, 0xd3, 0x7f, |
| 0xb8, 0xe6, 0x7c, 0xc6, 0xca, 0xe2, 0xc8, 0xaa, 0x68, 0x63, 0x5a, 0x6c, |
| 0x76, 0x48, 0xe3, 0x58, 0xc4, 0x74, 0x7a, 0x31, 0x24, 0x92, 0x22, 0x9f, |
| 0xc3, 0x94, 0xc5, 0x1a, 0xea, 0x26, 0x05, 0x91, 0x5f, 0xcb, 0x16, 0xdf, |
| 0x6d, 0x1a, 0xec, 0x4b, 0x33, 0xaa, 0x22, 0x17, 0x3d, 0xcc, 0x54, 0x6b, |
| 0xb8, 0xe8, 0x0d, 0x9f, 0x99, 0xd0, 0x03, 0xfa, 0x1c, 0x4b, 0xb8, 0x47, |
| 0x51, 0xdc, 0xc1, 0xbc, 0xd2, 0xa4, 0xd5, 0x90, 0xda, 0x36, 0x57, 0x7a, |
| 0x4a, 0x66, 0x03, 0xf2, 0x83, 0xfb, 0xfe, 0xbc, 0x23, 0xd9, 0xb9, 0xab, |
| 0x95, 0xdc, 0xed, 0xed, 0x34, 0xed, 0x48, 0xa5, 0x48, 0x20, 0x24, 0x3e, |
| 0x3e, 0x1f, 0x32, 0x78, 0xc9, 0x72, 0xe6, 0xb6, 0x53, 0x04, 0x29, 0x20, |
| 0x5a, 0x26, 0x25, 0x41, 0xd3, 0x44, 0x75, 0xee, 0xfa, 0x37, 0x07, 0xd5, |
| 0xfd, 0x40, 0x67, 0x91, 0x55, 0x49, 0x14, 0x49, 0x6c, 0x55, 0x53, 0xaf, |
| 0x14, 0xed, 0xe7, 0xfd, 0x6e, 0x3f, 0xff, 0xd9, |
| }; |
| size_t g_src_len = 0x224; |
| |
| static std::string // |
| decode() { |
| // Call wuffs_aux::DecodeImage, which is the entry point to Wuffs' high-level |
| // C++ API for decoding images. This API is easier to use than Wuffs' |
| // low-level C API but the low-level one (1) handles animation, (2) handles |
| // asynchronous I/O, (3) handles metadata and (4) does no dynamic memory |
| // allocation, so it can run under a `SECCOMP_MODE_STRICT` sandbox. |
| // Obviously, if you don't need any of those features, then these simple |
| // lines of code here suffices. |
| // |
| // This example program doesn't explicitly use Wuffs' low-level C API but, if |
| // you're curious to learn more, the wuffs_aux::DecodeImage implementation in |
| // internal/cgen/auxiliary/*.cc uses it, as does the example/convert-to-nia C |
| // program. There's also documentation at doc/std/image-decoders.md |
| // |
| // If you also want metadata like EXIF orientation and ICC color profiles, |
| // script/print-image-metadata.cc has some example code. It uses Wuffs' |
| // low-level API but it's a C++ program to use Wuffs' shorter convenience |
| // methods: `decoder->decode_frame_config(NULL, &src)` instead of C's |
| // `wuffs_base__image_decoder__decode_frame_config(decoder, NULL, &src)`. |
| wuffs_aux::DecodeImageCallbacks callbacks; |
| wuffs_aux::sync_io::MemoryInput input(&g_src_array[0], g_src_len); |
| wuffs_aux::DecodeImageResult result = |
| wuffs_aux::DecodeImage(callbacks, input); |
| if (!result.error_message.empty()) { |
| return result.error_message; |
| } |
| // If result.error_message is empty then the DecodeImage call succeeded. The |
| // decoded image is held in result.pixbuf, backed by memory that is released |
| // when result.pixbuf_mem_owner (a std::unique_ptr) is destroyed. In this |
| // example program, this happens at the end of this function. |
| |
| // Print result.pixbuf as ASCII art. |
| uint32_t w = result.pixbuf.pixcfg.width(); |
| uint32_t h = result.pixbuf.pixcfg.height(); |
| for (uint32_t y = 0; y < h; y++) { |
| for (uint32_t x = 0; x < w; x++) { |
| // color is 32 bits (4x8 bits). The blue channel occupies the low 8 bits. |
| // The green channel occupies the next 8 bits. Red the next 8 and alpha |
| // the high 8 bits. Since our hard-coded JPEG image is grayscale, this |
| // example program just prints an ASCII value based on the high 3 bits of |
| // the blue channel value. |
| // |
| // This example program also configures wuffs_aux::DecodeImage to only |
| // support JPEG images (and not BMP, PNG, etc). To add support for other |
| // image file formats, add e.g. "#define WUFFS_CONFIG__MODULE__BMP" (and |
| // any dependencies) next to the "#define WUFFS_CONFIG__MODULE__JPEG" |
| // line above. Dependencies are listed at |
| // https://github.com/google/wuffs/tree/main/doc/std#modules-and-dependencies |
| // |
| // Calling the color_u32_at method is simple and easy, but like any |
| // one-call-per-pixel approach, it has some performance overhead. An |
| // alternative approach calls result.pixbuf.plane instead, to get the |
| // table (base pointer, width, height and stride) for the interleaved |
| // (not multi-planar) WUFFS_BASE__PIXEL_FORMAT__BGRA_PREMUL pixel data, |
| // and proceeds with pointer arithmetic. See example/imageviewer code. |
| wuffs_base__color_u32_argb_premul color = |
| result.pixbuf.color_u32_at(x, y); |
| putchar("-:=+IOX@"[(color & 0xFF) >> 5]); |
| } |
| putchar('\n'); |
| } |
| return std::string(); |
| } |
| |
| int // |
| main(int argc, char** argv) { |
| std::string status_msg = decode(); |
| if (!status_msg.empty()) { |
| fprintf(stderr, "%s\n", status_msg.c_str()); |
| return 1; |
| } |
| return 0; |
| } |