背景
在一个动态壁纸中,我有一个Canvas实例,希望将通过Glide加载的GIF/WEBP内容绘制到其中。
我之所以选择使用Glide,是因为它相对于我过去发现的解决方案(这里,存储库这里)提供了一些优势:
- 使用Movie只能支持GIF。使用Glide,我还可以支持WEBP动画。
- 使用Movie似乎效率低下,因为它不告诉我每个帧之间需要等待的时间,所以我必须选择我想要尝试使用的FPS。它也已经在Android P上被弃用。
- Glide可能能够简化各种缩放的处理。
- Glide可能不会像原始代码那样崩溃,并且可能提供更好的机制控制。
问题
Glide似乎仅针对普通UI(视图)进行了优化。它具有一些基本功能,但对于我正在尝试做的最重要的功能似乎是私有的。
我发现的
我使用官方 Glide库 (v 3.8.0) 来加载 GIF,以及 GlideWebpDecoder 来加载 WEBP(版本相同)。
加载每个文件的基本调用方式如下:
GIF:
GlideApp.with(this).asGif()
.load("https://res.cloudinary.com/demo/image/upload/bored_animation.gif")
.into(object : SimpleTarget<GifDrawable>() {
override fun onResourceReady(resource: GifDrawable, transition: Transition<in GifDrawable>?) {
//example of usage:
imageView.setImageDrawable(resource)
resource.start()
}
})
WEBP:
GlideApp.with(this).asDrawable()
.load("https://res.cloudinary.com/demo/image/upload/fl_awebp/bored_animation.webp")
// .optionalTransform(WebpDrawable::class.java, WebpDrawableTransformation(CircleCrop()))
.into(object : SimpleTarget<Drawable>() {
override fun onResourceReady(resource: Drawable, transition: Transition<in Drawable>?) {
//example of usage:
imageView.setImageDrawable(resource)
if (resource is Animatable) {
(resource as Animatable).start()
}
}
})
现在,请记住我实际上没有ImageView,而是通过surfaceHolder.lockCanvas()
调用获得的Canvas。
resource.callback = object : Drawable.Callback {
override fun invalidateDrawable(who: Drawable) {
Log.d("AppLog", "frame ${resource.frameIndex}/${resource.frameCount}")
}
}
然而,当我尝试获取用于当前帧的位图时,我无法找到正确的函数。
例如,我尝试了这个(这只是一个示例,以查看它是否可以与画布一起使用):
val bitmap = Bitmap.createBitmap(100, 100, Bitmap.Config.ARGB_8888)
val canvas = Canvas(bitmap)
...
resource.draw(canvas)
但是它似乎没有将内容绘制到位图中,我认为这是因为它的 draw
函数有以下代码行:
@Override
public void draw(@NonNull Canvas canvas) {
if (isRecycled) {
return;
}
if (applyGravity) {
Gravity.apply(GRAVITY, getIntrinsicWidth(), getIntrinsicHeight(), getBounds(), getDestRect());
applyGravity = false;
}
Bitmap currentFrame = state.frameLoader.getCurrentFrame();
canvas.drawBitmap(currentFrame, null, getDestRect(), getPaint());
}
然而,getDestRect()
返回一个大小为0的矩形,我找不到如何修改它:它也是私有的,我没有看到任何改变它的方法。
问题
假设我已经获得了我想要使用的Drawable(GIF/WEBP),如何获取它可以生成的每一帧(而不仅仅是第一帧),并在画布上绘制它(当然需要正确的帧之间的时间)?
我是否也可以以某种方式设置缩放类型,就像ImageView上那样(居中裁剪、适合中心、居中内部…)?
也许有比这更好的选择吗?也许假设我有一个GIF/WEBP动画文件,Glide能让我只使用它的解码器吗?就像this library上那样?
