heygen-com · miga-heygen · Sep 16, 2026 · Sep 16, 2026 · Sep 16, 2026
diff --git a/packages/cli/src/commands/init.ts b/packages/cli/src/commands/init.ts
@@ -53,6 +53,11 @@ import {
   normalizeResolutionFlag,
   type CanvasResolution,
 } from "@hyperframes/core";
+import {
+  HTML_BODY_CSS_HEIGHT_FIRST_RE,
+  HTML_BODY_CSS_WIDTH_FIRST_RE,
+  VIEWPORT_META_SIZE_RE,
+} from "@hyperframes/parsers";
 
 function resolveScaffoldTemplateId(exampleFlag: string | undefined, hasMediaFile: boolean): string {
   const example = exampleFlag === "agent" ? "blank" : exampleFlag;
@@ -527,20 +532,18 @@ export function applyResolutionPreset(destDir: string, resolution: CanvasResolut
 
     // Inline `html, body { ... }` CSS: handle width-before-height and
     // height-before-width orderings. Hand-authored templates can use either.
-    const bodyCssRe = /(html\s*,\s*body\s*\{[^}]*?width:\s*)\d+px([^}]*?height:\s*)\d+px/i;
-    if (bodyCssRe.test(html)) {
-      html = html.replace(bodyCssRe, `$1${width}px$2${height}px`);
+    // Groups 1 and 3 are the text before each dimension, 2 and 4 the digits.
+    if (HTML_BODY_CSS_WIDTH_FIRST_RE.test(html)) {
+      html = html.replace(HTML_BODY_CSS_WIDTH_FIRST_RE, `$1${width}px$3${height}px`);
       changed = true;
     }
-    const bodyCssReverseRe = /(html\s*,\s*body\s*\{[^}]*?height:\s*)\d+px([^}]*?width:\s*)\d+px/i;
-    if (bodyCssReverseRe.test(html)) {
-      html = html.replace(bodyCssReverseRe, `$1${height}px$2${width}px`);
+    if (HTML_BODY_CSS_HEIGHT_FIRST_RE.test(html)) {
+      html = html.replace(HTML_BODY_CSS_HEIGHT_FIRST_RE, `$1${height}px$3${width}px`);
       changed = true;
     }
 
-    const viewportRe = /(<meta[^>]*name=["']viewport["'][^>]*content=["'])width=\d+,\s*height=\d+/i;
-    if (viewportRe.test(html)) {
-      html = html.replace(viewportRe, `$1width=${width}, height=${height}`);
+    if (VIEWPORT_META_SIZE_RE.test(html)) {
+      html = html.replace(VIEWPORT_META_SIZE_RE, `$1${width}$3${height}`);
       changed = true;
     }
 

diff --git a/packages/lint/src/rules/core.test.ts b/packages/lint/src/rules/core.test.ts
@@ -176,6 +176,71 @@ describe("core rules", () => {
     expect(result.findings.find((f) => f.code === "root_dimensions_mismatch")).toBeUndefined();
   });
 
