Conas a oibríonn aistrithe CSS?

Question

Accepted Answer

Anímíonn **transition** go réidh foluain a animate gach fhrithaithint ó a sheanluach go dtí an ceann nua thar am, in ionad a athrú go tobann. Dearbhú a dhéanann tú *cad* a animate agus *cá fhad* a thógann sé, agus ansin a spreagadh tríd an fhrithaithint a athrú (go minic trí `:hover` nó class).

```css
.button {
  background: blue;
  transition: background 0.3s ease;  /* animate background over 300ms */
}
.button:hover {
  background: darkblue;  /* on hover, it fades smoothly instead of snapping */
}
```

## Na ceithre chuid den ghealltanas gearr

```css
transition: background 0.3s ease 0s;
/*          │          │    │    └── delay before starting */
/*          │          │    └─────── timing function (the easing curve) */
/*          │          └──────────── duration */
/*          └─────────────────────── property to animate (or `all`) */
```

## Animating multiple properties

```css
.card {
  transition: transform 0.3s ease, box-shadow 0.3s ease;
}
.card:hover {
  transform: translateY(-4px);          /* lifts up */
  box-shadow: 0 8px 20px rgba(0,0,0,0.2); /* + deeper shadow */
}
```

Liostaigh gach fhrithaithint (scartha ag camóga) seachas `all` a úsáid, agus is féidir go ndéanann sé damáiste do rud ar bith nach raibh i gceist agat agus bheith ina bhagairt ar fheidhmíocht.

## Timing functions

```css
transition-timing-function: ease;        /* slow-fast-slow (default) */
/* linear | ease-in | ease-out | ease-in-out */
transition-timing-function: cubic-bezier(0.4, 0, 0.2, 1); /* custom curve */
```

## Performance: animate transform/opacity

```css
/* ✅ cheap — GPU-composited, no layout recalculation */
transition: transform 0.3s, opacity 0.3s;
/* ❌ expensive — animating width/top/left triggers layout on every frame */
transition: width 0.3s, left 0.3s;
```

Is fearr a bheith ag animate `transform` agus `opacity`; caitheamh ag an compositor a dhéanann siad gan layout a athlodáil, mar sin fanann siad réidh (60fps).

## Accessibility

```css
@media (prefers-reduced-motion: reduce) {
  * { transition: none; } /* respect users who get motion sickness */
}
```

## Cén fáth a bhíonn sé tábhachtach

Cuireann aistrithe an geal-bhreatha ar an UI nach fhéadann a bheith ina ghealadh agus beo (hover effects, athruithe stáit réidh) le líne amháin.

A bheith ag eolas a animate `transform`/`opacity` ar son fheidhmíocht — agus a rialú `prefers-reduced-motion` — is é seo a scarann gluaiseacht réidh agus inrochtana ó animation janky.