✨ Feature(custom): support jxl image preview in gallery

ISSUES CLOSED: #531

tests/gallery-preview.test.ts

@@ -0,0 +1,71 @@
+import { describe, expect, it } from 'vitest'
+
+import {
+  getGalleryPreviewSource,
+  getJxlPreviewSource,
+  JXL_ERROR_PREVIEW_SRC,
+  JXL_LOADING_PREVIEW_SRC,
+} from '../src/renderer/utils/galleryPreview'
+
+describe('gallery JXL preview helpers', () => {
+  it('detects local JPEG XL files from galleryPath, fileName, or extname', () => {
+    expect(getJxlPreviewSource({ galleryPath: 'C:\\images\\photo.jxl' })).toBe('C:\\images\\photo.jxl')
+    expect(getJxlPreviewSource({ galleryPath: '/tmp/photo', fileName: 'photo.JXL' })).toBe('/tmp/photo')
+    expect(getJxlPreviewSource({ galleryPath: '/tmp/photo', extname: 'jxl' })).toBe('/tmp/photo')
+  })
+
+  it('detects remote JPEG XL URLs but ignores inline image sources', () => {
+    expect(getJxlPreviewSource({ imgUrl: 'https://example.com/photo.jxl' })).toBe('https://example.com/photo.jxl')
+    expect(getJxlPreviewSource({ galleryPath: 'data:image/jxl;base64,abc', extname: '.jxl' })).toBe('')
+  })
+
+  it('does not decode a non-JXL galleryPath just because metadata says JXL', () => {
+    expect(
+      getJxlPreviewSource({
+        galleryPath: '/tmp/original.png',
+        imgUrl: 'https://example.com/uploaded',
+        extname: '.jxl',
+      }),
+    ).toBe('https://example.com/uploaded')
+
+    expect(
+      getJxlPreviewSource({
+        galleryPath: '/tmp/original.png',
+        extname: '.jxl',
+      }),
+    ).toBe('')
+  })
+
+  it('uses cached, loading, and error preview sources for local JXL images', () => {
+    const item = { galleryPath: '/tmp/photo.jxl', imgUrl: 'https://example.com/photo.jxl' }
+
+    expect(getGalleryPreviewSource(item, { '/tmp/photo.jxl': 'data:image/png;base64,abc' })).toBe(
+      'data:image/png;base64,abc',
+    )
+    expect(getGalleryPreviewSource(item, {}, { '/tmp/photo.jxl': true })).toBe(JXL_LOADING_PREVIEW_SRC)
+    expect(getGalleryPreviewSource(item, {}, {}, { '/tmp/photo.jxl': true })).toBe(JXL_ERROR_PREVIEW_SRC)
+  })
+
+  it('can keep the original JXL source after decoder failure when native rendering already worked', () => {
+    const item = { galleryPath: '/tmp/photo.jxl', imgUrl: 'https://example.com/photo.jxl' }
+
+    expect(getGalleryPreviewSource(item, {}, {}, { '/tmp/photo.jxl': true }, true)).toBe('/tmp/photo.jxl')
+  })
+
+  it('keeps a renderable gallery fallback while a separate JXL source is loading or failed', () => {
+    const item = {
+      galleryPath: '/tmp/original.png',
+      imgUrl: 'https://example.com/photo.jxl',
+      extname: '.jxl',
+    }
+
+    expect(getGalleryPreviewSource(item, {}, { 'https://example.com/photo.jxl': true })).toBe('/tmp/original.png')
+    expect(getGalleryPreviewSource(item, {}, {}, { 'https://example.com/photo.jxl': true })).toBe('/tmp/original.png')
+  })
+
+  it('falls back to the original source for non-JXL images', () => {
+    expect(
+      getGalleryPreviewSource({ galleryPath: '/tmp/photo.png', imgUrl: 'https://example.com/photo.png' }, {}),
+    ).toBe('/tmp/photo.png')
+  })
+})