+  it("does not report root_dimensions_mismatch for a full sub-composition document whose own viewport meta disagrees with its root", async () => {
+    // Matches the hf2550 flowchart-vertical fixture's shape: a full standalone
+    // document mounted as a sub-composition. See the rule's comment in core.ts
+    // for why its own <meta viewport> never reaches the rendering document.
+    const html = `
+<!doctype html>
+<html>
+<head>
+  <meta name="viewport" content="width=1440, height=2560" />
+</head>
+<body>
+  <div id="root" data-composition-id="c1" data-width="1080" data-height="1920"></div>
+  <script>window.__timelines = {};</script>
+</body>
+</html>`;
+    const result = await lintHyperframeHtml(html, { isSubComposition: true });
+    expect(result.findings.find((f) => f.code === "root_dimensions_mismatch")).toBeUndefined();
+  });
+
+  it("still reports root_dimensions_mismatch for the same shape linted as a top-level composition, with no-clipping-risk wording since there is no html/body CSS block at all", async () => {
+    const html = `
+<!doctype html>
+<html>
+<head>
+  <meta name="viewport" content="width=1440, height=2560" />
+</head>
+<body>
+  <div id="root" data-composition-id="c1" data-width="1080" data-height="1920"></div>
+  <script>window.__timelines = {};</script>
+</body>
+</html>`;
+    const result = await lintHyperframeHtml(html);
+    const finding = result.findings.find((f) => f.code === "root_dimensions_mismatch");
+    expect(finding).toBeDefined();
+    // No html/body CSS block is present here at all (the real hf2550 fixture
+    // shape) -- distinct from the "present and matching" case covered below --
+    // so the "absent" and "matches" cases of describeSizeMismatch must both
+    // route to the same no-clipping-risk wording, not just the "matches" one.
+    expect(finding?.message).not.toContain("clips");
+    expect(finding?.message.toLowerCase()).toContain("no effect on capture");
+  });
+
+  it("uses no-clipping-risk wording when only the viewport meta disagrees and html/body CSS matches the root", async () => {
+    const html = portraitCompositionWithScaffold(
+      "width: 1080px; height: 1920px;",
+      "width=1440, height=2560",
+    );
+    const result = await lintHyperframeHtml(html);
+    const finding = result.findings.find((f) => f.code === "root_dimensions_mismatch");
+    expect(finding).toBeDefined();
+    expect(finding?.message).toContain("the viewport meta is 1440x2560");
+    expect(finding?.message).not.toContain("clips");
+    expect(finding?.message.toLowerCase()).toContain("no effect on capture");
+  });
+
+  it("keeps the body-clipping wording when html/body CSS itself disagrees with the root", async () => {
+    const html = portraitCompositionWithScaffold(
+      "width: 1920px; height: 1080px;",
+      "width=1080, height=1920",
+    );
+    const result = await lintHyperframeHtml(html);
+    const finding = result.findings.find((f) => f.code === "root_dimensions_mismatch");
+    expect(finding?.message).toContain("clips");
+  });
+
   it("accepts body as the composition root", async () => {
     const html = `
 <html><body data-composition-id="c1" data-width="1920" data-height="1080">

diff --git a/packages/lint/src/rules/core.ts b/packages/lint/src/rules/core.ts
@@ -239,15 +239,17 @@ function findVisibleMarkupCommentLeak(source: string): string | null {
 
 type ScaffoldSize = { width: string; height: string };
 
+// Groups 1 and 3 are prefix text for applyResolutionPreset's in-place
+// replace; lint only reads the digit groups (2 and 4).
 function readHtmlBodyCssSize(source: string): ScaffoldSize | null {
   const widthFirst = source.match(HTML_BODY_CSS_WIDTH_FIRST_RE);
   if (widthFirst) {
-    const [, width = "", height = ""] = widthFirst;
+    const [, , width = "", , height = ""] = widthFirst;
     return { width, height };
   }
   const heightFirst = source.match(HTML_BODY_CSS_HEIGHT_FIRST_RE);
   if (heightFirst) {
-    const [, height = "", width = ""] = heightFirst;
+    const [, , height = "", , width = ""] = heightFirst;
     return { width, height };
   }
   return null;
@@ -256,7 +258,7 @@ function readHtmlBodyCssSize(source: string): ScaffoldSize | null {
 function readViewportMetaSize(source: string): ScaffoldSize | null {
   const match = source.match(VIEWPORT_META_SIZE_RE);
   if (!match) return null;
-  const [, width = "", height = ""] = match;
+  const [, , width = "", , height = ""] = match;
   return { width, height };
 }
 
@@ -270,15 +272,43 @@ function describeSizeMismatch(
   return `${label} is ${size.width}x${size.height}`;
 }
 
