Templating

Docraft includes a built-in template engine that replaces placeholders in the document tree with runtime values. This enables data-driven PDF generation from a single Craft Language template.

Variable Substitution

Register variables via DocraftTemplateEngine::add_template_variable() and reference them with ${name} syntax:

<Text>Invoice for ${customer_name}</Text>

Foreach Loops

The <Foreach> element repeats its children for each item in a JSON array. Inside the loop, use ${data("field")} to access item properties.

<Foreach model="${items}">
  <Layout orientation="horizontal">
    <Text weight="1">${data("name")}</Text>
    <Text weight="1">${data("price")}</Text>
  </Layout>
</Foreach>

Attribute	Type	Description
`model`	string	Template variable containing a JSON array.

Image Data Injection

Raw RGB images can be injected at runtime and referenced in templates:

engine->add_image_data("chart", pixel_data, 400, 300);
// or from base64
engine->add_base64_image_data("chart", base64_string, 400, 300);

<Image data="chart" data_width="400" data_height="300"
       width="200" height="150"/>

Templated Colors

Color attributes can also use template expressions:

<Text color="${status_color}">Status: ${status}</Text>

The template engine resolves the color at render time from the registered variable value (hex string or named color).