Questions with an exact answer that nobody wants to work out by hand: a ratio, a limit, a score, a size in millimetres. Each article carries the arithmetic and a field to put your own numbers into.
Photo Editing
Make a tidy application photo out of an ordinary phone snapshot
A face detector of 190 KB returns a grid of anchors, a box and five landmark points, and everything after that is arithmetic: head height, eye line, the angle to level by, millimetres to pixels. An application photo, explicitly not an official passport photo, made without uploading your face anywhere.
Turn a phone photo of a document into something that looks scanned
A photographed page is tilted, tapered, grey and shadowed, and all three faults are completely determined. Four corners give eight equations, a heavy blur estimates the lighting so it can be divided out, and Otsu picks the threshold. No model, no download, and it finishes before you let go of the button.
Responsive Hero Images: The Focal Point Decides Everything
Your hero becomes a 3.2:1 strip on desktop and a portrait crop on phones, and object-fit: cover decides what survives. The formula behind the crop, the CSS that steers it, and a simulator that shows all four breakpoints before you publish.
Perspective Correction: Four Corners and One Matrix Put It Straight
A photo taken at an angle is a projective map, not an affine one, which is why cropping and rotating cannot repair it. Four corners supply the eight numbers that can, and the geometry of the vanishing points can even hand back the object's true aspect ratio.
Remove Moire From a Scanned Image: Why Blurring Never Works
A scanned magazine page shows a wavy pattern that was never on the paper: the print screen beating against the scanner's sample grid. Blurring trades one problem for a worse one. Measuring the screen in a frequency picture and notching out exactly those frequencies does not, and the workbench in this article does it in your browser tab.
Fix White Balance: The One-Click Correction, Explained
A colour cast is a wrong assumption applied evenly, which means it can be divided back out. Click something that was neutral, read the three channel factors, and understand exactly where a global correction stops working.
Pick a connection profile and a target load time, and arithmetic hands you a byte budget per resource class. A web performance budget is a decision tool: it tells you which image, which font and which plugin gets told no, before the page ever gets slow.
Upload Simulator: What WordPress Actually Writes to Disk
One 3000 by 2000 photo becomes eight files on disk. A 1200 by 800 photo becomes five. Drop your own file in and see exactly which registered sizes fire, which ones core refuses, what dimensions come out and what the whole set weighs.
Working Out the Image Size Your Theme Actually Wants
A slot measured in CSS pixels needs a file measured in image pixels, and on a Retina screen the second number is twice the first. Here is how to measure the slot, choose a ratio without losing half the photograph, and check that WordPress will actually generate the size you need.
Type That Fits Every Screen Without a Single Media Query
One clamp() per level replaces a wall of media queries, but only if the middle term is solved rather than guessed. Here is how the slope and the intercept fall out of two viewport widths and two sizes, why a bare vw value fails the moment a reader zooms, and which three numbers your theme already knows.
