flutter_desktop: cursor image cache mismatch

Signed-off-by: fufesou <shuanglongchen@yeah.net>

flutter/lib/utils/image.dart

@@ -0,0 +1,49 @@
+import 'dart:typed_data';
+import 'dart:ui' as ui;
+
+Future<ui.Image> decodeImageFromPixels(
+  Uint8List pixels,
+  int width,
+  int height,
+  ui.PixelFormat format, {
+  int? rowBytes,
+  int? targetWidth,
+  int? targetHeight,
+  bool allowUpscaling = true,
+}) async {
+  if (targetWidth != null) {
+    assert(allowUpscaling || targetWidth <= width);
+  }
+  if (targetHeight != null) {
+    assert(allowUpscaling || targetHeight <= height);
+  }
+
+  final ui.ImmutableBuffer buffer =
+      await ui.ImmutableBuffer.fromUint8List(pixels);
+  final ui.ImageDescriptor descriptor = ui.ImageDescriptor.raw(
+    buffer,
+    width: width,
+    height: height,
+    rowBytes: rowBytes,
+    pixelFormat: format,
+  );
+  if (!allowUpscaling) {
+    if (targetWidth != null && targetWidth! > descriptor.width) {
+      targetWidth = descriptor.width;
+    }
+    if (targetHeight != null && targetHeight! > descriptor.height) {
+      targetHeight = descriptor.height;
+    }
+  }
+
+  final ui.Codec codec = await descriptor.instantiateCodec(
+    targetWidth: targetWidth,
+    targetHeight: targetHeight,
+  );
+
+  final ui.FrameInfo frameInfo = await codec.getNextFrame();
+  codec.dispose();
+  buffer.dispose();
+  descriptor.dispose();
+  return frameInfo.image;
+}