From a7597199d252276e0b43bd834630e01f5e0ea35e Mon Sep 17 00:00:00 2001
From: Eric <yangguchen@gmail.com>
Date: Thu, 7 Apr 2022 16:19:46 -0400
Subject: [PATCH 1/2] Update simpleheat.js

clear canvas
---
 simpleheat.js | 1 +
 1 file changed, 1 insertion(+)

diff --git a/simpleheat.js b/simpleheat.js
index dc06eb9..42a91a6 100644
--- a/simpleheat.js
+++ b/simpleheat.js
@@ -43,6 +43,7 @@ simpleheat.prototype = {
     },
 
     clear: function () {
+        this._ctx.clearRect(0, 0, this._width, this._height);
         this._data = [];
         return this;
     },

From 1e64cd3d9996c5a3e2ef00ae471e86c0be205c8a Mon Sep 17 00:00:00 2001
From: YGC <guchen.yang@johnsonoutdoors.com>
Date: Wed, 13 Apr 2022 16:00:04 -0400
Subject: [PATCH 2/2] add alpha support

---
 package.json  |  2 +-
 simpleheat.js | 10 +++++++---
 2 files changed, 8 insertions(+), 4 deletions(-)

diff --git a/package.json b/package.json
index 006858c..4931a3f 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "simpleheat",
-  "version": "0.4.0",
+  "version": "0.4.1",
   "description": "A tiny JavaScript library for drawing heatmaps with Canvas",
   "homepage": "https://github.com/mourner/simpleheat",
   "keywords": [
diff --git a/simpleheat.js b/simpleheat.js
index 42a91a6..63d6b18 100644
--- a/simpleheat.js
+++ b/simpleheat.js
@@ -96,7 +96,7 @@ simpleheat.prototype = {
         return this;
     },
 
-    draw: function (minOpacity) {
+    draw: function (minOpacity, alpha) {
         if (!this._circle) this.radius(this.defaultRadius);
         if (!this._grad) this.gradient(this.defaultGradient);
 
@@ -113,13 +113,13 @@ simpleheat.prototype = {
 
         // colorize the heatmap, using opacity value of each pixel to get the right color from our gradient
         var colored = ctx.getImageData(0, 0, this._width, this._height);
-        this._colorize(colored.data, this._grad);
+        this._colorize(colored.data, this._grad, alpha);
         ctx.putImageData(colored, 0, 0);
 
         return this;
     },
 
-    _colorize: function (pixels, gradient) {
+    _colorize: function (pixels, gradient, alpha) {
         for (var i = 0, len = pixels.length, j; i < len; i += 4) {
             j = pixels[i + 3] * 4; // get gradient color from opacity value
 
@@ -127,6 +127,10 @@ simpleheat.prototype = {
                 pixels[i] = gradient[j];
                 pixels[i + 1] = gradient[j + 1];
                 pixels[i + 2] = gradient[j + 2];
+                if (alpha)
+                {
+                    pixels[i + 3] = pixels[i + 3] * alpha;
+                }
             }
         }
     },