graphics/img2pdf: Added (conversion of raster images to PDF)

Signed-off-by: Dave Woodfall <dave@slackbuilds.org>

Signed-off-by: Willy Sudiarto Raharjo <willysr@slackbuilds.org>

1 files changed, 234 insertions, 0 deletions

diff --git a/graphics/img2pdf/README b/graphics/img2pdf/README
new file mode 100644
index 0000000000000..7da803e3acbda
--- /dev/null
+++ b/graphics/img2pdf/README
@@ -0,0 +1,234 @@
+img2pdf
+
+Lossless conversion of raster images to PDF. You should use img2pdf if
+your priorities are (in this order):
+
+    always lossless: the image embedded in the PDF will always have the
+exact same color information for every pixel as the input small: if
+possible, the difference in filesize between the input image and the
+output PDF will only be the overhead of the PDF container itself fast:
+if possible, the input image is just pasted into the PDF document as-is
+without any CPU hungry re-encoding of the pixel data
+
+Conventional conversion software (like ImageMagick) would either:
+
+    not be lossless because lossy re-encoding to JPEG not be small
+because using wasteful flate encoding of raw pixel data not be fast
+because input data gets re-encoded
+
+Another advantage of not having to re-encode the input (in most common
+situations) is, that img2pdf is able to handle much larger input than
+other software, because the raw pixel data never has to be loaded into
+memory.
+
+The following table shows how img2pdf handles different input depending
+on the input file format and image color space.  Format
+Colorspace 	Result JPEG 	any 	direct JPEG2000 	any
+direct PNG (non-interlaced) 	any 	direct TIFF (CCITT Group 4)
+monochrome 	direct any 	any except CMYK and monochrome 	PNG
+Paeth any 	monochrome 	CCITT Group 4 any 	CMYK 	flate
+
+For JPEG, JPEG2000, non-interlaced PNG and TIFF images with CCITT Group
+4 encoded data, img2pdf directly embeds the image data into the PDF
+without re-encoding it. It thus treats the PDF format merely as a
+container format for the image data. In these cases, img2pdf only
+increases the filesize by the size of the PDF container (typically
+around 500 to 700 bytes). Since data is only copied and not re-encoded,
+img2pdf is also typically faster than other solutions for these input
+formats.
+
+For all other input types, img2pdf first has to transform the pixel data
+to make it compatible with PDF. In most cases, the PNG Paeth filter is
+applied to the pixel data. For monochrome input, CCITT Group 4 is used
+instead. Only for CMYK input no filter is applied before finally
+applying flate compression.  Usage
+
+The images must be provided as files because img2pdf needs to seek in
+the file descriptor.
+
+If no output file is specified with the -o/--output option, output will
+be done to stdout. A typical invocation is:
+
+$ img2pdf img1.png img2.jpg -o out.pdf
+
+The detailed documentation can be accessed by running:
+
+$ img2pdf --help
+
+Bugs
+
+    If you find a JPEG, JPEG2000, PNG or CCITT Group 4 encoded TIFF file
+that, when embedded into the PDF cannot be read by the Adobe Acrobat
+Reader, please contact me.
+
+    I have not yet figured out how to determine the colorspace of
+JPEG2000 files. Therefore JPEG2000 files use DeviceRGB by default. For
+JPEG2000 files with other colorspaces, you must explicitly specify it
+using the --colorspace option.
+
+    Input images with alpha channels are not allowed. PDF only supports
+transparency using binary masks but is unable to store 8-bit
+transparency information as part of the image itself. But img2pdf will
+always be lossless and thus, input images must not carry transparency
+information.
+
+    img2pdf uses PIL (or Pillow) to obtain image meta data and to
+convert the input if necessary. To prevent decompression bomb denial of
+service attacks, Pillow limits the maximum number of pixels an input
+image is allowed to have. If you are sure that you know what you are
+doing, then you can disable this safeguard by passing the
+--pillow-limit-break option to img2pdf. This allows one to process even
+very large input images.
+
+Installation
+
+On a Debian- and Ubuntu-based systems, img2pdf can be installed from the
+official repositories:
+
+$ apt install img2pdf
+
+If you want to install it using pip, you can run:
+
+$ pip3 install img2pdf
+
+If you prefer to install from source code use:
+
+$ cd img2pdf/ $ pip3 install .
+
+To test the console script without installing the package on your
+system, use virtualenv:
+
+$ cd img2pdf/ $ virtualenv ve $ ve/bin/pip3 install .
+
+You can then test the converter using:
+
+$ ve/bin/img2pdf -o test.pdf src/tests/test.jpg
+
+For Microsoft Windows users, PyInstaller based .exe files are produced
+by appveyor. If you don't want to install Python before using img2pdf
+you can head to appveyor and click on "Artifacts" to download the latest
+version: https://ci.appveyor.com/project/josch/img2pdf GUI
+
+There exists an experimental GUI with all settings currently disabled.
