fromAssetImage method
- ImageConfiguration configuration,
- String assetName,
- {AssetBundle bundle,
- String package,
- bool mipmaps: true}
从资源图像创建BitmapDescriptor。
Flutter中的assert的资产图像按以下方式存储:
https://flutter.dev/docs/development/ui/assets and images声明-分辨率感知图像资源
该方法考虑了各种资产解决方案
并根据dpi将图像缩放到正确的分辨率。
将mipmaps1设置为false可加载图像的精确dpi版本,默认情况下,
mipmap`为true。
Implementation
static Future<BitmapDescriptor> fromAssetImage(
ImageConfiguration configuration,
String assetName, {
AssetBundle bundle,
String package,
bool mipmaps = true,
}) async {
if (!mipmaps && configuration.devicePixelRatio != null) {
return BitmapDescriptor._(<dynamic>[
'fromAssetImage',
assetName,
configuration.devicePixelRatio,
]);
}
final AssetImage assetImage =
AssetImage(assetName, package: package, bundle: bundle);
final AssetBundleImageKey assetBundleImageKey =
await assetImage.obtainKey(configuration);
return BitmapDescriptor._(<dynamic>[
'fromAssetImage',
assetBundleImageKey.name,
assetBundleImageKey.scale,
if (kIsWeb && configuration?.size != null)
[
configuration.size.width,
configuration.size.height,
],
]);
}