A shadow needs a shape, and Compose won't guess one for you
Drawing custom shapes means Path plus DrawScope. Shadows are separate, and Modifier.shadow takes its own shape parameter — omitting it is why rounded cards get square shadows.
android
118 posts
Your gradient is measured in pixels, and that's the bug
Compose gradients take pixel coordinates, so a hardcoded end point produces a different result on every screen size. Float.POSITIVE_INFINITY and DrawScope.size are the two ways to make a brush relative.
A Painter is the thing that knows how big it wants to be
Painter draws content and declares an intrinsic size, which is what lets it participate in layout the way a resource does. Writing one is the right answer when drawing needs to be reusable across Image, Icon and modifiers.
A vector costs CPU once, a bitmap costs memory forever
ImageVector is drawing commands executed at render time; ImageBitmap is pixels held in memory. The choice is about scaling fidelity versus per-frame cost, and the common mistakes run in both directions.
Constraints flow down, sizes flow up, and fillMaxSize means something specific
One measurement pass means a child cannot ask its parent how big it is.
contentScale and Modifier.size are answering different questions
Image sizing depends on the modifier constraints and contentScale together. Understanding which one crops, which one fits, and where the aspect ratio comes from resolves most image layout bugs in one pass.
remember is not a cache, and the key is the whole contract
It is scoped to a composition and keyed by its arguments. A missing key gives stale state; a wrong one recomputes every frame.
LaunchedEffect(Unit) runs once, and that is usually the wrong once
Keyed to Unit means once per composition entry — not once per screen visit, and not once per user.
Two lines of autofill are worth more than a week of form polish
Compose's autofill is a semantics property on a text field. Declaring content types lets password managers and the platform fill forms correctly, and omitting it is why users abandon sign-up.
A LazyColumn without keys loses your scroll position and your animations
Without a key, item identity is positional — so an insert at the top reuses every slot's state for the wrong item.
Modifier order is not style, it is semantics
padding then clickable gives a different touch target from clickable then padding — and both look identical.
Recomposition is not re-rendering, and that is why your list stutters
Compose re-executes functions whose inputs changed. An unstable parameter means all of them.