+You can directly convert images to PDF but you cannot set any options
+via the GUI yet. If you are interested in adding more features to the
+PDF, please submit a merge request. The GUI is based on tkinter and
+works on Linux, Windows and MacOS.
+
+Library
+
+The package can also be used as a library:
+
+import img2pdf
+
+# opening from filename with open("name.pdf","wb") as f:
+f.write(img2pdf.convert('test.jpg'))
+
+# opening from file handle with open("name.pdf","wb") as f1,
+open("test.jpg") as f2: f1.write(img2pdf.convert(f2))
+
+# using in-memory image data with open("name.pdf","wb") as f:
+f.write(img2pdf.convert("\x89PNG...")
+
+# multiple inputs (variant 1) with open("name.pdf","wb") as f:
+f.write(img2pdf.convert("test1.jpg", "test2.png"))
+
+# multiple inputs (variant 2) with open("name.pdf","wb") as f:
+f.write(img2pdf.convert(["test1.jpg", "test2.png"]))
+
+# convert all files ending in .jpg inside a directory dirname =
+"/path/to/images" with open("name.pdf","wb") as f: imgs = [] for fname
+in os.listdir(dirname): if not fname.endswith(".jpg"): continue path =
+os.path.join(dirname, fname) if os.path.isdir(path): continue
+imgs.append(path) f.write(img2pdf.convert(imgs))
+
+# convert all files ending in .jpg in a directory and its subdirectories
+dirname = "/path/to/images" with open("name.pdf","wb") as f: imgs = []
+for r, _, f in os.walk(dirname): for fname in f: if not
+fname.endswith(".jpg"): continue imgs.append(os.path.join(r, fname))
+f.write(img2pdf.convert(imgs))
+
+
+# convert all files matching a glob import glob with
+open("name.pdf","wb") as f:
+f.write(img2pdf.convert(glob.glob("/path/to/*.jpg")))
+
+# writing to file descriptor with open("name.pdf","wb") as f1,
+open("test.jpg") as f2: img2pdf.convert(f2, outputstream=f1)
+
+# specify paper size (A4) a4inpt =
+(img2pdf.mm_to_pt(210),img2pdf.mm_to_pt(297)) layout_fun =
+img2pdf.get_layout_fun(a4inpt) with open("name.pdf","wb") as f:
+f.write(img2pdf.convert('test.jpg', layout_fun=layout_fun))
+
+Comparison to ImageMagick
+
+Create a large test image:
+
+$ convert logo: -resize 8000x original.jpg
+
+Convert it into PDF using ImageMagick and img2pdf:
+
+$ time img2pdf original.jpg -o img2pdf.pdf $ time convert original.jpg
+imagemagick.pdf
+
+Notice how ImageMagick took an order of magnitude longer to do the
+conversion than img2pdf. It also used twice the memory.
+
+Now extract the image data from both PDF documents and compare it to the
+original:
+
+$ pdfimages -all img2pdf.pdf tmp $ compare -metric AE original.jpg
+tmp-000.jpg null: 0 $ pdfimages -all imagemagick.pdf tmp $ compare
+-metric AE original.jpg tmp-000.jpg null: 118716
+
+To get lossless output with ImageMagick we can use Zip compression but
+that unnecessarily increases the size of the output:
+
+$ convert original.jpg -compress Zip imagemagick.pdf $ pdfimages -all
+imagemagick.pdf tmp $ compare -metric AE original.jpg tmp-000.png null:
+0 $ stat --format="%s %n" original.jpg img2pdf.pdf imagemagick.pdf
+1535837 original.jpg 1536683 img2pdf.pdf 9397809 imagemagick.pdf
+
+Comparison to pdfLaTeX
+
+pdfLaTeX performs a lossless conversion from included images to PDF by
+default. If the input is a JPEG, then it simply embeds the JPEG into the
+PDF in the same way as img2pdf does it. But for other image formats it
+uses flate compression of the plain pixel data and thus needlessly
+increases the output file size:
+
+$ convert logo: -resize 8000x original.png $ cat << END > pdflatex.tex
+\documentclass{article} \usepackage{graphicx} \begin{document}
+\includegraphics{original.png} \end{document} END $ pdflatex
+pdflatex.tex $ stat --format="%s %n" original.png pdflatex.pdf 4500182
+original.png 9318120 pdflatex.pdf
+
+Comparison to podofoimg2pdf
+
+Like pdfLaTeX, podofoimg2pdf is able to perform a lossless conversion
+from JPEG to PDF by plainly embedding the JPEG data into the pdf
+container. But just like pdfLaTeX it uses flate compression for all
+other file formats, thus sometimes resulting in larger files than
+necessary.
+
+$ convert logo: -resize 8000x original.png $ podofoimg2pdf out.pdf
+original.png stat --format="%s %n" original.png out.pdf 4500181
+original.png 9335629 out.pdf
+
+It also only supports JPEG, PNG and TIF as input and lacks many of the
+convenience features of img2pdf like page sizes, borders, rotation and
+metadata.  Comparison to Tesseract OCR
+
+Tesseract OCR comes closest to the functionality img2pdf provides. It is
+able to convert JPEG and PNG input to PDF without needlessly increasing
+the filesize and is at the same time lossless. So if your input is JPEG
+and PNG images, then you should safely be able to use Tesseract instead
+of img2pdf. For other input, Tesseract might not do a lossless
+conversion. For example it converts CMYK input to RGB and removes the
+alpha channel from images with transparency. For multipage TIFF or
+animated GIF, it will only convert the first frame.
+
+OPTIONAL:
+
+python3