The information provided on Screenfly regarding screen sizes is only an estimate, as it simulates pixel dimensions rather than actual physical size. While the relationships between screen and pixel size on Screenfly are generally accurate, they may not apply universally.
There are two key factors to consider:
- Pixel density: Desktop screens typically have a pixel density of 96dpi, while notebooks may have around 116dpi. Most screens adhere to a 1:1 pixel ratio for images, meaning that an image with dimensions of 640x480 pixels may appear smaller on a notebook compared to a desktop due to the closer proximity of pixels.
- Aspect ratio: Screens can have varying aspect ratios, such as 4:3 for iPads and 16:9 or 16:10 for modern desktops or notebooks. The choice of aspect ratio can affect the suitability of a screen for different purposes, such as gaming or productivity.
For instance, Screenfly lists 23" screens as 1920x1080 (16:9) and 24" screens as 1920x1200 (16:10), but this is not always the case. Personal preferences and manufacturer choices can lead to variations in screen sizes and resolutions.
Devices like the 'retina' iPad with ultra-high DPI present unique challenges due to their high pixel densities. To address this, manufacturers may opt to scale content to maintain readability and usability.
In conclusion, there is no strict correlation between screen size and pixel dimensions, but practical considerations often outweigh these technical details. Third-party resources are available for specific needs, such as displaying items at "actual size" on a webpage.
I hope this clarifies things for you.