Draft Preview

Draft Preview reduces the cost of iterating on image-heavy Typst documents. It replaces supported static raster image() calls in Typsastra's private render mirror with placeholders that preserve the image's layout dimensions. The project source, original images, and exported PDFs are not rewritten.

Switch preview modes

Use the Normal / Draft control in the live preview toolbar. Normal mode renders the original images. Draft mode shows lightweight placeholders while keeping their measured dimensions and positions in the document. Switch back to Normal before export or final visual review; PDF export uses original assets.

Hover over a draft image placeholder to inspect a bounded cached thumbnail and its original dimensions and encoded size. Missing or unsupported images retain their layout space and report a diagnostic rather than silently shifting the document.

Image analysis and optimization

The preview toolbar and editor gutter can warn about raster assets whose decoded pixel dimensions or encoded size are unusually large. These are recommendations only: Typsastra does not silently resize or recompress source assets. Use Image Tools to preview and save an optimized copy explicitly.

Cache and project behavior

Draft image work is stored in Typsastra's machine-local project render cache, keyed to the configured main document and content mode. Source files remain the authority. Generated thumbnails can be discarded and rebuilt without changing the project.

The mode is shared across included files because they belong to the main document's preview. Opening an included chapter does not create a separate Draft Preview session or change the PDF page position.

Limitations

Draft Preview only replaces supported static raster image references that can be resolved inside the project. Dynamic paths, plugin-generated content, remote resources, or unsupported image formats may remain unchanged. Inspect the preview diagnostics when a specific image was not replaced.