Migrate Linux player from GStreamer Java/JNA to native C via JNI

mediaplayer/build.gradle.kts

@@ -108,9 +108,6 @@ kotlin {
 
         jvmMain.dependencies {
             implementation(libs.kotlinx.coroutines.swing)
-            implementation(libs.gst1.java.core)
-            implementation(libs.jna.jpms)
-            implementation(libs.jna.platform.jpms)
             implementation(libs.slf4j.simple)
         }
 
@@ -197,13 +194,30 @@ val buildNativeWindows by tasks.registering(Exec::class) {
     commandLine("cmd", "/c", nativeDir.file("build.bat").asFile.absolutePath)
 }
 
+val buildNativeLinux by tasks.registering(Exec::class) {
+    description = "Compiles the C native library into Linux .so (GStreamer + JNI)"
+    group = "build"
+    val hasPrebuilt = nativeResourceDir
+        .dir("linux-x86-64")
+        .file("libNativeVideoPlayer.so")
+        .asFile
+        .exists()
+    enabled = Os.isFamily(Os.FAMILY_UNIX) && !Os.isFamily(Os.FAMILY_MAC) && !hasPrebuilt
+
+    val nativeDir = layout.projectDirectory.dir("src/jvmMain/native/linux")
+    inputs.dir(nativeDir)
+    outputs.dir(nativeResourceDir)
+    workingDir(nativeDir)
+    commandLine("bash", "build.sh")
+}
+
 tasks.named("jvmProcessResources") {
-    dependsOn(buildNativeMacOs, buildNativeWindows)
+    dependsOn(buildNativeMacOs, buildNativeWindows, buildNativeLinux)
 }
 
 tasks.configureEach {
     if (name == "sourcesJar") {
-        dependsOn(buildNativeMacOs, buildNativeWindows)
+        dependsOn(buildNativeMacOs, buildNativeWindows, buildNativeLinux)
     }
 }
 

mediaplayer/src/jvmMain/kotlin/io/github/kdroidfilter/composemediaplayer/VideoPlayerState.jvm.kt

@@ -3,9 +3,9 @@ package io.github.kdroidfilter.composemediaplayer
 import androidx.compose.runtime.Stable
 import androidx.compose.ui.graphics.Color
 import androidx.compose.ui.text.TextStyle
-import com.sun.jna.Platform
 import io.github.kdroidfilter.composemediaplayer.linux.LinuxVideoPlayerState
 import io.github.kdroidfilter.composemediaplayer.mac.MacVideoPlayerState
+import io.github.kdroidfilter.composemediaplayer.util.CurrentPlatform
 import io.github.kdroidfilter.composemediaplayer.windows.WindowsVideoPlayerState
 import io.github.vinceglb.filekit.PlatformFile
 
@@ -37,11 +37,10 @@ actual fun createVideoPlayerState(): VideoPlayerState = DefaultVideoPlayerState(
  */
 @Stable
 open class DefaultVideoPlayerState: VideoPlayerState {
-    val delegate: VideoPlayerState = when {
-        Platform.isWindows() -> WindowsVideoPlayerState()
-        Platform.isMac() -> MacVideoPlayerState()
-        Platform.isLinux() -> LinuxVideoPlayerState()
-        else -> throw UnsupportedOperationException("Unsupported platform")
+    val delegate: VideoPlayerState = when (CurrentPlatform.os) {
+        CurrentPlatform.OS.WINDOWS -> WindowsVideoPlayerState()
+        CurrentPlatform.OS.MAC -> MacVideoPlayerState()
+        CurrentPlatform.OS.LINUX -> LinuxVideoPlayerState()
     }
 
     override val hasMedia: Boolean get() = delegate.hasMedia

mediaplayer/src/jvmMain/kotlin/io/github/kdroidfilter/composemediaplayer/linux/LinuxFrameUtils.kt

@@ -2,40 +2,7 @@ package io.github.kdroidfilter.composemediaplayer.linux
 
 import java.nio.ByteBuffer
 
-/**
- * Calculates a fast hash of the frame buffer to detect frame changes.
- * Samples approximately 200 pixels evenly distributed across the frame.
- *
- * @param buffer The source buffer containing RGBA pixel data
- * @param pixelCount Total number of pixels in the frame
- * @return A hash value representing the frame content
- */
-internal fun calculateFrameHash(buffer: ByteBuffer, pixelCount: Int): Int {
-    if (pixelCount <= 0) return 0
-
-    var hash = 1
-    val step = if (pixelCount <= 200) 1 else pixelCount / 200
-    for (i in 0 until pixelCount step step) {
-        hash = 31 * hash + buffer.getInt(i * 4)
-    }
-    return hash
-}
-
-/**
- * Copies RGBA frame data from source to destination buffer with minimal overhead.
- * Handles row padding when destination stride differs from source.
- *
- * This function performs a single memory copy operation when strides match,
- * achieving zero-copy performance (beyond the necessary single copy from
- * GStreamer buffer to Skia bitmap).
- *
- * @param src Source buffer containing RGBA pixel data from GStreamer
- * @param dst Destination buffer (Skia bitmap pixels via peekPixels)
- * @param width Frame width in pixels
- * @param height Frame height in pixels
- * @param dstRowBytes Destination row stride (may include padding)
- */
-internal fun copyRgbaFrame(
+internal fun copyBgraFrame(
     src: ByteBuffer,
     dst: ByteBuffer,
     width: Int,
@@ -63,15 +30,13 @@ internal fun copyRgbaFrame(
     srcBuf.rewind()
     dstBuf.rewind()
 
-    // Fast path: when strides match, do a single bulk copy
     if (dstRowBytes == srcRowBytes) {
         srcBuf.limit(requiredSrcBytes.toInt())
         dstBuf.limit(requiredSrcBytes.toInt())
         dstBuf.put(srcBuf)
         return
     }
 
-    // Slow path: copy row by row when there's padding
     val srcCapacity = srcBuf.capacity()
     val dstCapacity = dstBuf.capacity()
     for (row in 0 until height) {