rendering.md

Rendering

Every renderer implements RendererInterface::render(DiffResult|DiffBundle): string. An empty result produces an empty string, except that UnifiedRenderer can still emit explicitly configured labels.

Destination	Renderer	Integration
Patch or review text	UnifiedRenderer	Preserve newline markers and labels
Web page	HtmlRenderer	Add application CSS; source text is escaped
Data or API	JsonRenderer	Consume structured edits and metadata
Terminal	AnsiSideBySideRenderer	Select a width suitable for the terminal

Unified diff

Use UnifiedRenderer for familiar line-oriented output. Its optional constructor arguments label the old and new versions.

<?php

require __DIR__.'/vendor/autoload.php';

use Alto\Code\Diff\Diff;
use Alto\Code\Diff\Renderer\UnifiedRenderer;

$result = Diff::build()->compare("before\n", "after\n");
$output = (new UnifiedRenderer('a/example.txt', 'b/example.txt'))->render($result);

echo $output;

The renderer preserves \ No newline at end of file markers from the result.

HTML

HtmlRenderer escapes labels and content before producing an HTML table.

<?php

require __DIR__.'/vendor/autoload.php';

use Alto\Code\Diff\Diff;
use Alto\Code\Diff\Renderer\HtmlRenderer;

$result = Diff::build()
    ->withWordDiff()
    ->compare('<p>Old</p>', '<p>New</p>');

$html = (new HtmlRenderer(
    showLineNumbers: true,
    wrapLines: true,
    classPrefix: 'review-',
))->render($result);

echo $html;

The prefix is applied to table, hunk-header, add, del, ctx, line-num, old, new, prefix, content, wrap, word-add, and word-del classes. Supply the CSS for those classes in your application.

JSON

JsonRenderer serializes results and bundles for APIs or storage. It includes paths, headers, hunk ranges, edits, word spans, labels, and trailing-newline flags.

<?php

require __DIR__.'/vendor/autoload.php';

use Alto\Code\Diff\Diff;
use Alto\Code\Diff\Renderer\JsonRenderer;

$result = Diff::build()->compare("one\n", "two\n");
echo (new JsonRenderer(prettyPrint: true))->render($result);

Encoding uses JSON_THROW_ON_ERROR, unescaped Unicode, and unescaped slashes.

ANSI side by side

AnsiSideBySideRenderer is intended for terminals. It adds ANSI colors and truncates long columns to fit the configured total width.

<?php

require __DIR__.'/vendor/autoload.php';

use Alto\Code\Diff\Diff;
use Alto\Code\Diff\Renderer\AnsiSideBySideRenderer;

$result = Diff::build()
    ->withWordDiff()
    ->compare("Status: draft\n", "Status: published\n");

echo (new AnsiSideBySideRenderer(
    showLineNumbers: true,
    width: 100,
))->render($result);

All four renderers also accept a multi-file DiffBundle; see Formats for its structure.