Add alignment option

assets/default_config.toml

@@ -6,6 +6,9 @@ prompt = ''
 # space between window border and the content in pixel
 padding = 100
 
+# horizontal alignment of text content: "left" or "center"
+alignment = "left"
+
 fonts = [
     'Noto Sans Mono',
 ] # list of otf or ttf fonts. later elements work as fallback

src/app.rs

@@ -173,19 +173,42 @@
             Some(prompt) => prompt,
             None => &self.config.prompt,
         };
+
+        // Calculate horizontal and vertical offsets based on alignment mode
+        let (base_x_offset, vertical_padding) = if self.config.alignment == "center" {
+            // For center alignment: 
+            // - Use padding only for vertical spacing (top margin)
+            // - Calculate horizontal offset to center the text block
+            let estimated_text_width = width / 3; // Rough estimate for text block width
+            let horizontal_offset = if width > estimated_text_width {
+                (width - estimated_text_width) / 2
+            } else {
+                width / 4 // Fallback to quarter screen width
+            };
+            (horizontal_offset, padding)
+        } else {
+            // Default to left alignment: use padding for both horizontal and vertical spacing
+            (padding, padding)
+        };
+
         let prompt_width = if prompt.is_empty() {
             0
         } else {
-            let (width, _) = self.font.render(
+            let (pwidth, _) = self.font.measure_text(prompt);
+            pwidth + (font_size * 0.2) as u32
+        };
+
+        // Now render at the consistent position
+        if !prompt.is_empty() {
+            self.font.render(
                 prompt,
                 &self.config.colors.prompt,
                 &mut img,
-                padding,
-                padding,
+                base_x_offset,
+                vertical_padding,
                 None,
             );
-            width + (font_size * 0.2) as u32
-        };
+        }
 
         if !self.query.is_empty() {
             let color = if self.select_input {
@@ -197,16 +220,16 @@
                 &self.query,
                 color,
                 &mut img,
-                padding + prompt_width,
-                padding,
+                base_x_offset + prompt_width,
+                vertical_padding,
                 None,
             );
         }
 
         let spacer = (1.5 * font_size) as u32;
-        let max_entries = ((height.saturating_sub(2 * padding).saturating_sub(spacer)) as f32
+        let max_entries = ((height.saturating_sub(2 * vertical_padding).saturating_sub(spacer)) as f32
             / (font_size * 1.2)) as usize;
         let offset = if self.select_index > (max_entries / 2) {
             self.select_index - max_entries / 2
         } else {
             0
@@ -223,18 +246,20 @@
             } else {
                 &self.config.colors.text
             };
+
+            // Use the same base_x_offset for all search results to keep them aligned
             self.font.render(
                 &matched.name,
                 color,
                 &mut img,
-                padding,
-                padding + spacer + (i - offset) as u32 * (font_size * 1.2) as u32,
-                Some((width - (padding * 2)) as usize),
+                base_x_offset,
+                vertical_padding + spacer + (i - offset) as u32 * (font_size * 1.2) as u32,
+                Some((width - (base_x_offset * 2)) as usize),
             );
         }
 
         let elapsed = frame_draw_start.elapsed();
         debug!("frame time: {:.2?}", elapsed);
 
         img
     }

src/config.rs

@@ -51,6 +51,7 @@ pub struct SearchConfig {
 pub struct Config {
     pub prompt: String,
     pub padding: u32,
+    pub alignment: String,
     pub font: Option<String>,
     pub fonts: Vec<String>,
     pub font_size: f32,
@@ -135,6 +136,7 @@ impl Default for Config {
         Self {
             prompt: String::new(),
             padding: 100,
+            alignment: "left".to_string(),
             font: None,
             fonts: vec![],
             font_size: 32.,

src/font.rs

@@ -97,6 +97,32 @@ impl Font {
         res
     }
 
+    pub fn measure_text(&self, text: &str) -> (u32, u32) {
+        let mut width = 0;
+        let mut layout = self.layout.borrow_mut();
+        layout.reset(&LayoutSettings::default());
+
+        for c in Self::replace_tabs(text, self.tab_width).chars() {
+            let mut font_index = 0;
+            for (i, font) in self.fonts.iter().enumerate() {
+                if font.lookup_glyph_index(c) != 0 {
+                    font_index = i;
+                    break;
+                }
+            }
+            layout.append(
+                &self.fonts,
+                &TextStyle::new(&c.to_string(), self.size * self.scale as f32, font_index),
+            );
+        }
+
+        if let Some(glyph) = layout.glyphs().last() {
+            width = glyph.x as usize + glyph.width;
+        }
+
+        (width as u32, layout.height() as u32)
+    }
+
     pub fn render(
         &self,
         text: &str,