From 08af03380c9a8b634ec5d376c1631b84b464e427 Mon Sep 17 00:00:00 2001
From: Jean-Loup Beaussart <beaussartjl@gmail.com>
Date: Mon, 4 Nov 2024 00:24:20 +0100
Subject: [PATCH] Display test photo with automatic resize

---
 Cargo.toml          |  3 ++-
 examples/ferris.png |  3 ---
 examples/test.jpg   |  3 +++
 src/dimensions.rs   | 53 +++++++++++++++++++++++++++++++++++++++++
 src/main.rs         | 57 +++++++++++++++++++++++++++++++++++++++++----
 5 files changed, 111 insertions(+), 8 deletions(-)
 delete mode 100755 examples/ferris.png
 create mode 100755 examples/test.jpg
 create mode 100644 src/dimensions.rs

diff --git a/Cargo.toml b/Cargo.toml
index 83b4660..42fbb5a 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -4,4 +4,5 @@ version = "0.1.0"
 edition = "2021"
 
 [dependencies]
-macroquad = "0.4.13"
+image = "0.25.4"
+macroquad = { version = "0.4.13" }
diff --git a/examples/ferris.png b/examples/ferris.png
deleted file mode 100755
index 88e9d52..0000000
--- a/examples/ferris.png
+++ /dev/null
@@ -1,3 +0,0 @@
-version https://git-lfs.github.com/spec/v1
-oid sha256:bede91fb9164a251e4ecfba29935e954e102f88a156a98f6aa8640b536bfe035
-size 33061
diff --git a/examples/test.jpg b/examples/test.jpg
new file mode 100755
index 0000000..c3dcc00
--- /dev/null
+++ b/examples/test.jpg
@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:7854923d5985c6199dfa033793598d228b91c12acb54b957922bb6f5bf76f413
+size 1861675
diff --git a/src/dimensions.rs b/src/dimensions.rs
new file mode 100644
index 0000000..332ae78
--- /dev/null
+++ b/src/dimensions.rs
@@ -0,0 +1,53 @@
+#[derive(Debug, Clone, Copy)]
+pub struct Dimensions {
+    pub width: u32,
+    pub height: u32,
+}
+
+impl Dimensions {
+    pub fn new(width: u32, height: u32) -> Self {
+        Self { width, height }
+    }
+
+    pub fn aspect_ratio(&self) -> f32 {
+        self.width as f32 / self.height as f32
+    }
+}
+
+/// Calculates the dimensions to resize an image to fill the screen while preserving aspect ratio.
+/// The image will be scaled to fit the screen without cropping.
+///
+/// # Arguments
+///
+/// * `screen` - The dimensions of the screen
+/// * `image` - The original dimensions of the image
+///
+/// # Returns
+///
+/// * `Dimensions` - The new dimensions that will fit the screen
+///
+/// # Example
+///
+/// ```rust
+/// let screen = Dimensions::new(1920, 1080);
+/// let image = Dimensions::new(3000, 2000);
+/// let new_size = calculate_resize_dimensions(screen, image);
+/// ```
+pub fn calculate_resize_dimensions(screen: Dimensions, image: Dimensions) -> Dimensions {
+    let screen_ratio = screen.aspect_ratio();
+    let image_ratio = image.aspect_ratio();
+
+    if image_ratio > screen_ratio {
+        // Image is wider relative to its height than the screen
+        // Scale based on width
+        let new_width = screen.width;
+        let new_height = (screen.width as f32 / image_ratio).round() as u32;
+        Dimensions::new(new_width, new_height)
+    } else {
+        // Image is taller relative to its width than the screen
+        // Scale based on height
+        let new_height = screen.height;
+        let new_width = (screen.height as f32 * image_ratio).round() as u32;
+        Dimensions::new(new_width, new_height)
+    }
+}
diff --git a/src/main.rs b/src/main.rs
index e1a8292..bdc686b 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -1,12 +1,61 @@
+use dimensions::{calculate_resize_dimensions, Dimensions};
+use image::ImageReader;
 use macroquad::prelude::*;
 
-#[macroquad::main("Texture")]
+mod dimensions;
+
+fn window_conf() -> Conf {
+    Conf {
+        window_title: String::from("Photo"),
+        window_width: 2560,
+        window_height: 1440,
+        fullscreen: true,
+        ..Default::default()
+    }
+}
+
+fn display_image(texture: &Texture2D) {
+    let screen_width = screen_width();
+    let screen_height = screen_height();
+    draw_texture(
+        &texture,
+        clamp(screen_width - texture.width(), 0.0f32, screen_width) / 2.0f32,
+        clamp(screen_height - texture.height(), 0.0f32, screen_height) / 2.0f32,
+        WHITE,
+    );
+}
+
+#[macroquad::main(window_conf)]
 async fn main() {
-    let texture: Texture2D = load_texture("examples/ferris.png").await.unwrap();
+    show_mouse(false);
+    let image = ImageReader::open("examples/test.jpg")
+        .unwrap()
+        .decode()
+        .unwrap();
+
+    let screen_dim = Dimensions::new(screen_width() as u32, screen_height() as u32);
+    let image_dim = Dimensions::new(image.width(), image.height());
+
+    let new_dim = calculate_resize_dimensions(screen_dim, image_dim);
+    let image = image.resize(
+        new_dim.width,
+        new_dim.height,
+        image::imageops::FilterType::Lanczos3,
+    );
+
+    let texture = Texture2D::from_rgba8(
+        image.width().try_into().unwrap(),
+        image.height().try_into().unwrap(),
+        &image.into_rgba8().to_vec(),
+    );
 
     loop {
-        clear_background(LIGHTGRAY);
-        draw_texture(&texture, 0., 0., WHITE);
+        clear_background(BLACK);
+        if is_quit_requested() || is_key_released(KeyCode::Escape) {
+            break;
+        }
+
+        display_image(&texture);
         next_frame().await
     }
 }