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Crate printpdf

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printpdf is a library designed for creating printable PDF documents.

Crates.io | Documentation

[dependencies]
printpdf = "0.5.0"

§Features

Currently, printpdf can only write documents, not read them.

  • Page generation
  • Layers (Illustrator like layers)
  • Graphics (lines, shapes, bezier curves)
  • Images (currently BMP/PNG/JPG only or generate your own images)
  • Embedded fonts (TTF and OTF) with Unicode support
  • Advanced graphics - overprint control, blending modes, etc.
  • Advanced typography - character scaling, character spacing, superscript, subscript, outlining, etc.
  • PDF layers (you should be able to open the PDF in Illustrator and have the layers appear)

§Getting started

§Writing PDF

§Simple page

use printpdf::*;
use std::fs::File;
use std::io::BufWriter;

let (doc, page1, layer1) = PdfDocument::new("PDF_Document_title", Mm(247.0), Mm(210.0), "Layer 1");
let (page2, layer1) = doc.add_page(Mm(10.0), Mm(250.0),"Page 2, Layer 1");

doc.save(&mut BufWriter::new(File::create("test_working.pdf").unwrap())).unwrap();

§Adding graphical shapes

use printpdf::*;
use printpdf::path::{PaintMode, WindingOrder};
use std::fs::File;
use std::io::BufWriter;
use std::iter::FromIterator;

let (doc, page1, layer1) = PdfDocument::new("printpdf graphics test", Mm(297.0), Mm(210.0), "Layer 1");
let current_layer = doc.get_page(page1).get_layer(layer1);

// Quadratic shape. The "false" determines if the next (following)
// point is a bezier handle (for curves)
//
// If you want holes, use WindingOrder::EvenOdd
let points1 = vec![(Point::new(Mm(100.0), Mm(100.0)), false),
                   (Point::new(Mm(100.0), Mm(200.0)), false),
                   (Point::new(Mm(300.0), Mm(200.0)), false),
                   (Point::new(Mm(300.0), Mm(100.0)), false)];

let line1 = Polygon {
    rings: vec![points1],
    mode: PaintMode::FillStroke,
    winding_order: WindingOrder::NonZero,
};

let fill_color = Color::Cmyk(Cmyk::new(0.0, 0.23, 0.0, 0.0, None));
let outline_color = Color::Rgb(Rgb::new(0.75, 1.0, 0.64, None));
let mut dash_pattern = LineDashPattern::default();
dash_pattern.dash_1 = Some(20);

current_layer.set_fill_color(fill_color);
current_layer.set_outline_color(outline_color);
current_layer.set_outline_thickness(10.0);

// Draw first line
current_layer.add_polygon(line1);

let fill_color_2 = Color::Cmyk(Cmyk::new(0.0, 0.0, 0.0, 0.0, None));
let outline_color_2 = Color::Greyscale(Greyscale::new(0.45, None));

// More advanced graphical options
current_layer.set_overprint_stroke(true);
current_layer.set_blend_mode(BlendMode::Seperable(SeperableBlendMode::Multiply));
current_layer.set_line_dash_pattern(dash_pattern);
current_layer.set_line_cap_style(LineCapStyle::Round);

current_layer.set_fill_color(fill_color_2);
current_layer.set_outline_color(outline_color_2);
current_layer.set_outline_thickness(15.0);

// Triangle shape
let mut line2 = Line::from_iter(vec![
    (Point::new(Mm(150.0), Mm(150.0)), false),
    (Point::new(Mm(150.0), Mm(250.0)), false),
    (Point::new(Mm(350.0), Mm(250.0)), false)]);

// draw second line
current_layer.add_line(line2);

§Adding images

Note: Images only get compressed in release mode. You might get huge PDFs (6 or more MB) in debug mode. In release mode, the compression makes these files much smaller (~ 100 - 200 KB).

To make this process faster, use BufReader instead of directly reading from the file. Images are currently not a top priority.

Scaling of images is implicitly done to fit one pixel = one dot at 300 dpi.

