refactor: restructure project into a workspace by introducing a plugin API crate and modularizing individual plugin definitions.

plugins/native-image/Cargo.toml

@@ -0,0 +1,15 @@
+[package]
+name = "convertis-native-image"
+build = "../../plugin-build.rs"
+version.workspace = true
+edition.workspace = true
+authors.workspace = true
+license.workspace = true
+repository.workspace = true
+
+[lib]
+crate-type = ["cdylib"]
+
+[dependencies]
+convertis-plugin-api.workspace = true
+image.workspace = true

plugins/native-image/src/lib.rs

@@ -0,0 +1,61 @@
+// Copyright (C) 2026 Elias Wendland <eliaswendland@pm.me>
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, version 3 exclusively.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+use convertis_plugin_api::{Conversion, ConversionRequest, Plugin, PluginMetadata};
+use image::{ImageFormat, ImageReader};
+use std::{fs::File, io::BufReader};
+
+const FORMATS: &[&str] = &["png", "jpeg", "gif", "webp", "bmp", "tiff", "ico"];
+
+struct NativeImage;
+
+fn image_format(name: &str) -> Result<ImageFormat, String> {
+    ImageFormat::from_extension(name).ok_or_else(|| format!("unsupported image format '{name}'"))
+}
+
+impl Plugin for NativeImage {
+    fn metadata(&self) -> PluginMetadata {
+        PluginMetadata {
+            id: "native-image".into(),
+            package: "convertis-native-image".into(),
+            description: "Native common image conversion".into(),
+            conversions: FORMATS
+                .iter()
+                .flat_map(|from| {
+                    FORMATS
+                        .iter()
+                        .filter(move |to| to != &from)
+                        .map(move |to| Conversion::file(from, to, (255, 230, 240)))
+                })
+                .collect(),
+            options: vec![],
+        }
+    }
+
+    fn convert(&self, request: &ConversionRequest) -> Result<(), String> {
+        let reader = ImageReader::with_format(
+            BufReader::new(File::open(&request.input).map_err(|error| error.to_string())?),
+            image_format(&request.from)?,
+        );
+        let mut image = reader.decode().map_err(|error| error.to_string())?;
+        if request.to == "ico" && (image.width() > 256 || image.height() > 256) {
+            image = image.resize(256, 256, image::imageops::FilterType::Lanczos3);
+        }
+        image
+            .save_with_format(&request.output, image_format(&request.to)?)
+            .map_err(|error| error.to_string())
+    }
+}
+
+convertis_plugin_api::export_plugin!(NativeImage, "native-image");