Photo Horizontal Correction (PixPix)

The adjustment range is from –15° to +15°, with a precision of 0.1°. In addition, there are coarse adjustment options available for left and right angles of 90°. On the display screen, three grids are overlaid; the middle line serves as a reference for determining the horizon, while the horizontal and vertical lines of buildings can also be identified using this line.

The crucial step comes after the rotation: the tool calculates the largest inscribed rectangle of the rotated image and directly trims off the empty areas, resulting in a triangle without any blank spaces. Only one high-quality resampling process is required throughout the entire operation. The real reason for the degradation in image quality lies in the manual process of “rotating once, trimming once, discovering that it’s still not straight, and rotating again”; repeated resampling will lead to cumulative loss of image quality.

The larger the angle, the more content will be cut off – this is a fundamental principle of geometry. The difference in the amount of edge area lost when rotating by 3° compared to 12° is significant. For photos taken from the side, it’s more efficient to first align the image at a 90° angle and then adjust the settings using the slider than to make drastic adjustments manually. After alignment, take a look around the entire image to ensure that no important elements have been accidentally removed.

The text lines in both the reproduced documents and scanned files become distorted when using the same set of instructions.