// Compile with --feature="embedded_images"
extern crate printpdf;

// imports the `image` library with the exact version that we are using
use printpdf::*;

use std::convert::From;
use std::convert::TryFrom;
use std::fs::File;

fn main() {
    let (doc, page1, layer1) = PdfDocument::new("PDF_Document_title", Mm(247.0), Mm(210.0), "Layer 1");
    let current_layer = doc.get_page(page1).get_layer(layer1);

    // currently, the only reliable file formats are bmp/jpeg/png
    // this is an issue of the image library, not a fault of printpdf
    let mut image_file = File::open("assets/img/BMP_test.bmp").unwrap();
    let image = Image::try_from(image_crate::codecs::bmp::BmpDecoder::new(&mut image_file).unwrap()).unwrap();

    // translate x, translate y, rotate, scale x, scale y
    // by default, an image is optimized to 300 DPI (if scale is None)
    // rotations and translations are always in relation to the lower left corner
    image.add_to_layer(current_layer.clone(), ImageTransform::default());

    // you can also construct images manually from your data:
    let mut image_file_2 = ImageXObject {
        width: Px(200),
        height: Px(200),
        color_space: ColorSpace::Greyscale,
        bits_per_component: ColorBits::Bit8,
        interpolate: true,
        /* put your bytes here. Make sure the total number of bytes =
           width * height * (bytes per component * number of components)
           (e.g. 2 (bytes) x 3 (colors) for RGB 16bit) */
        image_data: Vec::new(),
        image_filter: None, /* does not work yet */
        clipping_bbox: None, /* doesn't work either, untested */
    };

    let image2 = Image::from(image_file_2);
}

§Adding fonts

Note: Fonts are shared between pages. This means that they are added to the document first and then a reference to this one object can be passed to multiple pages. This is different to images, for example, which can only be used once on the page they are created on (since that’s the most common use-case).

use printpdf::*;
use std::fs::File;

let (doc, page1, layer1) = PdfDocument::new("PDF_Document_title", Mm(247.0), Mm(210.0), "Layer 1");
let current_layer = doc.get_page(page1).get_layer(layer1);

let text = "Lorem ipsum";
let text2 = "unicode: стуфхfцчшщъыьэюя";

let font = doc.add_external_font(File::open("assets/fonts/RobotoMedium.ttf").unwrap()).unwrap();
let font2 = doc.add_external_font(File::open("assets/fonts/RobotoMedium.ttf").unwrap()).unwrap();

// text, font size, x from left edge, y from bottom edge, font
current_layer.use_text(text, 48.0, Mm(200.0), Mm(200.0), &font);

// For more complex layout of text, you can use functions
// defined on the PdfLayerReference
// Make sure to wrap your commands
// in a `begin_text_section()` and `end_text_section()` wrapper
current_layer.begin_text_section();

    // setup the general fonts.
    // see the docs for these functions for details
    current_layer.set_font(&font2, 33.0);
    current_layer.set_text_cursor(Mm(10.0), Mm(10.0));
    current_layer.set_line_height(33.0);
    current_layer.set_word_spacing(3000.0);
    current_layer.set_character_spacing(10.0);
    current_layer.set_text_rendering_mode(TextRenderingMode::Stroke);

    // write two lines (one line break)
    current_layer.write_text(text.clone(), &font2);
    current_layer.add_line_break();
    current_layer.write_text(text2.clone(), &font2);
    current_layer.add_line_break();

    // write one line, but write text2 in superscript
    current_layer.write_text(text.clone(), &font2);
    current_layer.set_line_offset(10.0);
    current_layer.write_text(text2.clone(), &font2);

current_layer.end_text_section();

§Changelog

See the CHANGELOG.md file.

§Further reading

The PdfDocument is hidden behind a PdfDocumentReference, which locks the things you can do behind a facade. Pretty much all functions operate on a PdfLayerReference, so that would be where to look for existing functions or where to implement new functions. The PdfDocumentReference is a reference-counted document. It uses the pages and layers for inner mutablility, because I ran into borrowing issues with the document. IMPORTANT: All functions that mutate the state of the document, “borrow” the document mutably for the duration of the function. It is important that you don’t borrow the document twice (your program will crash if you do so). I have prevented this wherever possible, by making the document only public to the crate so you cannot lock it from outside of this library.

