القيود والقياسات الجوهرية

A parent passes constraints to each child: the allowed min and max width and height. The child must choose a size that fits inside them. 📏

Every Constraints object holds minWidth, maxWidth, minHeight, and maxHeight. Together they describe the range of sizes a child may pick.

A max can be a real number or Infinity. Scrollable parents pass infinite height so children can be as tall as they need.

Use copy to relax constraints before measuring. Setting minWidth to zero lets a child be smaller than the parent demands.

Set min equal to max and you force an exact size. The child has no choice but to be exactly that big.

Layout is a negotiation: the parent offers bounds, the child reports a size, the parent places it. Both sides shape the final result.

Sometimes a parent needs a child's size before the real measure pass. Intrinsic measurements answer that question without committing.

Ask minIntrinsicWidth for the smallest width that shows content without clipping, or maxIntrinsicWidth for the natural unwrapped width.

The built-in IntrinsicSize.Min modifier uses intrinsics to make a Row's children share the tallest height, like a divider matching its neighbors.

Intrinsic queries run extra work, so use them only when needed. Most custom layouts get by with constraints alone. ⚡

Constraints cascade from the root down through every parent. Mastering how to tighten and loosen them is the heart of custom layout work.

How do you force a child to be an exact, fixed size?

Constraints set a child's allowed size range; loosen or tighten them with copy. Intrinsics peek at a size early, but cost extra and are used sparingly. ✅