Only clamp to source projection extent

rendering/cases/reproj-azimuthal-equal-area/main.js

@@ -0,0 +1,57 @@
+import ImageCanvas from '../../../src/ol/source/ImageCanvas.js';
+import ImageLayer from '../../../src/ol/layer/Image.js';
+import Map from '../../../src/ol/Map.js';
+import View from '../../../src/ol/View.js';
+import proj4 from 'proj4';
+import {get as getProjection, transform} from '../../../src/ol/proj.js';
+import {register} from '../../../src/ol/proj/proj4.js';
+
+const llpos = [-72, 40];
+
+proj4.defs(
+  'az',
+  '+proj=aeqd +lat_0=' +
+    llpos[1] +
+    ' +lon_0=' +
+    llpos[0] +
+    ' +x_0=0 +y_0=0 +a=6371000 +b=6371000 +units=m'
+);
+register(proj4);
+const aeqd = getProjection('az');
+
+function canvasFunction(extent, resolution, pixelRatio, size) {
+  size = [Math.round(size[0]), Math.round(size[1])];
+  const canvas = document.createElement('canvas');
+  canvas.width = size[0];
+  canvas.height = size[1];
+
+  // fill the canvas with blue
+  const ctx = canvas.getContext('2d');
+  ctx.fillStyle = 'blue';
+  ctx.fillRect(0, 0, canvas.width, canvas.height);
+  return canvas;
+}
+
+const canvasLayer = new ImageLayer({
+  source: new ImageCanvas({
+    projection: 'EPSG:4326',
+    canvasFunction: canvasFunction,
+  }),
+});
+
+const center = transform(llpos, 'EPSG:4326', aeqd);
+
+new Map({
+  pixelRatio: 1,
+  target: 'map',
+  layers: [canvasLayer],
+  view: new View({
+    center: center,
+    projection: aeqd,
+    zoom: 0,
+  }),
+});
+
+render({
+  tolerance: 0.001,
+});

