--- /dev/null
+/*
+ * transupp.h
+ *
+ * Copyright (C) 1997-2001, Thomas G. Lane.
+ * This file is part of the Independent JPEG Group's software.
+ * For conditions of distribution and use, see the accompanying README 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.)
+ *
+ * If both crop and a rotate/flip transform are requested, the crop is applied
+ * last --- that is, the crop region is specified in terms of the destination
+ * image.
+ *
+ * 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.
+ */
+
+
+/* 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 max_h_samp_factor; /* destination iMCU size */
+ int max_v_samp_factor;
+} 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));
+/* 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_transform
+ JPP((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
+ JPP((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 */
+} JCOPY_OPTION;
+
+#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));
+/* 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));
projects / opencv / blobdiff