Update column width sizing

.changeset/mean-hornets-sip.md

@@ -0,0 +1,5 @@
+---
+"gitbook": patch
+---
+
+Update to column width sizing

packages/gitbook/src/components/DocumentView/Columns/Columns.tsx

@@ -1,17 +1,57 @@
 import { tcls } from '@/lib/tailwind';
 import { type DocumentBlockColumns, type Length, VerticalAlignment } from '@gitbook/api';
+import React from 'react';
 import type { BlockProps } from '../Block';
 import { Blocks } from '../Blocks';
 
 export function Columns(props: BlockProps<DocumentBlockColumns>) {
     const { block, style, ancestorBlocks, document, context } = props;
+
+    const columnWidths = React.useMemo(() => {
+        const widths = block.nodes.map((block) => {
+            const width = block.data.width;
+            return width ? getFractionalWidth(width) : 0;
+        });
+
+        const totalWidth = widths.reduce<number>((acc, width) => acc + width, 0);
+        // If not all columns widths are set, distribute the remaining widths as equally as we can
+        if (totalWidth < 1.0 && widths.some((width) => width === 0)) {
+            const unsetWidths = widths.filter((width) => width === 0);
+            let remainingWidth = 1.0 - totalWidth;
+            let unsetWidthsLength = unsetWidths.length;
+            widths.forEach((width, index) => {
+                if (width === 0) {
+                    const calculatedWidth =
+                        Math.round((remainingWidth / unsetWidthsLength) * COLUMN_DIVISIONS) /
+                        COLUMN_DIVISIONS;
+                    widths[index] = calculatedWidth; // Assign width to empty columns
+                    unsetWidthsLength--;
+                    remainingWidth -= calculatedWidth;
+                }
+            });
+        }
+        return widths;
+    }, [block.nodes]);
+
     return (
-        <div className={tcls('flex flex-col gap-x-8 md:flex-row', style)}>
-            {block.nodes.map((columnBlock) => {
+        <div
+            className={tcls(
+                'grid w-full grid-cols-1 gap-x-8 gap-y-4 md:grid-flow-col md:grid-cols-[repeat(var(--grid-slices),minmax(0,1fr))] md:grid-rows-1',
+                style
+            )}
+            style={{ '--grid-slices': COLUMN_DIVISIONS } as React.CSSProperties}
+        >
+            {block.nodes.map((columnBlock, index) => {
+                const columnWidth = columnWidths[index];
                 return (
                     <Column
                         key={columnBlock.key}
-                        width={columnBlock.data.width}
+                        width={
+                            columnBlock.data.width ??
+                            (columnWidth
+                                ? { value: columnWidth * 100, unit: '%' }
+                                : { value: 0, unit: '%' })
+                        }
                         verticalAlignment={columnBlock.data.verticalAlignment}
                     >
                         <Blocks
@@ -31,11 +71,11 @@ export function Columns(props: BlockProps<DocumentBlockColumns>) {
 
 export function Column(props: {
     children?: React.ReactNode;
-    width?: Length;
+    width: Length;
     verticalAlignment?: VerticalAlignment;
 }) {
     const { width, verticalAlignment } = props;
-    const { className, style } = transformLengthToCSS(width);
+    const { className, style } = transformLengthToCSS(width) ?? {};
     return (
         <div
             className={tcls(
@@ -53,41 +93,25 @@ export function Column(props: {
     );
 }
 
-function transformLengthToCSS(length: Length | undefined) {
-    if (!length) {
-        return { className: ['md:w-full'] }; // default to full width if no length is specified
-    }
+const COLUMN_DIVISIONS = 12;
 
+export function transformLengthToCSS(length: Length) {
     if (typeof length === 'number') {
-        return { style: undefined }; // not implemented yet with non-percentage lengths
+        return; // not implemented yet with non-percentage lengths
     }
-
     if (length.unit === '%') {
         return {
-            className: [
-                'md:shrink-0',
-                COLUMN_WIDTHS[Math.round(length.value * 0.01 * (COLUMN_WIDTHS.length - 1))],
-            ],
+            className: 'md:flex-shrink-0 md:[grid-column:var(--grid-col)]',
+            style: {
+                '--grid-col': `auto / span ${Math.round(length.value * 0.01 * COLUMN_DIVISIONS)}`,
+            } as React.CSSProperties,
         };
     }
-
-    return { style: undefined }; // not implemented yet with non-percentage lengths
 }
 
-// Tailwind CSS classes for column widths.
-// The index of the array corresponds to the percentage width of the column.
-const COLUMN_WIDTHS = [
-    'md:w-0',
-    'md:w-1/12',
-    'md:w-2/12',
-    'md:w-3/12',
-    'md:w-4/12',
-    'md:w-5/12',
-    'md:w-6/12',
-    'md:w-7/12',
-    'md:w-8/12',
-    'md:w-9/12',
-    'md:w-10/12',
-    'md:w-11/12',
-    'md:w-full',
-];
+function getFractionalWidth(length: Length) {
+    if (typeof length === 'number') {
+        return 0;
+    }
+    return length.value / 100;
+}