-function findScaffoldSizeMismatches(
+// Only html/body CSS actually clips the root; the CDP viewport comes from
+// data-width/data-height, not `<meta viewport>` — so a viewport-only drift gets distinct wording.
+function describeRootDimensionsDrift(
   source: string,
   dataWidth: string,
   dataHeight: string,
-): string[] {
-  return [
-    describeSizeMismatch("html/body CSS", readHtmlBodyCssSize(source), dataWidth, dataHeight),
-    describeSizeMismatch("the viewport meta", readViewportMetaSize(source), dataWidth, dataHeight),
-  ].filter((mismatch): mismatch is string => mismatch !== null);
+): { message: string; fixHint: string } | null {
+  const bodyCssMismatch = describeSizeMismatch(
+    "html/body CSS",
+    readHtmlBodyCssSize(source),
+    dataWidth,
+    dataHeight,
+  );
+  const viewportMismatch = describeSizeMismatch(
+    "the viewport meta",
+    readViewportMetaSize(source),
+    dataWidth,
+    dataHeight,
+  );
+  if (!bodyCssMismatch && !viewportMismatch) return null;
+
+  const declared = `Root composition declares data-width="${dataWidth}" data-height="${dataHeight}"`;
+  if (!bodyCssMismatch) {
+    return {
+      message: `${declared}, but ${viewportMismatch}. The viewport meta has no effect on capture — the renderer sizes the viewport from the root's own data-width/data-height — so this is stale metadata, not a clipping risk.`,
+      fixHint:
+        "update the meta viewport to match, or scaffold with `hyperframes init --resolution portrait`",
+    };
+  }
+  const mismatches = viewportMismatch
+    ? `${bodyCssMismatch} and ${viewportMismatch}`
+    : bodyCssMismatch;
+  return {
+    message: `${declared}, but ${mismatches}. The scaffolded body clips the composition at its old size.`,
+    fixHint:
+      "update html/body CSS and the meta viewport to match, or scaffold with `hyperframes init --resolution portrait`",
+  };
 }
 
 export const coreRules: Array<(ctx: LintContext) => HyperframeLintFinding[]> = [
@@ -339,28 +369,26 @@ export const coreRules: Array<(ctx: LintContext) => HyperframeLintFinding[]> = [
   // root. `hyperframes check`'s layout audits can't see it: they measure
   // against the root's own (already-correct) rect, not the body's.
   //
-  // A sub-composition fragment has no html/body or viewport to compare
-  // against, which makes this top-level-only without a separate guard.
-  ({ rootTag, source }) => {
-    if (!rootTag) return [];
+  // Sub-compositions are exempt: loadExternalCompositions (packages/core/src/
+  // runtime/compositionLoader.ts) mounts only the matched <template>/<body>
+  // subtree, so a sub-comp's own <html>/<head>/<meta viewport> never reach
+  // the rendering document, even when it's a full standalone document.
+  ({ rootTag, source, options }) => {
+    if (!rootTag || options.isSubComposition) return [];
     const dataWidth = readAttr(rootTag.raw, "data-width");
     const dataHeight = readAttr(rootTag.raw, "data-height");
     if (!dataWidth || !dataHeight) return [];
 
-    const mismatches = findScaffoldSizeMismatches(source, dataWidth, dataHeight);
-    if (mismatches.length === 0) return [];
+    const drift = describeRootDimensionsDrift(source, dataWidth, dataHeight);
+    if (!drift) return [];
 
     return [
       {
         code: "root_dimensions_mismatch",
         severity: "warning",
-        message:
-          `Root composition declares data-width="${dataWidth}" data-height="${dataHeight}", ` +
-          `but ${mismatches.join(" and ")}. The scaffolded body clips the composition at its ` +
-          `old size.`,
+        message: drift.message,
         elementId: readAttr(rootTag.raw, "id") || undefined,
-        fixHint:
-          "update html/body CSS and the meta viewport to match, or scaffold with `hyperframes init --resolution portrait`",
+        fixHint: drift.fixHint,
         snippet: truncateSnippet(rootTag.raw),
       },
     ];

