Avoid some potential divisions by zero in height estimates

marijnh · marijnh · commit 014076ae6e47 · 2025-07-04T09:22:52.000+02:00
Issue #72
diff --git a/src/heightmap.ts b/src/heightmap.ts
@@ -28,7 +28,7 @@ export class HeightOracle {
 
   heightForLine(length: number): number {
     if (!this.lineWrapping) return this.lineHeight
-    let lines = 1 + Math.max(0, Math.ceil((length - this.lineLength) / (this.lineLength - 5)))
+    let lines = 1 + Math.max(0, Math.ceil((length - this.lineLength) / Math.max(1, this.lineLength - 5)))
     return lines * this.lineHeight
   }
 
diff --git a/src/viewstate.ts b/src/viewstate.ts
@@ -326,7 +326,7 @@ export class ViewState {
       if (refresh || oracle.lineWrapping && Math.abs(contentWidth - this.contentDOMWidth) > oracle.charWidth) {
         let {lineHeight, charWidth, textHeight} = view.docView.measureTextSize()
         refresh = lineHeight > 0 && oracle.refresh(whiteSpace, lineHeight, charWidth, textHeight,
-                                                   contentWidth / charWidth, lineHeights)
+                                                   Math.max(5, contentWidth / charWidth), lineHeights)
         if (refresh) {
           view.docView.minWidth = 0
           result |= UpdateFlag.Geometry

Original file line number	Diff line number	Diff line change
`@@ -28,7 +28,7 @@ export class HeightOracle {`
`28`	`28`
`29`	`29`	`heightForLine(length: number): number {`
`30`	`30`	`if (!this.lineWrapping) return this.lineHeight`
`31`		`- let lines = 1 + Math.max(0, Math.ceil((length - this.lineLength) / (this.lineLength - 5)))`
	`31`	`+ let lines = 1 + Math.max(0, Math.ceil((length - this.lineLength) / Math.max(1, this.lineLength - 5)))`
`32`	`32`	`return lines * this.lineHeight`
`33`	`33`	`}`
`34`	`34`