Implement lossless crop feature from jpeg v7 and v8

git-svn-id: svn+ssh://svn.code.sf.net/p/libjpeg-turbo/code/trunk@243 632fc199-4ca6-4c93-a231-07263d6284db

Makefile.am

@@ -118,6 +118,8 @@ test: testclean all
 	cmp $(srcdir)/testimgp.jpg testoutp.jpg
 	./jpegtran -outfile testoutt.jpg testoutp.jpg
 	cmp $(srcdir)/testimgint.jpg testoutt.jpg
+	./jpegtran -crop 100x100+10+10 -transpose -perfect -outfile testoutcrop.jpg $(srcdir)/testorig.jpg
+	cmp $(srcdir)/testimgcrop.jpg testoutcrop.jpg
 
 else
 
@@ -141,6 +143,8 @@ test: testclean all
 	cmp $(srcdir)/testimgp.jpg testoutp.jpg
 	./jpegtran -outfile testoutt.jpg testoutp.jpg
 	cmp $(srcdir)/testimgint.jpg testoutt.jpg
+	./jpegtran -crop 100x100+10+10 -transpose -perfect -outfile testoutcrop.jpg $(srcdir)/testorig.jpg
+	cmp $(srcdir)/testimgcrop.jpg testoutcrop.jpg
 
 endif
 

jcmarker.c

@@ -2,6 +2,7 @@
  * jcmarker.c
  *
  * Copyright (C) 1991-1998, Thomas G. Lane.
+ * Copyright (C) 2010, D. R. Commander.
  * This file is part of the Independent JPEG Group's software.
  * For conditions of distribution and use, see the accompanying README file.
  *
@@ -11,6 +12,7 @@
 #define JPEG_INTERNALS
 #include "jinclude.h"
 #include "jpeglib.h"
+#include "jpegcomp.h"
 
 
 typedef enum {			/* JPEG marker codes */
@@ -285,13 +287,13 @@ emit_sof (j_compress_ptr cinfo, JPEG_MARKER code)
   emit_2bytes(cinfo, 3 * cinfo->num_components + 2 + 5 + 1); /* length */
 
   /* Make sure image isn't bigger than SOF field can handle */
-  if ((long) cinfo->image_height > 65535L ||
-      (long) cinfo->image_width > 65535L)
+  if ((long) cinfo->_jpeg_height > 65535L ||
+      (long) cinfo->_jpeg_width > 65535L)
     ERREXIT1(cinfo, JERR_IMAGE_TOO_BIG, (unsigned int) 65535);
 
   emit_byte(cinfo, cinfo->data_precision);
-  emit_2bytes(cinfo, (int) cinfo->image_height);
-  emit_2bytes(cinfo, (int) cinfo->image_width);
+  emit_2bytes(cinfo, (int) cinfo->_jpeg_height);
+  emit_2bytes(cinfo, (int) cinfo->_jpeg_width);
 
   emit_byte(cinfo, cinfo->num_components);
 

jcmaster.c

@@ -16,6 +16,7 @@
 #define JPEG_INTERNALS
 #include "jinclude.h"
 #include "jpeglib.h"
+#include "jpegcomp.h"
 
 
 /* Private state */
@@ -65,7 +66,7 @@ jpeg_calc_jpeg_dimensions (j_compress_ptr cinfo)
 
 
 LOCAL(void)
-initial_setup (j_compress_ptr cinfo)
+initial_setup (j_compress_ptr cinfo, boolean transcode_only)
 /* Do computations that are needed before master selection phase */
 {
   int ci;
@@ -74,17 +75,18 @@ initial_setup (j_compress_ptr cinfo)
   JDIMENSION jd_samplesperrow;
 
 #if JPEG_LIB_VERSION >= 70
-  jpeg_calc_jpeg_dimensions(cinfo);
+  if (!transcode_only)
+    jpeg_calc_jpeg_dimensions(cinfo);
 #endif
 
   /* Sanity check on image dimensions */
-  if (cinfo->image_height <= 0 || cinfo->image_width <= 0
+  if (cinfo->_jpeg_height <= 0 || cinfo->_jpeg_width <= 0
       || cinfo->num_components <= 0 || cinfo->input_components <= 0)
     ERREXIT(cinfo, JERR_EMPTY_IMAGE);
 
   /* Make sure image isn't bigger than I can handle */
-  if ((long) cinfo->image_height > (long) JPEG_MAX_DIMENSION ||
-      (long) cinfo->image_width > (long) JPEG_MAX_DIMENSION)
+  if ((long) cinfo->_jpeg_height > (long) JPEG_MAX_DIMENSION ||
+      (long) cinfo->_jpeg_width > (long) JPEG_MAX_DIMENSION)
     ERREXIT1(cinfo, JERR_IMAGE_TOO_BIG, (unsigned int) JPEG_MAX_DIMENSION);
 
