kc3-lang/libjpeg-turbo/src/transupp.h
-
Show log
Commit
-
Hash : e69dd40c
Author :
Date : 2024-01-23T13:26:41
Reorganize source to make things easier to find - Move all libjpeg documentation, except for README.ijg, into the doc/ subdirectory. - Move the TurboJPEG C API documentation from doc/html/ into doc/turbojpeg/. - Move all C source code and headers into a src/ subdirectory. - Move turbojpeg-jni.c into the java/ subdirectory. Referring to #226, there is no ideal solution to this problem. A semantically ideal solution would have involved placing all source code, including the SIMD and Java source code, under src/ (or perhaps placing C library source code under lib/ and C test program source code under test/), all header files under include/, and all documentation under doc/. However: - To me it makes more sense to have separate top-level directories for each language, since the SIMD extensions and the Java API are technically optional features. src/ now contains only the code that is relevant to the core C API libraries and associated programs. - I didn't want to bury the java/ and simd/ directories or add a level of depth to them, since both directories already contain source code that is 3-4 levels deep. - I would prefer not to separate the header files from the C source code, because: 1. It would be disruptive. libjpeg and libjpeg-turbo have historically placed C source code and headers in the same directory, and people who are familiar with both projects (self included) are used to looking for the headers in the same directory as the C source code. 2. In terms of how the headers are used internally in libjpeg-turbo, the distinction between public and private headers is a bit fuzzy. - It didn't make sense to separate the test source code from the library source code, since there is not a clear distinction in some cases. (For instance, the IJG image I/O functions are used by cjpeg and djpeg as well as by the TurboJPEG API.) This solution is minimally disruptive, since it keeps all C source code and headers together and keeps java/ and simd/ as top-level directories. It is a bit awkward, because java/ and simd/ technically contain source code, even though they are not under src/. However, other solutions would have been more awkward for different reasons. Closes #226
-
src/transupp.h
-
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231
/* * transupp.h * * This file was part of the Independent JPEG Group's software: * Copyright (C) 1997-2019, Thomas G. Lane, Guido Vollbeding. * libjpeg-turbo Modifications: * Copyright (C) 2017, 2021, D. R. Commander. * For conditions of distribution and use, see the accompanying README.ijg * file. * * This file contains declarations for image transformation routines and * other utility code used by the jpegtran sample application. These are * NOT part of the core JPEG library. But we keep these routines separate * from jpegtran.c to ease the task of maintaining jpegtran-like programs * that have other user interfaces. * * NOTE: all the routines declared here have very specific requirements * about when they are to be executed during the reading and writing of the * source and destination files. See the comments in transupp.c, or see * jpegtran.c for an example of correct usage. */ /* If you happen not to want the image transform support, disable it here */ #ifndef TRANSFORMS_SUPPORTED #define TRANSFORMS_SUPPORTED 1 /* 0 disables transform code */ #endif /* * Although rotating and flipping data expressed as DCT coefficients is not * hard, there is an asymmetry in the JPEG format specification for images * whose dimensions aren't multiples of the iMCU size. The right and bottom * image edges are padded out to the next iMCU boundary with junk data; but * no padding is possible at the top and left edges. If we were to flip * the whole image including the pad data, then pad garbage would become * visible at the top and/or left, and real pixels would disappear into the * pad margins --- perhaps permanently, since encoders & decoders may not * bother to preserve DCT blocks that appear to be completely outside the * nominal image area. So, we have to exclude any partial iMCUs from the * basic transformation. * * Transpose is the only transformation that can handle partial iMCUs at the * right and bottom edges completely cleanly. flip_h can flip partial iMCUs * at the bottom, but leaves any partial iMCUs at the right edge untouched. * Similarly flip_v leaves any partial iMCUs at the bottom edge untouched. * The other transforms are defined as combinations of these basic transforms * and process edge blocks in a way that preserves the equivalence. * * The "trim" option causes untransformable partial iMCUs to be dropped; * this is not strictly lossless, but it usually gives the best-looking * result for odd-size images. Note that when this option is active, * the expected mathematical equivalences between the transforms may not hold. * (For example, -rot 270 -trim trims only the bottom edge, but -rot 90 -trim * followed by -rot 180 -trim trims both edges.) * * We also offer a lossless-crop option, which discards data outside a given * image region but losslessly preserves what is inside. Like the rotate and * flip transforms, lossless crop is restricted by the JPEG format: the upper * left corner of the selected region must fall on an iMCU boundary. If this * does not hold for the given crop parameters, we silently move the upper left * corner up and/or left to make it so, simultaneously increasing the region * dimensions to keep the lower right crop corner unchanged. (Thus, the * output image covers at least the requested region, but may cover more.) * The adjustment of the region dimensions may be optionally disabled. * * A complementary lossless wipe option is provided to discard (gray out) data * inside a given image region while losslessly preserving what is outside. * A lossless drop option is also provided, which allows another JPEG image to * be inserted ("dropped") into the source image data at a given position, * replacing the existing image data at that position. Both the source image * and the drop image must have the same subsampling level. It is best if they * also have the