Use niri_render_elements! for the screenshot UI

1 files changed, 32 insertions, 10 deletions

diff --git a/src/render_helpers/render_elements.rs b/src/render_helpers/render_elements.rs
index 1f100536..8b30e1ac 100644
--- a/src/render_helpers/render_elements.rs
+++ b/src/render_helpers/render_elements.rs
@@ -2,13 +2,39 @@
 // This macro does it for us.
 #[macro_export]
 macro_rules! niri_render_elements {
+    // The two callable variants: with <R> and without <R>. They include From impls because nested
+    // repetitions ($type and $variant with + and $R with ?) don't work properly.
+    ($name:ident<R> => { $($variant:ident = $type:ty),+ $(,)? }) => {
+        $crate::niri_render_elements!(@impl $name () ($name<R>) => { $($variant = $type),+ });
+
+        $(impl<R: $crate::render_helpers::renderer::NiriRenderer> From<$type> for $name<R> {
+            fn from(x: $type) -> Self {
+                Self::$variant(x)
+            }
+        })+
+    };
+
     ($name:ident => { $($variant:ident = $type:ty),+ $(,)? }) => {
+        $crate::niri_render_elements!(@impl $name ($name) () => { $($variant = $type),+ });
+
+        $(impl From<$type> for $name {
+            fn from(x: $type) -> Self {
+                Self::$variant(x)
+            }
+        })+
+    };
+
+    // The internal variant that generates most of the code. $name_no_R and $name_R are necessary
+    // for the impl RenderElement<SomeRenderer> for $name<SomeRenderer>: since $R does not appear
+    // in this line, we cannot condition based on $R like elsewhere, so we condition on duplicate
+    // names instead. Like this: $($name_R<SomeRenderer>)? $($name_no_R)? so only one is chosen.
+    (@impl $name:ident ($($name_no_R:ident)?) ($($name_R:ident<$R:ident>)?) => { $($variant:ident = $type:ty),+ }) => {
         #[derive(Debug)]
-        pub enum $name<R: $crate::render_helpers::renderer::NiriRenderer> {
+        pub enum $name$(<$R: $crate::render_helpers::renderer::NiriRenderer>)? {
             $($variant($type)),+
         }
 
-        impl<R: $crate::render_helpers::renderer::NiriRenderer> smithay::backend::renderer::element::Element for $name<R> {
+        impl$(<$R: $crate::render_helpers::renderer::NiriRenderer>)? smithay::backend::renderer::element::Element for $name$(<$R>)? {
             fn id(&self) -> &smithay::backend::renderer::element::Id {
                 match self {
                     $($name::$variant(elem) => elem.id()),+
@@ -68,7 +94,9 @@ macro_rules! niri_render_elements {
             }
         }
 
-        impl smithay::backend::renderer::element::RenderElement<smithay::backend::renderer::gles::GlesRenderer> for $name<smithay::backend::renderer::gles::GlesRenderer> {
+        impl smithay::backend::renderer::element::RenderElement<smithay::backend::renderer::gles::GlesRenderer>
+            for $($name_R<smithay::backend::renderer::gles::GlesRenderer>)? $($name_no_R)?
+        {
             fn draw(
                 &self,
                 frame: &mut smithay::backend::renderer::gles::GlesFrame<'_>,
@@ -91,7 +119,7 @@ macro_rules! niri_render_elements {
         }
 
         impl<'render> smithay::backend::renderer::element::RenderElement<$crate::backend::tty::TtyRenderer<'render>>
-            for $name<$crate::backend::tty::TtyRenderer<'render>>
+            for $($name_R<$crate::backend::tty::TtyRenderer<'render>>)? $($name_no_R)?
         {
             fn draw(
                 &self,
@@ -116,11 +144,5 @@ macro_rules! niri_render_elements {
                 }
             }
         }
-
-        $(impl<R: $crate::render_helpers::renderer::NiriRenderer> From<$type> for $name<R> {
-            fn from(x: $type) -> Self {
-                Self::$variant(x)
-            }
-        })+
     };
 }