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Change Log

[0.36] - 2017-12-27

Minor updates, no significant code changes.

  • Minor changes to avoid a few compile warnings.
  • Updates to email address, URL, copyright notices.

[0.35] - 2016-06-23

Added CHANGELOG.md

[0.34] - 2016-06-23

Many fixes and enhancements from Palomar Corporation

  • Modify "bitblt.h" to undefine BITS_PER_WORD, which is defined in the netpbm header "pm_config.h", so that the tumble use takes precedence.

  • Fix a bug in "bitblt_write_g4" (bitblt_g4.c). Tumble would crash in "g4_get_pixel" with bad pointer access when trying to encode a TIFF image that was 14400 x 6100 (24" x 11"). "g4_get_pixel" was called with index 14400, which accesses the first byte beyond the allocated array.

  • "bitblt_write_g4" is called to encode and write a TIFF bitmap to the PDF file. It allocates and zeros a temporary buffer to hold a scan line and then calls "g4_encode_row" for each line. "g4_find_pixel" is called to find the first 1 bit in the temporary buffer. Because the buffer has been zeroed, "g4_find_pixel" returned the image width (14400) when the specified pixel could not be found in scan line. A subsequent call to "g4_get_pixel" specified this pixel number (14400), which accessed memory beyond the allocation.

    The crash wasn't repeatable. To occur, the image width had to be a multiple of 32 (else the last pixel + 1 would still be within the final word), and the allocation had to end exactly on a page boundary (so the first byte beyond the allocation was read-protected).

    Fix is to pad the temporary buffer with an extra word if the width is an exact multiple of 32. Note that access beyond the source bitmap is prohibited by the "if (a0 >= width) break;" test prior to the "g4_get_pixel" call.

  • Modify the makefile to add PNG and blank-page support files.

  • Modify "parser.y" to enable push and pop of input contexts. This allows "{" and "}" to create a local context for modifiers, such as TRANSPARENT. Input modifiers specified outside of a local context become global for subsequent input clauses.

  • Modify "pdf.c" to add creation and modification dates to the PDF properties. The "CreationDate" and "ModDate" values are set to the time that the PDF was created.

  • Modify "pdf.h" to change the page size limit from 45 inches (Reader 3.x) to 200 inches (Reader 4.x and later), to add structures and parameters to support the new features added to the parser, and to add the PDF "producer" definition.

  • Modify "pdf_g4.c" to add support for color-mapping bilevel images. Mapping allows a black and white image to be drawn as any two specified colors. Useful for pages that are black-on-color or white-on-color. The color mapping syntax is:

     COLORMAP (<red> <green> <blue>) , (<red> <green> <blue>) ;

    ...where the first triplet specifies the color to be displayed for black and the second triplet specifies the color to be displayed for white.

    Note that a two-color PNG is about twice the size of a Group 4 TIFF.

    Implementation note: the colormap is added to the PDF as a string resource and an indirect reference is made from the XObject. Tumble should keep each colormap only once in the file by keeping a global list of the string resources created. It doesn't. However, if the colormap used on an image is identical to the one used on the previous image, it will reuse the string resource. This covers the case of a section of colored pages. However, a discontiguous run of colored pages, e.g., the front and back covers, will store the colormap twice.

  • Modify "pdf_g4.c", "pdf_jpeg.c", "tumble.c", "tumble_jpeg.c", and "tumble_pbm.c" to support color key masking (using the PDF Mask operator). The syntax is:

     TRANSPARENT ( <gray_range> ) ;

    or:

     TRANSPARENT ( <red_range> <green_range> <blue_range> ) ;

    ...as a modifier to an input statement. may be either a single integer or a low..high range.

    The range values must be compatible with the color space of the image. For full-color images, the ranges would be 0..255. For grayscale images, the range would be 0..255. For paletted images, the range is expressed in palette entry numbers, which is much less likely to be useful than a single palette value.

  • Modify "pdf_g4.c", "tumble_input.h", and "tumble_tiff.c" to add handling of TIFF images with min-is-black photometric interpretation.

  • Modify "pdf_g4.c," "pdf_jpeg.c," and "pdf_png.c" to fix bugs in the callbacks within these files. "pdf_write_stream" was called to write "Do" commands with the XObject names without escaping restricted characters in the name, which had been escaped when the corresponding directory was written. This led to "Undefined XObject resource" errors when more than 26 images were overlaid on a page ("pdf_new_XObject" generates names of the form "ImA", "ImB", etc., and the 27th name was "Im[", which must be escaped, as "[" is a restricted character; the dictionary name was being escaped to "Im#5b", but the "Do" command name was not).

  • Modify "pdf_page_label.c" to fix a bug wherein a page label specifying prefix without a style (e.g., LABEL ) produces bad PDF (no labels are displayed). Should output "/P " but instead was outputting "/S /P ".

  • Add new files "pdf_png.c" and "tumble_png.c" and modify "tumble_input.h" to support PNG images (code from Daniel Glöckner via the tumble mailing list).

  • Change PDF string handling in "pdf_prim.c" and "pdf_prim.h" to allow embedded nulls by storing strings as character arrays plus length words.

  • Modify "parser.y", "scanner.l", "semantics.c", and "semantics.h" to support blank pages, overlay images, color mapping, color-key masking, and push/pop of input contexts.

  • Modify "tumble.c", "tumble_jpeg.c", and "tumble_pbm.c" to support overlay images. Overlays allow one image to be placed on top of another, e.g., a JPEG photo on a bilevel TIFF text page, at a specified position. Overlays are drawn after the page on which the overlay is specified. The overlay syntax is:

     PAGE <number> [ { OVERLAY <length>, <length> ;  ... } ] ;

    To support multiple images per page, the "Contents" stream is replaced by an array of stream objects.

  • Modify "tumble.c" to add a new -V option that prints the program version to stdio. The version string printed is the PDF producer string.

  • Add new file "tumble_blank.c" and modify "tumble_input.c" and "tumble_input.h" to support true blank pages. A blank page is a new PDF page with no content. The blank page syntax is:

     BLANK <size_clause>

  • Fix a bug that caused a double free in "tumble_input.c".

  • Modify "tumble_tiff.c" to suppress a "function defined but not used" warning.

  • Modify "semantics.c" to reduce page label redundancy in the PDF. Tumble was outputting a PageLabel entry for every page, rather than just for pages where the labelling changed. This resulted in an unnecessarily large label dictionary. Now allows page labels to default to auto-generation when appropriate.

  • Modify "semantics.c" to change the program report from " pages specified" to " images specified" because, due to overlay images, the number of images does not necessarily equal the number of pages.