src/ol/proj.js

@@ -71,14 +71,7 @@ import {
   clear as clearTransformFuncs,
   get as getTransformFunc,
 } from './proj/transforms.js';
-import {
-  applyTransform,
-  getBottomLeft,
-  getBottomRight,
-  getTopLeft,
-  getTopRight,
-  getWidth,
-} from './extent.js';
+import {applyTransform, getWidth} from './extent.js';
 import {clamp, modulo} from './math.js';
 import {getDistance} from './sphere.js';
 import {getWorldsAway} from './coordinate.js';
@@ -636,56 +629,35 @@ export function fromUserExtent(extent, destProjection) {
 /**
  * Creates a safe coordinate transform function from a coordinate transform function.
  * "Safe" means that it can handle wrapping of x-coordinates for global projections,
- * and that coordinates exceeding the projection validity extent's range will be
+ * and that coordinates exceeding the source projection validity extent's range will be
  * clamped to the validity range.
  * @param {Projection} sourceProj Source projection.
  * @param {Projection} destProj Destination projection.
- * @param {function(import("./coordinate.js").Coordinate): import("./coordinate.js").Coordinate} forward Transform function (source to destiation).
- * @param {function(import("./coordinate.js").Coordinate): import("./coordinate.js").Coordinate} inverse Transform function (destiation to source).
+ * @param {function(import("./coordinate.js").Coordinate): import("./coordinate.js").Coordinate} transform Transform function (source to destiation).
  * @return {function(import("./coordinate.js").Coordinate): import("./coordinate.js").Coordinate} Safe transform function (source to destiation).
  */
-export function createSafeCoordinateTransform(
-  sourceProj,
-  destProj,
-  forward,
-  inverse
-) {
+export function createSafeCoordinateTransform(sourceProj, destProj, transform) {
   return function (coord) {
-    let x, y, worldsAway;
+    let sourceX = coord[0];
+    let sourceY = coord[1];
+    let transformed, worldsAway;
     if (sourceProj.canWrapX()) {
       const sourceExtent = sourceProj.getExtent();
       const sourceExtentWidth = getWidth(sourceExtent);
       worldsAway = getWorldsAway(coord, sourceProj, sourceExtentWidth);
       if (worldsAway) {
         // Move x to the real world
-        x = coord[0] - worldsAway * sourceExtentWidth;
-      }
-    }
-    let transformed = forward(x === undefined ? coord : [x, coord[1]]);
-    const destExtent = destProj.getExtent();
-    if (!isFinite(transformed[0]) || !isFinite(transformed[1])) {
-      // Try to recover from out-of-bounds transform
-      if (destExtent) {
-        const corner1 = inverse(getBottomLeft(destExtent));
-        const corner2 = inverse(getBottomRight(destExtent));
-        const corner3 = inverse(getTopLeft(destExtent));
-        const corner4 = inverse(getTopRight(destExtent));
-        const minX = Math.min(corner1[0], corner2[0], corner3[0], corner4[0]);
-        const maxX = Math.max(corner1[0], corner2[0], corner3[0], corner4[0]);
-        const minY = Math.min(corner1[1], corner2[1], corner3[1], corner4[1]);
-        const maxY = Math.max(corner1[1], corner2[1], corner3[1], corner4[1]);
-        if (isFinite(minX) && isFinite(maxX)) {
-          x = clamp(x == undefined ? coord[1] : x, minX, maxX);
-        }
-        if (isFinite(minY) && isFinite(maxY)) {
-          y = clamp(coord[1], minY, maxY);
-        }
-        transformed = forward([x, y]);
+        sourceX = sourceX - worldsAway * sourceExtentWidth;
       }
+      sourceX = clamp(sourceX, sourceExtent[0], sourceExtent[2]);
+      sourceY = clamp(sourceY, sourceExtent[1], sourceExtent[3]);
+      transformed = transform([sourceX, sourceY]);
+    } else {
+      transformed = transform(coord);
     }
     if (worldsAway && destProj.canWrapX()) {
       // Move transformed coordinate back to the offset world
-      transformed[0] += worldsAway * getWidth(destExtent);
+      transformed[0] += worldsAway * getWidth(destProj.getExtent());
     }
     return transformed;
   };

src/ol/proj/proj4.js

@@ -61,18 +61,8 @@ export function register(proj4) {
           addCoordinateTransforms(
             proj1,
             proj2,
-            createSafeCoordinateTransform(
-              proj1,
-              proj2,
-              transform.forward,
-              transform.inverse
-            ),
-            createSafeCoordinateTransform(
-              proj2,
-              proj1,
-              transform.inverse,
-              transform.forward
-            )
+            createSafeCoordinateTransform(proj1, proj2, transform.forward),
+            createSafeCoordinateTransform(proj2, proj1, transform.inverse)
           );
         }
       }

test/spec/ol/proj.test.js

@@ -571,13 +571,18 @@ describe('ol.proj', function () {
       const epsg3857 = getProjection('EPSG:3857');
       google.setExtent(epsg3857.getExtent());
       google.setGlobal(true);
-      const coord = [-190, 90];
-      const transformed = transform(coord, wgs84, google);
-      expect(transformed).to.eql(transform(coord, epsg4326, epsg3857));
-      const got = transform(transformed, google, wgs84);
-      const expected = transform(transformed, epsg3857, epsg4326);
-      expect(got[0]).to.roughlyEqual(expected[0], 1e-9);
-      expect(got[1]).to.roughlyEqual(expected[1], 1e-9);
+
+      const coord = [-190, 85];
+
+      let expected = transform(coord, wgs84, google);
+      let got = transform(coord, epsg4326, epsg3857);
+      expect(got[0]).to.roughlyEqual(expected[0], 1e-7);
+      expect(got[1]).to.roughlyEqual(expected[1], 1e-7);
+
+      expected = transform(expected, google, wgs84);
+      got = transform(got, epsg3857, epsg4326);
+      expect(got[0]).to.roughlyEqual(expected[0], 1e-7);
+      expect(got[1]).to.roughlyEqual(expected[1], 1e-7);
     });
   });