pdf-export Library for exporting view faces to pdf

Examples

Single face with draw commands

File generated with face-to-pdf

Subfaces with some draw commands

Results in the PDF file. Do not look at the pdf using Github since it does not render the pdf correctly. Use your favourite pdf viewer. Observe! Two of these subfaces are functions (for implementing lists). Those are not implemented in pdf-export.

Usage

Quick start

Create the face to export

view vface: layout [
    h1 "Export this"
    bo: box 200x200 effect [
	draw [
	    pen black line-width 3
	    circle 100x100 75
	]
    ]
]

Load the library lib: do %face-to-pdf-lib.r

Export to pdf

write %vface.pdf lib/face-to-pdf vface

You can export any face such as bo in the example.

Writing more than one page is not yet implemented.

Alternative loading

An alternative way of loading only the main interface function face-to-pdf do/args %face-to-pdf-lib.r 'face-to-pdf Thereafter processing can be done as

write %vface.pdf face-to-pdf vface

Exceptions, known bugs

• face/pane as functions are not implemented.

File related

• Only PDF standard fonts are used.

  There is a conversion table in face-to-pdf-lib/font-translations that can be used to translate the font used in view int the correpsonding pdf font.

• Each PDF file only contain one page with one face.

• The size of the PDF is set to the size of the face.

• No compression is done, so large images will result in large files.

Effects related

• None of the image processing commands (invert, luma, contrast ... ) are implemented.
• Tiling is not implemented.
• merge, clip and crop are not implemented.
• The gradient commands gradcol and gradmul are not implemented. gradient is.
• Algorithmic shapes related commands cross, oval and round are not implemented.
• shadow is not implemented. (partly becauyse I cannot figure out what it does).

Draw related

• When using draw without setting a drawing color, REBOL automatically chooses some color different from the background. I have put some effort to find what transformation it does without success.
• The draw pen cannot be an image
• Images can have linear transformations, so the general method of setting all four corners of an image uses the first three corners and makes an affine transformation of the whole image.
• Spline not implemented
• Nothing from Shape subdialect is implemented

Standard compliance

• When resulting pdf file is checked with veraPDF a few warnings/errors are detected. However, none seemingly critical.

File overview

The library is contained in mainly two files. pdf-lib.r and face-to-pdf-lib.r where the latter calls the former. pdf-lib.r is for handling the pdf structure, creating objects, keeping track of their relations .. face-to-pdf.r extracts the information from view and is responsible for filling the structure given by pdf-lib.r.

Test files are found under test directory. Simply execute them from a rebol prompt and they should show some graphics and leave a pdf file.

External libraries used

• printf.r from the rebol script library. Thanks to Jamie and Ladislav.

License

MIT license, see specific file.