fix: the defaultFontFamily not working

__test__/index.spec.ts

@@ -449,6 +449,29 @@ test('should return undefined if bbox is invalid', (t) => {
   t.is(resvg.innerBBox(), undefined)
 })
 
+test('should be load custom fonts', (t) => {
+  const svg = `
+  <svg xmlns="http://www.w3.org/2000/svg" width="200" height="200" viewBox="0 0 200 200">
+    <text fill="blue" font-family="serif" font-size="120">
+      <tspan x="40" y="143">水</tspan>
+    </text>
+  </svg>
+  `
+  const resvg = new Resvg(svg, {
+    font: {
+      fontFiles: ['./example/SourceHanSerifCN-Light-subset.ttf'],
+      loadSystemFonts: false,
+      defaultFontFamily: 'Source Han Serif CN Light',
+    },
+    logLevel: 'debug',
+  })
+  const pngData = resvg.render()
+  const originPixels = pngData.pixels.toJSON().data
+
+  // Find the number of blue `rgb(0,255,255)`pixels
+  t.is(originPixels.join(',').match(/0,0,255/g)?.length, 1726)
+})
+
 test('should throw because invalid SVG attribute (width attribute is 0)', (t) => {
   const error = t.throws(
     () => {

example/text.js

@@ -0,0 +1,32 @@
+const { promises } = require('fs')
+const { join } = require('path')
+const { performance } = require('perf_hooks')
+
+const { Resvg } = require('../index')
+
+async function main() {
+  const svg = `
+  <svg xmlns="http://www.w3.org/2000/svg" width="200" height="200" viewBox="0 0 200 200">
+    <text fill="blue" font-family="serif" font-size="120">
+      <tspan x="40" y="143">水</tspan>
+    </text>
+  </svg>
+  `
+  const t = performance.now()
+  const resvg = new Resvg(svg, {
+    background: 'pink',
+    font: {
+      fontFiles: ['./example/SourceHanSerifCN-Light-subset.ttf'], // Load custom fonts.
+      loadSystemFonts: false, // It will be faster to disable loading system fonts.
+      defaultFontFamily: 'Source Han Serif CN Light',
+    },
+    logLevel: 'debug', // Default Value: error
+  })
+  const pngData = resvg.render()
+  const pngBuffer = pngData.asPng()
+  console.info('✨ Done in', performance.now() - t, 'ms')
+
+  await promises.writeFile(join(__dirname, './text2-out.png'), pngBuffer)
+}
+
+main()

src/fonts.rs

@@ -42,11 +42,21 @@ pub fn load_fonts(font_options: &JsFontOptions) -> Database {
     // - `cursive` - Comic Sans MS
     // - `fantasy` - Impact (Papyrus on macOS)
     // - `monospace` - Courier New
-    fontdb.set_serif_family(&font_options.serif_family);
-    fontdb.set_sans_serif_family(&font_options.sans_serif_family);
-    fontdb.set_cursive_family(&font_options.cursive_family);
-    fontdb.set_fantasy_family(&font_options.fantasy_family);
-    fontdb.set_monospace_family(&font_options.monospace_family);
+    if !font_options.default_font_family.is_empty() {
+        // If a default font family exists, set all other families to that family.
+        // This prevents fonts from not being rendered in SVG.
+        fontdb.set_serif_family(&font_options.default_font_family);
+        fontdb.set_sans_serif_family(&font_options.default_font_family);
+        fontdb.set_cursive_family(&font_options.default_font_family);
+        fontdb.set_fantasy_family(&font_options.default_font_family);
+        fontdb.set_monospace_family(&font_options.default_font_family);
+    } else {
+        fontdb.set_serif_family(&font_options.serif_family);
+        fontdb.set_sans_serif_family(&font_options.sans_serif_family);
+        fontdb.set_cursive_family(&font_options.cursive_family);
+        fontdb.set_fantasy_family(&font_options.fantasy_family);
+        fontdb.set_monospace_family(&font_options.monospace_family);
+    }
     debug!(
         "Loaded {} font faces in {}ms.",
         fontdb.len(),