same quantization (quality.) Otherwise, the quantization of * the output image will be adapted to accommodate the higher of the source * image quality and the drop image quality. The trim option can be used with * the drop option to requantize the drop image to match the source image. * * We also provide a lossless-resize option, which is kind of a lossless-crop * operation in the DCT coefficient block domain - it discards higher-order * coefficients and losslessly preserves lower-order coefficients of a * sub-block. * * Rotate/flip transform, resize, and crop can be requested together in a * single invocation. The crop is applied last --- that is, the crop region * is specified in terms of the destination image after transform/resize. * * We also offer a "force to grayscale" option, which simply discards the * chrominance channels of a YCbCr image. This is lossless in the sense that * the luminance channel is preserved exactly. It's not the same kind of * thing as the rotate/flip transformations, but it's convenient to handle it * as part of this package, mainly because the transformation routines have to * be aware of the option to know how many components to work on. */ /* * Codes for supported types of image transformations. */ typedef enum { JXFORM_NONE, /* no transformation */ JXFORM_FLIP_H, /* horizontal flip */ JXFORM_FLIP_V, /* vertical flip */ JXFORM_TRANSPOSE, /* transpose across UL-to-LR axis */ JXFORM_TRANSVERSE, /* transpose across UR-to-LL axis */ JXFORM_ROT_90, /* 90-degree clockwise rotation */ JXFORM_ROT_180, /* 180-degree rotation */ JXFORM_ROT_270, /* 270-degree clockwise (or 90 ccw) */ JXFORM_WIPE, /* wipe */ JXFORM_DROP /* drop */ } JXFORM_CODE; /* * Codes for crop parameters, which can individually be unspecified, * positive or negative for xoffset or yoffset, * positive or force or reflect for width or height. */ typedef enum { JCROP_UNSET, JCROP_POS, JCROP_NEG, JCROP_FORCE, JCROP_REFLECT } JCROP_CODE; /* * Transform parameters struct. * NB: application must not change any elements of this struct after * calling jtransform_request_workspace. */ typedef struct { /* Options: set by caller */ JXFORM_CODE transform; /* image transform operator */ boolean perfect; /* if TRUE, fail if partial MCUs are requested */ boolean trim; /* if TRUE, trim partial MCUs as needed */ boolean force_grayscale; /* if TRUE, convert color image to grayscale */ boolean crop; /* if TRUE, crop or wipe source image, or drop */ boolean slow_hflip; /* For best performance, the JXFORM_FLIP_H transform normally modifies the source coefficients in place. Setting this to TRUE will instead use a slower, double-buffered algorithm, which leaves the source coefficients in tact (necessary if other transformed images must be generated from the same set of coefficients. */ /* Crop parameters: application need not set these unless crop is TRUE. * These can be filled in by jtransform_parse_crop_spec(). */ JDIMENSION crop_width; /* Width of selected region */ JCROP_CODE crop_width_set; /* (force-disables adjustment) */ JDIMENSION crop_height; /* Height of selected region */ JCROP_CODE crop_height_set; /* (force-disables adjustment) */ JDIMENSION crop_xoffset; /* X offset of selected region */ JCROP_CODE crop_xoffset_set; /* (negative measures from right edge) */ JDIMENSION crop_yoffset; /* Y offset of selected region */ JCROP_CODE crop_yoffset_set; /* (negative measures from bottom edge) */ /* Drop parameters: set by caller for drop request */ j_decompress_ptr drop_ptr; jvirt_barray_ptr *drop_coef_arrays; /* Internal workspace: caller should not touch these */ int num_components; /* # of components in workspace */ jvirt_barray_ptr *workspace_coef_arrays; /* workspace for transformations */ JDIMENSION output_width; /* cropped destination dimensions */ JDIMENSION output_height; JDIMENSION x_crop_offset; /* destination crop offsets measured in iMCUs */ JDIMENSION y_crop_offset; JDIMENSION drop_width; /* drop/wipe dimensions measured in iMCUs */ JDIMENSION drop_height; int iMCU_sample_width; /* destination iMCU size */ int iMCU_sample_height; } jpeg_transform_info; #if TRANSFORMS_SUPPORTED /* Parse a crop specification (written in X11 geometry style) */ EXTERN(boolean) jtransform_parse_crop_spec(jpeg_transform_info *info, const char *spec); /* Request any required workspace */ EXTERN(boolean) jtransform_request_workspace(j_decompress_ptr srcinfo, jpeg_transform_info *info); /* Adjust output image parameters */ EXTERN(jvirt_barray_ptr *) jtransform_adjust_parameters (j_decompress_ptr srcinfo, j_compress_ptr dstinfo, jvirt_barray_ptr *src_coef_arrays, jpeg_transform_info *info); /* Execute the actual transformation, if any */ EXTERN(void) jtransform_execute_transform(j_decompress_ptr srcinfo, j_compress_ptr dstinfo, jvirt_barray_ptr *src_coef_arrays, jpeg_transform_info *info); /* Determine whether lossless transformation is perfectly * possible for a specified image and transformation. */ EXTERN(boolean) jtransform_perfect_transform(JDIMENSION image_width, JDIMENSION image_height, int MCU_width, int MCU_height, JXFORM_CODE transform); /* jtransform_execute_transform used to be called * jtransform_execute_transformation, but some compilers complain about * routine names that long. This macro is here to avoid breaking any * old source code that uses the original name... */ #define jtransform_execute_transformation jtransform_execute_transform #endif /* TRANSFORMS_SUPPORTED */ /* * Support for copying optional markers from source to destination file. */ typedef enum { JCOPYOPT_NONE, /* copy no optional markers */ JCOPYOPT_COMMENTS, /* copy only comment (COM) markers */ JCOPYOPT_ALL, /* copy all optional markers */ JCOPYOPT_ALL_EXCEPT_ICC, /* copy all optional markers except APP2 */ JCOPYOPT_ICC /* copy only ICC profile (APP2) markers */ } JCOPY_OPTION; #define JCOPYOPT_DEFAULT JCOPYOPT_COMMENTS /* recommended default */ /* Setup decompression object to save desired markers in memory */ EXTERN(void) jcopy_markers_setup(j_decompress_ptr srcinfo, JCOPY_OPTION option); /* Copy markers saved in the given source object to the destination object */ EXTERN(void) jcopy_markers_execute(j_decompress_ptr srcinfo, j_compress_ptr dstinfo, JCOPY_OPTION option);