cyclist-grid

v0.3.1

Published

3 years ago

An HTML5 typographic-grid system using Sass.

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robenkleene

css scss sass grid

Cyclist Grid

Cyclist Grid is an HTML/CSS typography and grid framework written in SCSS.

It replaces the default sizes for header elements (i.e., H1-H6) based on the traditional point scale.
- The header font sizes are not fixed, instead they're defined as ratios (based on 12px body type). This means if the body font size is not 12px, then the sizes of the headers maintain their proportional size relative to the body font size. For example, at a font size of 12px, the H1 element will have a font size of 36px (the "double great primer" size), but if the body font size is 11px, then the H1 element will have a font size of 33px (36/12 * 11 = 33).
Text is aligned to the baseline grid using the following rules:
- Headers are given a line-height that's a multiple of the leading.
- All block level elements are given a top-margin of 0 and a bottom-margin equal to the leading.
Cyclist Grid also includes features for defining a horizontal layout grid based on the leading, so that the horizontal spacing is also derived from the vertical rhythm of the typography.

Usage

There are two ways to use Cyclist Grid: either by simply linking the default CSS, or by recompiling the SCSS for finer-grained control.

Use Default CSS

Simply import the compiled CSS file from dist/css/cyclist-grid.css in HTML:

<link rel="stylesheet" href="[path to cyclist]/dist/css/cyclist.css">

This pre-compiled version uses the browsers default font size and a line-height equal to 1.25rem. Since all the line-height and font-size calculations are done in rem units, any font size can be specified on the root HTML element and the header elements will continue to maintain their proportional sizes and all text elements will stay aligned to the baseline grid.

Recompile SCSS

Recompile Sass with a new line-height, font-size, or both by importing the SCSS file at dist/scss/cyclist-grid.scss. Simply set the $font-size and $line-height variables before importing the SCSS file.

$font-size: 15px;
$line-height: 20px;
@import "[path to cyclist]/dist/scss/cyclist-grid";

Caveats

Due to the imprecisions of CSS math, font-size and line-height combinations that result in a leading with a decimal will not align to the baseline grid. For example, a font-size of 16px and line-height of 120% results in a decimal number leading of 19.2 (1.2 * 16 = 19.2). WebKit's handling of the decimal results in inconsistent leading sizes causing the text to drift from the baseline. There are three work-arounds for this problem:
1. Specify a $line-height and $font-size in pixels. The text will always align properly to the baseline grid if the $line-height and $font-size are specified in pixels.
2. Make sure your font-size and line-height combination results in a whole number leading. For example, a $font-size of 12px and a line-height of 125%, results in a leading of 15px (12px × 1.25 = 15px). Since 15px is a whole number, the text will align to the baseline.
3. Just don't worry about the slight drift caused by off-by-one errors rendering text to the baseline.

Typography

Typographic Hierarchy

Traditional typography defines defines the following font sizes:

6pt: nonpareil
7pt: minion
8pt: brevier or small text
9pt: bourgeois or galliard
10pt: long primer or garamond
11pt: small pica or philosophy
12pt: pica
14pt: english or augustin
18pt: great primer
21pt: double small pica or double pica
24pt: double pica or two-line pica
36pt: double great primer or 2-line great primer

It's easy to use these values "as is" in CSS, but then only a few font sizes are available for body text. Only the sizes between 10pt to 18pt are appropriate as body font sizes, and going above 12pt throws off the proportional harmony with the larger sizes.

Cyclist Grid's solution to this problem is to treat these as proportional font sizes rather than specific font sizes. Cyclist Grid uses 12pt ("pica") as the default font size and defines the rest as ratios as follows:

"double great primer": 36 / 12
"double pica": 24 / 12
"double small pica": 21 / 12
"great primer": 18 / 12s
"english": 14 / 12
"pica": 12 / 12
"small pica": 11 / 12
"long primer": 10 / 12
"bourgeois": 9 / 12
"brevier": 8 / 12
"minion": 7 / 12
"nonpareil": 6 / 12

These ratios are then mapped to these HTML header tags:

H1: double great primer
H2: double pica
H3: double small pica
H4: great primer
H5: english
H6: pica

Since these header sizes are defined as ratios to the body size, the header sizes will stay in proportion to the body size, even if the body size is change from 12px. The header font size calculation is [body size] * [ratio]. For example, a body font of 15px will result in an H1 header font size of 45px (15 * (36 / 12) = 45px).

