blocklayout

A html preprocessor to transform a simple block graphic into a flex grid.

Example

You write this

<div data-grid style="height:20em; width:20em">
blue         | green|
red  |grey   |  "   |
 "   |yellow        |
</div>
<div data-field="blue" style="background: blue;"></div>
<div data-field="green" style="background: green"></div>
<div data-field="red" style="background:red"></div>
<div data-field="yellow" style="background:yellow"></div>
<div data-field="grey" style="background:grey"></div>

blocklayout transforms it to this

<div style="height: 20em; width: 20em; display: grid;">
<div style="background: blue; grid-column-start: 1; grid-column-end: 3; grid-row-start: 1; grid-row-end: 2;"></div>
<div style="background: green; grid-column-start: 3; grid-column-end: 4; grid-row-start: 1; grid-row-end: 3;"></div>
<div style="background: red; grid-column-start: 1; grid-column-end: 2; grid-row-start: 2; grid-row-end: 4;"></div>
<div style="background: grey; grid-column-start: 2; grid-column-end: 3; grid-row-start: 2; grid-row-end: 3;"></div>
<div style="background: yellow; grid-column-start: 2; grid-column-end: 4; grid-row-start: 3; grid-row-end: 4;"></div>
</div>

and this is the result

Usage

Install with

npm install blocklayout --save-dev

To run the preprocessor call

npx blocklayout foo.html > processed.html

For svelte there is a preprocessor plugin for svelte.config.js

import adapter from '@sveltejs/adapter-auto';
import blocklayout from "blocklayout/svelte";

/** @type {import('@sveltejs/kit').Config} */
const config = {
  kit: {
    adapter: adapter()
  },
  preprocess: [
    blocklayout(),
  ],
};

export default config;

Documentation

A grid layout is defined by the attribute data-grid, the content of the flex grid cells is defined by the attribute data-field. The design is fairly simple: columns are separated by a | and rows are separated by a new line. If a cell shall be spanned over multiple rows use ".

Alignment

You can align cells to the grid by adding a specification in curly brackets {}.

<div data-grid style="height: 20em; width: 20em; border: 1px solid black">
top-left{tl}   |top-center{tc}   |top-right{tr}
middle-left{ml}|middle-center{mc}|middle-right{mr}
bottom-left{bl}|bottom-center{bc}|bottom-right{br}
</div>

|Alignment Char | Effect | |---- | ---- | |l | cell is aligned to the left| |c | cell is aligned in the center | |r | cell is aligned to right | |j | cell is horizontally stretched| |t | cell is aligned to the top| |m | cell is aligned in the middle | |b | cell is aligned to bottom | |e | cell is vertically stretched|

Stretchers

You can define which columns or rows should be stretched by including the stretch factor at the last column/row in straight brackets [].

<div data-grid style="height: 10em; width: 20em; border: 1px solid black">
column-stretched |column-fixed|
column-spanned                |
row-fixed        |row-spanned |
row-stretched    |   "        |[1]
[1]              |
</div>

Tabindex

You can define the tab order of the cells by adding a number in curly brackets {}

<div data-grid="10">
one{1}  |sub{4}
two{2}  | "
three{3}| "
</div>
<a data-field="one" tabindex="1">one</a>
<a data-field="two" tabindex="1">two</a>
<a data-field="three" tabindex="1">three</a>
<div data-grid data-field="sub">
five{2}
four{1}
six{3}
</div>
<a data-field="four" tabindex="1">four</a>
<a data-field="five" tabindex="1">five</a>
<a data-field="six" tabindex="1">six</a>

Results in

<div style="display: grid;">
  <a tabindex="10" style="...">one</a>
  <div style="display: grid; ...">
    <a tabindex="14" style="...">five</a>
    <a tabindex="13" style="...">four</a>
    <a tabindex="15" style="...">six</a>
  </div>
  <a tabindex="11" style="...">two</a>
  <a tabindex="12" style="...">three</a>
</div>

• blocklayout cares for tabindexes of sub designs
• blocklayout will only modify elements with an tabindex >= 0
• you can specify the starting tabindex by setting the data-grid attribute to a number.
• if there is an alignment specification the tabindex must be after the alignment.