feat: add frame_image, for emitting low-res frame screenshots

Refs: nagisa#96

tracy-client/src/frame.rs

@@ -114,6 +114,30 @@ impl Client {
         }
         Frame(self.clone(), name)
     }
+
+    /// Emits an image of the current frame.
+    ///
+    /// The following restrictions apply:
+    /// - The image must be in RGBA format.
+    /// - The image width and height must be divisible by four.
+    /// - The image data must be less than 256 KB, and should be as small as
+    ///   possible.
+    ///
+    /// The offset indicates how many frames in the past the image was captured.
+    /// For example, an offset of 1 would associate the image with the previous
+    /// call to [frame_mark].
+    ///
+    /// The `flip` parameter indicates that the image should be flipped before
+    /// displaying, for example if the image is an OpenGL texture.
+    pub fn frame_image(&self, image: &[u8], width: u16, height: u16, offset: u8, flip: bool) {
+        #[cfg(feature = "enable")]
+        unsafe {
+            // SAFE: Tracy copies the data before returning.
+            let ptr = image.as_ptr();
+
+            let () = sys::___tracy_emit_frame_image(ptr.cast(), width, height, offset, flip as i32);
+        }
+    }
 }
 
 /// Construct a [`FrameName`].
@@ -150,6 +174,13 @@ pub fn frame_mark() {
         .frame_mark();
 }
 
+/// Convenience shortcut for [`Client::frame_image`] on the current client.
+pub fn frame_image(image: &[u8], width: u16, height: u16, offset: u8, flip: bool) {
+    Client::running()
+        .expect("frame_image without a running Client")
+        .frame_image(image, width, height, offset, flip);
+}
+
 /// Convenience macro for [`Client::secondary_frame_mark`] on the current client.
 ///
 /// # Panics

tracy-client/src/lib.rs

@@ -28,7 +28,7 @@
 #![doc = include_str!("../FEATURES.mkd")]
 #![cfg_attr(tracy_client_docs, feature(doc_auto_cfg))]
 
-pub use crate::frame::{frame_mark, Frame, FrameName};
+pub use crate::frame::{frame_image, frame_mark, Frame, FrameName};
 pub use crate::gpu::{
     GpuContext, GpuContextCreationError, GpuContextType, GpuSpan, GpuSpanCreationError,
 };