refactor: 完成图像加载模块重构，对齐 ddddocr Python 原版 IO 逻辑

src/image_io.rs

@@ -1,24 +1,103 @@
-use anyhow::{Context, Result};
+use anyhow::{Context, Result, anyhow};
 use base64::{Engine as _, engine::general_purpose};
-use image::{DynamicImage, GenericImageView, ImageBuffer, Luma, Rgb, RgbImage};
+use image::{DynamicImage, GenericImageView, ImageBuffer, ImageFormat, Luma, Rgb, RgbImage, Rgba};
+use std::fs;
 use std::path::{Path, PathBuf};
-use tract_onnx::prelude::tract_ndarray::Array3;
-
+use tract_onnx::prelude::tract_ndarray::{Array3, ArrayD, ArrayViewD};
 /// 定义支持的输入类型枚举
 pub enum ImageInput {
     Bytes(Vec<u8>),
-    Array(Array3<u8>),
+    Array(ArrayD<u8>), // 对应 numpy 数组
     Path(PathBuf),
     Base64(String),
     DynamicImage(DynamicImage),
 }
 
+impl From<&str> for ImageInput {
+    fn from(s: &str) -> Self {
+        if Path::new(s).exists() {
+            ImageInput::Path(s.into())
+        } else {
+            ImageInput::Base64(s.to_string())
+        }
+    }
+}
 /// 模拟 Python 的 load_image_from_input
 #[allow(dead_code)]
-pub fn load_image_from_input(input: ImageInput) -> Result<DynamicImage> {
-    match input {
+pub fn load_image_from_input(img_input: ImageInput) -> Result<DynamicImage> {
+    match img_input {
+        // 2. 处理字节流 (Bytes)
+        ImageInput::Bytes(bytes) => {
+            image::load_from_memory(&bytes).context("Failed to load image from bytes")
+        }
+        // 1. 已经是 DynamicImage
         ImageInput::DynamicImage(img) => Ok(img),
-        _ => todo!("后续补充"),
+        // 5. 处理 ndarray (Numpy-like)
+        // 假设输入是 HWC 格式的 Array3<u8>
+        ImageInput::Array(arr) => numpy_to_pil_image(arr.view()),
+        // 4. 处理 Base64 字符串
+        ImageInput::Base64(b64_str) => base64_to_image(&b64_str),
+        // 3. 处理文件路径 (Path)
+        ImageInput::Path(path) => image::open(path).context("Failed to open image from path"),
+    }
+}
+fn base64_to_image(img_base64: &str) -> Result<DynamicImage> {
+    // 过滤掉可能存在的 base64 前缀，例如 "data:image/png;base64,"
+    let clean_b64 = if let Some(pos) = img_base64.find(",") {
+        &img_base64[pos + 1..]
+    } else {
+        &img_base64
+    };
+
+    let bytes = general_purpose::STANDARD
+        .decode(clean_b64.trim())
+        .map_err(|e| anyhow!("Base64 decode error: {}", e))?;
+
+    image::load_from_memory(&bytes).context("Failed to load image from decoded base64")
+}
+/// 封装数组转图像的逻辑，对齐 Python 版 _numpy_to_pil_image
+fn numpy_to_pil_image(array: ArrayViewD<u8>) -> Result<DynamicImage> {
+    let shape = array.shape();
+    let dim = shape.len();
+
+    // 1. 确保数据在内存中是连续的 (C order / Standard Layout)
+    // 如果 arr 是经过切片或转置的，这一步会进行必要的内存拷贝
+    let standard = array.as_standard_layout();
+    let (raw_data, _offset) = standard.to_owned().into_raw_vec_and_offset();
+
+    match dim {
+        // 对应 Python: len(array.shape) == 2 (灰度图 H, W)
+        2 => {
+            let (h, w) = (shape[0], shape[1]);
+            ImageBuffer::<Luma<u8>, _>::from_raw(w as u32, h as u32, raw_data)
+                .map(DynamicImage::ImageLuma8)
+                .ok_or_else(|| anyhow!("Failed to create Luma image from 2D array"))
+        }
+
+        // 对应 Python: len(array.shape) == 3 (H, W, C)
+        3 => {
+            let (h, w, c) = (shape[0], shape[1], shape[2]);
+            match c {
+                // 对应 Python: array.shape[2] == 1 (单通道 H, W, 1)
+                1 => ImageBuffer::<Luma<u8>, _>::from_raw(w as u32, h as u32, raw_data)
+                    .map(DynamicImage::ImageLuma8),
+
+                // 对应 Python: array.shape[2] == 3 (RGB H, W, 3)
+                3 => ImageBuffer::<Rgb<u8>, _>::from_raw(w as u32, h as u32, raw_data)
+                    .map(DynamicImage::ImageRgb8),
+
+                // 对应 Python: array.shape[2] == 4 (RGBA H, W, 4)
+                4 => ImageBuffer::<Rgba<u8>, _>::from_raw(w as u32, h as u32, raw_data)
+                    .map(DynamicImage::ImageRgba8),
+
+                _ => {
+                    return Err(anyhow!("不支持的通道数: {}", c));
+                }
+            }
+            .ok_or_else(|| anyhow!("转换彩色图失败"))
+        }
+
+        _ => Err(anyhow!("不支持的数组维度: {}，仅支持 2D 或 3D", dim)),
     }
 }