Files
base-examples/firebase.md
2020-04-19 03:26:45 +01:00

1175 lines
33 KiB
Markdown

# Firebase
API documentation (JS): <https://firebase.google.com/docs/reference/js>
Guides documentation: <https://firebase.google.com/docs/guides>
Handling errors
List of errors: <https://firebase.google.com/docs/reference/js/firebase.auth.Auth#createuserwithemailandpassword>
You can catch the error and use if/else to capture the specific error.
```javascript
firebase
.auth()
.createUserWithEmailAndPassword(email, password)
.catch(function(error) {
// Handle Errors here.
var errorCode = error.code;
var errorMessage = error.message;
if (errorCode == "auth/weak-password") {
alert("The password is too weak.");
} else {
alert(errorMessage);
}
console.log(error);
});
```
Firebase User object:
<https://firebase.google.com/docs/reference/js/firebase.User>
All properties that it takes/available listed above
## Create new User
Use `firebase.auth().createUserWithEmailAndPassword(email, password)` to create a new user.
Only an email address and password is needed to create a new account. The user itself has a few additional attributes you can attach to it - the `displayName` and the `photoURL` among a few others. You can see all of them in the properties of the user object:
`https://firebase.google.com/docs/reference/js/firebase.User#properties`
Any additional information you want to store alongside the user should use a firestore. You should have a collecton for users, then each document should be named after the `User.uid` and contain the additional data you want to store.
## Update password/email
The instructions to update a password/email:
<https://firebase.google.com/docs/auth/web/manage-users#re-authenticate_a_user>
mention using `reauthenticateWithCredential`. This is only needed if using a 3rd party auth method which returns this credential object. If using native firebase logins then simply forcing the user to resign in is sufficient.
## Adding material icons to Vuetify project
`yarn add @mdi/font -D`
## Controlling layouts
### Spacing
<https://vuetifyjs.com/en/styles/spacing/>
You can use helper classes to apply custom margins/padding to elements.
You can apply padding to left: `class="pl-3"`.
Or apply margin to all: `class="ma-4"`.
You can use this to center objects without using flex:
`class="mx-auto"`.
### Display helpers
The display helpers allow you to control the dispaly of content. These can be used to hide/show elements based on the current viewport, or the actual display element type.
<https://vuetifyjs.com/en/styles/display/>
### Hide/Display elements for different widths
You can hide specific viewport sizes with:
<https://vuetifyjs.com/en/styles/display/#visibility>
`d-flex` by default without any size will apply to `xs` and above.
You can make things visible only on one viewport with:
`class="d-none d-lg-flex d-xl-none"`
You can make things hide only on one viewport with:
`class="d-lg-none d-xl-flex"`
You can hide multiple by using combinations of the above, or, use the following lateral display helper classes:
`class="hidden-md-and-up"` and `class="hidden-sm-and-down"`
### flex
Using flex will make the object fill the entire viewport, rather than adhering to the margins/widths by default. There is a lot more to flex - you can make things align left/right, vertical alignment and more:
<https://vuetifyjs.com/en/styles/flex/#flex>
### cols
In a `<v-row>` you can have many `<v-col>`. You can have as many of these and use the `cols` prop to control how wide the content should be.
```html
<v-col cols="4" class="appTitle d-flex justify-start">
<v-toolbar-title>
Savvy Firebase tutorial
</v-toolbar-title>
</v-col>
```
You can combine this with `d-flex` and justify to control the positioning and alignment:
<https://vuetifyjs.com/en/styles/flex/#flex-justify>
Justify classes include:
- `justify-start`
- `justify-end`
- `justify-center`
- `justify-space-between`
- `justify-space-around`
Using `cols`, `d-flex` and `justify` you can control precisely how things should be laid out for different screen sizes.
- Use `<v-col>`, use the prop `cols=""` to control how wide it should be.
- Use `<v-spacer>`, to dynamically fill space.
- Use `class="d-flex"` and the justify classes.
- Use `class="d-none d-xl-flex"` to control layouts for different sizes.
- Use `class="hidden-md-and-up"` to quickly control layouts for different sizes.
### Dual layouts
You can have the same html element for different sizes.
The layout you want for the screen you want to break on should **not** include it.
For example, to break on the medium viewport and have the second layout apply to it:
```html
<v-app-bar flat color="indigo" app class="hidden-md-and-up"></v-app-bar>
<v-app-bar flat color="indigo" app class="hidden-sm-and-down"></v-app-bar>
```
Here the second layout does not include the medium layout, hence the medium layout will apply to it.
## App bar
### Gradient as a background colour
The background image to the app bar is provided with a `src` prop.