   /* Width of an input scanline must be representable as JDIMENSION. */
@@ -129,17 +131,17 @@ initial_setup (j_compress_ptr cinfo)
 #endif
     /* Size in DCT blocks */
     compptr->width_in_blocks = (JDIMENSION)
-      jdiv_round_up((long) cinfo->image_width * (long) compptr->h_samp_factor,
+      jdiv_round_up((long) cinfo->_jpeg_width * (long) compptr->h_samp_factor,
 		    (long) (cinfo->max_h_samp_factor * DCTSIZE));
     compptr->height_in_blocks = (JDIMENSION)
-      jdiv_round_up((long) cinfo->image_height * (long) compptr->v_samp_factor,
+      jdiv_round_up((long) cinfo->_jpeg_height * (long) compptr->v_samp_factor,
 		    (long) (cinfo->max_v_samp_factor * DCTSIZE));
     /* Size in samples */
     compptr->downsampled_width = (JDIMENSION)
-      jdiv_round_up((long) cinfo->image_width * (long) compptr->h_samp_factor,
+      jdiv_round_up((long) cinfo->_jpeg_width * (long) compptr->h_samp_factor,
 		    (long) cinfo->max_h_samp_factor);
     compptr->downsampled_height = (JDIMENSION)
-      jdiv_round_up((long) cinfo->image_height * (long) compptr->v_samp_factor,
+      jdiv_round_up((long) cinfo->_jpeg_height * (long) compptr->v_samp_factor,
 		    (long) cinfo->max_v_samp_factor);
     /* Mark component needed (this flag isn't actually used for compression) */
     compptr->component_needed = TRUE;
@@ -149,7 +151,7 @@ initial_setup (j_compress_ptr cinfo)
    * main controller will call coefficient controller).
    */
   cinfo->total_iMCU_rows = (JDIMENSION)
-    jdiv_round_up((long) cinfo->image_height,
+    jdiv_round_up((long) cinfo->_jpeg_height,
 		  (long) (cinfo->max_v_samp_factor*DCTSIZE));
 }
 
@@ -377,10 +379,10 @@ per_scan_setup (j_compress_ptr cinfo)
 
     /* Overall image size in MCUs */
     cinfo->MCUs_per_row = (JDIMENSION)
-      jdiv_round_up((long) cinfo->image_width,
+      jdiv_round_up((long) cinfo->_jpeg_width,
 		    (long) (cinfo->max_h_samp_factor*DCTSIZE));
     cinfo->MCU_rows_in_scan = (JDIMENSION)
-      jdiv_round_up((long) cinfo->image_height,
+      jdiv_round_up((long) cinfo->_jpeg_height,
 		    (long) (cinfo->max_v_samp_factor*DCTSIZE));
 
     cinfo->blocks_in_MCU = 0;
@@ -584,7 +586,7 @@ jinit_c_master_control (j_compress_ptr cinfo, boolean transcode_only)
   master->pub.is_last_pass = FALSE;
 
   /* Validate parameters, determine derived values */
-  initial_setup(cinfo);
+  initial_setup(cinfo, transcode_only);
 
   if (cinfo->scan_info != NULL) {
 #ifdef C_MULTISCAN_FILES_SUPPORTED

jerror.h

@@ -2,6 +2,7 @@
  * jerror.h
  *
  * Copyright (C) 1994-1997, Thomas G. Lane.
+ * Modified 1997-2009 by Guido Vollbeding.
  * This file is part of the Independent JPEG Group's software.
  * For conditions of distribution and use, see the accompanying README file.
  *
@@ -45,6 +46,7 @@ JMESSAGE(JERR_BAD_ALIGN_TYPE, "ALIGN_TYPE is wrong, please fix")
 JMESSAGE(JERR_BAD_ALLOC_CHUNK, "MAX_ALLOC_CHUNK is wrong, please fix")
 JMESSAGE(JERR_BAD_BUFFER_MODE, "Bogus buffer control mode")
 JMESSAGE(JERR_BAD_COMPONENT_ID, "Invalid component ID %d in SOS")
+JMESSAGE(JERR_BAD_CROP_SPEC, "Invalid crop request")
 JMESSAGE(JERR_BAD_DCT_COEF, "DCT coefficient out of range")
 JMESSAGE(JERR_BAD_DCTSIZE, "IDCT output block size %d not supported")
 JMESSAGE(JERR_BAD_HUFF_TABLE, "Bogus Huffman table definition")

