From 6fddbae15736551e4f11d329dc7e7e1b901f5da2 Mon Sep 17 00:00:00 2001
From: acalcutt <acalcutt@techidiots.net>
Date: Thu, 2 Jan 2025 18:17:19 -0500
Subject: [PATCH] merge elevation changes

---
 src/serve_data.js | 146 ++++++++++++++++++++++++++++++++++++++++++++++
 src/server.js     |   2 +-
 2 files changed, 147 insertions(+), 1 deletion(-)

diff --git a/src/serve_data.js b/src/serve_data.js
index 84b9234..ff896d0 100644
--- a/src/serve_data.js
+++ b/src/serve_data.js
@@ -123,6 +123,152 @@ export const serve_data = {
       return res.status(200).send(data);
     });
 
+    app.get('/:id/elevation/:z/:x/:y',
+      async (req, res, next) => {
+        try {
+          const item = repo?.[req.params.id];
+          if (!item) return res.sendStatus(404);
+          if (!item.source) return res.status(404).send('Missing source');
+          if (!item.tileJSON) return res.status(404).send('Missing tileJSON');
+          if (!item.sourceType)
+            return res.status(404).send('Missing sourceType');
+          const { source, tileJSON, sourceType } = item;
+          if (sourceType !== 'pmtiles' && sourceType !== 'mbtiles') {
+            return res
+              .status(400)
+              .send('Invalid sourceType. Must be pmtiles or mbtiles.');
+          }
+          const encoding = tileJSON?.encoding;
+          if (encoding == null) {
+            return res.status(400).send('Missing tileJSON.encoding');
+          } else if (encoding !== 'terrarium' && encoding !== 'mapbox') {
+            return res
+              .status(400)
+              .send('Invalid encoding. Must be terrarium or mapbox.');
+          }
+          const format = tileJSON?.format;
+          if (format == null) {
+            return res.status(400).send('Missing tileJSON.format');
+          } else if (format !== 'webp' && format !== 'png') {
+            return res.status(400).send('Invalid format. Must be webp or png.');
+          }
+          const z = parseInt(req.params.z, 10);
+          const x = parseFloat(req.params.x);
+          const y = parseFloat(req.params.y);
+          if (tileJSON.minzoom == null || tileJSON.maxzoom == null) {
+            return res.status(404).send(JSON.stringify(tileJSON));
+          }
+          const TILE_SIZE = 256;
+          let tileCenter;
+          let xy;
+          if (Number.isInteger(x) && Number.isInteger(y)) {
+            const intX = parseInt(req.params.x, 10);
+            const intY = parseInt(req.params.y, 10);
+            if (
+              z < tileJSON.minzoom ||
+              z > tileJSON.maxzoom ||
+              intX < 0 ||
+              intY < 0 ||
+              intX >= Math.pow(2, z) ||
+              intY >= Math.pow(2, z)
+            ) {
+              return res.status(404).send('Out of bounds');
+            }
+            xy = [intX, intY];
+            tileCenter = new SphericalMercator().bbox(intX, intY, z);
+          } else {
+            if (
+              z < tileJSON.minzoom ||
+              z > tileJSON.maxzoom ||
+              x < -180 ||
+              y < -90 ||
+              x > 180 ||
+              y > 90
+            ) {
+              return res.status(404).send('Out of bounds');
+            }
+            tileCenter = [y, x, y + 0.1, x + 0.1];
+            const { minX, minY } = new SphericalMercator().xyz(tileCenter, z);
+            xy = [minX, minY];
+          }
+		  const fetchTile = await fetchTileData(
+			source,
+			sourceType,
+			z,
+			x,
+			y,
+		  );
+		  if (fetchTile == null) return res.status(204).send();
+
+		  let data = fetchTile.data;
+          const image = new Image();
+          await new Promise(async (resolve, reject) => {
+            image.onload = async () => {
+              const canvas = createCanvas(TILE_SIZE, TILE_SIZE);
+              const context = canvas.getContext('2d');
+              context.drawImage(image, 0, 0);
+              const imgdata = context.getImageData(0, 0, TILE_SIZE, TILE_SIZE);
+              const arrayWidth = imgdata.width;
+              const arrayHeight = imgdata.height;
+              const bytesPerPixel = 4;
+              const xPixel = Math.floor(xy[0]);
+              const yPixel = Math.floor(xy[1]);
+              if (
+                xPixel < 0 ||
+                yPixel < 0 ||
+                xPixel >= arrayWidth ||
+                yPixel >= arrayHeight
+              ) {
+                return reject('Out of bounds Pixel');
+              }
+              const index = (yPixel * arrayWidth + xPixel) * bytesPerPixel;
+              const red = imgdata.data[index];
+              const green = imgdata.data[index + 1];
+              const blue = imgdata.data[index + 2];
+              let elevation;
+              if (encoding === 'mapbox') {
+                elevation =
+                  -10000 + (red * 256 * 256 + green * 256 + blue) * 0.1;
+              } else if (encoding === 'terrarium') {
+                elevation = red * 256 + green + blue / 256 - 32768;
+              } else {
+                elevation = 'invalid encoding';
+              }
+              resolve(
+                res.status(200).send({
+                  z,
+                  x: xy[0],
+                  y: xy[1],
+                  red,
+                  green,
+                  blue,
+                  latitude: tileCenter[0],
+                  longitude: tileCenter[1],
+                  elevation,
+                }),
+              );
+            };
+            image.onerror = (err) => reject(err);
+            if (format === 'webp') {
+              try {
+                const img = await sharp(data).toFormat('png').toBuffer();
+                image.src = img;
+              } catch (err) {
+                reject(err);
+              }
+            } else {
+              image.src = data;
+            }
+          });
+        } catch (err) {
+          return res
+            .status(500)
+            .header('Content-Type', 'text/plain')
+            .send(err.message);
+        }
+      },
+    );
+
     app.get('/:id.json', (req, res) => {
       const item = repo[req.params.id];
       if (!item) {
diff --git a/src/server.js b/src/server.js
index df1134f..beee4b3 100644
--- a/src/server.js
+++ b/src/server.js
@@ -621,7 +621,7 @@ async function start(opts) {
     };
   });
 
-  serveTemplate('^/data{/:view}/:id/', 'data', (req) => {
+  serveTemplate('/data{/:view}/:id/', 'data', (req) => {
     const { id, view } = req.params;
     const data = serving.data[id];