Add a complexity limit on displaying layer thumbnails to improve performance (#2828)

* Skip complex layer thumbnails

* Set Raster<GPU> to have usize::MAX render complexity

* Code review

---------

Co-authored-by: Keavon Chambers <keavon@keavon.com>

node-graph/gcore/src/render_complexity.rs

@@ -0,0 +1,61 @@
+use crate::instances::Instances;
+use crate::raster_types::{CPU, GPU, Raster};
+use crate::vector::VectorData;
+use crate::{Artboard, Color, GraphicElement};
+use glam::DVec2;
+
+pub trait RenderComplexity {
+	fn render_complexity(&self) -> usize {
+		0
+	}
+}
+
+impl<T: RenderComplexity> RenderComplexity for Instances<T> {
+	fn render_complexity(&self) -> usize {
+		self.instance_ref_iter().map(|instance| instance.instance.render_complexity()).fold(0, usize::saturating_add)
+	}
+}
+
+impl RenderComplexity for Artboard {
+	fn render_complexity(&self) -> usize {
+		self.graphic_group.render_complexity()
+	}
+}
+
+impl RenderComplexity for GraphicElement {
+	fn render_complexity(&self) -> usize {
+		match self {
+			Self::GraphicGroup(instances) => instances.render_complexity(),
+			Self::VectorData(instances) => instances.render_complexity(),
+			Self::RasterDataCPU(instances) => instances.render_complexity(),
+			Self::RasterDataGPU(instances) => instances.render_complexity(),
+		}
+	}
+}
+
+impl RenderComplexity for VectorData {
+	fn render_complexity(&self) -> usize {
+		self.segment_domain.ids().len()
+	}
+}
+
+impl RenderComplexity for Raster<CPU> {
+	fn render_complexity(&self) -> usize {
+		(self.width * self.height / 500) as usize
+	}
+}
+
+impl RenderComplexity for Raster<GPU> {
+	fn render_complexity(&self) -> usize {
+		// GPU textures currently can't have a thumbnail
+		usize::MAX
+	}
+}
+
+impl RenderComplexity for String {}
+impl RenderComplexity for bool {}
+impl RenderComplexity for f32 {}
+impl RenderComplexity for f64 {}
+impl RenderComplexity for DVec2 {}
+impl RenderComplexity for Option<Color> {}
+impl RenderComplexity for Vec<Color> {}