Sometimes, when a publication is created from a PDF file, it may display fractional white lines even though the original PDF appears fine. In some cases, the white lines may appear or disappear when zooming in or out.
Note: When you upload a PDF file to Joomag, it is converted to SVG format and displayed in an HTML5 viewer. This conversion enables you to add interactive elements to your publication.
This issue occurs when the PDF uses clipping with very tight tolerances, typically seen in files that split images into smaller tiles. It is most common in files produced by InDesign.
These files rely on a PDF feature called Scan Conversion — a renderer-controlled process that determines how to paint a pixel when content only partially overlaps it. The PDF specification calls for forgiving scan conversion that fully paints a partial pixel. However, when converting to HTML and SVG, web browsers handle this rendering, and Joomag has no control over how they process it.