diff options
Diffstat (limited to 'src/transupp.h')
| -rw-r--r-- | src/transupp.h | 129 |
1 files changed, 99 insertions, 30 deletions
diff --git a/src/transupp.h b/src/transupp.h index 056a282..4f01d29 100644 --- a/src/transupp.h +++ b/src/transupp.h @@ -1,7 +1,7 @@ /* * transupp.h * - * Copyright (C) 1997, Thomas G. Lane. + * Copyright (C) 1997-2009, Thomas G. Lane, Guido Vollbeding. * This file is part of the Independent JPEG Group's software. * For conditions of distribution and use, see the accompanying README file. * @@ -22,31 +22,6 @@ #define TRANSFORMS_SUPPORTED 1 /* 0 disables transform code */ #endif -/* Short forms of external names for systems with brain-damaged linkers. */ - -#ifdef NEED_SHORT_EXTERNAL_NAMES -#define jtransform_request_workspace jTrRequest -#define jtransform_adjust_parameters jTrAdjust -#define jtransform_execute_transformation jTrExec -#define jcopy_markers_setup jCMrkSetup -#define jcopy_markers_execute jCMrkExec -#endif /* NEED_SHORT_EXTERNAL_NAMES */ - -/* - * 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_CODE; - /* * Although rotating and flipping data expressed as DCT coefficients is not * hard, there is an asymmetry in the JPEG format specification for images @@ -74,6 +49,24 @@ typedef enum { * (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.) + * + * 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 @@ -82,30 +75,107 @@ typedef enum { * be aware of the option to know how many components to work on. */ + +/* Short forms of external names for systems with brain-damaged linkers. */ + +#ifdef NEED_SHORT_EXTERNAL_NAMES +#define jtransform_parse_crop_spec jTrParCrop +#define jtransform_request_workspace jTrRequest +#define jtransform_adjust_parameters jTrAdjust +#define jtransform_execute_transform jTrExec +#define jtransform_perfect_transform jTrPerfect +#define jcopy_markers_setup jCMrkSetup +#define jcopy_markers_execute jCMrkExec +#endif /* NEED_SHORT_EXTERNAL_NAMES */ + + +/* + * 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_CODE; + +/* + * Codes for crop parameters, which can individually be unspecified, + * positive, or negative. (Negative width or height makes no sense, though.) + */ + +typedef enum { + JCROP_UNSET, + JCROP_POS, + JCROP_NEG +} 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 source image */ + + /* 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; + JDIMENSION crop_height; /* Height of selected region */ + JCROP_CODE crop_height_set; + 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) */ /* 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; + 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 JPP((jpeg_transform_info * info, const char *spec)); /* Request any required workspace */ -EXTERN(void) jtransform_request_workspace JPP((j_decompress_ptr srcinfo, jpeg_transform_info * info)); +EXTERN(boolean) jtransform_request_workspace JPP((j_decompress_ptr srcinfo, jpeg_transform_info * info)); /* Adjust output image parameters */ EXTERN(jvirt_barray_ptr *) jtransform_adjust_parameters JPP((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_transformation +EXTERN(void) jtransform_execute_transform JPP((j_decompress_ptr srcinfo, j_compress_ptr dstinfo, jvirt_barray_ptr * src_coef_arrays, jpeg_transform_info * info)); +/* 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. */ @@ -119,7 +189,6 @@ typedef enum { #define JCOPYOPT_DEFAULT JCOPYOPT_COMMENTS /* recommended default */ /* Setup decompression object to save desired markers in memory */ -EXTERN(void) -jcopy_markers_setup JPP((j_decompress_ptr srcinfo, JCOPY_OPTION option)); +EXTERN(void) jcopy_markers_setup JPP((j_decompress_ptr srcinfo, JCOPY_OPTION option)); /* Copy markers saved in the given source object to the destination object */ EXTERN(void) jcopy_markers_execute JPP((j_decompress_ptr srcinfo, j_compress_ptr dstinfo, JCOPY_OPTION option)); |