Images have to be added to the pages resources before using them. Meaning, you can only use an image on the page that you added it to. Otherwise, you may end up with a corrupt PDF.

Fonts are embedded using freetype. There is a rusttype branch in this repository, but rusttype does fails to get the height of an unscaled font correctly, so that’s why you currently have to use freetype

Please report issues if you have any, especially if you see BorrowMut errors (they should not happen). Kerning is currently not done, because neither freetype nor rusttype can reliably read kerning data. However, “correct” kerning / placement requires a full font shaping engine, etc. This would be a completely different project.

For learning how a PDF is actually made, please read the wiki (currently not completely finished). When I began making this library, these resources were not available anywhere, so I hope to help other people with these topics. Reading the wiki is essential if you want to contribute to this library.

§Goals and Roadmap

The goal of printpdf is to be a general-use PDF library, such as libharu or similar. PDFs generated by printpdf should always adhere to a PDF standard, except if you turn it off. Currently, only the standard PDF/X-3:2002 is covered (i.e. valid PDF according to Adobe Acrobat). Over time, there will be more standards supported. Checking a PDF for errors is currently only a stub.

§Planned features / Not done yet

The following features aren’t implemented yet, most

  • Clipping
  • Aligning / layouting text
  • Open Prepress Interface
  • Halftoning images, Gradients, Patterns
  • SVG / instantiated content
  • Forms, annotations
  • Bookmarks / Table of contents
  • Conformance / error checking for various PDF standards
  • Embedded Javascript
  • Reading PDF
  • Completion of printpdf wiki

§Testing

Currently the testing is pretty much non-existent, because PDF is very hard to test. This should change over time: Testing should be done in two stages. First, test the individual PDF objects, if the conversion into a PDF object is done correctly. The second stage is manual inspection of PDF objects via Adobe Preflight.

Put the tests of the first stage in /tests/mod.rs. The second stage tests are better to be handled inside the plugins’ mod.rs file. printpdf depends highly on lopdf, so you can either construct your test object against a real type or a debug string of your serialized type. Either way is fine - you just have to check that the test object is conform to what PDF expects.

Here are some resources I found while working on this library:

PDFXPlorer, shows the DOM tree of a PDF, needs .NET 2.0

Official PDF 1.7 reference

[GERMAN] How to embed unicode fonts in PDF

PDF X/1-a Validator

PDF X/3 technical notes

Re-exports§

pub extern crate image as image_crate;
pub extern crate log;
pub use lopdf;

Modules§

color
Color module (CMYK or RGB). Shared between 2D and 3D module.
ctm
Current transformation matrix, for transforming shapes (rotate, translate, scale)
date
document_info
Info dictionary of a PDF document
errors
Errors for printpdf
extgstate
Extended graphics state, for advanced graphical operation (overprint, black point control, etc.)
font
Embedding fonts in 2D for Pdf
icc_profile
ICC profile that can be embedded into a PDF
image
Abstraction class for images. Please use this class instead of adding ImageXObjects yourself
indices
These indices are for library internal use only. Use the add_* functions to get an index instead.
line
link_annotation
ocg
path
Utilities to work with path objects.
pattern
pdf_conformance
Module regulating the comparison and feature sets / allowed plugins of a PDF document
pdf_document
A PDFDocument represents the whole content of the file
pdf_layer
PDF layer management. Layers can contain referenced or real content.
pdf_metadata
Wapper type for shared metadata between XMP Metadata and the DocumentInfo dictionary
pdf_page
PDF page management
pdf_resources
point
rectangle
Utilities for rectangle paths.
scale
Scaling types for reducing errors between conversions between point (pt) and millimeter (mm)
svg
Abstraction class for images. Please use this class instead of adding ImageXObjects yourself
utils
Utility / conveniece functions for commonly use graphical shapes
xmp_metadata
Stub plugin for XMP Metadata streams, to be expanded later
xobject

