refactor(adapter): extract image_area from image_show

Exposing `image_area` separately allows future Lua integration to handle
image placement more flexibly, without needing to invoke full rendering.
This change promotes modularity and simplifies obtaining image dimensions alone.

This refactor provides the foundation for feature PR sxyazi#1897, preparing for easier integration.

Author: gaesa

Diff for: yazi-adapter/src/adapter.rs

@@ -5,7 +5,7 @@ use ratatui::layout::Rect;
 use tracing::warn;
 use yazi_shared::env_exists;
 
-use super::{Iip, Kgp, KgpOld};
+use super::{Iip, Image, Kgp, KgpOld};
 use crate::{Chafa, Emulator, SHOWN, Sixel, TMUX, Ueberzug, WSL};
 
 #[derive(Clone, Copy, PartialEq, Eq, Debug)]
@@ -36,6 +36,20 @@ impl Display for Adapter {
 }
 
 impl Adapter {
+	pub async fn image_area(self, path: &Path, max: Rect) -> Result<Rect> {
+		if max.is_empty() {
+			return Ok(Rect::default());
+		}
+
+		match self {
+			Self::Kgp | Self::KgpOld | Self::Iip | Self::Sixel => {
+				Image::image_area(path, max).await.map(|(_img, area)| area)
+			}
+			Self::X11 | Self::Wayland => Ueberzug::image_area(path, max).await,
+			Self::Chafa => Chafa::image_area(path, max).await,
+		}
+	}
+
 	pub async fn image_show(self, path: &Path, max: Rect) -> Result<Rect> {
 		if max.is_empty() {
 			return Ok(Rect::default());

Diff for: yazi-adapter/src/chafa.rs

@@ -11,7 +11,11 @@ use crate::{Adapter, Emulator};
 pub(super) struct Chafa;
 
 impl Chafa {
-	pub(super) async fn image_show(path: &Path, max: Rect) -> Result<Rect> {
+	async fn symbol_bytes_with<F: Fn((Vec<&[u8]>, Rect)) -> Result<Rect>>(
+		path: &Path,
+		max: Rect,
+		cb: F,
+	) -> Result<Rect> {
 		let output = Command::new("chafa")
 			.args([
 				"-f",
@@ -52,16 +56,26 @@ impl Chafa {
 			width:  first.width() as u16,
 			height: lines.len() as u16,
 		};
+		cb((lines, area))
+	}
 
-		Adapter::Chafa.image_hide()?;
-		Adapter::shown_store(area);
-		Emulator::move_lock((max.x, max.y), |stderr| {
-			for (i, line) in lines.into_iter().enumerate() {
-				stderr.write_all(line)?;
-				queue!(stderr, MoveTo(max.x, max.y + i as u16 + 1))?;
-			}
-			Ok(area)
+	pub(super) async fn image_area(path: &Path, max: Rect) -> Result<Rect> {
+		Self::symbol_bytes_with(path, max, |(_, area)| Ok(area)).await
+	}
+
+	pub(super) async fn image_show(path: &Path, max: Rect) -> Result<Rect> {
+		Self::symbol_bytes_with(path, max, |(lines, area)| {
+			Adapter::Chafa.image_hide()?;
+			Adapter::shown_store(area);
+			Emulator::move_lock((max.x, max.y), |stderr| {
+				for (i, line) in lines.into_iter().enumerate() {
+					stderr.write_all(line)?;
+					queue!(stderr, MoveTo(max.x, max.y + i as u16 + 1))?;
+				}
+				Ok(area)
+			})
 		})
+		.await
 	}
 
 	pub(super) fn image_erase(area: Rect) -> Result<()> {

Diff for: yazi-adapter/src/iip.rs

@@ -14,8 +14,7 @@ pub(super) struct Iip;
 
 impl Iip {
 	pub(super) async fn image_show(path: &Path, max: Rect) -> Result<Rect> {
-		let img = Image::downscale(path, max).await?;
-		let area = Image::pixel_area((img.width(), img.height()), max);
+		let (img, area) = Image::image_area(path, max).await?;
 		let b = Self::encode(img).await?;
 
