The uploaded image is drawn onto an HTML Canvas, scaled to the target width while preserving aspect ratio (height is halved to compensate for characters being taller than wide).

Each pixel is converted to grayscale using luminance weights (0.299R + 0.587G + 0.114B), then mapped to a character from the selected ramp — darker pixels get denser characters, lighter pixels get sparser ones.

Everything runs client-side in your browser. No data is sent to a server.