Added SKImage.IsLazyGenerated to help with cases like #445

binding/Binding/SKImage.cs

@@ -355,6 +355,8 @@ namespace SkiaSharp
 
 		public bool IsTextureBacked => SkiaApi.sk_image_is_texture_backed (Handle);
 
+		public bool IsLazyGenerated => SkiaApi.sk_image_is_lazy_generated (Handle);
+
 		public bool ReadPixels (SKImageInfo dstInfo, IntPtr dstPixels, int dstRowBytes, int srcX, int srcY)
 		{
 			return ReadPixels (dstInfo, dstPixels, dstRowBytes, srcX, srcY, SKImageCachingHint.Allow);

binding/Binding/SkiaApi.cs

@@ -552,6 +552,9 @@ namespace SkiaSharp
 		public extern static bool sk_image_is_texture_backed(sk_image_t image);
 		[DllImport(SKIA, CallingConvention = CallingConvention.Cdecl)]
 		[return: MarshalAs(UnmanagedType.I1)]
+		public extern static bool sk_image_is_lazy_generated(sk_image_t image);
+		[DllImport(SKIA, CallingConvention = CallingConvention.Cdecl)]
+		[return: MarshalAs(UnmanagedType.I1)]
 		public extern static bool sk_image_read_pixels(sk_image_t image, ref SKImageInfoNative dstInfo, IntPtr dstPixels, IntPtr dstRowBytes, int srcX, int srcY, SKImageCachingHint cachingHint);
 		[DllImport(SKIA, CallingConvention = CallingConvention.Cdecl)]
 		[return: MarshalAs(UnmanagedType.I1)]

docs/en/SkiaSharp/SKImage.xml

@@ -1129,6 +1129,24 @@
         </remarks>
       </Docs>
     </Member>
+    <Member MemberName="IsLazyGenerated">
+      <MemberSignature Language="C#" Value="public bool IsLazyGenerated { get; }" />
+      <MemberSignature Language="ILAsm" Value=".property instance bool IsLazyGenerated" />
+      <MemberType>Property</MemberType>
+      <AssemblyInfo>
+        <AssemblyVersion>1.60.0.0</AssemblyVersion>
+      </AssemblyInfo>
+      <ReturnValue>
+        <ReturnType>System.Boolean</ReturnType>
+      </ReturnValue>
+      <Docs>
+        <summary>Gets a value indicating whether the image is backed by an image-generator or other source that creates (and caches) its pixels / texture on-demand.</summary>
+        <value>
+          <para></para>
+        </value>
+        <remarks>If this method returns <see langword="false" />, then <see cref="M:SkiaSharp.SKImage.PeekPixels" /> will return <see langword="null" />.</remarks>
+      </Docs>
+    </Member>
     <Member MemberName="PeekPixels">
       <MemberSignature Language="C#" Value="public SkiaSharp.SKPixmap PeekPixels ();" />
       <MemberSignature Language="ILAsm" Value=".method public hidebysig instance class SkiaSharp.SKPixmap PeekPixels() cil managed" />

externals/skia

@@ -1 +1 @@
-Subproject commit 2ef76f9178eb9d9d97064f164ac055913d07b79c
+Subproject commit 176bd71755347e14ff59f3fe6fe125af800c3c8e

tests/Tests/SKImageTest.cs

@@ -1,10 +1,35 @@
 using System;
+using System.IO;
 using Xunit;
 
 namespace SkiaSharp.Tests
 {
 	public class SKImageTest : SKTest
 	{
+		[SkippableFact]
+		public void TestLazyImage()
+		{
+			var data = SKData.Create(Path.Combine(PathToImages, "baboon.jpg"));
+			Assert.NotNull(data);
+
+			var image = SKImage.FromEncodedData(data);
+			Assert.NotNull(image);
+
+			Assert.True(image.IsLazyGenerated);
+		}
+
+		[SkippableFact]
+		public void TestNotLazyImage()
+		{
+			var bitmap = CreateTestBitmap();
+			Assert.NotNull(bitmap);
+
+			var image = SKImage.FromBitmap(bitmap);
+			Assert.NotNull(image);
+
+			Assert.False(image.IsLazyGenerated);
+		}
+
 		[SkippableFact]
 		public void EncodeWithSimpleSerializer()
 		{