gles2: Expose transformation of a `Frame`

src/backend/renderer/gles2/mod.rs

@@ -186,6 +186,7 @@ pub struct Gles2Renderer {
 /// Handle to the currently rendered frame during [`Gles2Renderer::render`](Renderer::render)
 pub struct Gles2Frame {
     current_projection: Matrix3<f32>,
+    transform: Transform,
     gl: ffi::Gles2,
     tex_programs: [Gles2TexProgram; shaders::FRAGMENT_COUNT],
     solid_program: Gles2SolidProgram,
@@ -1129,6 +1130,7 @@ impl Renderer for Gles2Renderer {
             solid_program: self.solid_program.clone(),
             // output transformation passed in by the user
             current_projection: flip180 * transform.matrix() * renderer,
+            transform,
             vbos: self.vbos,
             size,
         };
@@ -1318,6 +1320,10 @@ impl Frame for Gles2Frame {
 
         self.render_texture(texture, mat, Some(&damage), tex_verts, alpha)
     }
+
+    fn transformation(&self) -> Transform {
+        self.transform
+    }
 }
 
 impl Gles2Frame {

src/backend/renderer/mod.rs

@@ -219,6 +219,9 @@ pub trait Frame {
         src_transform: Transform,
         alpha: f32,
     ) -> Result<(), Self::Error>;
+
+    /// Output transformation that is applied to this frame
+    fn transformation(&self) -> Transform;
 }
 
 /// Abstraction of commonly used rendering operations for compositors.

wlcs_anvil/src/renderer.rs

@@ -112,6 +112,10 @@ impl Frame for DummyFrame {
     ) -> Result<(), Self::Error> {
         Ok(())
     }
+
+    fn transformation(&self) -> Transform {
+        Transform::Normal
+    }
 }
 
 pub struct DummyTexture {