Overview
Introduction
This tool draws a line of text onto an uploaded JPG, entirely client-side, using a compact built-in pixel font.
It's aimed at quick captions, labels, or credits rather than typographic precision; for pixel-perfect font rendering, a full image editor is a better fit.
What Is JPG Text Adder?
A client-side JPG text-stamping tool that decodes an uploaded photo into raw pixel data, rasterizes a chosen string against a hand-built 5x7 bitmap font, and writes the resulting glyph pixels directly into the image at a chosen position and scale.
The same bitmap font is shared with the JPG Annotator and JPG Watermarker tools, so text across all three looks visually consistent.
How JPG Text Adder Works
Each character maps to a 5x7 grid of on/off pixels; the tool walks the string character by character, drawing every "on" cell as an NxN solid block (N being the chosen font scale) at the appropriate offset, advancing a cursor by one glyph width plus spacing between characters.
Position presets compute the text block's total rendered width and height first, then place its top-left corner so the block sits flush against the chosen corner, centered, or at an exact custom coordinate.
When To Use JPG Text Adder
Use it to quickly caption a photo, add a date or location stamp, label a screenshot, or credit a photographer before sharing an image.
It's a good fit anywhere a short, legible label matters more than font styling. The chunky bitmap look is intentionally utilitarian.
Often used alongside JPG Watermarker, JPG Annotator and PNG Text Adder.
Features
Advantages
- Runs entirely client-side; nothing is uploaded to a server.
- No font-loading dependency: the bitmap font is built in, so results are identical across browsers/devices.
- Simple position presets cover the most common placements without manual coordinate math.
Limitations
- Only uppercase letters, digits, and a small set of punctuation are supported; unsupported characters are silently skipped.
- There's no word-wrap; long text simply runs past the image edge and gets clipped.
Examples
Best Practices & Notes
Best Practices
- Pick a text color that contrasts with the area you're placing it over so it stays legible.
- Increase font scale for text meant to be read at a glance in a thumbnail; keep it small for subtle captions.
Developer Notes
addTextToJpg clones the source PixelBuffer, computes the rendered text block's pixel dimensions via measureText, resolves the requested TextPosition preset into concrete top-left coordinates, then calls the shared stampBitmapText helper (also reused by jpg-annotator and jpg-watermarker) to write opaque glyph pixels directly into the buffer.
JPG Text Adder Use Cases
- Captioning a photo before sharing it
- Adding a date/location stamp to an image
- Labeling a screenshot for documentation
Common Mistakes
- Expecting lowercase or accented characters to render distinctly; they're uppercased or skipped.
- Choosing a text color too close to the background color, making the stamp hard to read.
Tips
- Use the JPG Watermarker tool instead if you want semi-transparent, repeating text rather than one solid opaque line.
- Combine with JPG Border Adder afterward if you want the text to sit in a dedicated caption strip rather than over the photo itself.