编辑:
我找到了一个不错的替代库,可以逐帧加载 GIF,在这里。它似乎没有逐帧加载的效率高,但是它是开源的,可以很容易地进行修改以提高效率。
当然,如果能够在 Glide 上完成这个功能会更好,因为 Glide 还支持缩放和 WEBP 加载。
我做了一个 POC(链接 在这里),显示它确实可以逐帧运行,并在它们之间等待合适的时间。如果有人能成功地在 Glide(最新版本的 Glide)上完成与我相同的操作,我将接受答案并授予悬赏。以下是代码:
** GifPlayer.kt,基于 NsGifPlayer.java **
open class GifPlayer {
companion object {
const val ENABLE_CACHING = false
const val MEM_CACHE_SIZE_PERCENT = 0.8
fun calculateMemCacheSize(percent: Double): Long {
if (percent < 0.05f || percent > 0.8f) {
throw IllegalArgumentException("setMemCacheSizePercent - percent must be " + "between 0.05 and 0.8 (inclusive)")
}
val maxMem = Runtime.getRuntime().maxMemory()
// Log.d("AppLog", "max mem :$maxMem")
return Math.round(percent * maxMem)
}
}
private val uiHandler = Handler(Looper.getMainLooper())
private var playerHandlerThread: HandlerThread? = null
private var playerHandler: Handler? = null
private val gifDecoder: GifDecoder = GifDecoder()
private var currentFrame: Int = -1
var listener: GifListener? = null
var state: State = State.IDLE
private set
private val playRunnable: Runnable
private val frames = HashMap<Int, AnimationFrame>()
private var currentUsedMemByCache = 0L
class AnimationFrame(val bitmap: Bitmap, val duration: Long)
enum class State {
IDLE, PAUSED, PLAYING, RECYCLED, ERROR
}
interface GifListener {
fun onGotFrame(bitmap: Bitmap, frame: Int, frameCount: Int)
fun onError()
}
init {
val memCacheSize = if (ENABLE_CACHING) calculateMemCacheSize(MEM_CACHE_SIZE_PERCENT) else 0L
// Log.d("AppLog", "memCacheSize:$memCacheSize = ${memCacheSize / 1024L} MB")
playRunnable = object : Runnable {
override fun run() {
val frameCount = gifDecoder.frameCount
gifDecoder.setCurIndex(currentFrame)
currentFrame = (currentFrame + 1) % frameCount
val animationFrame = if (ENABLE_CACHING) frames[currentFrame] else null
if (animationFrame != null) {
// Log.d("AppLog", "cache hit - $currentFrame")
val bitmap = animationFrame.bitmap
val delay = animationFrame.duration
uiHandler.post {
listener?.onGotFrame(bitmap, currentFrame, frameCount)
if (state == State.PLAYING)
playerHandler!!.postDelayed(this, delay)
}
} else {
// Log.d("AppLog", "cache miss - $currentFrame fill:${frames.size}/$frameCount")
val bitmap = gifDecoder.bitmap
val delay = gifDecoder.decodeNextFrame().toLong()
if (ENABLE_CACHING) {
val bitmapSize = BitmapCompat.getAllocationByteCount(bitmap)
if (bitmapSize + currentUsedMemByCache < memCacheSize) {
val cacheBitmap = Bitmap.createBitmap(bitmap)
frames[currentFrame] = AnimationFrame(cacheBitmap, delay)
currentUsedMemByCache += bitmapSize
}
}
uiHandler.post {
listener?.onGotFrame(bitmap, currentFrame, frameCount)
if (state == State.PLAYING)
playerHandler!!.postDelayed(this, delay)
}
}
}
}
}
@Suppress("unused")
protected fun finalize() {
stop()
}
@UiThread
fun start(filePath: String): Boolean {
if (state != State.IDLE && state != State.ERROR)
return false
currentFrame = -1
state = State.PLAYING
playerHandlerThread = HandlerThread("GifPlayer")
playerHandlerThread!!.start()
val looper = playerHandlerThread!!.looper
playerHandler = Handler(looper)
playerHandler!!.post {
try {
gifDecoder.load(filePath)
} catch (e: Exception) {
uiHandler.post {
state = State.ERROR
listener?.onError()
}
return@post
}
val bitmap = gifDecoder.bitmap
if (bitmap != null) {
playRunnable.run()
} else {
frames.clear()
gifDecoder.recycle()
uiHandler.post {
state = State.ERROR
listener?.onError()
}
return@post
}
}
return true
}
@UiThread
fun stop(): Boolean {
if (state == State.IDLE)
return false
state = State.IDLE
playerHandler!!.removeCallbacks(playRunnable)
playerHandlerThread!!.quit()
playerHandlerThread = null
playerHandler = null
return true
}
@UiThread
fun pause(): Boolean {
if (state != State.PLAYING)
return false
state = State.PAUSED
playerHandler?.removeCallbacks(playRunnable)
return true
}
@UiThread
fun resume(): Boolean {
if (state != State.PAUSED)
return false
state = State.PLAYING
playerHandler?.removeCallbacks(playRunnable)
playRunnable.run()
return true
}
@UiThread
fun toggle(): Boolean {
when (state) {
State.PLAYING -> pause()
State.PAUSED -> resume()
else -> return false
}
return true
}
}
MainActivity.kt
class MainActivity : AppCompatActivity() {
private lateinit var player: GifPlayer
@SuppressLint("StaticFieldLeak")
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_main)
val file = File(this@MainActivity.filesDir, "file.gif")
object : AsyncTask<Void, Void, Void?>() {
override fun doInBackground(vararg params: Void?): Void? {
val inputStream = resources.openRawResource(R.raw.fast)
if (!file.exists()) {
file.parentFile.mkdirs()
val outputStream = FileOutputStream(file)
val buf = ByteArray(1024)
var len: Int
while (true) {
len = inputStream.read(buf)
if (len <= 0)
break
outputStream.write(buf, 0, len)
}
inputStream.close()
outputStream.close()
}
return null
}
override fun onPostExecute(result: Void?) {
super.onPostExecute(result)
player.setFilePath(file.absolutePath)
player.start()
}
}.execute()
player = GifPlayer(object : GifPlayer.GifListener {
override fun onGotFrame(bitmap: Bitmap, frame: Int, frameCount: Int) {
Log.d("AppLog", "onGotFrame $frame/$frameCount")
imageView.post {
imageView.setImageBitmap(bitmap)
}
}
override fun onError() {
Log.d("AppLog", "onError")
}
})
}
override fun onStart() {
super.onStart()
player.resume()
}
override fun onStop() {
super.onStop()
player.pause()
}
override fun onDestroy() {
super.onDestroy()
player.stop()
}
}