--- jpegtran.1.orig Sun Aug 3 16:01:01 1997 +++ jpegtran.1 Fri Oct 8 14:51:56 2004 @@ -71,12 +71,23 @@ .PP The image can be losslessly transformed by giving one of these switches: .TP +.B \-crop WxH+X+Y +Crop to a rectangular subarea of width W, height H starting at point X,Y. +Allows the Width and or Height of the image to exceed the image. +.TP +.B \-drop +X+Y +Drop another image. Overlay part of the source image at point width +W + height H. +.TP .B \-flip horizontal Mirror image horizontally (left-right). .TP .B \-flip vertical Mirror image vertically (top-bottom). .TP +.B \-perfect +Fails with an error if there is any loss durring the transformation. +.TP .B \-rotate 90 Rotate image 90 degrees clockwise. .TP @@ -161,6 +172,14 @@ 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. +See 'EXIF FILES' for special tratement of EXIF markers. +.TP +.B \-copy exif +This setting preserves the EXIF marker, commonly found in JPEG files produced +by digital cameras, in addition to any comment markers. If there is an EXIF +marker it is copied and the JFIF marker (incompatible with EXIF) is +omitted. If there is no EXIF marker a JFIF one is emitted as usual. See 'EXIF +FILES' for special tratement of EXIF markers. .PP The default behavior is .BR "\-copy comments" . @@ -189,6 +208,26 @@ .B \-debug Same as .BR \-verbose . +.SH EXIF FILES +The EXIF variety of JPEG files, which are often produced by digital cameras, +are recognized by jpegtran as EXIF files (i.e. not as JFIF, the +usual variety of JPEG files). If the input file is recognized as EXIF (i.e., +there is an EXIF marker and no JFIF marker) the '-copy exif' option is +automatically turned on if '-copy comments', or no '-copy' option, was +specified. Thus, unless '-copy none' is specified an EXIF file is kept as EXIF +and not converted to JFIF. +.PP +If a geometrical transformation is applied (e.g., rotate, transpose) the EXIF +width and height fields are set to the width and height of the output +image. Furthermore, the orientation field is reset to one, meaning tha the +orientation of the output image is upright (i.e. normal). +.PP +Note that an explicitely given '-copy exif' option will output an EXIF file if +the input is an EXIF file that was saved as JFIF, and that the EXIF marker is +still present. This option is useful for recovering EXIF files that where +converted to JFIF by a non EXIF-aware software. Note however, that the data in +the EXIF marker is not validated, unless a geometrical transformation is +applied. .SH EXAMPLES .LP This example converts a baseline JPEG file to progressive form: