devoxx belgium: css grid layout
TRANSCRIPT
CSS Grid Layout
Rachel Andrew
Devoxx.be, November 2015
Tweet @rachelandrew #devoxx #cssgrid
Rachel Andrew
http://rachelandrew.co.uk
@rachelandrew
http://grabaperch.com
CSS in 2015 is amazing.
The trouble with CSS layout
• Floats and clearfix hacks
• Absolute positioning means elements are taken out of document flow and risk overlaps
• Redundant markup and positioning oddities with display: table
• White space issues with inline-block
https://www.flickr.com/photos/zervas/2810241612
Flexbox?
Seeing Flexbox as the silver bullet for layout issues is likely to lead us down
another path of layout hacks.
The cost of taming layout methods
• Developer hours spent learning non-obvious concepts.
• Compromises in terms of document semantics in order to achieve responsive layouts.
• Needing to lean on frameworks to help with complex math.
• Adding markup to create grids
• Using preprocessors to abstract layout hacks
We need a designed for purpose layout system for the sites and applications we develop today.
CSS Grid Layout
Our HTML consists of a div with a class of wrapper and two child elements, a and b.
<div class="wrapper"> <div class="a">A</div> <div class="b">B</div> </div>
To create a grid we use a new value of the display property.
display: grid
.wrapper { display: grid;
}
We describe the grid using the new properties:
grid-template-columns
grid-template-rows
.wrapper { display: grid; grid-template-columns: 100px 100px 100px; grid-template-rows: auto auto; }
We position items using the new properties:
grid-column-startgrid-column-endgrid-row-startgrid-row-end
.a { grid-column-start: 1; grid-column-end: 2; grid-row-start: 1; grid-row-end: 2; }
To position an item bottom centre, I start at column line 2 and end at column line 3.
.b { grid-column-start: 2; grid-column-end: 3; grid-row-start: 2; grid-row-end: 3; }
To span more tracks we just change the end row or column line.
.b { grid-column-start: 2; grid-column-end: 4; grid-row-start: 2; grid-row-end: 3; }
http://bit.ly/aeasf-simple
The longhand for line-based placement means up to 4 properties to position each element. .a {
grid-column-start: 1; grid-column-end: 2; grid-row-start: 1; grid-row-end: 2; }
.b { grid-column-start: 2; grid-column-end: 4; grid-row-start: 2; grid-row-end: 3; }
Declare start and end values with grid-column and grid-row.
Values are separated by a / symbol.
.a { grid-column: 1 / 2; grid-row: 1 / 2; }
.b { grid-column: 2 / 4; grid-row: 2 / 3; }
Declare all 4 values using the grid-area property.
.a { grid-area: 1 / 1 / 2 / 2; }
.b { grid-area: 2 / 2 / 3 / 4; }
Grid lines relate to writing mode. In a right to left language such as
Arabic the first column line is the right-hand line.
Grid Terminology
Grid Lines
Lines can be horizontal or vertical. They are referred to by number and can be
named.
Highlighted is Column Line 2.
Grid Track
A Grid Track is the space between two Grid Lines. Tracks can be horizontal or
vertical (rows or columns).
The highlighted Grid Track is between Row Lines 2 and 3.
Grid Cell
The smallest unit on our grid, a Grid Cell is the space between four Grid Lines. It’s
just like a table cell.
The highlighted Grid Cell is between row lines 2 and 3 and column lines 2 and 3.
Grid Area
Any area of the Grid bound by 4 Grid Lines. It can contain many Grid Cells.
The highlighted Grid Area is between row lines 1 and 3, column lines 2 and 4.
All examples can be found at http://gridbyexample.com. Use Chrome. Enable “Experimental Web Platform Features” flag.
Line-based placement
The HTML around my page content.
The various areas of my page are child elements of a div with a class of wrapper.
<div class="wrapper">
<header class="mainheader"></header>
<div class="panel"></div>
<div class="content"></div>
</div>
Declaring a grid on wrapper.
The grid has two columns and two rows, making 3 column lines and 3 row lines.
.wrapper { width: 100%; max-width: 960px; margin: 0 auto; display: grid; grid-template-columns: 2fr 4fr; grid-template-rows: auto auto; grid-column-gap: 2em; grid-row-gap: 20px; }
The fr unit
• Assigns to the track a fraction of the available space in the container.
• Before fractions are calculated the space assigned to any fixed width tracks and gaps is removed.
• Acts in a similar way to flex-grow in Flexbox.
Grid Layout
I am creating three grid column tracks, all 1fr in width.
This gives me three equally sized column tracks.
.wrapper { display: grid; grid-template-columns: 1fr 1fr 1fr; }
Grid Layout
If I create the first column as 600 pixels and then have two 1fr columns the 600 pixel track is removed from the available space and the remainder is distributed equally between the two columns.
.wrapper { display: grid; grid-template-columns: 600px 1fr 1fr; }
Grid Layout
With a 600 pixel column, a 1fr and a 3fr column. The 600 pixels is removed from the available space then the remaining space is divided by 4.
The 1fr column gets 25% and the 3fr column 75%.
.wrapper { display: grid; grid-template-columns: 600px 1fr 3fr; }
http://alistapart.com/article/holygrail
Three columns. One fixed-width sidebar for your navigation, another for, say, your Google Ads or your Flickr photos—and, as in a fancy truffle, a liquid center for the real substance.
Grid Layout
CSS Grid “Holy Grail”. //css
.wrapper { display: grid; grid-template-columns: 300px 1fr 300px; grid-template-rows: auto; grid-column-gap: 20px; }
.header { grid-column: 1 / 4; }
.content { grid-column: 2 / 3; grid-row: 2 / 3; }
.side1 { grid-column: 1 / 2; grid-row: 2 / 3; }
.side2 { grid-column: 3 / 4; grid-row: 2 / 3; }
.footer { grid-column: 1 / 4; grid-row: 3 / 4; }
//html <div class="wrapper"> <header class="header">This is the header</header> <article class="content"></article> <div class="side1"></div> <div class="side2"></div> <footer class="footer"></div> </div>
Declaring a grid on wrapper.
The grid has two columns and two rows, making 3 column lines and 3 row lines.
.wrapper { width: 100%; max-width: 960px; margin: 0 auto; display: grid; grid-template-columns: 2fr 4fr; grid-template-rows: auto auto; grid-column-gap: 2em; grid-row-gap: 20px; }
Positioning our elements using the grid-column and grid-row shorthand.
This is all we need to do to create our layout.
.mainheader { grid-column: 1 / 3; grid-row: 1 / 2; }
.panel { grid-column: 1 / 2; grid-row: 2 / 3; }
.content { grid-column: 2 / 3; grid-row: 2 / 3; }
I can add a footer to this layout.
<div class="wrapper">
<header class="mainheader"></header>
<div class="panel"></div>
<div class="content"></div>
<footer class="mainfooter"></footer>
</div>
Positioning the footer between row lines three and four.
.mainfooter { grid-column: 1 / 3; grid-row: 3 / 4; }
Our grid only has 3 row lines specified - yet we placed an item between row lines 3 and 4.
Grid creates an implicit grid line for us.
.wrapper { display: grid; grid-template-columns: 2fr 4fr; grid-template-rows: auto auto; grid-column-gap: 2em; grid-row-gap: 20px; }
.mainfooter { grid-column: 1 / 3; grid-row: 3 / 4; }
Grid lines can be explicit or implicit
• Explicit grid lines are those specified using grid-template-rows or grid-template-columns.
• Implicit lines are created when you place something into a row or column track outside of the explicit grid.
• Default behaviour is those tracks are auto sized. You can specify a size with the grid-auto-columns and grid-auto-rows properties.
For many layouts you may be able to not specify grid-template-rows at all. Grid will create rows as you position content.
.wrapper { display: grid; grid-template-columns: 2fr 4fr; grid-column-gap: 2em; grid-row-gap: 20px; }
Grid is “table like” however …
• Unlike a table for layout Grid does not rely on your content being a particular order in the source.
• Being entirely described in CSS we can move things around the Grid at different breakpoints, introduce or redefine a Grid for any breakpoint.
Using Grid to order the page elements in a single column for narrow screen widths.
.wrapper { display: grid; grid-row-gap: 10px; } .mainheader { grid-row: 1 / 2; }
.content { grid-row: 2 / 3; }
.panel { grid-row: 3 / 4; }
.mainfooter { grid-row: 4 / 5; }
Redefine the Grid at min-width 550 pixels.
Position items as in the earlier example.
@media (min-width: 550px) { .wrapper { grid-template-columns: 2fr 4fr; grid-column-gap: 2em; grid-row-gap: 20px; } .mainheader { grid-column: 1 / 3; grid-row: 1 / 2; } .panel { grid-column: 1 / 2; grid-row: 2 / 3; } .content { grid-column: 2 / 3; grid-row: 2 / 3; } .mainfooter { grid-column: 1 / 3; grid-row: 3 / 4; } }
Named Grid Lines
Name lines with the name in square brackets.
Remember we are naming grid lines and not grid tracks. .wrapper {
display: grid; grid-row-gap: 10px; grid-template-rows: [row-header-start] auto [row-content-start] auto [row-panel-start] auto [row-footer-start] auto [row-footer-end]; }
Here we are positioning based on line numbers.
.mainheader { grid-row: 1 / 2; }
.content { grid-row: 2 / 3; }
.panel { grid-row: 3 / 4; }
.mainfooter { grid-row: 4 / 5; }
Here we are positioning by named lines.
.mainheader { grid-row: row-header-start; }
.content { grid-row: row-content-start; }
.panel { grid-row: row-panel-start; }
.mainfooter { grid-row: row-footer-start; }
Named Areas
We assign a name to the elements on our page.
I am doing this outside of any Media Queries.
.mainheader { grid-area: header; }
.content { grid-area: content; }
.panel { grid-area: sidebar; }
.mainfooter { grid-area: footer; }
Describe the layout on the parent element using the grid-template-areas property.
.wrapper { display: grid; grid-row-gap: 10px; grid-template-areas: "header" "content" "sidebar" "footer"; }
Redefining the template areas for the wider layout. @media (min-width: 550px) {
.wrapper { grid-column-gap: 2em; grid-row-gap: 20px; grid-template-columns: 2fr 4fr; grid-template-areas: "header header" "sidebar content" "footer footer" }
}
Repeating the name of an area causes the area to span across those grid cells.
This can be seen in the header and footer of this layout.
@media (min-width: 550px) {
.wrapper { grid-column-gap: 2em; grid-row-gap: 20px; grid-template-columns: 2fr 4fr; grid-template-areas: "header header" "sidebar content" "footer footer" }
}
Repeating the name of an area causes the area to span across those grid cells.
This can be seen in the header and footer of this layout.
@media (min-width: 550px) {
.wrapper { grid-column-gap: 2em; grid-row-gap: 20px; grid-template-columns: 2fr 4fr; grid-template-areas: "header header" "sidebar content" " . footer" }
}
Implicit Named Grid Lines
Named grid areas create four implicit named lines. You can use these in the same way as lines you have explicitly named.
.wrapper { .wrapper { grid-column-gap: 2em; grid-row-gap: 20px; grid-template-columns: 2fr 4fr; grid-template-areas: "header header" "sidebar content" "footer footer" } }
.test { z-index: 100; background-color: red; grid-column: content-start / content-end; grid-row: content-start / footer-end; }
Items on the Grid can be layered using the z-index property.
A 12 column, flexible grid
The Bootstrap grid, and those in other frameworks relies on our describing the layout in the markup.
<!-- Stack the columns on mobile by making one full-width and the other half-width --> <div class="row"> <div class="col-xs-12 col-md-8">.col-xs-12 .col-md-8</div> <div class="col-xs-6 col-md-4">.col-xs-6 .col-md-4</div> </div>
<!-- Columns start at 50% wide on mobile and bump up to 33.3% wide on desktop --> <div class="row"> <div class="col-xs-6 col-md-4">.col-xs-6 .col-md-4</div> <div class="col-xs-6 col-md-4">.col-xs-6 .col-md-4</div> <div class="col-xs-6 col-md-4">.col-xs-6 .col-md-4</div> </div>
<!-- Columns are always 50% wide, on mobile and desktop --> <div class="row"> <div class="col-xs-6">.col-xs-6</div> <div class="col-xs-6">.col-xs-6</div> </div>
With CSS Grid Layout we describe the layout in the CSS and can redefine that description at any breakpoint.
You can use the repeat keyword to repeat all or part of the grid definition.
This would create 4 200 pixel wide tracks, separated by a 100 pixel wide track.
grid-template-columns: repeat(4, 200px 100px);
We can give multiple grid lines the same name.
This means we can use the span keyword to span n number of lines, rather than specifying a specific grid line.
.wrapper { grid-template-columns: repeat(4, [col-a] 200px [col-b] 100px); }
.content { grid-column: col-a 2 / span 2; }
.aside { grid-column: col-a 2 / span col-b 2; }
The markup used to create the Grid using the Skeleton framework.
Like the Bootstrap Grid and other similar frameworks it requires classes that describe the grid to be added to the markup.
<div class="container"> <h1>Skeleton Grid</h1> <div class="example-grid"> <div class="row"> <div class="four columns">Four columns</div> <div class="four columns">Four columns</div> <div class="four columns">Four columns</div> </div> <div class="row"> <div class="eight columns">Eight columns</div> <div class="four columns">Four columns</div> </div> <div class="row"> <div class="three columns">Three columns</div> <div class="three columns">Three columns</div> <div class="three columns">Three columns</div> <div class="three columns">Three columns</div> </div> <div class="row"> <div class="six columns">Six columns</div> <div class="six columns">Six columns</div> </div> </div>
When using CSS Grid Layout we have no need to describe our grid in markup.
<div class="wrapper skeleton"> <h1 class="header">CSS Grid Layout Version</h1> <div class="box1">Four columns</div> <div class="box2">Four columns</div> <div class="box3">Four columns</div> <div class="box4">Eight columns</div> <div class="box5">Four columns</div> <div class="box6">Three columns</div> <div class="box7">Three columns</div> <div class="box8">Three columns</div> <div class="box9">Three columns</div> <div class="box10">Six columns</div> <div class="box11">Six columns</div> </div>
Defining the 12 column grid.
The repeat keyword repeats the pattern of columns or rows the number of times specified before the comma.
.wrapper { display: grid; grid-template-columns: repeat(12, [col] 1fr ); grid-template-rows: repeat(5, [row] auto) ; grid-column-gap: 1em; grid-row-gap: 15px; }
Placing box1 on the grid.
Multiple lines have the same name. This means we can use the span keyword. Here I place box1 starting at the first line named col, spanning to the 4th line.
The box is placed in the first line named row and spans 1 line - the default.
.box1 { grid-column: col / span 4; grid-row: row ; }
Placing box8 on the grid.
Starting on column line 7, spanning 3 lines.
In the 3rd row named row, spanning 1 line.
.box8 { grid-column: col 7 / span 3; grid-row: row 3 ; }
With Grid Layout we can easily span rows just like columns.
.box1b { grid-column: col / span 4; grid-row: row / span 2; }
.box2b { grid-column: col 5 / span 4; grid-row: row / span 3; }
The header and footer span the full grid.
The content and panel display side by side.
.mainheader { grid-column: col / span 12; grid-row: row ; }
.mainfooter { grid-column: col / span 12; grid-row: row 3 ; }
.content { grid-column: col 5 / span 8; grid-row: row 2 ; }
.panel { grid-column: col / span 4; grid-row: row 2 ; }
The header and footer span the full grid.
The content and panel display side by side.
.mainheader { grid-column: col / span 12; grid-row: row ; }
.mainfooter { grid-column: col / span 12; grid-row: row 3 ; }
.content { grid-column: col 5 / span 8; grid-row: row 2 ; }
.panel { grid-column: col / span 4; grid-row: row 2 ; }
I change three values to make our panel extend to the foot of the page.
.mainheader { grid-column: col / span 12; grid-row: row ; }
.mainfooter { grid-column: col 5 / span 8; grid-row: row 3 ; }
.content { grid-column: col 5 / span 8; grid-row: row 2 ; }
.panel { grid-column: col / span 4; grid-row: row 2 / span 2 ; }
Grid Item Placement Algorithm
http://dev.w3.org/csswg/css-grid/#grid-item-placement-algorithm
“The following grid item placement algorithm resolves automatic positions of grid items into definite positions, ensuring that every grid item has a well-defined grid area to lay out into.”
My markup is an unordered list with a class of wrapper.
The first list item contains text. The rest an image.
Two list items have a class of ‘wide’.
<ul class="wrapper"> <li class="text"><p>…</p></li> <li><img src="../images/balloon1.jpg" alt="hot air balloon" /> <p>Balloons 1</p></li> <li><img src="../images/balloon2.jpg" alt="hot air balloon" /> <p>Balloons 2</p></li> <li><img src="../images/balloon3.jpg" alt="hot air balloon" /> <p>Balloons 3</p></li> <li class="wide"><img src="../images/balloon4.jpg" alt="hot air balloon" /> <p>Balloons 4</p></li> <li><img src="../images/balloon5.jpg" alt="hot air balloon" /> <p>Balloons 5</p></li> <li><img src="../images/balloon6.jpg" alt="hot air balloon" /> <p>Balloons 6</p></li> <li class="wide"><img src="../images/balloon7.jpg" alt="hot air balloon" /> <p>Balloons 7</p></li> <li><img src="../images/balloon8.jpg" alt="hot air balloon" /> <p>Balloons 8</p></li> </ul>
Narrow screen layout, before any media queries.
A single column, single row grid.
Grid layout will create implicit rows for any additional list items.
.wrapper { display: grid; grid-template-columns: 1fr; grid-template-rows: auto; grid-auto-flow: dense; }
At a 460 pixel breakpoint we redefine the grid to have two equal columns.
With grid-auto-flow set to dense gaps are not left in the grid if they can be filled.
@media (min-width: 460px) { .wrapper { grid-template-columns: 1fr 1fr; } .text { grid-column: 1 / 3; } .wide { grid-column: auto / span 2; } }
We move to 4 equal columns at 660 pixels.
I position the li with a class of text between column lines 2 and 4, and row lines 1 and 3.
@media (min-width: 660px) { .wrapper { grid-template-columns: 1fr 1fr 1fr 1fr; }
.text { grid-column: 2 / 4; grid-row: 1 / 3; } }
The complete CSS for this grid.
.wrapper { display: grid; max-width: 960px; grid-template-columns: 1fr; grid-template-rows: auto; grid-auto-flow: dense; }
@media (min-width: 460px) { .wrapper { grid-template-columns: 1fr 1fr; } .text { grid-column: 1 / 3; } .wide { grid-column: auto / span 2; } }
@media (min-width: 660px) { .wrapper { grid-template-columns: 1fr 1fr 1fr 1fr; } .text { grid-column: 2 / 4; grid-row: 1 / 3; } }
We change the value of grid-auto-flow to sparse.
.wrapper { display: grid; max-width: 960px; grid-template-columns: 1fr; grid-template-rows: auto; grid-auto-flow: sparse; }
@media (min-width: 460px) { .wrapper { grid-template-columns: 1fr 1fr; } .text { grid-column: 1 / 3; } .wide { grid-column: auto / span 2; } }
@media (min-width: 660px) { .wrapper { grid-template-columns: 1fr 1fr 1fr 1fr; } .text { grid-column: 2 / 4; grid-row: 1 / 3; } }
Grid and the Box Alignment Module
CSS Box Alignment Module Level 3
“This module contains the features of CSS relating to the alignment of boxes within their containers in the various CSS box layout models: block layout, table layout, flex layout, and grid layout.” - https://drafts.csswg.org/css-align/
Grid Layout
Creating a grid with the align-items property set to centre.
All items will be centered inside their grid area.
.wrapper { display: grid; align-items: center; grid-template-columns: repeat(5, 150px 10px) 150px; grid-template-rows: 150px 10px 150px 10px 150px 10px 150px; } .a { grid-column: 1 / 4; grid-row: 1 / 4; } .b { grid-column: 5 / 8; grid-row: 1 / 4; } .c { grid-column: 1 / 4; grid-row: 5 / 10; } .d { grid-column: 5 / 8; grid-row: 5 / 10; } .e { grid-column: 9 / 12; grid-row: 1 / 10; }
Grid Layout
Creating a grid with the justify-items property set to centre.
All items will be centered horizontally inside their grid area.
.wrapper { display: grid; justify-items: center; grid-template-columns: repeat(5, 150px 10px) 150px; grid-template-rows: 150px 10px 150px 10px 150px 10px 150px; } .a { grid-column: 1 / 4; grid-row: 1 / 4; } .b { grid-column: 5 / 8; grid-row: 1 / 4; } .c { grid-column: 1 / 4; grid-row: 5 / 10; } .d { grid-column: 5 / 8; grid-row: 5 / 10; } .e { grid-column: 9 / 12; grid-row: 1 / 10; }
Grid Layout
As with flexbox we can use align-self and justify-self to target individual grid items.
