From 18639412c260c2af1d4268cb3a3209e208276005 Mon Sep 17 00:00:00 2001
From: triethyl <triethylammonium@pm.me>
Date: Sun, 15 Feb 2026 23:37:22 -0500
Subject: changed background

---
 site/themes/sine/static/js/oldish-background.js | 90 +++++++++++++++++++++++++
 1 file changed, 90 insertions(+)
 create mode 100644 site/themes/sine/static/js/oldish-background.js

(limited to 'site/themes/sine/static/js/oldish-background.js')

diff --git a/site/themes/sine/static/js/oldish-background.js b/site/themes/sine/static/js/oldish-background.js
new file mode 100644
index 0000000..3a55a0f
--- /dev/null
+++ b/site/themes/sine/static/js/oldish-background.js
@@ -0,0 +1,90 @@
+document.addEventListener("DOMContentLoaded", () => {
+  const canvas = document.getElementById("background");
+
+  if (canvas.getContext) {
+    const ctx = canvas.getContext("2d");
+
+    // Source - https://stackoverflow.com/a/58673385
+    // Posted by Sanxofon, modified by community. See post 'Timeline' for change history
+    // Retrieved 2026-02-15, License - CC BY-SA 4.0
+    
+    var w = canvas.width; // Canvas width => Frequency is relative to this
+    var h = canvas.height/2; // Canvas height over two => Amplitude: Volume
+    var f=1; // How many cycles per canvas width => Frequency: Tone & Speed
+    // Calculates y position from x
+    function calcSineY(x) {
+      // This is the meat (unles you are vegan)
+      // Note that:
+      // h is the amplitude of the wave
+      // x is the current x value we get every time interval
+      // 2 * PI is the length of one cycle (full circumference)
+      // f/w is the frequency fraction
+      return h - h * Math.sin( x * 2 * Math.PI * (f/w) );
+    }
+    function drawSine(x){
+      ctx.clearRect(0, 0, w, h*2);
+      //draw x axis
+      ctx.beginPath(); // Draw a new path
+      ctx.strokeStyle = "green"; // Pick a color
+      ctx.moveTo(0,h); // Where to start drawing
+      ctx.lineTo(w,h); // Where to draw to
+      ctx.stroke(); // Draw
+      
+      // // draw horizontal line of current amplitude
+      // ctx.beginPath(); // Draw a new path
+      // ctx.moveTo(0,h); // Where to start drawing
+      // ctx.strokeStyle = "gray"; // Pick a color
+      // for(var i=0;i<x;i++){ // Loop from left side to current x
+      //   var y = calcSineY(x); // Calculate y value from x
+      //   ctx.moveTo(i,y); // Where to start drawing
+      //   ctx.lineTo(x,y); // Where to draw to
+      // }
+      // ctx.stroke(); // Draw
+      //
+      // // draw amplitude bar at current point
+      // ctx.beginPath(); // Draw a new path
+      // ctx.strokeStyle = "red"; // Pick a color
+      // for(var i=0;i<x;i++){ // Loop from left side to current x
+      //   var y = calcSineY(x); // Calculate y value from x
+      //   ctx.moveTo(x,h); // Where to start drawing
+      //   ctx.lineTo(x,y); // Where to draw to
+      // }
+      // ctx.stroke(); // Draw
+      //
+      // // draw area below y
+      // ctx.beginPath(); // Draw a new path
+      // ctx.strokeStyle = "orange"; // Pick a color
+      // for(var i=0;i<x;i++){ // Loop from left side to current x
+      //   if(i/3==Math.round(i/3)) { // Draw only one line each 3 pixels
+      //     var y = calcSineY(i); // Calculate y value from x
+      //     ctx.moveTo(i,h); // Where to start drawing
+      //     ctx.lineTo(i,y); // Where to draw to
+      //   }
+      // }
+      // ctx.stroke(); // Draw
+      
+      // draw sin curve point to point until x
+      ctx.beginPath(); // Draw a new path
+      ctx.strokeStyle = "black"; // Pick a color
+      for(var i=0;i<x;i++){ // Loop from left side to current x
+        var y = calcSineY(i); // Calculate y value from x
+        ctx.lineTo(i,y); // Where to draw to
+      }
+      ctx.stroke(); // Draw
+    }
+    // Define initial value of x positiom (leftmost side of cnanvas)
+    var x=0;
+    // Start time interval
+    var interval = setInterval(function(){
+      drawSine(x); // Call draww function every cycle
+      x++; // Increment x by 1
+      // if(x>w){
+      //     x=0; // x cannot be more than canvas with, so back to 0
+      //       f++; // increment frequency for demonstration
+      //   }
+    },10); // Loop every 10 milliseconds
+
+  } else {
+
+  }
+});
-- 
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