jpegcomp.h

@@ -12,7 +12,15 @@
 #if JPEG_LIB_VERSION >= 70
 #define _DCT_scaled_size DCT_h_scaled_size
 #define _min_DCT_scaled_size min_DCT_h_scaled_size
+#define _min_DCT_h_scaled_size min_DCT_h_scaled_size
+#define _min_DCT_v_scaled_size min_DCT_v_scaled_size
+#define _jpeg_width jpeg_width
+#define _jpeg_height jpeg_height
 #else
 #define _DCT_scaled_size DCT_scaled_size
 #define _min_DCT_scaled_size min_DCT_scaled_size
+#define _min_DCT_h_scaled_size min_DCT_scaled_size
+#define _min_DCT_v_scaled_size min_DCT_scaled_size
+#define _jpeg_width image_width
+#define _jpeg_height image_height
 #endif

jpegtran.1

@@ -1,4 +1,4 @@
-.TH JPEGTRAN 1 "3 August 1997"
+.TH JPEGTRAN 1 "28 December 2009"
 .SH NAME
 jpegtran \- lossless transformation of JPEG files
 .SH SYNOPSIS
@@ -91,12 +91,12 @@ Transpose image (across UL-to-LR axis).
 .TP
 .B \-transverse
 Transverse transpose (across UR-to-LL axis).
-.PP
+.IP
 The transpose transformation has no restrictions regarding image dimensions.
 The other transformations operate rather oddly if the image dimensions are not
 a multiple of the iMCU size (usually 8 or 16 pixels), because they can only
 transform complete blocks of DCT coefficient data in the desired way.
-.PP
+.IP
 .BR jpegtran 's
 default behavior when transforming an odd-size image is designed
 to preserve exact reversibility and mathematical consistency of the
@@ -108,7 +108,7 @@ able to flip all columns.  The other transforms can be built up as sequences
 of transpose and flip operations; for consistency, their actions on edge
 pixels are defined to be the same as the end result of the corresponding
 transpose-and-flip sequence.
-.PP
+.IP
 For practical use, you may prefer to discard any untransformable edge pixels
 rather than having a strange-looking strip along the right and/or bottom edges
 of a transformed image.  To do this, add the
@@ -117,7 +117,7 @@ switch:
 .TP
 .B \-trim
 Drop non-transformable edge blocks.
-.PP
+.IP
 Obviously, a transformation with
 .B \-trim
 is not reversible, so strictly speaking
@@ -130,12 +130,43 @@ trims only the bottom edge, but
 followed by
 .B \-rot 180 -trim
 trims both edges.
+.IP
+If you are only interested in perfect transformation, add the
+.B \-perfect
+switch:
+.TP
+.B \-perfect
+Fails with an error if the transformation is not perfect.
+.IP
+For example you may want to do
+.IP
+.B (jpegtran \-rot 90 -perfect
+.I foo.jpg
+.B || djpeg
+.I foo.jpg
+.B | pnmflip \-r90 | cjpeg)
+.IP
+to do a perfect rotation if available or an approximated one if not.
+.PP
+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 current 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 image can be losslessly cropped by giving the switch:
+.TP
+.B \-crop WxH+X+Y
+Crop to a rectangular subarea of width W, height H starting at point X,Y.
 .PP
-Another not-strictly-lossless transformation switch is:
+Other not-strictly-lossless transformation switches are:
 .TP
 .B \-grayscale
 Force grayscale output.
-.PP
+.IP
 This option discards the chrominance channels if the input image is YCbCr
 (ie, a standard color JPEG), resulting in a grayscale JPEG file.  The
 luminance channel is preserved exactly, so this is a better method of reducing
@@ -155,13 +186,13 @@ comments and other excess baggage present in the source file.
 .TP
 .B \-copy comments
 Copy only comment markers.  This setting copies comments from the source file,
-but discards any other inessential data.
+but discards any other inessential (for image display) data.
 .TP
 .B \-copy all
 Copy all extra markers.  This setting preserves miscellaneous markers
-found in the source file, such as JFIF thumbnails and Photoshop settings.
-In some files these extra markers can be sizable.
-.PP
+found in the source file, such as JFIF thumbnails, Exif data, and Photoshop
+settings.  In some files these extra markers can be sizable.
+.IP
 The default behavior is
 .BR "\-copy comments" .
 (Note: in IJG releases v6 and v6a,
@@ -231,7 +262,9 @@ Arithmetic coding is not supported for legal reasons.
 .PP
 The transform options can't transform odd-size images perfectly.  Use
 .B \-trim
-if you don't like the results without it.
+or
+.B \-perfect
+if you don't like the results.
 .PP
 The entire image is read into memory and then written out again, even in
 cases where this isn't really necessary.  Expect swapping on large images,