.a { grid-column: 1 / 4; grid-row: 1 / 4; align-self: stretch; } .b { grid-column: 5 / 8; grid-row: 1 / 4; align-self: end; } .c { grid-column: 1 / 4; grid-row: 5 / 10; align-self: start; } .d { grid-column: 5 / 8; grid-row: 5 / 10; align-self: center; } .e { grid-column: 9 / 12; grid-row: 1 / 10; }
Grid and Accessibility
With great power comes responsibility.
Power and responsibility
• Good = creating the most accessible source order and using Grid or Flexbox to get the optimal display for each device.
• Bad = using Grid or Flexbox as an excuse to forget about the source.
• Terrible - stripping out semantic elements to make everything a grid or flex item.
https://drafts.csswg.org/css-grid/#source-independence
Grid item placement and reordering must not be used as a substitute for correct source ordering, as that can ruin the accessibility of the document.
http://adrianroselli.com/2015/10/html-source-order-vs-css-display-order.html
https://rachelandrew.co.uk/archives/2015/07/28/modern-css-layout-power-and-responsibility/
Nested Grids and Subgrids
In this markup the boxes e, f and g are children of the element with a class of d.
<div class="wrapper"> <div class="box a">A</div> <div class="box b">B</div> <div class="box c">C</div> <div class="box d"> <div class="box e">E</div> <div class="box f">F</div> <div class="box g">G</div> </div> </div>
I have declared a grid on the wrapper div, and positioned the immediate children - the elements with classes a to d.
.wrapper { display: grid; grid-gap: 10px; grid-template-columns: repeat(4, [col] 150px); repeat(2, [row] auto); } .a { grid-column: col / span 2; grid-row: row; } .b { grid-column: col 3 / span 2; grid-row: row; } .c { grid-column: col / span 2; grid-row: row 2; } .d{ grid-column: col 3 / span 2; grid-row: row 2; }
To make box d a grid itself I declare a grid as normal then position the children of this element.
They take their grid lines from the grid declared on box d.
.d{ grid-column: col 3 / span gutter 2; grid-row: row 2; display: grid; grid-gap: 10px; grid-template-columns: 1fr 1fr; }
.e { grid-column: 1 / 3; grid-row: 1; }
.f { grid-column: 1; grid-row: 2; }
.g { grid-column: 2; grid-row: 2; }
Declaring a subgrid
In our existing layout we are creating a completely new grid on box d.
.d{ grid-column: col 3 / span 2; grid-row: row 2; display: grid; grid-gap: 10px; grid-template-columns: 1fr 1fr; }
If we declare that this grid is a subgrid, we can then position the children of this element on the same grid their parent is placed on. .d{
grid-column: col 3 / span 2; grid-row: row 2; display: grid; grid-template-columns: subgrid; grid-template-rows: subgrid; }
http://dev.w3.org/csswg/css-grid/
“The following features are at-risk, and may be dropped during the CR period:
the subgrid value of grid-template-columns and grid-template-rows, and its component parts individually”
Without subgrid we create the potential for accessibility problems. Authors may remove semantic markup in order to use grid layout.
Grid needs your feedback!
Enable Experimental Web Platform Features in Chrome.
Play with my examples and think up ways you would use Grid.
Follow the CSS Grid conversation on www-style by searching for [css-grid].
See the current issues in the Editor’s Draft http://dev.w3.org/csswg/css-grid/#issues-index
Browser SupportAll my examples work in Chrome unprefixed - you need to enable the Experimental Web Platform Features flag.
You can also use Webkit nightlies, with the -webkit prefix.
The work in Blink and Webkit is being done by Igalia, sponsored by Bloomberg.
IE10 and up has support for the old syntax, with an -ms prefix.
Grid is on the Edge backlog, marked as High Priority.
Mozilla are currently implementing Grid in Firefox. Some examples work in Firefox Nightlies.
There is a Polyfill under active development: https://github.com/FremyCompany/css-grid-polyfill/
All examples can be found at http://gridbyexample.com. Use Chrome. Enable “Experimental Web Platform Features” flag.
Thank you!
https://rachelandrew.co.uk/presentations/css-grid
@rachelandrew