变换：平移、缩放与旋转
支持捏合和多点触控手势。
变换：平移、缩放与旋转 是 CoddyKit 上的免费 Jetpack Compose Academy 课时。 这是第 3 节课，共 4 节。 你可以在下方免费阅读本课时的完整内容 — 然后在浏览器中使用内置代码编辑器和全天候 AI 导师进行实践。 这是 Jetpack Compose Academy 学习路径的一部分，你的进度在网页和 CoddyKit 应用中同步。 Jetpack Compose Academy 课程共包含 4 节课。
本课时的部分内容尚未翻译，以英文显示。
Pinch, Zoom, Rotate
Some gestures use two fingers at once. Compose bundles pan, zoom, and rotate into a single helper called detectTransformGestures. 🤏
One Detector, Three Values
Inside pointerInput, detectTransformGestures hands you pan as an Offset, zoom as a Float scale, and rotation in degrees together.
detectTransformGestures { _, pan, zoom, rotation -> }Store the Three States
Keep a scale, an offset, and a rotation in remembered state. Update each from the gesture so the element transforms live.
var scale by remember { mutableStateOf(1f) }Multiply the Zoom
The zoom value is relative, so multiply it into your scale rather than replacing it. Pinch out grows, pinch in shrinks.
scale *= zoomAdd the Rotation
The rotation delta is in degrees per gesture step. Accumulate it so twisting two fingers spins your content smoothly.
angle += rotationPan Moves It Around
The pan Offset reports how far the gesture's center moved. Add it to your offset state to slide the content under the fingers.
offset += panApply with graphicsLayer
The clean way to render transforms is the graphicsLayer modifier. Set scaleX, scaleY, rotationZ, and translation in one place.
Modifier.graphicsLayer(scaleX = scale, scaleY = scale, rotationZ = angle)Translate Inside the Layer
Inside graphicsLayer, set translationX and translationY from your offset. It transforms without forcing a costly layout pass.
translationX = offset.x; translationY = offset.yClamp the Scale
Users will pinch wildly, so clamp your scale to sane bounds with coerceIn. This stops content from vanishing or filling the world.
scale = scale.coerceIn(0.5f, 5f)Order of Operations
graphicsLayer applies scale, then rotation, then translation. Knowing this order helps you predict where transformed content lands.
Centered Around the Pivot
By default transforms pivot around the element's center. Adjust transformOrigin in graphicsLayer to zoom and rotate around another point.
Modifier.graphicsLayer(transformOrigin = TransformOrigin(0f, 0f))Quick Check
How should you apply the incoming zoom value to your scale state?
Recap: Multi-Touch Magic
You used detectTransformGestures for pan, zoom, and rotate, then applied them through graphicsLayer with clamping. Pinch-to-zoom is yours. 🎉
常见问题解答
「变换：平移、缩放与旋转」课时是免费的吗？
是的 — 「变换：平移、缩放与旋转」的完整文本可在网页上免费阅读。要进行交互式练习（内置代码编辑器和全天候 AI 导师）并解锁 Jetpack Compose Academy 课程的其余内容，请升级到 CoddyKit PRO。 Jetpack Compose Academy 课程共包含 4 节课。
「变换：平移、缩放与旋转」这节课中我会学到什么？
支持捏合和多点触控手势。 你通过在浏览器中直接运行的动手代码来练习 Jetpack Compose Academy，全天候 AI 导师会在你学习这节课的过程中回答你的问题。
学习 Jetpack Compose Academy 需要有经验吗？
无需任何先前经验。CoddyKit 上的 Jetpack Compose Academy 课程适合初学者到高级学习者，你可以从这里开始或从头开始，按照自己的节奏学习。 这是第 3 节课，共 4 节。
「变换：平移、缩放与旋转」课时需要多长时间？
大多数 CoddyKit 课程大约需要 5–10 分钟。每节课都很精短且互动，所以你能稳步进步，并在网页和应用中从离开的地方继续。
我能在这节 Jetpack Compose Academy 课中编写并运行代码吗？
能。每节 Jetpack Compose Academy 课都包含内置代码编辑器，你可以在浏览器中直接编写并运行真实代码，并获得即时 AI 反馈 — 无需本地设置。