Structs§

Actions
Cmyk
CMYK color
CustomPdfConformance
Allows building custom conformance profiles. This is useful if you want very small documents for example and you don’t need conformance with any PDF standard, you just want a PDF file.
DashPhase
DirectFontRef
Direct reference (wrapper for lopdf::Object::Reference) for increased type safety
DocumentInfo
“Info” dictionary of a PDF document. Actual data is contained in DocumentMetadata, to keep it in sync with the XmpMetadata (if the timestamps / settings are not in sync, Preflight will complain)
ExtendedGraphicsState
ExtGState dictionary
ExtendedGraphicsStateBuilder
ExtendedGraphicsStateList
List of many ExtendedGraphicsState
ExtendedGraphicsStateRef
A reference to the graphics state, for reusing the graphics state during a stream without adding new graphics states all the time
ExternalFont
FontIndex
Index of a font
FontList
Font list for tracking fonts within a single PDF document
FontMetrics
The unscaled base metrics for a font provided by a FontData implementation.
FormXObject
THIS IS NOT A PDF FORM! A form XObject can be nearly everything. PDF allows you to reuse content for the graphics stream in a FormXObject. A FormXObject is basically a layer-like content stream and can contain anything as long as it’s a valid strem. A FormXObject is intended to be used for reapeated content on one page.
FormXObjectRef
GlyphMetrics
The metrics for a glyph provided by a FontData implementation.
Greyscale
Greyscale color
GroupXObject
IccProfile
Icc profile
IccProfileList
IccProfileRef
Named reference for an ICC profile
Image
Image - wrapper around an ImageXObject to allow for more control within the library
ImageRotation
ImageTransform
Transform that is applied immediately before the image gets painted. Does not affect anything other than the image.
ImageXObject
ImageXObjectRef
Named reference to an image
IndirectFontRef
Indexed reference to a font that was added to the document This is a “reference by postscript name”
Line
LineDashPattern
Line dash pattern is made up of a total width
LinkAnnotation
LinkAnnotationList
LinkAnnotationRef
Named reference to a LinkAnnotation
Mm
Scale in millimeter
OCGList
OCGRef
OffsetDateTime
A PrimitiveDateTime with a UtcOffset.
OptionalContentGroup
Optional content group, for PDF layers. Only available in PDF 1.4 but (I think) lower versions of PDF allow this, too. Used to create Adobe Illustrator-like layers in PDF
Pattern
STUB
PatternList
PatternRef
Named reference to a pattern
PdfContentIndex
Index of the arbitrary content data
PdfDocument
PDF document
PdfDocumentReference
Marker struct for a document. Used to make the API a bit nicer. It simply calls PdfDocument functions.
PdfLayer
One layer of PDF data
PdfLayerIndex
Index of the layer on the nth page
PdfLayerReference
A “reference” to the current layer, allows for inner mutability but only inside this library
PdfMetadata
This is a wrapper in order to keep shared data between the documents XMP metadata and the “Info” dictionary in sync
PdfPage
PDF page
PdfPageIndex
Index of the page (0-based)
PdfPageReference
A “reference” to the current page, allows for inner mutability but only inside this library
PdfResources
Struct for storing the PDF Resources, to be used on a PDF page
Point
Polygon
PostScriptXObject
TODO, very low priority
Pt
Scale in point
Px
Scale in pixels
Rect
A helper struct to insert rectangular shapes into a PDF.
ReferenceXObject
PDF 1.4 and higher Contains a PDF file to be embedded in the current PDF
Rgb
RGB color
SMask
SMask dictionary. A soft mask (or SMask) is a greyscale image that is used to mask another image
SoftMask
A soft mask is used for transparent images such as PNG with an alpha component The bytes range from 0xFF (opaque) to 0x00 (transparent). The alpha channel of a PNG image have to be sorted out. Can also be used for Vignettes, etc. Beware of color spaces! See PDF Reference Page 545 - Soft masks
SpotColor
Spot color Spot colors are like Cmyk, but without color space They are essentially “named” colors from specific vendors currently they are the same as a CMYK color.
Svg
SVG - wrapper around an XObject to allow for more control within the library.
SvgIndex
Index of a svg file
SvgRotation
SvgTransform
Transform that is applied immediately before the image gets painted. Does not affect anything other than the image.
SvgXObjectRef
XObjectList
List of XObjects
XObjectRef
Named reference to an XObject
XmpMetadata
Initial struct for Xmp metatdata. This should be expanded later for XML handling, etc. Right now it just fills out the necessary fields

