Fix lossless image rotation

Apparently, the old code was based on libjpeg6. However, most systems use
libjpeg8 now, which has a few new features like cropping, leading to a lot
of fuckup with feh on libjpeg8 systems. Now feh works with libjpeg8,
but probably doesn't support libjpeg6 anymore.

Also, this code copypasta really sucks :-)

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));