diff --git a/packages/parsers/src/canvasScaffoldPatterns.test.ts b/packages/parsers/src/canvasScaffoldPatterns.test.ts
@@ -0,0 +1,53 @@
+import { describe, expect, it } from "vitest";
+import {
+  HTML_BODY_CSS_HEIGHT_FIRST_RE,
+  HTML_BODY_CSS_WIDTH_FIRST_RE,
+  VIEWPORT_META_SIZE_RE,
+} from "./canvasScaffoldPatterns.js";
+
+// Both callers key off group numbers: @hyperframes/lint's
+// root_dimensions_mismatch reads the digits, @hyperframes/cli's
+// applyResolutionPreset substitutes `$1<new>$3<new>` to keep the text around
+// them. Pin the layout here so neither can renumber against the other.
+const CASES = [
+  {
+    name: "HTML_BODY_CSS_WIDTH_FIRST_RE",
+    re: HTML_BODY_CSS_WIDTH_FIRST_RE,
+    source: "html, body { margin: 0; width: 1920px; height: 1080px; overflow: hidden; }",
+    digits: ["1920", "1080"],
+    replacement: "$13840px$32160px",
+    replaced: "html, body { margin: 0; width: 3840px; height: 2160px; overflow: hidden; }",
+  },
+  {
+    name: "HTML_BODY_CSS_HEIGHT_FIRST_RE",
+    re: HTML_BODY_CSS_HEIGHT_FIRST_RE,
+    source: "html, body { margin: 0; height: 1080px; width: 1920px; overflow: hidden; }",
+    digits: ["1080", "1920"],
+    replacement: "$12160px$33840px",
+    replaced: "html, body { margin: 0; height: 2160px; width: 3840px; overflow: hidden; }",
+  },
+  {
+    name: "VIEWPORT_META_SIZE_RE",
+    re: VIEWPORT_META_SIZE_RE,
+    source: '<meta name="viewport" content="width=1920, height=1080" />',
+    digits: ["1920", "1080"],
+    replacement: "$13840$32160",
+    replaced: '<meta name="viewport" content="width=3840, height=2160" />',
+  },
+];
+
+describe("canvas scaffold patterns", () => {
+  it.each(CASES)("$name exposes the two dimensions as groups 2 and 4", ({ re, source, digits }) => {
+    const match = source.match(re);
+    expect(match).not.toBeNull();
+    expect(match?.slice(1)).toHaveLength(4);
+    expect([match?.[2], match?.[4]]).toEqual(digits);
+  });
+
+  it.each(CASES)(
+    "$name replaces both dimensions in place, leaving the rest untouched",
+    ({ re, source, replacement, replaced }) => {
+      expect(source.replace(re, replacement)).toBe(replaced);
+    },
+  );
+});
diff --git a/packages/parsers/src/canvasScaffoldPatterns.ts b/packages/parsers/src/canvasScaffoldPatterns.ts
@@ -1,25 +1,16 @@
 /**
- * Where a scaffolded project's canvas resolution lives besides the composition
- * root's own `data-width`/`data-height`: the inline `html, body { width;
- * height }` CSS block and the `<meta name="viewport">` `content` attribute.
- * `@hyperframes/cli`'s `applyResolutionPreset` rewrites those same two places
- * when a project scaffolds with `--resolution`, but keeps its own
- * prefix-capturing regexes for that replace — these are a separate read-only
- * definition of the same locations, not the literal patterns it uses.
- *
- * Lives in `@hyperframes/parsers` rather than `@hyperframes/cli` because
- * `@hyperframes/lint` cannot depend on `cli` (`cli` depends on `lint`, not the
- * reverse), and `parsers` is a dependency both already share.
+ * Where a scaffolded project's canvas resolution lives besides the root's own
+ * data-width/data-height: the html/body CSS size and the meta viewport content.
  */
 
-/** Matches `html, body { ...width: <n>px... height: <n>px... }`. */
+/** html/body CSS, width first. Groups 1/3 are the surrounding text, 2/4 the digits. */
 export const HTML_BODY_CSS_WIDTH_FIRST_RE =
-  /html\s*,\s*body\s*\{[^}]*?width:\s*(\d+)px[^}]*?height:\s*(\d+)px/i;
+  /(html\s*,\s*body\s*\{[^}]*?width:\s*)(\d+)px([^}]*?height:\s*)(\d+)px/i;
 
-/** Matches the same block with height authored before width. */
+/** Same block, height authored first. */
 export const HTML_BODY_CSS_HEIGHT_FIRST_RE =
-  /html\s*,\s*body\s*\{[^}]*?height:\s*(\d+)px[^}]*?width:\s*(\d+)px/i;
+  /(html\s*,\s*body\s*\{[^}]*?height:\s*)(\d+)px([^}]*?width:\s*)(\d+)px/i;
 
-/** Matches `<meta ... name="viewport" ... content="width=<n>, height=<n>">`. */
+/** Viewport meta content. Shared by lint (reads groups 2/4) and cli (replaces via 1/3). */
 export const VIEWPORT_META_SIZE_RE =
-  /<meta[^>]*name=["']viewport["'][^>]*content=["']width=(\d+),\s*height=(\d+)/i;
+  /(<meta[^>]*name=["']viewport["'][^>]*content=["']width=)(\d+)(,\s*height=)(\d+)/i;