Add test support for intrinsic sized nodes

Summary: This diff adds support for intrinsic sizing in generated tests. This is done by importing a testing font called "Ahem" which, as used, has an exact width and height of 10px for each character. Support has been added for C++, Java, and Javascript generated tests.

Differential Revision: D58307002

javascript/tests/tools/utils.ts

@@ -0,0 +1,81 @@
+/**
+ * Copyright (c) Meta Platforms, Inc. and affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+import {MeasureMode} from 'yoga-layout';
+
+export function instrinsicSizeMeasureFunc(
+  this: string,
+  width: number,
+  widthMode: MeasureMode,
+  height: number,
+  heightMode: MeasureMode,
+): {width: number; height: number} {
+  const textLength = this.length;
+  const words = this.split(' ');
+  const widthPerChar = 10;
+  const heightPerChar = 10;
+
+  let measuredWidth: number;
+  let measuredHeight: number;
+
+  switch (widthMode) {
+    case MeasureMode.Exactly:
+      measuredWidth = width;
+      break;
+    case MeasureMode.AtMost:
+      measuredWidth = Math.min(width, textLength * widthPerChar);
+      break;
+    default:
+      measuredWidth = textLength * widthPerChar;
+  }
+
+  switch (heightMode) {
+    case MeasureMode.Exactly:
+      measuredHeight = height;
+      break;
+    case MeasureMode.AtMost:
+      measuredHeight = Math.min(height, calculateHeight());
+      break;
+    default:
+      measuredHeight = calculateHeight();
+  }
+
+  function longestWordWidth() {
+    return Math.max(...words.map(word => word.length)) * widthPerChar;
+  }
+
+  function calculateHeight() {
+    if (textLength * widthPerChar <= measuredWidth) {
+      return heightPerChar;
+    }
+
+    const maxLineWidth = Math.max(longestWordWidth(), measuredWidth);
+
+    //if fixed width < width of widest word, take width of widest word
+
+    let lines = 1;
+    let currentLineLength = 0;
+    for (const word of words) {
+      const wordWidth = word.length * widthPerChar;
+      if (wordWidth > maxLineWidth) {
+        if (currentLineLength > 0) {
+          lines++;
+        }
+        lines++;
+        currentLineLength = 0;
+      } else if (currentLineLength + wordWidth <= maxLineWidth) {
+        currentLineLength += widthPerChar + wordWidth;
+      } else {
+        lines++;
+        currentLineLength = widthPerChar + wordWidth;
+      }
+    }
+    return (currentLineLength === 0 ? lines - 1 : lines) * heightPerChar;
+  }
+
+  return {width: measuredWidth, height: measuredHeight};
+}