The full range of font sizes can also be used directly as SCSS variables:

$double-great-primer
$double-pica
$double-small-pica
$great-primer
$english
$pica
$small-pica
$long-primer
$bourgeois
$brevier
$minion
$nonpareil

Vertical Rhythm

A vertical rhythm means making the spacing of elements consistently align to the baseline grid.

Cyclist Grid aligns elements to the baseline grid using the following rules:

All default margins and padding are set to zero by the CSS reset.
The line height is used as the leading.
All block level elements are given a bottom margin equal to the leading. (The exception to this is hierarchical sublists, which have a bottom margin of zero, i.e., a list within a list does not have a bottom margin).
Headers are fitted to the closest matching line height that's a multiple of the leading. For example, if the calculated header height is 21px and the leading is 17px, then the line height of the header will be 34px. (This is in addition to having a bottom margin because headers are also block level elements).

Layout

Cyclist Grid's grid approach is to expose Sass variables and functions for positioning elements. In most cases, the columns-width and units-width functions should be used when specifying widths (and horizontal padding and margins). These functions return the width for an integer count multiplier while accounting for the gutter space spanning between the specified division size. For example, to specify an element that spans two columns and is indented two units:

#sidebar {
	margin-left: units-width(2);
	width: columns-width(2);
}

Semantic Classes

Cyclist Grid does not expose any classes of its own, allowing HTML authors to choose semantic classes without interfering.

Grid Functions

These functions are designed to specify the widths of elements that to be laid out on the grid.

@function columns-width($num-columns): Returns a width equal to the number of columns, while adding space for gutters between columns.
@function units-width($num-units): Returns a width equal to the number of units, while adding space for gutters between units.

Grid Variables

While in most cases, it's preferable to use the grid functions to horizontally space elements, it can be useful in some cases to access the widths from the backing Sass variables directly:

$gutter-width: The width of the gutter between columns.
$unit-width: The width of the smallest vertical division, the column is made of up multiples of this.
$column-width: The width of the smallest usable vertical division.

Any of these variables can be overridden.

Calculation Variables

While the grid variables can be overridden directly, a better approach is to use the calculation variables which in turn define the grid variables by default (q.v. dist/sass/_setup.scss). The idea is for the $gutter-width to be defined based on the font size, and then have all the vertical divisions be defined based on the $gutter-width. As a result all the vertical divisions will end up being proportional to the font size of the body text. So the calculation variables allow the sizes of the grid variables to be adjusted (for example, adjusting the $column-width), while maintaining the proportional relationship of the body font size to the sizes of the vertical divisions.

$num-indent-gutters: The multiple of $gutter-width for indenting hierarchical elements (e.g., blockquote and li).
$num-unit-gutters: The multiple of $gutter-width used to set the $unit-width.
$num-column-units: The multiple of $unit-width used to set the $column-width.

By default, the $gutter-width is set to 1rem, this variable can also be overridden.

Overriding Variables

To override any of these variables, simply set them before importing cyclist-grid.scss:

$num-column-units: 4;
@import "[path to cyclist]/dist/cyclist-grid";

Debugging Tools

Cyclist Grid comes with tools to display the baseline grid, to use them:

Import the JavaScript file at dist/js/cyclist-grid.js:

<script src="[path to cyclist]/dist/js/cyclist-grid.js"></script>

Add the class cyclist-show-baseline to the element to show the baseline in (usually the body tag):
```
<body class="cyclist-show-baseline">
```

Tests

Tests can be run by opening the test-*.html files in test/build/html/ in a browser.