Aspect-Ratio Visualizer

The two percentages measure the same thing from opposite ends. Contain reports how much of the frame gets used, and Cover reports how much of the picture survives. A frame filled 75% by the one is a picture 25% cut away by the other. The two always total 100%, so no setting can improve both.

When the readout says a circle becomes an ellipse 1.333 times as wide as it is tall, 1.333 is the axis ratio of the shape actually drawn on your screen, sized from the same arithmetic rather than illustrated beside it. That is why a number close to 1 looks like nothing happened: it did not.

A shape is recognised by name within about half a percent, so 1920x1080 comes back as 16:9 widescreen. Outside that tolerance you get the plain numbers instead of a name. Rounding 1.9:1 to 16:9 would hide the difference you came here to measure. Only the relationship between the two numbers is ever read, so 3840x2160 and 1920x1080 are the same shape here and a resolution is never a size.

It never opens your picture: the rectangles are the two shapes drawn at a readable size, not your image scaled into a frame. So it can tell you how much is cut off and along which axis, but not what is in the part that is cut. Whether filling the frame takes someone out of the shot is a question about the picture rather than about its shape, and nothing you type here leaves the page, because there is nothing to send.

cargo build --release --bin aspect-cli