From c08a4e851bc927347c26e4be8a3093fce26cd8b5 Mon Sep 17 00:00:00 2001
From: litetex <40789489+litetex@users.noreply.github.com>
Date: Tue, 15 Feb 2022 20:09:21 +0100
Subject: [PATCH] Improved image-minimizer

* Don't minimize images that are too wide -> they will get stretched otherwise
* Don't try to modify the issue/comment when nothing changed
* Fixed typo
---
 .github/workflows/image-minimizer.js | 29 +++++++++++++++++++++++++---
 1 file changed, 26 insertions(+), 3 deletions(-)

diff --git a/.github/workflows/image-minimizer.js b/.github/workflows/image-minimizer.js
index 8d10a1e77..273c6d328 100644
--- a/.github/workflows/image-minimizer.js
+++ b/.github/workflows/image-minimizer.js
@@ -4,7 +4,12 @@
 module.exports = async ({github, context}) => {
     const IGNORE_KEY = '<!-- IGNORE IMAGE MINIFY -->';
     const IGNORE_ALT_NAME_END = 'ignoreImageMinify';
+    // Targeted maximum height
     const IMG_MAX_HEIGHT_PX = 600;
+    // maximum width of GitHub issues/comments
+    const IMG_MAX_WIDTH_PX = 800;
+    // all images that have a lower aspect ration (-> have a smaller width) than this will be minimized
+    const MIN_ASPECT_RATION = IMG_MAX_WIDTH_PX / IMG_MAX_HEIGHT_PX
 
     // Get the body of the image
     let initialBody = null;
@@ -38,6 +43,8 @@ module.exports = async ({github, context}) => {
 
     // Require the probe lib for getting the image dimensions
     const probe = require('probe-image-size');
+    
+    var wasMatchModified = false;
 
     // Try to find and replace the images with minimized ones
     let newBody = await replaceAsync(initialBody, REGEX_IMAGE_LOOKUP, async (match, g1, g2) => {
@@ -48,7 +55,7 @@ module.exports = async ({github, context}) => {
             return match;
         }
         
-        let shouldModifiy = false;
+        let shouldModify = false;
         try {
             console.log(`Probing ${g2}`);
             let probeResult = await probe(g2);
@@ -58,15 +65,26 @@ module.exports = async ({github, context}) => {
             if (probeResult.hUnits != 'px') {
                 throw `Unexpected probeResult.hUnits (expected px but got ${probeResult.hUnits})`;
             }
+            if (probeResult.height <= 0) {
+                throw `Unexpected probeResult.height (height is invalid: ${probeResult.height})`;
+            }
+            if (probeResult.wUnits != 'px') {
+                throw `Unexpected probeResult.wUnits (expected px but got ${probeResult.wUnits})`;
+            }
+            if (probeResult.width <= 0) {
+                throw `Unexpected probeResult.width (width is invalid: ${probeResult.width})`;
+            }
+            console.log(`Probing resulted in ${probeResult.width}x${probeResult.height}px`);
             
-            shouldModifiy = probeResult.height > IMG_MAX_HEIGHT_PX;
+            shouldModify = probeResult.height > IMG_MAX_HEIGHT_PX && (probeResult.width / probeResult.height) < MIN_ASPECT_RATION;
         } catch(e) {
             console.log('Probing failed:', e);
             // Immediately abort
             return match;
         }
         
-        if (shouldModifiy) {
+        if (shouldModify) {
+            wasMatchModified = true;
             console.log(`Modifying match '${match}'`);
             return `<img alt="${g1}" src="${g2}" height=${IMG_MAX_HEIGHT_PX} />`;
         }
@@ -74,6 +92,11 @@ module.exports = async ({github, context}) => {
         console.log(`Match '${match}' is ok/will not be modified`);
         return match;
     });
+    
+    if (!wasMatchModified) {
+        console.log('Nothing was modified. Skipping update');
+        return;
+    }
 
     // Update the corresponding element
     if (context.eventName == 'issue_comment') {