fix: Adjust piechart viewbox for mobile devices with small width

cypress/integration/rendering/pie.spec.ts

@@ -44,7 +44,7 @@ describe('pie chart', () => {
       const style = svg.attr('style');
       expect(style).to.match(/^max-width: [\d.]+px;$/);
       const maxWidthValue = parseFloat(style.match(/[\d.]+/g).join(''));
-      expect(maxWidthValue).to.eq(984);
+      expect(maxWidthValue).to.be.within(590, 600); // depends on installed fonts: 596.2 on my PC, 597.5 on CI
     });
   });
 
@@ -59,7 +59,7 @@ describe('pie chart', () => {
     );
     cy.get('svg').should((svg) => {
       const width = parseFloat(svg.attr('width'));
-      expect(width).to.eq(984);
+      expect(width).to.be.within(590, 600); // depends on installed fonts: 596.2 on my PC, 597.5 on CI
       expect(svg).to.not.have.attr('style');
     });
   });

packages/mermaid/src/diagrams/pie/pieRenderer.ts

@@ -1,6 +1,5 @@
 import type d3 from 'd3';
 import { scaleOrdinal, pie as d3pie, arc } from 'd3';
-
 import { log } from '../../logger.js';
 import { configureSvgSize } from '../../setupGraphViewbox.js';
 import { getConfig } from '../../diagram-api/diagramAPI.js';
@@ -38,33 +37,25 @@ const createPieArcs = (sections: Sections): d3.PieArcDatum<D3Sections>[] => {
  */
 export const draw: DrawDefinition = (text, id, _version, diagObj) => {
   log.debug('rendering pie chart\n' + text);
-
   const db = diagObj.db as PieDB;
   const globalConfig: MermaidConfig = getConfig();
   const pieConfig: Required<PieDiagramConfig> = cleanAndMerge(db.getConfig(), globalConfig.pie);
-
-  const height = 450;
-  // TODO: remove document width
-  const width: number =
-    document.getElementById(id)?.parentElement?.offsetWidth ?? pieConfig.useWidth;
-  const svg: SVG = selectSvgElement(id);
-  // Set viewBox
-  svg.attr('viewBox', `0 0 ${width} ${height}`);
-  configureSvgSize(svg, height, width, pieConfig.useMaxWidth);
-
   const MARGIN = 40;
   const LEGEND_RECT_SIZE = 18;
   const LEGEND_SPACING = 4;
-
+  const height = 450;
+  const pieWidth: number = height;
+  const svg: SVG = selectSvgElement(id);
   const group: Group = svg.append('g');
-  group.attr('transform', 'translate(' + width / 2 + ',' + height / 2 + ')');
+  const sections: Sections = db.getSections();
+  group.attr('transform', 'translate(' + pieWidth / 2 + ',' + height / 2 + ')');
 
   const { themeVariables } = globalConfig;
   let [outerStrokeWidth] = parseFontSize(themeVariables.pieOuterStrokeWidth);
   outerStrokeWidth ??= 2;
 
   const textPosition: number = pieConfig.textPosition;
-  const radius: number = Math.min(width, height) / 2 - MARGIN;
+  const radius: number = Math.min(pieWidth, height) / 2 - MARGIN;
   // Shape helper to build arcs:
   const arcGenerator: d3.Arc<unknown, d3.PieArcDatum<D3Sections>> = arc<
     d3.PieArcDatum<D3Sections>
@@ -84,7 +75,6 @@ export const draw: DrawDefinition = (text, id, _version, diagObj) => {
     .attr('r', radius + outerStrokeWidth / 2)
     .attr('class', 'pieOuterCircle');
 
-  const sections: Sections = db.getSections();
   const arcs: d3.PieArcDatum<D3Sections>[] = createPieArcs(sections);
 
   const myGeneratedColors = [
@@ -177,6 +167,19 @@ export const draw: DrawDefinition = (text, id, _version, diagObj) => {
       }
       return label;
     });
+
+  const longestTextWidth = Math.max(
+    ...legend
+      .selectAll('text')
+      .nodes()
+      .map((node) => (node as Element)?.getBoundingClientRect().width ?? 0)
+  );
+
+  const totalWidth = pieWidth + MARGIN + LEGEND_RECT_SIZE + LEGEND_SPACING + longestTextWidth;
+
+  // Set viewBox
+  svg.attr('viewBox', `0 0 ${totalWidth} ${height}`);
+  configureSvgSize(svg, height, totalWidth, pieConfig.useMaxWidth);
 };
 
 export const renderer = { draw };

packages/mermaid/src/setupGraphViewbox.js

@@ -44,6 +44,7 @@ export const configureSvgSize = function (svgElem, height, width, useMaxWidth) {
   const attrs = calculateSvgSizeAttrs(height, width, useMaxWidth);
   d3Attrs(svgElem, attrs);
 };
+
 export const setupGraphViewbox = function (graph, svgElem, padding, useMaxWidth) {
   const svgBounds = svgElem.node().getBBox();
   const sWidth = svgBounds.width;
@@ -55,26 +56,13 @@ export const setupGraphViewbox = function (graph, svgElem, padding, useMaxWidth)
   let height = 0;
   log.info(`Graph bounds: ${width}x${height}`, graph);
 
-  // let tx = 0;
-  // let ty = 0;
-  // if (sWidth > width) {
-  //   tx = (sWidth - width) / 2 + padding;
   width = sWidth + padding * 2;
-  // } else {
-  //   if (Math.abs(sWidth - width) >= 2 * padding + 1) {
-  //     width = width - padding;
-  //   }
-  // }
-  // if (sHeight > height) {
-  //   ty = (sHeight - height) / 2 + padding;
   height = sHeight + padding * 2;
-  // }
 
   log.info(`Calculated bounds: ${width}x${height}`);
   configureSvgSize(svgElem, height, width, useMaxWidth);
 
   // Ensure the viewBox includes the whole svgBounds area with extra space for padding
-  // const vBox = `0 0 ${width} ${height}`;
   const vBox = `${svgBounds.x - padding} ${svgBounds.y - padding} ${
     svgBounds.width + 2 * padding
   } ${svgBounds.height + 2 * padding}`;