 		Adapter::Iip.image_hide()?;

Diff for: yazi-adapter/src/image.rs

@@ -84,6 +84,13 @@ impl Image {
 			.unwrap_or(rect)
 	}
 
+	#[inline]
+	pub(super) async fn image_area(path: &Path, max: Rect) -> Result<(DynamicImage, Rect)> {
+		let img = Self::downscale(path, max).await?;
+		let area = Self::pixel_area((img.width(), img.height()), max);
+		Ok((img, area))
+	}
+
 	#[inline]
 	fn filter() -> FilterType {
 		match PREVIEW.image_filter.as_str() {

Diff for: yazi-adapter/src/kgp.rs

@@ -314,8 +314,7 @@ pub(super) struct Kgp;
 
 impl Kgp {
 	pub(super) async fn image_show(path: &Path, max: Rect) -> Result<Rect> {
-		let img = Image::downscale(path, max).await?;
-		let area = Image::pixel_area((img.width(), img.height()), max);
+		let (img, area) = Image::image_area(path, max).await?;
 
 		let b1 = Self::encode(img).await?;
 		let b2 = Self::place(&area)?;

Diff for: yazi-adapter/src/kgp_old.rs

@@ -13,8 +13,7 @@ pub(super) struct KgpOld;
 
 impl KgpOld {
 	pub(super) async fn image_show(path: &Path, max: Rect) -> Result<Rect> {
-		let img = Image::downscale(path, max).await?;
-		let area = Image::pixel_area((img.width(), img.height()), max);
+		let (img, area) = Image::image_area(path, max).await?;
 		let b = Self::encode(img).await?;
 
 		Adapter::KgpOld.image_hide()?;

Diff for: yazi-adapter/src/sixel.rs

@@ -13,8 +13,7 @@ pub(super) struct Sixel;
 
 impl Sixel {
 	pub(super) async fn image_show(path: &Path, max: Rect) -> Result<Rect> {
-		let img = Image::downscale(path, max).await?;
-		let area = Image::pixel_area((img.width(), img.height()), max);
+		let (img, area) = Image::image_area(path, max).await?;
 		let b = Self::encode(img).await?;
 
 		Adapter::Sixel.image_hide()?;

Diff for: yazi-adapter/src/ueberzug.rs

@@ -41,23 +41,29 @@ impl Ueberzug {
 		DEMON.init(Some(tx))
 	}
 
+	pub(super) async fn image_area(path: &Path, max: Rect) -> Result<Rect> {
+		let p = path.to_owned();
+		let ImageSize { width: w, height: h } =
+			tokio::task::spawn_blocking(move || imagesize::size(p)).await??;
+
+		Ok(
+			Dimension::ratio()
+				.map(|(r1, r2)| Rect {
+					x:      max.x,
+					y:      max.y,
+					width:  max.width.min((w.min(PREVIEW.max_width as _) as f64 / r1).ceil() as _),
+					height: max.height.min((h.min(PREVIEW.max_height as _) as f64 / r2).ceil() as _),
+				})
+				.unwrap_or(max),
+		)
+	}
+
 	pub(super) async fn image_show(path: &Path, max: Rect) -> Result<Rect> {
 		let Some(tx) = &*DEMON else {
 			bail!("uninitialized ueberzugpp");
 		};
 
-		let p = path.to_owned();
-		let ImageSize { width: w, height: h } =
-			tokio::task::spawn_blocking(move || imagesize::size(p)).await??;
-
-		let area = Dimension::ratio()
-			.map(|(r1, r2)| Rect {
-				x:      max.x,
-				y:      max.y,
-				width:  max.width.min((w.min(PREVIEW.max_width as _) as f64 / r1).ceil() as _),
-				height: max.height.min((h.min(PREVIEW.max_height as _) as f64 / r2).ceil() as _),
-			})
-			.unwrap_or(max);
+		let area = Self::image_area(path, max).await?;
 
 		tx.send(Some((path.to_owned(), area)))?;
 		Adapter::shown_store(area);