added specific resolution output for rasterized image formats

src/exporter.rs

@@ -2,7 +2,7 @@ use std::collections::HashSet;
 use std::fmt::Write as _;
 use std::path::PathBuf;
 
-use image::{DynamicImage, ImageFormat, RgbaImage};
+use image::{DynamicImage, ImageFormat, RgbaImage, imageops::FilterType};
 use rfd::FileDialog;
 use tiny_skia::{FillRule, Paint, PathBuilder, Pixmap, Rect, Stroke, StrokeDash, Transform};
 
@@ -105,9 +105,7 @@ pub fn export_with_dialog(
         }
         ExportFormat::Png | ExportFormat::Jpeg | ExportFormat::Webp => {
             let pixmap = render_pixmap(layout, settings)?;
-            let rgba = RgbaImage::from_raw(pixmap.width(), pixmap.height(), pixmap.data().to_vec())
-                .ok_or_else(|| "Failed to build image buffer".to_string())?;
-            let img = DynamicImage::ImageRgba8(rgba);
+            let img = raster_image_from_pixmap(&pixmap, settings)?;
             let format = match settings.export_format {
                 ExportFormat::Png => ImageFormat::Png,
                 ExportFormat::Jpeg => ImageFormat::Jpeg,
@@ -216,6 +214,44 @@ fn render_pixmap(layout: &DungeonLayout, settings: &UiSettings) -> Result<Pixmap
     Ok(pixmap)
 }
 
+fn raster_image_from_pixmap(
+    pixmap: &Pixmap,
+    settings: &UiSettings,
+) -> Result<DynamicImage, String> {
+    let rgba = RgbaImage::from_raw(pixmap.width(), pixmap.height(), pixmap.data().to_vec())
+        .ok_or_else(|| "Failed to build image buffer".to_string())?;
+    let mut img = DynamicImage::ImageRgba8(rgba);
+
+    let target = raster_target_size(settings);
+    if img.width() != target.0 || img.height() != target.1 {
+        img = img.resize_exact(target.0, target.1, FilterType::Lanczos3);
+    }
+
+    Ok(img)
+}
+
+fn raster_target_size(settings: &UiSettings) -> (u32, u32) {
+    let mut width = settings.export_width.clamp(1, 10_000);
+    let mut height = settings.export_height.clamp(1, 10_000);
+
+    if !settings.allow_export_aspect_change {
+        let cols = settings.cols.max(1) as f32;
+        let rows = settings.rows.max(1) as f32;
+        let ratio = cols / rows;
+        height = ((width as f32) / ratio).round() as u32;
+        height = height.clamp(1, 10_000);
+    }
+
+    if width == 0 {
+        width = 1;
+    }
+    if height == 0 {
+        height = 1;
+    }
+
+    (width, height)
+}
+
 fn build_svg(layout: &DungeonLayout, settings: &UiSettings) -> String {
     let g = ExportGeometry::new(settings.cols, settings.rows);
     let wall_w = (g.cell / 5.0).max(1.0);

src/ui.rs

@@ -47,6 +47,10 @@ impl ExportFormat {
             ExportFormat::Svg => ".svg",
         }
     }
+
+    pub fn is_raster(self) -> bool {
+        !matches!(self, ExportFormat::Svg)
+    }
 }
 
 #[derive(Debug, Clone, Serialize, Deserialize)]
@@ -67,6 +71,9 @@ pub struct UiSettings {
     pub allow_middle_corridor_doors: bool,
     pub colorblind_mode: bool,
     pub export_format: ExportFormat,
+    pub export_width: u32,
+    pub export_height: u32,
+    pub allow_export_aspect_change: bool,
     active_tab: Tab,
 }
 
@@ -88,6 +95,9 @@ impl Default for UiSettings {
             allow_middle_corridor_doors: false,
             colorblind_mode: false,
             export_format: ExportFormat::Png,
+            export_width: 1920,
+            export_height: 1080,
+            allow_export_aspect_change: false,
             active_tab: Tab::Generate,
         }
     }
@@ -204,6 +214,63 @@ fn draw_generate_tab(ui: &mut egui::Ui, settings: &mut UiSettings, result: &mut
             });
     });
 
+    if settings.export_format.is_raster() {
+        ui.add_space(8.0);
+        ui.checkbox(
+            &mut settings.allow_export_aspect_change,
+            "Allow aspect ratio change",
+        );
+
+        let mut width_changed = false;
+        let mut height_changed = false;
+
+        ui.add_space(6.0);
+        ui.label("Resolution Width");
+        ui.horizontal(|ui| {
+            width_changed |= ui
+                .add(egui::Slider::new(&mut settings.export_width, 1..=10_000).show_value(false))
+                .changed();
+            width_changed |= ui
+                .add(
+                    egui::DragValue::new(&mut settings.export_width)
+                        .speed(1.0)
+                        .range(1..=10_000),
+                )
+                .changed();
+        });
+
+        ui.add_space(6.0);
+        ui.label("Resolution Height");
+        ui.horizontal(|ui| {
+            height_changed |= ui
+                .add(
+                    egui::Slider::new(&mut settings.export_height, 1..=10_000).show_value(false),
+                )
+                .changed();
+            height_changed |= ui
+                .add(
+                    egui::DragValue::new(&mut settings.export_height)
+                        .speed(1.0)
+                        .range(1..=10_000),
+                )
+                .changed();
+        });
+
+        if !settings.allow_export_aspect_change {
+            let cols = settings.cols.max(1) as f32;
+            let rows = settings.rows.max(1) as f32;
+            let ratio = cols / rows;
+
+            if width_changed {
+                let h = ((settings.export_width as f32) / ratio).round() as u32;
+                settings.export_height = h.clamp(1, 10_000);
+            } else if height_changed {
+                let w = ((settings.export_height as f32) * ratio).round() as u32;
+                settings.export_width = w.clamp(1, 10_000);
+            }
+        }
+    }
+
     ui.add_space(6.0);
     if ui.button("Export Image").clicked() {
         result.export_clicked = true;