add initial marp implementation with sample content and build configuration

node_modules/@marp-team/marpit/lib/markdown/background_image/parse.js

@@ -0,0 +1,77 @@
+"use strict";
+
+Object.defineProperty(exports, "__esModule", {
+  value: true
+});
+exports.default = exports.backgroundImageParse = void 0;
+var _plugin = _interopRequireDefault(require("../../plugin"));
+function _interopRequireDefault(e) { return e && e.__esModule ? e : { default: e }; }
+/** @module */
+
+const bgSizeKeywords = {
+  auto: 'auto',
+  contain: 'contain',
+  cover: 'cover',
+  fit: 'contain'
+};
+const splitSizeMatcher = /^(left|right)(?::((?:\d*\.)?\d+%))?$/;
+
+/**
+ * Marpit background image parse plugin.
+ *
+ * Parse Marpit's image token and mark as background image when the alternate
+ * text includes `bg`. The marked images will not show as the regular image.
+ *
+ * Furthermore, it parses additional keywords needed for background image.
+ *
+ * @function backgroundImageParse
+ * @param {MarkdownIt} md markdown-it instance.
+ */
+function _backgroundImageParse(md) {
+  md.inline.ruler2.after('marpit_parse_image', 'marpit_background_image', ({
+    tokens
+  }) => {
+    for (const t of tokens) {
+      if (t.type === 'image') {
+        const {
+          marpitImage
+        } = t.meta;
+        if (marpitImage.options.some(v => !v.consumed && v.content === 'bg')) {
+          marpitImage.background = true;
+          t.hidden = true;
+          for (const opt of marpitImage.options) {
+            if (opt.consumed) continue;
+            let consumed = false;
+
+            // bg keyword
+            if (opt.content === 'bg') consumed = true;
+
+            // Background size keyword
+            if (bgSizeKeywords[opt.content]) {
+              marpitImage.backgroundSize = bgSizeKeywords[opt.content];
+              consumed = true;
+            }
+
+            // Split background keyword
+            const matched = opt.content.match(splitSizeMatcher);
+            if (matched) {
+              const [, splitSide, splitSize] = matched;
+              marpitImage.backgroundSplit = splitSide;
+              marpitImage.backgroundSplitSize = splitSize;
+              consumed = true;
+            }
+
+            // Background aligned direction
+            if (opt.content === 'vertical' || opt.content === 'horizontal') {
+              marpitImage.backgroundDirection = opt.content;
+              consumed = true;
+            }
+            if (consumed) opt.consumed = true;
+          }
+        }
+      }
+    }
+  });
+}
+const backgroundImageParse = exports.backgroundImageParse = (0, _plugin.default)(_backgroundImageParse);
+var _default = exports.default = backgroundImageParse;