Fix AnimatedImage component (#2174)

* Fix and optimize image animation for 0 and 1 frames

* Change default frame duration to 10fps to match those of a browser

* Fix zero-size image with ImageBitmap.Blank

components/AnimatedImage/library/src/desktopMain/kotlin/org/jetbrains/compose/animatedimage/DesktopAnimatedImage.kt

@@ -10,7 +10,7 @@ import org.jetbrains.skia.Codec
 import java.net.MalformedURLException
 import java.net.URL
 
-private const val DEFAULT_FRAME_DURATION = 50
+private const val DEFAULT_FRAME_DURATION = 100
 
 actual class AnimatedImage(val codec: Codec)
 
@@ -26,6 +26,17 @@ actual suspend fun loadResourceAnimatedImage(path: String): AnimatedImage {
 
 @Composable
 actual fun AnimatedImage.animate(): ImageBitmap {
+    when (codec.frameCount) {
+        0 -> return ImageBitmap.Blank // No frames at all
+        1 -> {
+            // Just one frame, no animation
+            val bitmap = remember(codec) { Bitmap().apply { allocPixels(codec.imageInfo) } }
+            remember(bitmap) {
+                codec.readPixels(bitmap, 0)
+            }
+            return bitmap.asComposeImageBitmap()
+        }
+        else -> {
             val transition = rememberInfiniteTransition()
             val frameIndex by transition.animateValue(
                 initialValue = 0,
@@ -51,17 +62,14 @@ actual fun AnimatedImage.animate(): ImageBitmap {
             }
 
             return bitmap.asComposeImageBitmap()
+        }
+    }
 }
 
 private fun calcFrameDuration(frame: AnimationFrameInfo): Int {
-    var frameDuration = frame.duration
-
     // If the frame does not contain information about a duration, set a reasonable constant duration
-    if (frameDuration == 0) {
-        frameDuration = DEFAULT_FRAME_DURATION
-    }
-
-    return frameDuration
+    val frameDuration = frame.duration
+    return if (frameDuration == 0) DEFAULT_FRAME_DURATION else frameDuration
 }
 
 /**