Load indexed png

src/Tools/tim_tool/Cargo.toml

@@ -7,6 +7,7 @@ edition = "2021"
 panic = "abort"
 
 [dependencies]
+png         = "0.17.16"
 rfd         = "0.15.2"
 slint       = "1.9.2"
 tiny-skia   = "0.11.4"

src/Tools/tim_tool/src/logic/mod.rs

@@ -40,6 +40,6 @@ impl UnaddedTIM {
     }
 
     fn empty() -> UnaddedTIM {
-        UnaddedTIM{info: TIMInfo{}, image: Image::default()}
+        UnaddedTIM{info: TIMInfo::default(), image: Image::default()}
     }
 }

src/Tools/tim_tool/src/logic/tim.rs

@@ -1,14 +1,63 @@
-use std::path::PathBuf;
+use std::{default, fmt::format, fs::File, path::PathBuf};
+use slint::{Rgba8Pixel, SharedPixelBuffer};
 use tool_helper::Error;
 
-pub struct TIMInfo {}
+pub struct TIMInfo {
+    image_data: SharedPixelBuffer<Rgba8Pixel>,
+    palette:    Option<Vec<Rgba8Pixel>>,
+}
 
 impl std::default::Default for TIMInfo {
     fn default() -> Self {
-        TIMInfo{}
+        TIMInfo{image_data: SharedPixelBuffer::new(1, 1), palette: None}
     }
 }
 
-pub fn load_image(path: PathBuf) -> Result<(slint::Image, TIMInfo), Error> {
+pub fn load_image(path: &PathBuf) -> Result<(slint::Image, TIMInfo), Error> {
-    Ok((slint::Image::load_from_path(&path).or_else(|_| {Err(Error::from_str("Failed loading image"))})?, TIMInfo{}))
+    fn make_color(iter: &mut dyn std::iter::Iterator<Item = &u8>) -> Option<Rgba8Pixel> { 
+        Some(Rgba8Pixel::new(
+            *iter.next()?, *iter.next()?, *iter.next()?, 
+            0xFF))
+    }
+
+    let mut reader = png::Decoder::new(File::open(path)?).read_info().or_else(|error| {Err(Error::from_error(error))})?;
+    let     info   = reader.info().clone();
+    
+    let mut buffer     = vec![0; reader.output_buffer_size()];
+    let     frame_info = reader.next_frame(&mut buffer).or_else(|error| {Err(Error::from_error(error))})?;
+    let     bit_depth  = frame_info.bit_depth;
+    let mut image_data = SharedPixelBuffer::new(frame_info.width, frame_info.height);
+
+    if info.color_type == png::ColorType::Indexed {
+        let palette = info.palette.ok_or(Error::from_str("Found indexed PNG without palette"))?;
+        let mut palette_colors = Vec::new();
+        let mut iter           = palette.iter();
+
+        while let Some(color) = make_color(&mut iter) {
+            palette_colors.push(color);
+        }
+
+        let mut dst_pixels  = image_data.make_mut_slice();
+        for byte in buffer.into_iter() {
+            match bit_depth {
+                png::BitDepth::Four  => {
+                    dst_pixels[0] = palette_colors[(byte >>  4) as usize];
+                    dst_pixels[1] = palette_colors[(byte & 0xF) as usize];
+                    dst_pixels    = &mut dst_pixels[2..];
+                },
+                png::BitDepth::Eight => {
+                    dst_pixels[0] = palette_colors[byte as usize];
+                    dst_pixels    = &mut dst_pixels[1..];
+                },
+                _                    => {return Err(Error::from_str("Only 4 and 8bit color depth are supported"));}
+            }
+        }
+
+        let image = slint::Image::from_rgba8_premultiplied(image_data.clone());
+        Ok((image, TIMInfo{image_data, palette: Some(palette_colors)}))
+    }
+
+    else {
+        Err(Error::not_implemented("Support for non indexed images"))
+    }
 }

src/Tools/tim_tool/src/main.rs

@@ -47,8 +47,8 @@ fn setup_file_tab(gui_elements_ref: Rc<RefCell<GUIElements>>, logic_ref: Rc<RefC
         }
 
         let file = FileDialog::new()
-            .add_filter("Images (.png; .bmp; .jpeg)", &["png", "bmp", "jpeg"])
+            .add_filter("PNG image (.png)", &["png"])
-            .set_title("Select image file")
+            .set_title("PNG image file")
             .pick_file();
 
         if let Some(file) = file {
@@ -59,7 +59,7 @@ fn setup_file_tab(gui_elements_ref: Rc<RefCell<GUIElements>>, logic_ref: Rc<RefC
             let file_tab  = &gui_elements.file_tab;
             let file_name = if let Some(name) = file.file_name() {Some(name.to_string_lossy().to_string())} else {None};
             
-            let (image, info) = match load_image(file) {
+            let (image, info) = match load_image(&file) {
                 Ok((image, info)) => (image, info),
                 Err(error)        => {
                     file_tab.clear_load();