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PDF Rendering backend for the HTML Canvas (2D) API


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This is a Raku PDF rendering back-end for the HTML::Canvas module.

This back-end is experimental.

This module is an alternative to HTML::Canvas, which is also able to save PDF files.

It may be useful, if you wish to manipulate existing PDF files using the HTML Canvas API, or are wishing to integrate with Raku PDF modules such as PDF::Lite or PDF::API6.

If this module is installed, the PDF::Content canvas() method will automatically render to a graphics stream using the HTML::Canvas::To::PDF back-end. The backend can thus be used on PDF Pages or XObject Forms:

use v6;
# Finish an existing PDF. Add a background color and page numbers

use PDF::Lite;
use PDF::Content;
use PDF::Content::Page;
use HTML::Canvas::To::PDF;

# render to a PDF page
my PDF::Lite $pdf .= open: "examples/render-pdf-test-sheets.pdf";

# use a cache for shared resources such as fonts and images.
# for faster production and smaller multi-page PDF files
my HTML::Canvas::To::PDF::Cache $cache .= new;

my UInt $pages = $;

for 1 .. $pages -> $page-num {
    my PDF::Content::Page $page = $$page-num);
    my PDF::Content $gfx = $page.pre-gfx;
    $gfx.html-canvas: :$cache, -> \ctx {
        ctx.fillStyle = "rgba(0, 0, 200, 0.2)";
        ctx.fillRect(10, 25, $page.width - 20, $page.height - 45);
        ctx.font = "12px Arial";
        ctx.fillStyle = "rgba(50, 50, 200, 0.8)";
        ctx.fillText("Page $page-num/$pages", 550, 15);

$ "examples/demo.pdf";