pdfImages

Typing of XObjects (Image + Form) — ISO 32000-2 §8.9 / §8.10.

Module pdfImages | Source packages/front/office/pdf/src/content/images.js | Deps pdfErrors, pdfParser | Worker-safe yes

Types an XObject stream into a flat, ready-to-consume structure. It distinguishes:

• Image XObject (/Subtype /Image, §8.9) — carries Width, Height, ColorSpace, BitsPerComponent, Filter, DecodeParms, Decode, ImageMask, Mask, SMask, Interpolate, Intent, Metadata.
• Form XObject (/Subtype /Form, §8.10) — carries FormType, BBox, Matrix, Resources, Group, Metadata, StructParent(s).

The raw bytes are passed through untouched: it is the consumer's job (renderer) to decode the /Filter chain via pdfFilterDispatch.

Resolve

const im = runtime.resolve('pdfImages');
// Returns: { typeImageXObject, typeFormXObject, typeXObject }

API

ImageXObject shape

{
    kind: 'image',
    width, height,
    bitsPerComponent,        // int or null
    colorSpace, filter, decodeParms, decode,   // raw typed objects or null
    imageMask,               // boolean, default false
    mask, sMask,
    interpolate,             // boolean, default false
    intent,                  // name or null
    metadata,
    raw: Uint8Array, dict
}

FormXObject shape

{
    kind: 'form',
    formType: 1,             // /FormType, default 1
    bbox:   [llx,lly,urx,ury] | null,
    matrix: [1,0,0,1,0,0],   // default
    resources, group, metadata,
    structParents, structParent,   // ints or null
    raw: Uint8Array, dict
}

When /Subtype is neither Image nor Form (e.g. the PostScript XObject deprecated in PDF 2.0), typeXObject returns { kind: <subtype>, raw, dict }.

Examples

Type an XObject invoked by Do

const im = runtime.resolve('pdfImages');
const xobjName = op.args[0].value;  // 'Im1'
const stream = doc._raw.resolve(resources.XObject[xobjName]);
const typed = im.typeXObject(stream);
if (typed.kind === 'image') console.log(typed.width, typed.height);

Type an image directly

const img = im.typeImageXObject(stream);
img.colorSpace;   // typed name / array / ref
img.filter;       // typed name / array
img.raw;          // Uint8Array — feed to pdfFilterDispatch

Form XObject with a BBox

const form = im.typeFormXObject(stream);
form.bbox;        // [0, 0, 612, 792]
form.matrix;      // [1, 0, 0, 1, 0, 0]
form.resources;   // dict — pass to typeResources

Errors

See also

• pdfContentStream — emits the Do op.
• pdfResources — resolves the named /XObject.
• Filters — decoding raw.