If you want to apply a fade gradient colour on top of the image, you should use a scoped slot:
```html
<v-app-bar
flat
app
class="hidden-sm-and-down"
src="https://www.stellamccartney.com/cloud/smcwp/uploads/2016/01/1920x1080-black-solid-color-background.jpg"
>
<template v-slot:img="{props}">
<v-img
v-bind="props"
gradient="to top right, rgba(100,115,201,.7), rgba(25,32,72,.7)"
></v-img> </template
></v-app-bar>
```
If you want to just use a gradient (no img), then apply a solid colour image and then use a scoped slot with the gradient you want.
## Router
When linking to routes, you should use `<router-link>`:
```html
<router-link :to="{ name: 'Login' }">
<span class="mr-3">Sign In</span>
</router-link>
```
You can apply transitions on a route change:
```html
<transition name="slide">
<router-view></router-view>
</transition>
```
## vue-responsive-video-background-player
<https://github.com/avidofood/vue-responsive-video-background-player>
yarn add vue-responsive-video-background-player
ffmpeg -an -i Optical\ Fibers\ 1.mov -vcodec libx264 -pix_fmt yuv420p -profile:v baseline -level 3 optical.mp4
<https://cli.vuejs.org/guide/html-and-static-assets.html#disable-index-generation>
If using the public folder (not `./assets`) then follow these instructions:
<https://cli.vuejs.org/guide/html-and-static-assets.html#the-public-folder>
For videos in ./assets do the following:
```javascript
export default {
data() {
return {
video: require("../assets/videos/optical.mp4")
};
}
};
```
and reference it in the component:
```html
<video-background :src="video" style=" height: 100vh;"> </video-background>
```
This is done this way because webpack will apply custom names to the assets - this is so it can handle caching.
You can find full props to customise the video:
<https://github.com/avidofood/vue-responsive-video-background-player#props>
You can set a gradient to the image to improve visibility:
```javascript
style = " height: 100vh;";
overlay = "linear-gradient(45deg,#2a4ae430,#fb949e6b)";
```
## Dynamically hide app bar
Use the Vuex store to determine when you want to hide the app bar:
```javascript
state: {
fullScreen: false
},
getters: {
fullScreen: state => {
return state.fullScreen
}
},
mutations: {
fullScreen(state, fullScreen) {
state.fullScreen = fullScreen;
}
},
```
and create the lifecycle actions in the component that houses the appbar:
```javascript
created () {
this.$store.commit("fullScreen", true);
},
beforeDestroy () {
this.$store.commit("fullScreen", false);
},
```
Then you can wrap the appbar in a `v-if`:
```html
<v-app-bar
flat
app
class="hidden-sm-and-down"
color="#EEEEEE"
v-if="!this.$store.getters.fullScreen"
></v-app-bar>
```
## Change default font colour
In `_variables.scss` create a variable with the colour you want:
```scss
$mainColor: #323947;
```
Then create a new class `fontColor` to apply to the router, and edit the default `theme--light` class for Vuetify to apply this colour:
```scss
.theme--light.v-application,
.fontColor,
.theme--light.v-sheet {
color: $mainColor !important;
// color: red !important;
}
```
Then in `App.vue` apply the `fontColor` class to the `<v-app>`:
```html
<v-app
:style="{ background: $vuetify.theme.themes.light.background }"
class="fontColor"
></v-app>
```
## Grids
<https://vuetifyjs.com/en/components/grids/#row-and-column-breakpoints>
In addition to using the flex classes you can use the grid system. The grid system allows you to create rows and columns and use props to control how the content should be displayed.
This playground demonstrates what `align` and `justify` can do:
<https://vuetifyjs.com/en/components/grids/#playground>
The grid system applies to `<v-row>` and you can use the following props:
- `align` controls the y-axis. You have `start`, `center`, `end`, `baseline` and `stretch`.
- `justify` controls the x-axis. You have `start`, `center`, `end`, `space-around` and `space-between`.
For `<v-col>` only `align-self` is available. To align content on a column, or any other element like a card, you should use the same classes as in the flex system. For example:
```html
<v-col cols="5" align-self="start" class="d-flex justify-end pr-0"></v-col>
```
## Container filling whole page
A container should be used whenever you want to use `<v-col>` and `<v-row>`. To make this container fill the whole page (and be able to use `align` props and flex classes) you should specify the following two props:
- `fill-height`
- `fluid`.
To make content fill the width of the element it is in, you can use the following css:
```css
.full-width {
width: 100%;
}
```
`width` sets the element to the percentage of its parent. So to have a textbox fill the width of the v-card element it is in you should set the `<v-card>`, `<v-form>` and `<v-text-field>` to `width: 100%;`. As long as the parent elements have 100%, you can set the text input to be a percentage of this, say 50%.
