Implement HiDPI scaling

rust/crates/clean_flash_ui/src/lib.rs

@@ -5,6 +5,20 @@ pub mod widgets;
 pub use font::FontManager;
 pub use renderer::Renderer;
 
+/// Query the system DPI scale factor (1.0 = 100%, 1.5 = 150%, 2.0 = 200%).
+/// The process must already be DPI-aware (declared in the manifest) for this
+/// to return the true hardware DPI rather than the virtualised 96.
+pub fn get_dpi_scale() -> f32 {
+    #[cfg(target_os = "windows")]
+    unsafe {
+        use windows_sys::Win32::UI::HiDpi::GetDpiForSystem;
+        let dpi = GetDpiForSystem();
+        if dpi == 0 { 1.0 } else { dpi as f32 / 96.0 }
+    }
+    #[cfg(not(target_os = "windows"))]
+    { 1.0 }
+}
+
 /// Set the window icon from the icon resource already embedded in the binary
 /// by `winresource` (resource ID 1). No-op on non-Windows platforms.
 pub fn set_window_icon(window: &minifb::Window) {

rust/crates/clean_flash_ui/src/renderer.rs

@@ -109,6 +109,29 @@ impl Renderer {
         }
     }
 
+    /// Draw an RGBA image scaled to (w, h) at (x, y) using nearest-neighbor interpolation.
+    pub fn draw_image_scaled(&mut self, x: i32, y: i32, w: i32, h: i32, img: &RgbaImage) {
+        if w <= 0 || h <= 0 || img.width == 0 || img.height == 0 {
+            return;
+        }
+        for dy in 0..h {
+            for dx in 0..w {
+                let src_x = (dx as f32 * img.width as f32 / w as f32) as usize;
+                let src_y = (dy as f32 * img.height as f32 / h as f32) as usize;
+                let idx = (src_y * img.width + src_x) * 4;
+                let r = img.data[idx];
+                let g = img.data[idx + 1];
+                let b = img.data[idx + 2];
+                let a = img.data[idx + 3];
+                if a == 255 {
+                    self.set_pixel(x + dx, y + dy, Self::rgb(r, g, b));
+                } else if a > 0 {
+                    self.blend_pixel(x + dx, y + dy, Self::rgb(r, g, b), a);
+                }
+            }
+        }
+    }
+
     /// Draw an RGBA image onto the framebuffer at (x, y).
     pub fn draw_image(&mut self, x: i32, y: i32, img: &RgbaImage) {
         for iy in 0..img.height as i32 {

rust/crates/clean_flash_ui/src/widgets/button.rs

@@ -6,6 +6,7 @@ use crate::renderer::Renderer;
 pub struct GradientButton {
     pub rect: Rect,
     pub text: String,
+    pub font_size: f32,
     pub color1: u32,
     pub color2: u32,
     pub back_color: u32,
@@ -23,6 +24,7 @@ impl GradientButton {
         Self {
             rect: Rect::new(x, y, w, h),
             text: text.to_string(),
+            font_size: 13.0,
             color1: Renderer::rgb(118, 118, 118),
             color2: Renderer::rgb(81, 81, 81),
             back_color: Renderer::rgb(0, 0, 0),
@@ -77,7 +79,7 @@ impl GradientButton {
         renderer.draw_rect(r.x, r.y, r.w, r.h, bg);
 
         // Measure text to centre it.
-        let font_size = 13.0;
+        let font_size = self.font_size;
         let (tw, th) = fonts.measure_text(&self.text, font_size);
         let tx = r.x + ((r.w as f32 - tw) / 2.0) as i32;
         let ty = r.y + ((r.h as f32 - th) / 2.0) as i32;

rust/crates/clean_flash_ui/src/widgets/checkbox.rs

@@ -11,8 +11,12 @@ pub struct ImageCheckBox {
 
 impl ImageCheckBox {
     pub fn new(x: i32, y: i32) -> Self {
+        Self::with_size(x, y, 21)
+    }
+
+    pub fn with_size(x: i32, y: i32, size: i32) -> Self {
         Self {
-            rect: Rect::new(x, y, 21, 21),
+            rect: Rect::new(x, y, size, size),
             checked: true,
             enabled: true,
             visible: true,
@@ -43,7 +47,7 @@ impl ImageCheckBox {
             unchecked_img
         };
         if img.width > 0 && img.height > 0 {
-            renderer.draw_image(self.rect.x, self.rect.y, img);
+            renderer.draw_image_scaled(self.rect.x, self.rect.y, self.rect.w, self.rect.h, img);
         } else {
             // Fallback: draw a simple square.
             let bg = if self.checked {

rust/crates/clean_flash_ui/src/widgets/label.rs

@@ -8,6 +8,7 @@ pub struct Label {
     pub text: String,
     pub color: u32,
     pub font_size: f32,
+    pub line_spacing: f32,
     pub visible: bool,
 }
 
@@ -18,6 +19,7 @@ impl Label {
             text: text.to_string(),
             color: Renderer::rgb(245, 245, 245),
             font_size,
+            line_spacing: 2.0,
             visible: true,
         }
     }
@@ -33,7 +35,7 @@ impl Label {
             &self.text,
             self.font_size,
             self.color,
-            2.0,
+            self.line_spacing,
         );
     }