From 591e5ce01bbf9ccffe9e4d749584abcc1f77c5f3 Mon Sep 17 00:00:00 2001
From: mike-000 <49240900+mike-000@users.noreply.github.com>
Date: Wed, 26 Feb 2020 22:17:49 +0000
Subject: [PATCH] More validation. Handle voids in some projections.

Handle NaN latitude transform results at void centers of some projections (e.g. Pole LAEA).
Clamp latitudes to not go beyond the poles when calculating intervals.
Further improve polar projections by checking if extent contains max and min intersection coordinates when calculating max and min.
---
 src/ol/layer/Graticule.js | 66 ++++++++++++++++++++++++++++++++++++---
 1 file changed, 61 insertions(+), 5 deletions(-)

diff --git a/src/ol/layer/Graticule.js b/src/ol/layer/Graticule.js
index 42b5c380fa..e7e61a7aba 100644
--- a/src/ol/layer/Graticule.js
+++ b/src/ol/layer/Graticule.js
@@ -16,6 +16,7 @@ import {
 } from '../proj.js';
 import {
   applyTransform,
+  containsCoordinate,
   equals,
   getCenter,
   getHeight,
@@ -285,6 +286,30 @@ class Graticule extends VectorLayer {
      */
     this.projectionCenterLonLat_ = null;
 
+    /**
+     * @type {import("../coordinate.js").Coordinate}
+     * @private
+     */
+    this.blLonLatP_ = null;
+
+    /**
+     * @type {import("../coordinate.js").Coordinate}
+     * @private
+     */
+    this.brLonLatP_ = null;
+
+    /**
+     * @type {import("../coordinate.js").Coordinate}
+     * @private
+     */
+    this.tlLonLatP_ = null;
+
+    /**
+     * @type {import("../coordinate.js").Coordinate}
+     * @private
+     */
+    this.trLonLatP_ = null;
+
     /**
      * @type {Array<GraticuleLabelDataType>}
      * @private
@@ -679,19 +704,40 @@ class Graticule extends VectorLayer {
     ];
 
     const centerLonLat = this.toLonLatTransform_(validCenter);
+    if (isNaN(centerLonLat[1])) {
+      centerLonLat[1] = Math.abs(this.maxLat_) >= Math.abs(this.minLat_) ?
+        this.maxLat_ : this.minLat_;
+    }
     let centerLon = clamp(centerLonLat[0], this.minLon_, this.maxLon_);
     let centerLat = clamp(centerLonLat[1], this.minLat_, this.maxLat_);
     const maxLines = this.maxLines_;
     let cnt, idx, lat, lon;
 
-    let validExtent = [
+    const validExtentP = [
       clamp(extent[0], this.minLonP_, this.maxLonP_),
       clamp(extent[1], this.minLatP_, this.maxLatP_),
       clamp(extent[2], this.minLonP_, this.maxLonP_),
       clamp(extent[3], this.minLatP_, this.maxLatP_)
     ];
 
-    validExtent = applyTransform(validExtent, this.toLonLatTransform_, undefined, 8);
+    const validExtent = applyTransform(validExtentP, this.toLonLatTransform_, undefined, 8);
+
+    if (containsCoordinate(validExtentP, this.blLonLatP_)) {
+      validExtent[0] = this.minLon_;
+      validExtent[1] = this.minLat_;
+    }
+    if (containsCoordinate(validExtentP, this.brLonLatP_)) {
+      validExtent[2] = this.maxLon_;
+      validExtent[1] = this.minLat_;
+    }
+    if (containsCoordinate(validExtentP, this.tlLonLatP_)) {
+      validExtent[0] = this.minLon_;
+      validExtent[3] = this.maxLat_;
+    }
+    if (containsCoordinate(validExtentP, this.trLonLatP_)) {
+      validExtent[2] = this.maxLon_;
+      validExtent[3] = this.maxLat_;
+    }
 
     const maxLat = clamp(validExtent[3], centerLat, this.maxLat_);
     const maxLon = clamp(validExtent[2], centerLon, this.maxLon_);
@@ -767,11 +813,12 @@ class Graticule extends VectorLayer {
     /** @type {Array<number>} **/
     const p2 = [];
     for (let i = 0, ii = this.intervals_.length; i < ii; ++i) {
-      const delta = this.intervals_[i] / 2;
+      const delta = clamp(this.intervals_[i] / 2, 0, 90);
+      const clampedLat = clamp(centerLat, -90 + delta, 90 - delta);
       p1[0] = centerLon - delta;
-      p1[1] = centerLat - delta;
+      p1[1] = clampedLat - delta;
       p2[0] = centerLon + delta;
-      p2[1] = centerLat + delta;
+      p2[1] = clampedLat + delta;
       this.fromLonLatTransform_(p1, p1);
       this.fromLonLatTransform_(p2, p2);
       const dist = Math.pow(p2[0] - p1[0], 2) + Math.pow(p2[1] - p1[1], 2);
@@ -948,7 +995,16 @@ class Graticule extends VectorLayer {
     this.minLatP_ = worldExtentP[1];
     this.minLonP_ = worldExtentP[0];
 
+    this.blLonLatP_ = this.fromLonLatTransform_([this.minLon_, this.minLat_]);
+    this.brLonLatP_ = this.fromLonLatTransform_([this.maxLon_, this.minLat_]);
+    this.tlLonLatP_ = this.fromLonLatTransform_([this.minLon_, this.maxLat_]);
+    this.trLonLatP_ = this.fromLonLatTransform_([this.maxLon_, this.maxLat_]);
+
     this.projectionCenterLonLat_ = this.toLonLatTransform_(getCenter(projection.getExtent()));
+    if (isNaN(this.projectionCenterLonLat_[1])) {
+      this.projectionCenterLonLat_[1] = Math.abs(this.maxLat_) >= Math.abs(this.minLat_) ?
+        this.maxLat_ : this.minLat_;
+    }
 
     this.projection_ = projection;
   }