## Multi column layouts
An example can be found here:
<https://git.panaetius.co.uk/web-development/savvy-firebase/src/branch/base-template/src/views/forms/LoginForm.vue>
You can make use of the above to create dynamic layouts.
One idea (for a login page) might be to use the following nested layout:
### Container
A `<v-container>` with `fill-height` and `fluid` props.
### Row
A `<v-row>`
### Columns
A `<v-col>` with `align-self="stretch"` and `class="d-flex flex-column justify-space-between"`.
`align-self=stretch` allows each child of the column to _stretch_ (<https://developer.mozilla.org/en-US/docs/Web/CSS/align-items)>.
`class="d-flex flex-column justify-space-between"` allows each child of the column to flex - with justify-space-between putting them equally apart top to bottom. It's used to equally space out the _rows_ inside this column. Even though we are not using `<v-row>`.
### Cards
A `<v-card>` with `class="d-flex align-end flex-column"`.
`class="d-flex align-end flex-column"` allows content inside the card to flex. The `align-end` means they will be on the right hand side and flex-column means they are flexing across columns.
To make text align right, you should use the `text-right` class:
`<p class="whiteText font-regular text-right mb-0">`
This is because although the `<p>` element will align to the right becasue of the class from the `<v-card>`, the text inside will align to the left.
We can add `color="rgb(0, 0, 0, 0)"` and `flat` props to the card - allowing it to seamlessly blend in with the background.
We can add mulitple cards to this layout in this column - and control how they are spaced with the props on the column.
We can add `<v-spacer>` and then add additional colums with the same props to add content in a column like manner.
Important!
If you want content to be aligned in a column with each item on a new line, then use:
```html
<v-col cols="6" align-self="center" class="">
<v-card color="rgb(0, 0, 0, 0)" flat class="d-flex align-center flex-column">
<v-icon color="white" size="3em">mdi-account-circle</v-icon>
<p class="mb-0 display-2">Login</p></v-card
></v-col
>
```
## Helper classes
### Spacing
<https://vuetifyjs.com/en/styles/spacing/>
You can use classes like `ma-2` and `pd-3` to control margin/padding in directions for any component.
See the playground for a quick demonstration on what each one does:
<https://vuetifyjs.com/en/styles/spacing/#playground>
## Typography
There are quite a few helper classes available to control font sizes and styles.
<https://vuetifyjs.com/en/styles/typography/>
There are two types of styles: Typography Display Classes and Style and Weight Classes.
Examples include `.display-2` and `.font-weight-black`.
### Replace Vuetify default font with custom
Fonts needed to replace the Roboto default:
- Thin
- Regular
- Medium
- Light
- Condensed Light (Light)
- Bold
- Black
- italic
- Light italic
- Medium italic
- Bold italic
If font styles dont exist then substitute them with the closest type.
An example of a stylesheet replacing all of these with the Gilroy font is here:
<https://git.panaetius.co.uk/web-development/savvy-firebase/src/branch/base-template/src/scss/_variables.scss>
## Custom colour theme
Creating a custom colour theme for Vuetify is straightforward.
<https://mycolor.space> is a good resource to generate palettes from a colour.
See <https://vuetifyjs.com/en/customization/theme/#customizing> for details on customising a theme.
### Editable colours
You change the `Vuetify` object in `vuetify.js`:
```javascript
export default new Vuetify({
icons: {
iconfont: "mdi"
},
theme: {
themes: {
light: {
primary: "#051937",
secondary: "#374366",
accent: "#d4a418",
background: "#e8e8e8"
}
}
}
});
```
These are the editable colours you can choose for Vuetify
```json
{
"primary": "#1976D2",
"secondary": "#424242",
"accent": "#82B1FF",
"error": "#FF5252",
"info": "#2196F3",
"success": "#4CAF50",
"warning": "#FFC107"
}
```
These follow the Material style of colours:
<https://material.io/design/color/the-color-system.html#color-theme-creation>
The accent colour in Vuetify isn't really specified in the Material colour design - typically the secondary colour would be used as an accent colour - with shades of the primary used throughout the UI. However in some themes you may wish to use primary and secondary together, and have a seperate accent colour.
