ensure marking edges are at least one pixel wide

CHANGELOG.md

@@ -11,6 +11,7 @@ Note that since we don't clearly distinguish between a public and private interf
 - Reduce over-blurring occlusion at larger view distances
 - Fix occlusion artefact with non-canvas viewport and pixel-ratio > 1
 - Update nodejs-shims conditionals to handle polyfilled document object in NodeJS environment.
+- Ensure marking edges are at least one pixel wide
 
 ## [v3.31.4] - 2023-02-24
 

src/mol-canvas3d/passes/marking.ts

@@ -106,7 +106,7 @@ export class MarkingPass {
         const { highlightEdgeColor, selectEdgeColor, edgeScale, innerEdgeFactor, ghostEdgeStrength, highlightEdgeStrength, selectEdgeStrength } = props;
 
         const { values: edgeValues } = this.edge;
-        const _edgeScale = Math.round(edgeScale * this.webgl.pixelRatio);
+        const _edgeScale = Math.max(1, Math.round(edgeScale * this.webgl.pixelRatio));
         if (edgeValues.dEdgeScale.ref.value !== _edgeScale) {
             ValueCell.update(edgeValues.dEdgeScale, _edgeScale);
             this.edge.update();