✨ (pagetop): Añade PageTopSvg::Tile y ajusta Image

tests/html_logo.rs

@@ -0,0 +1,53 @@
+use pagetop::prelude::*;
+
+// The background is made of `rect`s; only the logo paths use the line color.
+fn line_color(bg: (u8, u8, u8)) -> &'static str {
+    let svg = PageTopSvg::TileRGB(bg.0, bg.1, bg.2).markup().into_string();
+    let dark = svg.contains("<path fill=\"rgb(10,11,9)\"");
+    let white = svg.contains("<path fill=\"rgb(255,255,255)\"");
+    assert_ne!(dark, white, "the line must use exactly one color");
+    if dark { "dark" } else { "white" }
+}
+
+// **< PageTopSvg::TileRGB >************************************************************************
+
+#[pagetop::test]
+async fn tile_rgb_uses_a_white_line_on_dark_backgrounds() {
+    assert_eq!(line_color((0, 82, 204)), "white");
+    assert_eq!(line_color((0, 0, 0)), "white");
+    assert_eq!(line_color((220, 20, 60)), "white");
+}
+
+#[pagetop::test]
+async fn tile_rgb_uses_a_dark_line_on_light_backgrounds() {
+    assert_eq!(line_color((255, 184, 75)), "dark");
+    assert_eq!(line_color((0, 255, 0)), "dark");
+    assert_eq!(line_color((255, 255, 255)), "dark");
+}
+
+#[pagetop::test]
+async fn tile_rgb_switches_line_color_around_the_contrast_threshold() {
+    // Relative luminance ~0.181 and ~0.188 respectively; with the default dark and light lines the
+    // contrast with both is equal at ~0.186.
+    assert_eq!(line_color((118, 118, 118)), "white");
+    assert_eq!(line_color((120, 120, 120)), "dark");
+}
+
+#[pagetop::test]
+async fn tile_keeps_a_white_line_on_its_default_dark_background() {
+    let svg = PageTopSvg::Tile.markup().into_string();
+
+    assert!(svg.contains("<path fill=\"rgb(255,255,255)\""));
+}
+
+#[pagetop::test]
+async fn tile_keeps_a_square_bottom_right_corner() {
+    for svg in [
+        PageTopSvg::Tile.markup().into_string(),
+        PageTopSvg::TileRGB(0, 82, 204).markup().into_string(),
+    ] {
+        // Rounded background plus a square of the same color covering the bottom-right corner.
+        assert!(svg.contains("rx=\"200\""));
+        assert!(svg.contains("<rect x=\"1414\" y=\"1414\" width=\"200\" height=\"200\""));
+    }
+}