Enums§

BlackGenerationExtraFunction
BlackGenerationFunction
Black generation calculates the amount of black to be used when trying to reproduce a particular color.
BlendMode
BorderArray
BuiltinFont
Standard built-in PDF fonts
Color
Wrapper for Rgb, Cmyk and other color types
ColorArray
ColorBits
How many bits does a color have?
ColorSpace
Color space (enum for marking the number of bits a color has)
CurTransMat
PDF “current transformation matrix”. Once set, will operate on all following shapes, until the layer.restore_graphics_state() is called. It is important to call layer.save_graphics_state() earlier.
Error
Font
The font
FormType
GroupXObjectType
HalftoneType
In PDF 1.2, the graphics state includes a current halftone parameter, which determines the halftoning process to be used by the painting operators. It may be defined by either a dictionary or a stream, depending on the type of halftone; the term halftone dictionary is used generically throughout this section to refer to either a dictionary object or the dictionary portion of a stream object. (The halftones that are defined by streams are specifically identified as such in the descriptions of particular halftone types; unless otherwise stated, they are understood to be defined by simple dictionaries instead.) Deserialized into Integer: 1, 5, 6, 10 or 16
HighlightingMode
IccProfileType
Type of the icc profile
ImageFilter
Describes the format the image bytes are compressed with.
IndexError
LineCapStyle
See PDF Reference (Page 216) - Line cap (ending) style
LineJoinStyle
See PDF Reference Page 216 - Line join style
NonSeperableBlendMode
Since the nonseparable blend modes consider all color components in combination, their computation depends on the blending color space in which the components are interpreted. They may be applied to all multiple-component color spaces that are allowed as blending color spaces (see Section 7.2.3, “Blending Color Space”).
OCGIntent
Intent to use for the optional content groups
OverprintMode
(PDF 1.3) A code specifying whether a color component value of 0 in a DeviceCMYK color space should erase that component (EraseUnderlying) or leave it unchanged (KeepUnderlying) when overprinting (see Section 4.5.6, “Over- print Control”). Initial value: EraseUnderlying
PdfColor
Tuple for differentiating outline and fill colors
PdfConformance
List of (relevant) PDF versions Please note the difference between PDF/A (archiving), PDF/UA (universal acessibility), PDF/X (printing), PDF/E (engineering / CAD), PDF/VT (large volume transactions with repeated content)
PdfError
RenderingIntent
Although CIE-based color specifications are theoretically device-independent, they are subject to practical limitations in the color reproduction capabilities of the output device. Such limitations may sometimes require compromises to be made among various properties of a color specification when rendering colors for a given device. Specifying a rendering intent (PDF 1.1) allows a PDF file to set priorities regarding which of these properties to preserve and which to sacrifice.
SeperableBlendMode
PDF Reference 1.7, Page 520, Table 7.2 Blending modes for objects In the following reference, each function gets one new color (the thing to paint on top) and an old color (the color that was already present before the object gets painted)
SoftMaskFunction
SpotFunction
Spot functions, Table 6.1, Page 489 in Pdf Reference v1.7 The code is pseudo code, returning the grey component at (x, y).
SvgParseError
TextMatrix
Text matrix. Text placement is a bit different, but uses the same concepts as a CTM that’s why it’s merged here
TextRenderingMode
The text rendering mode determines how a text is drawn The default rendering mode is Fill. The color of the fill / stroke is determine by the current pages outline / fill color.
TransferExtraFunction
TransferFunction
UnderColorRemovalExtraFunction
UnderColorRemovalFunction
See BlackGenerationFunction, too. Undercolor removal reduces the amounts of the cyan, magenta, and yellow components to compensate for the amount of black that was added by black generation.
XObject
External object that gets reference outside the PDF content stream Gets constructed similar to the ExtGState, then inserted into the /XObject dictionary on the page. You can instantiate XObjects with the /Do operator. The layer.add_xobject() (or better yet, the layer.add_image(), layer.add_form()) methods will do this for you.

