From f92910ee0c2d454a54e169796d07e209f51f375f Mon Sep 17 00:00:00 2001
From: Georges Gomes <georges.gomes@gmail.com>
Date: Wed, 11 Sep 2024 16:16:04 +0200
Subject: [PATCH] srcset step is configurable

---
 src/config-default.ts | 1 +
 src/config-types.ts   | 1 +
 src/optimize.ts       | 2 +-
 3 files changed, 3 insertions(+), 1 deletion(-)

diff --git a/src/config-default.ts b/src/config-default.ts
index 4db7481..8f2e253 100644
--- a/src/config-default.ts
+++ b/src/config-default.ts
@@ -18,6 +18,7 @@ const default_options: Options = {
     embed_size: 1500,
     srcset_min_width: 390 * 2, // HiDPI phone
     srcset_max_width: 1920 * 2, // 4K
+    srcset_step: 300,
     max_width: 99999,
     src_include: /^.*$/,
     src_exclude: /^\/vercel\/image\?/, // Ignore /vervel/image? URLs because not local and most likely already optimized,
diff --git a/src/config-types.ts b/src/config-types.ts
index db87b6a..dc8fac0 100644
--- a/src/config-types.ts
+++ b/src/config-types.ts
@@ -31,6 +31,7 @@ export type Options = {
     embed_size: number; // Embed above the fold images if size < embed_size
     srcset_min_width: number; // Minimum width of generate image in srcset
     srcset_max_width: number; // Maximum width of generate image in srcset
+    srcset_step: number; // Number of pixels between sizes in srcset
     max_width: number; // Maximum width of original images - if bigger => resized output
     src_include: RegExp;
     src_exclude: RegExp | null;
diff --git a/src/optimize.ts b/src/optimize.ts
index fddecc4..8d423cb 100755
--- a/src/optimize.ts
+++ b/src/optimize.ts
@@ -737,7 +737,7 @@ async function _generateSrcSet(
   }
 
   // Start reduction
-  const step = 300; //px
+  const step = options.image.srcset_step; //px
   let valueW = !startSrc ? imageWidth : imageWidth - step;
   valueW = Math.min(valueW, options.image.srcset_max_width);