Rendering and export

use Janalis\Viz\Viz;
use Janalis\Viz\Render\Format;
use Janalis\Viz\Render\RenderOptions;
use Janalis\Viz\Source\SourceFormat;

$viz = new Viz();
$svg = $viz->render("flowchart LR\n  a --> b", SourceFormat::Mermaid, Format::Svg)->bytes;

$viz->export('digraph { a -> b }', SourceFormat::Dot, 'graph.pdf');   // format from the extension
$viz->export($puml, SourceFormat::PlantUml, 'seq.png', options: new RenderOptions(dpi: 192));

An export writes the file only once the image has rendered in full, so a failed render leaves an earlier file as it was. A failure is a RenderFailure that carries the tool's stderr, or the syntax error with its line and column.

Formats

Language	SVG	PNG	PDF
Native (Mermaid, Graphviz, PlantUML)	always	ext-gd with FreeType	always: vector, with the font embedded and the text selectable
Mermaid (mmdc fallback)	yes	yes	yes
Graphviz (dot fallback)	yes	yes, when dot has libgd	yes
PlantUML (plantuml fallback)	yes	yes	needs the Batik and FOP jars beside plantuml

Native or command line

A language is drawn natively where it can be, with its tool as the fallback. engine: Engine::Native or Engine::Cli forces one or the other:

use Janalis\Viz\Render\Engine;

$native = new Viz(engine: Engine::Native);   // the native renderer alone: what it cannot draw fails, with the reason
$cli = new Viz(engine: Engine::Cli);         // the command-line tool alone

Images in DOT graphs

A DOT graph's images (a node's image, an HTML label's <IMG>) are drawn natively only from the directories you allow:

$viz = new Viz(imageDirectories: [__DIR__.'/images']);

A name must resolve, links followed, to a PNG, JPEG, GIF or WebP file inside one of them; the graph's own imagepath is ignored. Any other image, and every image when no directory is allowed, leaves the graph to dot.

Renderers on their own

Each renderer implements Janalis\Viz\Render\Renderer and can be used on its own:

Class	What it is
Draw\NativeRenderer	the native renderer, over a language's Draw\Pipeline (new NativeRenderer(new MermaidPipeline()))
Process\CommandRenderer	a command-line tool, described by a Process\Command: MermaidCommand (mmdc), DotCommand, PlantUmlCommand
Render\FallbackRenderer	chains renderers, native first

GraphViz\DotTool also exposes layout(), dot's own laid-out geometry.

Step by step

The native pipeline is also exposed step by step, for a host with an event loop: NativeRenderer::image(), and Mermaid\MermaidPipeline for the scene and the drawing. Every step is a generator that yields between small units of work, so a large diagram can be spread over several frames; Render\Work::run() runs one to the end.