fix compile errors except for ffmpeg

nokhwa-core/src/decoder.rs

@@ -8,7 +8,7 @@ use bytemuck::try_cast_slice_mut;
 use crate::pixel_destination::PixelDestination;
 
 pub trait Decoder {
-    type Config: Clone + Debug;
+    type Config: Clone + Debug + ConfigHasResolution;
     type OutputMeta: Clone + Debug;
     const SUPPORTED_DESTINATIONS: &'static [PixelDestination];
 
@@ -27,10 +27,7 @@ pub trait Decoder {
     where
         <P as Pixel>::Subpixel: NonFloatScalarWidth
     {
-        let destination = match PixelDestination::get_by_pixel::<P>() {
-            Some(dest) => dest,
-            None => return Err(NokhwaError::DecoderUnknownDestinationPixelFormat(P::COLOR_MODEL, P::Subpixel::WIDTH_BYTES))
-        };
+        let Some(destination) = PixelDestination::get_by_pixel::<P>() else { return Err(NokhwaError::DecoderUnknownDestinationPixelFormat(P::COLOR_MODEL, P::Subpixel::WIDTH_BYTES)) };
 
         if !Self::supports_destination(destination) {
             return Err(NokhwaError::DecoderUnsupportedDestinationPixelFormat(destination))
@@ -43,13 +40,29 @@ pub trait Decoder {
 
         self.decode_to_buffer(to_decode, cast_slice, destination)
     }
-
     fn decode<P: Pixel>(
         &mut self,
-        to_decode: FrameBuffer,
+        to_decode: FrameBuffer<'_>,
     ) -> Result<DecodedImage<P, Self::OutputMeta>, NokhwaError>
     where
-        <P as Pixel>::Subpixel: NonFloatScalarWidth;
+        <P as Pixel>::Subpixel: NonFloatScalarWidth,
+    {
+        let resolution = self.config().resolution();
+        let min_size_alloc = self.output_decoder_min_size_pixel::<P>(resolution)?;
+        let mut out_buffer: Vec<P::Subpixel> = vec![P::Subpixel::DEFAULT_MIN_VALUE; min_size_alloc];
+        let meta = self.decode_to_pixel_buffer::<P>(to_decode, &mut out_buffer)?;
+        Ok(DecodedImage::new(
+            ImageBuffer::from_vec(
+                resolution.width(),
+                resolution.height(),
+                out_buffer,
+            )
+                .ok_or(NokhwaError::Decoder(
+                    "failed to convert into an image buffer".to_string(),
+                ))?,
+            meta,
+        ))
+    }
     
     fn output_decoder_min_size_pixel<P>(&self, resolution: Resolution) -> Result<usize, NokhwaError> where
         P: Pixel,
@@ -58,9 +71,29 @@ pub trait Decoder {
 
     }
     
-    fn output_decoder_min_size(&self, resolution: Resolution, destination_format: PixelDestination) -> Result<usize, NokhwaError>;
+    fn output_decoder_min_size(&self, resolution: Resolution, destination_format: PixelDestination) -> Result<usize, NokhwaError> {
+        if !Self::supports_destination(destination_format) {
+            return Err(NokhwaError::DecoderUnsupportedDestinationPixelFormat(destination_format))
+        }
 
+        let px_size = match destination_format {
+            PixelDestination::Rgb8 | PixelDestination::Bgr8 => 3_u32,
+            PixelDestination::Rgba8 | PixelDestination::Bgra8 | PixelDestination::LumaA16 => 4_u32,
+            PixelDestination::Rgb16 | PixelDestination::Bgr16 => 3_u32 * 2_u32,
+            PixelDestination::Rgba16 | PixelDestination::Bgra16 => 4_u32 * 2_u32,
+            PixelDestination::Luma8 => 1_u32,
+            PixelDestination::LumaA8 | PixelDestination::Luma16 => 2_u32,
+            };
+        let reso = resolution.width() * resolution.height();
+        Ok((reso as usize) * (px_size as usize))
+    }
+
+    #[must_use]
     fn supports_destination(pixel_destination: PixelDestination) -> bool {
         Self::SUPPORTED_DESTINATIONS.contains(&pixel_destination)
     }
 }
+
+pub trait ConfigHasResolution {
+    fn resolution(&self) -> Resolution;
+}

nokhwa-core/src/frame_format.rs

@@ -206,6 +206,7 @@ define_frame_format_with_groups! {
 }
 
 impl FrameFormat {
+    #[must_use]
     pub fn is_custom(&self) -> bool {
         if let FrameFormat::Custom(_) = self {
             return true

nokhwa-core/src/pixel_destination.rs

@@ -19,6 +19,7 @@ pub enum PixelDestination {
 }
 
 impl PixelDestination {
+    #[must_use]
     pub fn get_by_pixel<P>() -> Option<Self>
     where
         P: Pixel,

nokhwa-core/src/stream.rs

@@ -165,7 +165,7 @@ impl<'a> StreamHandle<'a> {
                         return Err(NokhwaError::ReadFrameError(why));
                     }
                 }
-                Event::Error(e) => return Err(NokhwaError::ReadFrameError(e.to_string())),
+                Event::Error(e) => return Err(NokhwaError::ReadFrameError(e.clone())),
                 _ => {}
             }
         }

nokhwa-core/src/types.rs

@@ -43,7 +43,7 @@ impl CameraIndex {
     pub fn as_string(&self) -> String {
         match self {
             CameraIndex::Index(i) => i.to_string(),
-            CameraIndex::String(s) | CameraIndex::Stable(s) => s.to_string(),
+            CameraIndex::String(s) | CameraIndex::Stable(s) => s.clone(),
             }
     }