A grid scan with, say, a 20 um step in x and a 5 um step in y was drawn as a
square grid, so the picture had nothing to do with the shape of the area that
was scanned. The cells now carry that proportion.
The anisotropy lives only in the view transform: JFJochImage gains a
pixel_aspect_ (the drawn height of one pixel in units of its width, 1.0 for a
detector image), the initial fit fits the image as if it were that much taller
and then puts the factor back into the transform, and the grid view sets it
from |step_y / step_x|. Scene coordinates stay one unit per cell, so the mouse
mapping, the selected-image box, the pixel labels and the ROI code need no
change and the uniform wheel zoom keeps the proportion.
Measured on an 8x4 grid driven offscreen: m11/m22 comes out 4.000 for steps
20/5 um, 0.250 for 5/20, 12.333 for 37/3 and exactly 1.000 - the old
behaviour - for a square step. Every cell centre still maps back through
mapToScene to its own cell in all four cases.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Hcoh6VNrmSswjfeMeDQqWP
leonarski_fandClaude Opus 5
d189faeec7