Constants§

ICC_PROFILE_ECI_V2
OP_COLOR_SET_FILL_COLOR
set fill color (PDF 1.1)
OP_COLOR_SET_FILL_COLOR_ICC
set fill color (PDF 1.2) with support for Icc, etc.
OP_COLOR_SET_FILL_CS
non-stroking color space (PDF 1.1)
OP_COLOR_SET_FILL_CS_DEVICECMYK
Set the fill color to DeviceCMYK
OP_COLOR_SET_FILL_CS_DEVICEGRAY
Set the fill color space to DeviceGray
OP_COLOR_SET_FILL_CS_DEVICERGB
Set the fill color space to DeviceRGB
OP_COLOR_SET_STROKE_COLOR
set stroking color (PDF 1.1)
OP_COLOR_SET_STROKE_COLOR_ICC
set stroking color (PDF 1.2) with support for ICC, etc.
OP_COLOR_SET_STROKE_CS
Color
OP_COLOR_SET_STROKE_CS_DEVICECMYK
Set the stroking color space to DeviceCMYK
OP_COLOR_SET_STROKE_CS_DEVICEGRAY
Set the stroking color space to DeviceGray
OP_COLOR_SET_STROKE_CS_DEVICERGB
Set the stroking color space to DeviceRGB
OP_PATH_CONST_3BEZIER_V1
Cubic bezier with two points in v1
OP_PATH_CONST_3BEZIER_V2
Cubic bezier with two points in v2
OP_PATH_CONST_4BEZIER
Cubic bezier over four following points
OP_PATH_CONST_CLIP_EO
Current path is a clip path, non-zero winding order
OP_PATH_CONST_CLIP_NZ
Current path is a clip path, non-zero winding order (usually in like h W S)
OP_PATH_CONST_CLOSE_SUBPATH
Close current sub-path (for appending custom patterns along line)
OP_PATH_CONST_LINE_TO
Straight line to the two following points
OP_PATH_CONST_MOVE_TO
Path construction Move to point
OP_PATH_CONST_RECT
Add rectangle to the path (width / height): x y width height re
OP_PATH_PAINT_END
End path without filling or stroking
OP_PATH_PAINT_FILL_EO
Fill path using even-odd rule
OP_PATH_PAINT_FILL_NZ
Fill path using nonzero winding number rule
OP_PATH_PAINT_FILL_NZ_OLD
Fill path using nonzero winding number rule (obsolete)
OP_PATH_PAINT_FILL_STROKE_CLOSE_EO
Close, fill and stroke path using even odd rule
OP_PATH_PAINT_FILL_STROKE_CLOSE_NZ
Close, fill and stroke path using nonzero winding number rule
OP_PATH_PAINT_FILL_STROKE_EO
Fill and stroke path using even-odd rule
OP_PATH_PAINT_FILL_STROKE_NZ
Fill and stroke path using nonzero winding number rule
OP_PATH_PAINT_STROKE
Path painting Stroke path
OP_PATH_PAINT_STROKE_CLOSE
Close and stroke path
OP_PATH_STATE_SET_FLATNESS_TOLERANCE
Set flatness tolerance
OP_PATH_STATE_SET_GS_FROM_PARAM_DICT
(PDF 1.2) Set graphics state from parameter dictionary
OP_PATH_STATE_SET_LINE_CAP
Set line cap
OP_PATH_STATE_SET_LINE_DASH
Set line dash pattern
OP_PATH_STATE_SET_LINE_JOIN
Set line join
OP_PATH_STATE_SET_LINE_WIDTH
General graphics state
OP_PATH_STATE_SET_MITER_LIMIT
Set miter limit
OP_PATH_STATE_SET_RENDERING_INTENT
Set rendering intent

Traits§

FontData
Provides access to font metrics.
FontDataClone
Helper trait for cloning boxed FontData implementors.

Functions§

calculate_points_for_circle
Calculates and returns the points for an approximated circle, given a radius and an offset into the centre of circle (starting from bottom left corner of page).
calculate_points_for_rect
Calculates and returns the points for a rectangle, given a horizontal and vertical scale. and an offset into the centre of rectangle (starting from bottom left corner of page).