From 63691f53b1dd021681bb392c362a176ecaa6fbdc Mon Sep 17 00:00:00 2001
From: Jonathan Berrisch <Jonathan@Berrisch.biz>
Date: Sun, 18 May 2025 01:13:04 +0200
Subject: [PATCH] Make it d3

---
 app.qmd | 166 +++++++++++++++++++++++++++++++++++++++++++++-----------
 1 file changed, 134 insertions(+), 32 deletions(-)

diff --git a/app.qmd b/app.qmd
index e4a8bee..9fe3004 100644
--- a/app.qmd
+++ b/app.qmd
@@ -10,13 +10,15 @@ execute:
 highlight-style: github
 ---
 
-#### B-spline Basis Functions
+## B-spline Basis Functions
 
 ```{ojs}
-bsplineData = FileAttachment("basis_functions.csv").csv({ typed: true })
+d3 = require("d3@7")
 ```
 
 ```{ojs}
+bsplineData = FileAttachment("basis_functions.csv").csv({ typed: true })
+
 knotValues = Array.from(new Set(bsplineData.map(d => d.knots))).sort((a, b) => a - b)
 minKnots = Math.min(...knotValues)
 maxKnots = Math.max(...knotValues)
@@ -24,9 +26,7 @@ maxKnots = Math.max(...knotValues)
 muValues = Array.from(new Set(bsplineData.map(d => d.mu))).sort((a, b) => a - b)
 minMu = Math.min(...muValues)
 maxMu = Math.max(...muValues)
-```
 
-```{ojs}
 // Create a more compact layout for controls
 viewof controls = Inputs.form({
   knots: Inputs.range([minKnots, maxKnots], {value: minKnots, step: 1, label: "Knots:", width: 200}),
@@ -39,39 +39,141 @@ viewof controls = Inputs.form({
 
 selectedKnots = controls.knots
 selectedMu = controls.mu
-```
 
-```{ojs}
 filteredBspline = bsplineData.filter(function(row) {
   return selectedKnots == row.knots && Math.abs(selectedMu - row.mu) < 0.001;
 })
 ```
 
 ```{ojs}
-Plot.plot({
-  grid: true,
-  y: {domain: [0, 0.7]},
-  x: {label: "x", domain: [0, 1]},
-  marks: [
-    Plot.line(filteredBspline, {
-      x: "x", 
-      y: "y", 
-      stroke: "b", 
-      strokeWidth: 5,
-    }),
-    Plot.ruleY([0])
-  ],
-  color: {
-    legend: false,
-    label: "Basis Function"
-  },
-  marginRight: 80,
-  width: 800,
-  height: 400,
-  // title: `B-spline Basis Functions (${selectedKnots} knots, μ = ${selectedMu})`
-})
+// D3-based visualization for B-spline basis functions
+chart = {
+  // Create chart dimensions
+  const width = 800;
+  const height = 400;
+  const margin = {top: 40, right: 20, bottom: 40, left: 40};
+  const innerWidth = width - margin.left - margin.right;
+  const innerHeight = height - margin.top - margin.bottom;
+  
+  // Create scales
+  const x = d3.scaleLinear()
+    .domain([0, 1])
+    .range([0, innerWidth]);
+    
+  const y = d3.scaleLinear()
+    .domain([0, 0.7])
+    .range([innerHeight, 0]);
+  
+  // Create a color scale for the basis functions
+  const color = d3.scaleOrdinal(d3.schemeCategory10);
+  
+  // Create SVG
+  const svg = d3.create("svg")
+    .attr("width", width)
+    .attr("height", height)
+    .attr("viewBox", [0, 0, width, height])
+    .attr("style", "max-width: 100%; height: auto;");
+  
+  // Add chart title
+  svg.append("text")
+    .attr("class", "chart-title")
+    .attr("x", width / 2)
+    .attr("y", 20)
+    .attr("text-anchor", "middle")
+    .attr("font-size", "16px")
+    .attr("font-weight", "bold");
+  
+  // Create the chart group
+  const g = svg.append("g")
+    .attr("transform", `translate(${margin.left},${margin.top})`);
+  
+  // Add axes
+  const xAxis = g.append("g")
+    .attr("transform", `translate(0,${innerHeight})`)
+    .call(d3.axisBottom(x).ticks(10));
+  
+  const yAxis = g.append("g")
+    .call(d3.axisLeft(y).ticks(5));
+  
+  // Add axis labels
+  g.append("text")
+    .attr("x", innerWidth / 2)
+    .attr("y", innerHeight + 35)
+    .attr("text-anchor", "middle")
+    .text("x");
+  
+  g.append("text")
+    .attr("transform", "rotate(-90)")
+    .attr("x", -innerHeight / 2)
+    .attr("y", -30)
+    .attr("text-anchor", "middle")
+    .text("y");
+  
+  // Add a horizontal line at y = 0
+  g.append("line")
+    .attr("x1", 0)
+    .attr("x2", innerWidth)
+    .attr("y1", y(0))
+    .attr("y2", y(0))
+    .attr("stroke", "#000")
+    .attr("stroke-opacity", 0.2);
+  
+  // Add gridlines
+  g.append("g")
+    .attr("class", "grid-lines")
+    .selectAll("line")
+    .data(y.ticks(5))
+    .join("line")
+    .attr("x1", 0)
+    .attr("x2", innerWidth)
+    .attr("y1", d => y(d))
+    .attr("y2", d => y(d))
+    .attr("stroke", "#ccc")
+    .attr("stroke-opacity", 0.5);
+  
+  // Create a line generator
+  const line = d3.line()
+    .x(d => x(d.x))
+    .y(d => y(d.y));
+  
+  // Group to contain the basis function lines
+  const linesGroup = g.append("g")
+    .attr("class", "basis-functions");
+  
+  // Function to update the chart with new data
+  function updateChart(data) {
+    // Group data by basis function
+    const groupedData = d3.group(data, d => d.b);
+    
+    // Update the chart title
+    svg.select(".chart-title")
+      .text(`B-spline Basis Functions (${selectedKnots} knots, μ = ${selectedMu})`);
+    
+    // Update or create paths
+    const paths = linesGroup.selectAll("path")
+      .data(Array.from(groupedData.values()));
+    
+    // Remove paths that are no longer needed
+    paths.exit().remove();
+    
+    // Add new paths
+    paths.enter()
+      .append("path")
+      .attr("fill", "none")
+      .attr("stroke-width", 3)
+      .attr("stroke", (_, i) => color(i))
+      .merge(paths) // Merge with existing paths for transition
+      .transition()
+      .duration(750)
+      .attr("d", line);
+  }
+  
+  // Store the update function
+  svg.node().update = updateChart;
+  
+  // Initial render
+  updateChart(filteredBspline);
+  
+  return svg.node();
+}
 ```
-
-::: {.callout-note}
-TODO
-:::