render

Documentation

Overview

Package render is the orchestrator that turns a kardec.Document into a PDF byte stream. It plugs three internal subsystems together:

• internal/layout walks the Document tree, breaks lines, places blocks
• internal/typography resolves font faces and provides text measurement
• internal/pdf writes the final PDF 1.7 byte stream

Importing this package wires Document.Render / RenderTo / Bytes via an init() hook in kardec; the public surface here is therefore optional — users can call render.ToFile / ToWriter / Bytes directly, or rely on the method API after a blank import:

import (
    "github.com/arthurhrc/kardec"
    _ "github.com/arthurhrc/kardec/render"
)

The indirection avoids an import cycle: kardec cannot import internal/layout because layout already imports kardec to walk the document tree.

Index

• func Bytes(d *kardec.Document) ([]byte, error)
• func ToFile(d *kardec.Document, path string) error
• func ToWriter(d *kardec.Document, w io.Writer) error

Examples

• Bytes
• ToFile

Functions

func Bytes

func Bytes(d *kardec.Document) ([]byte, error)

Bytes renders d as a PDF and returns the bytes. Convenient for tests and HTTP handlers that buffer responses.

Example

ExampleBytes shows the in-memory render path: build a Document, call render.Bytes, and inspect the resulting PDF byte stream. The output is asserted as the PDF magic header so godoc shows a runnable, deterministic example.

package main

import (
	"fmt"

	"github.com/arthurhrc/kardec"
	"github.com/arthurhrc/kardec/render"
)

func main() {
	doc := kardec.New(kardec.PageA4, kardec.MarginsNormal).
		Heading(1, kardec.Text("Monthly Report")).
		Paragraph(
			kardec.Text("Sales grew "),
			kardec.Bold("12%"),
			kardec.Text(" this quarter."),
		)
	out, err := render.Bytes(doc.Document)
	if err != nil {
		fmt.Println("render error:", err)
		return
	}
	fmt.Println("PDF starts with:", string(out[:8]))
}

Output:
PDF starts with: %PDF-1.7

func ToFile

func ToFile(d *kardec.Document, path string) error

ToFile renders d as a PDF and writes it to path. The file is created (or truncated) and closed before ToFile returns.

Example

ExampleToFile writes the document to a path. Errors from os.Create or the underlying renderer surface through the returned error.

package main

import (
	"github.com/arthurhrc/kardec"
	"github.com/arthurhrc/kardec/render"
)

func main() {
	doc := kardec.New(kardec.PageA4, kardec.MarginsNormal).
		Paragraph(kardec.Text("Hello, file."))
	_ = doc           // build steps
	_ = render.ToFile // render.ToFile(doc.Document, "out.pdf")
}

func ToWriter

func ToWriter(d *kardec.Document, w io.Writer) error

ToWriter renders d as a PDF to the supplied io.Writer.