From de6add6f0e7b112a599ad96e95d384ee6e4764e5 Mon Sep 17 00:00:00 2001
From: Sidharth Vinod <sidharthv96@gmail.com>
Date: Wed, 6 Sep 2023 10:33:19 +0530
Subject: [PATCH] chore: Remove background color logic

---
 packages/mermaid/src/dagre-wrapper/markers.js | 71 ++-----------------
 packages/mermaid/src/diagrams/class/styles.js | 12 ++++
 2 files changed, 18 insertions(+), 65 deletions(-)

diff --git a/packages/mermaid/src/dagre-wrapper/markers.js b/packages/mermaid/src/dagre-wrapper/markers.js
index 97279eaf4..2948645d3 100644
--- a/packages/mermaid/src/dagre-wrapper/markers.js
+++ b/packages/mermaid/src/dagre-wrapper/markers.js
@@ -2,59 +2,6 @@
 
 import { log } from '../logger.js';
 
-const getSvgParent = (elem) => {
-  let container = elem;
-
-  // the intent here is to find the first parent element that is NOT part of the SVG element
-  // I know there has to be a better way, but could not find one that worked
-  // tried using checking if elem was instanceof SVGGraphicsElement or SVGElement, but it failed to detect correctly
-  if (container._groups) {
-    container = container._groups[0][0];
-  }
-  if (container.tagName.toLowerCase() === 'g') {
-    container = container.parentElement;
-  }
-  if (container.localName.toLowerCase() === 'svg') {
-    container = container.parentElement;
-  }
-  return container;
-};
-
-/**
- * Finds the parent background color of an SVG element.
- *
- * Used to make a "hollow" arrowhead for an arrow.
- *
- * We can't use a transparent fill,
- * because the arrow line is behind the arrowhead
- * (ideally we'd stop drawing the line behind the arrowhead,
- *  but this is pretty complicated to do).
- *
- * **Limitations**:
- * - If the parent background color is a partial transparency,
- *   the arrowhead will also be partially transparent.
- * - More complicated backgrounds like pictures/animations won't work.
- * @param elem The SVG element.
- */
-const getBackgroundColor = (elem) => {
-  let parent = getSvgParent(elem);
-
-  let backgroundColor;
-  while (parent && parent.tagName.toLowerCase() !== 'body') {
-    if (parent instanceof Element) {
-      const computedStyle = getComputedStyle(parent);
-      backgroundColor = computedStyle.backgroundColor;
-
-      if (backgroundColor !== 'rgba(0, 0, 0, 0)') {
-        break;
-      }
-      parent = parent.parentNode;
-    }
-  }
-
-  return backgroundColor === 'rgba(0, 0, 0, 0)' ? 'white' : backgroundColor;
-};
-
 // Only add the number of markers that the diagram needs
 const insertMarkers = (elem, markerArray, type, id) => {
   markerArray.forEach((markerName) => {
@@ -64,7 +11,6 @@ const insertMarkers = (elem, markerArray, type, id) => {
 
 const extension = (elem, type, id) => {
   log.trace('Making markers for ', id);
-  const backgroundColor = getBackgroundColor(elem);
 
   elem
     .append('defs')
@@ -77,8 +23,7 @@ const extension = (elem, type, id) => {
     .attr('markerHeight', 240)
     .attr('orient', 'auto')
     .append('path')
-    .attr('d', 'M 1,7 L18,13 V 2 Z')
-    .attr('fill', backgroundColor);
+    .attr('d', 'M 1,7 L18,13 V 1 Z');
 
   elem
     .append('defs')
@@ -91,41 +36,37 @@ const extension = (elem, type, id) => {
     .attr('markerHeight', 28)
     .attr('orient', 'auto')
     .append('path')
-    .attr('d', 'M 1,1 V 13 L18,7 Z')
-    .attr('fill', backgroundColor); // this is actual shape for arrowhead
+    .attr('d', 'M 1,1 V 13 L18,7 Z'); // this is actual shape for arrowhead
 };
 
 const realization = (elem, type, id) => {
   log.trace('Making markers for ', id);
-  let backgroundColor = getBackgroundColor(elem);
 
   elem
     .append('defs')
     .append('marker')
     .attr('id', type + '-realizationStart')
     .attr('class', 'marker realization ' + type)
-    .attr('refX', 0)
+    .attr('refX', 18)
     .attr('refY', 7)
     .attr('markerWidth', 190)
     .attr('markerHeight', 240)
     .attr('orient', 'auto')
     .append('path')
-    .attr('d', 'M 1,7 L18,13 V 2 Z')
-    .attr('fill', backgroundColor);
+    .attr('d', 'M 1,7 L18,13 V 1 Z');
 
   elem
     .append('defs')
     .append('marker')
     .attr('id', type + '-realizationEnd')
     .attr('class', 'marker realization ' + type)
-    .attr('refX', 19)
+    .attr('refX', 1)
     .attr('refY', 7)
     .attr('markerWidth', 20)
     .attr('markerHeight', 28)
     .attr('orient', 'auto')
     .append('path')
-    .attr('d', 'M 1,1 V 13 L18,7 Z')
-    .attr('fill', backgroundColor); // this is actual shape for arrowhead
+    .attr('d', 'M 1,1 V 13 L18,7 Z'); // this is actual shape for arrowhead
 };
 
 const composition = (elem, type) => {
diff --git a/packages/mermaid/src/diagrams/class/styles.js b/packages/mermaid/src/diagrams/class/styles.js
index f12f609f9..db65b9b4a 100644
--- a/packages/mermaid/src/diagrams/class/styles.js
+++ b/packages/mermaid/src/diagrams/class/styles.js
@@ -120,6 +120,18 @@ g.classGroup line {
   stroke-width: 1;
 }
 
+#realizationStart, .realization {
+  fill: transparent !important;
+  stroke: ${options.lineColor} !important;
+  stroke-width: 1;
+}
+
+#realizationEnd, .realization {
+  fill: transparent !important;
+  stroke: ${options.lineColor} !important;
+  stroke-width: 1;
+}
+
 #aggregationStart, .aggregation {
   fill: transparent !important;
   stroke: ${options.lineColor} !important;