Raster text is text that has been turned into a bitmap, meaning it exists purely as an image made up of pixels and does not retain its underlying character information.
Understanding Raster Text
Based on the provided reference, rasterized text is fundamentally text that has been converted into a bitmap image. This process reduces the original characters, which might have been stored as fonts or vector shapes, into a grid of tiny squares called pixels.
Imagine looking closely at a digital photo; you see individual squares of color. Raster text is just like that but forming letters.
Crucially, when text becomes rasterized, it does not have any Unicode behind it. This means the computer no longer recognizes the image as actual letters or words. It's just a pattern of colored pixels.
Raster Text vs. Other Text Types
It's helpful to compare raster text with other ways text can exist digitally:
| Feature | Raster Text | Vector Text | Live Text (Font-based) |
|---|---|---|---|
| Format | Pixels (Bitmap) | Mathematical Paths | Character data + Font file |
| Scalability | Loses quality when enlarged | Scales infinitely without loss | Scales without loss |
| Editability | Difficult/Impossible (image) | Editable (software dependent) | Fully Editable (if font available) |
| Searchable | No (requires OCR) | Yes (if originally vector text) | Yes |
| Unicode | No (just pixels) | Sometimes (depending on creation) | Yes |
Where You Encounter Raster Text
You often see raster text in various digital formats, typically when text is part of an image:
- Scanned Documents: Text in a document scanned as an image file (like a JPG or PNG) becomes raster text.
- Text in Photos: Any text that appears within a photograph is rasterized.
- Flat Images: Text saved as part of a flattened image file (e.g., a logo saved as a JPG) is no longer selectable or editable as text.
- Some PDFs: While many PDFs retain live text, some are essentially images containing rasterized text, especially older or scanned ones.
Implications and Limitations
The key takeaway is that because raster text is just an image, you cannot select it, copy it, or easily edit it using standard text tools. To convert raster text back into usable, searchable text, you typically need to use Optical Character Recognition (OCR) software, which attempts to interpret the pixel patterns and identify the original characters. Scaling raster text up usually results in a blurry or pixelated appearance.
