add support for flex gap (#2160)

* setup flex gap

* add types

* throw error when gap is in percents

* add changeset

* fix tests

Author: jeetiss

.changeset/healthy-lobsters-provide.md

@@ -0,0 +1,8 @@
+---
+'@react-pdf/layout': minor
+'@react-pdf/renderer': minor
+'@react-pdf/stylesheet': minor
+'@react-pdf/types': minor
+---
+
+implement flex gap

packages/layout/src/node/setGap.js

@@ -0,0 +1,46 @@
+import Yoga from '@react-pdf/yoga';
+import { isNil, matchPercent } from '@react-pdf/fns';
+
+const checkPercents = (attr, value) => {
+  const percent = matchPercent(value);
+
+  if (percent) {
+    throw new Error(`You can't pass percentage values to ${attr} property`);
+  }
+};
+
+/**
+ * Set rowGap value to node's Yoga instance
+ *
+ * @param {Number} gap value
+ * @param {Object} node instance
+ * @return {Object} node instance
+ */
+export const setRowGap = value => node => {
+  const { yogaNode } = node;
+
+  if (!isNil(value) && yogaNode) {
+    checkPercents('rowGap', value);
+    yogaNode.setGap(Yoga.GUTTER_ROW, value);
+  }
+
+  return node;
+};
+
+/**
+ * Set columnGap value to node's Yoga instance
+ *
+ * @param {Number} gap value
+ * @param {Object} node instance
+ * @return {Object} node instance
+ */
+export const setColumnGap = value => node => {
+  const { yogaNode } = node;
+
+  if (!isNil(value) && yogaNode) {
+    checkPercents('columnGap', value);
+    yogaNode.setGap(Yoga.GUTTER_COLUMN, value);
+  }
+
+  return node;
+};

packages/layout/src/steps/resolveDimensions.js

@@ -52,6 +52,7 @@ import {
   setMinHeight,
   setMaxHeight,
 } from '../node/setDimension';
+import { setRowGap, setColumnGap } from '../node/setGap';
 import measureSvg from '../svg/measureSvg';
 import measureText from '../text/measureText';
 import measureImage from '../image/measureImage';
@@ -119,6 +120,8 @@ const setYogaValues = node => {
     setFlexBasis(node.style.flexBasis),
     setFlexGrow(node.style.flexGrow),
     setFlexShrink(node.style.flexShrink),
+    setRowGap(node.style.rowGap),
+    setColumnGap(node.style.columnGap),
   )(node);
 };
 

packages/renderer/tests/gap.test.js

@@ -0,0 +1,91 @@
+/* eslint-disable react/no-array-index-key */
+import React from 'react';
+import { Document, Page, View } from '..';
+import renderToImage from './renderComponent';
+
+const mount = async children => {
+  const image = await renderToImage(
+    <Document>
+      <Page size={[100, 100]}>{children}</Page>
+    </Document>,
+  );
+
+  return image;
+};
+
+const items = [
+  'red',
+  'red',
+  'red',
+  'green',
+  'green',
+  'green',
+  'blue',
+  'blue',
+  'blue',
+];
+
+describe('flex', () => {
+  test('should support gap', async () => {
+    const image = await mount(
+      <View
+        style={{
+          height: '100%',
+          width: '100%',
+          display: 'flex',
+          flexWrap: 'wrap',
+          backgroundColor: '#e2e2e2',
+          gap: 30,
+        }}
+      >
+        {items.map((color, index) => (
+          <View
+            key={index}
+            style={{
+              width: 10,
+              height: 10,
+              backgroundColor: color,
+            }}
+          />
+        ))}
+      </View>,
+    );
+
+    expect(image).toMatchImageSnapshot();
+  });
+
+  test('should support rowGap and columnGap', async () => {
+    const image = await mount(
+      <View
+        style={{
+          height: '100%',
+          width: '100%',
+          display: 'flex',
+          flexWrap: 'wrap',
+          backgroundColor: '#e2e2e2',
+          rowGap: '60px',
+          columnGap: '80px',
+        }}
+      >
+        {items.slice(0, 4).map((color, index) => (
+          <View
+            key={index}
+            style={{
+              width: 10,
+              height: 10,
+              backgroundColor: color,
+            }}
+          />
+        ))}
+      </View>,
+    );
+
+    expect(image).toMatchImageSnapshot();
+  });
+
+  test('should throw when value is percent', async () => {
+    expect(mount(<View style={{ gap: '10%' }} />)).rejects.toThrow(
+      "You can't pass percentage values to columnGap property",
+    );
+  });
+});

packages/renderer/tests/renderComponent.js

@@ -86,7 +86,7 @@ const renderComponent = async element => {
   const source = await renderToBuffer(element);
 
   const document = await pdfjs.getDocument({
-    data: source.buffer,
+    data: source,
     verbosity: 0,
   }).promise;
 

packages/renderer/tests/snapshots/gap-test-js-flex-should-support-gap-1-snap.png

@@ -0,0 +1,10 @@
+const expandGap = (key, value) => {
+  const match = `${value}`.split(' ');
+
+  return {
+    rowGap: match?.[0] || value,
+    columnGap: match?.[1] || value,
+  };
+};
+
+export default expandGap;

packages/renderer/tests/snapshots/gap-test-js-flex-should-support-row-gap-and-column-gap-1-snap.png

@@ -14,9 +14,11 @@ import {
 } from './paddings';
 import processObjectPosition from './objectPosition';
 import processTransformOrigin from './transformOrigin';
+import processGap from './gap';
 
 const shorthands = {
   flex: processFlex,
+  gap: processGap,
   margin: processMargin,
   marginHorizontal: processMarginHorizontal,
   marginVertical: processMarginVertical,

packages/stylesheet/src/expand/gap.js

@@ -12,6 +12,9 @@ export interface Style {
   flexShrink?: number;
   flexBasis?: number | string;
   justifyContent?: 'flex-start' | 'flex-end' | 'center' | 'space-around' | 'space-between' | 'space-evenly';
+  gap?: number | string;
+  rowGap?: number;
+  columnGap?: number;
 
   // Layout