From 2e6e885071f709b4a52750f4d138567c1343ceec Mon Sep 17 00:00:00 2001
From: "Florine W. Dekker" <florine@fwdekker.com>
Date: Sun, 17 Apr 2022 17:44:15 +0200
Subject: [PATCH] Use correct bounds checking on maximum

---
 src/main/js/Painter.ts | 11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)

diff --git a/src/main/js/Painter.ts b/src/main/js/Painter.ts
index 66092ce..f299a94 100644
--- a/src/main/js/Painter.ts
+++ b/src/main/js/Painter.ts
@@ -56,7 +56,7 @@ export class Painter {
 
     public set scrollX(scrollX: number) {
         const min = this.model?.minX;
-        const max = this.model?.maxX;
+        const max = this.model?.maxX != null ? Math.max(0, this.model.maxX - this.width) : null;
 
         this._scrollX = min != null && scrollX < min ? min : (max != null && scrollX > max ? max : scrollX);
     }
@@ -72,7 +72,7 @@ export class Painter {
 
     public set scrollY(scrollY: number) {
         const min = this.model?.minY;
-        const max = this.model?.maxY;
+        const max = this.model?.maxY != null ? Math.max(0, this.model.maxY - this.height) : null;
 
         this._scrollY = min != null && scrollY < min ? min : (max != null && scrollY > max ? max : scrollY);
     }
@@ -142,8 +142,8 @@ export class Painter {
         this.ctx.save();
         this.ctx.scale(this.scale, this.scale);
         this.ctx.translate(0.2, 0.2);
-        this.drawBoundaries();
         this.drawPrimes();
+        this.drawBoundaries();
         this.ctx.restore();
     }
 
@@ -159,6 +159,11 @@ export class Painter {
         this.ctx.restore();
     }
 
+    /**
+     * Draws the boundaries of the `Model`.
+     *
+     * @private
+     */
     private drawBoundaries(): void {
         this.ctx.save();
         this.ctx.beginPath();