<https://material.io/design/color/the-color-system.html#color-theme-creation>
### Colour variants
Vuetify will automatically generate darken and lighten colour variants of the primary and secondary colours in the theme. If you want to control these manually you can do so following the instructions:
<https://vuetifyjs.com/en/customization/theme/#custom-theme-variants>
The variants you can use are:
```json
{
"base": "string",
"lighten5": "string",
"lighten4": "string",
"lighten3": "string",
"lighten2": "string",
"lighten1": "string",
"darken1": "string",
"darken2": "string",
"darken3": "string",
"darken4": "string"
}
```
You can apply these as a class to the object you want to darken/lighten.
For example:
`<v-btn color="primary" class="darken-2">Hello</v-btn>`
## Forms
### Changing the colour of form inputs
You can change the background colour, and the highlight colour (when clicked) with the following props:
```html
<v-text-field
v-model="username"
background-color="rgb(100%, 100%, 100%, 10%)"
color="rgb(100%, 100%, 100%, 10%)"
class="white-placeholder"
></v-text-field>
```
To change the placeholder (text) colour you should use a custom class that overwrites this colour:
```css
.white-placeholder ::v-deep input::placeholder {
color: white !important;
opacity: 1;
}
```
To change the label (text) colour:
```css
.white-placeholder ::v-deep .v-label {
color: white !important;
opacity: 1;
}
```
To change the input colour (the text that is typed in by the user) we should use another custom class:
```css
.white-placeholder ::v-deep input {
color: white !important;
opacity: 1;
}
```
We have to use `::v-deep` because we are in a scoped component. Any nested css classes/variables in a scoped component will have a random id attached to them (vue does this dynamically). The `::v-deep` will make sure that the nested css gets the formatting applied. See <https://vue-loader.vuejs.org/guide/scoped-css.html#deep-selectors> for details.
## Overwriting sass/scss variables
<https://vuetifyjs.com/en/customization/sass-variables/>
Create a `_variables.scss` in `./src/scss`.
If Vuetify is installed through the Vuetify CLI then this `scss` file will be automatically bootstrapped into the App. If you want to write additional sheets then you should edit the `vue.config.js` file and add the following to `module.exports`:
```scss
module.exports = {
css: {
loaderOptions: {
scss: {
prependData: `
@import "@/scss/_variables.scss";
`
}
}
},
transpileDependencies: ["vuetify"]
};
```
Overwriting `sass` variables is easy. You need to simply define them in this `_variables.scss` file and they will be used in the main app.
You can find a list of default variables <https://vuetifyjs.com/en/customization/sass-variables/>.
Or you can use the variables defined in the `sass` section of the components api documentation.
## Slots
When using slots in Vuetify find the slot name from the api documentation.
To use a slot, you should create a `<template>` inside the component and pass a `v-slot:$NAME` directive.
For example:
`<template v-slot:prepend-inner>`
You can also use `#` as a keybinding for `v-slot`:
`<template #prepend-inner>`
An example of passing a prepend icon to a `<v-text-field>`:
```html
<template #prepend-inner>
<v-icon>
mdi-account-circle
</v-icon>
</template>
```
Expects the v-img component. Scoped props should be applied with
v-bind="props".
## Forms
Forms should be done dynamically - creating a `v-for` on a text field input. You should create all the props values in an object in `data`.
The `<v-form>` should specify a `v-model` prop, which should reference a boolean on whether the form is valid or not. You should set a `ref` prop, which is the name you will refer to the form.
```html
<v-form
v-model="valid"
ref="form"
class="pt-4 d-flex flex-column align-center full-width"
></v-form>
```
You would refer to this form with `this.$refs.form`.
```html
<v-text-field
v-for="field in formFields"
:key="field.name"
outlined
rounded
required
:type="field.password ? 'password' : 'text'"
background-color="rgb(100%, 100%, 100%, 10%)"
color="rgb(100%, 100%, 100%, 20%)"
class="white-placeholder full-width"
v-model="field.value"
:rules="field.rules"
:placeholder="field.placeholder"
:success="!!field.value"
@click:append="field.showIconData = !field.showIconData"
>
<template #prepend-inner>
<v-icon color="white" class="pr-3">
{{ field.prependIcon }}
</v-icon>
</template>
<template #append>
<div class="innerIcon">
<v-btn
v-if="field.appendIconShow"
flat
icon
text
x-small
@click="
() => {
field.showIconData = !field.showIconData;
field.password = !field.password;
}
"
>
<v-icon color="white">
{{ field.showIconData ? field.appendIconShow : field.appendIconHide }}
</v-icon>
</v-btn>
</div>
</template>
</v-text-field>
```
Here we have created the text fields we want to render and we are looping over `formFields` to fill in the props and slots.
```javascript
{
valid: false,
load: false,
formFields: [
{
name: "Email",
rules: [
v => !!v || "You must enter an email address.",
v => /.+@.+/.test(v) || "Email is not valid."
],
placeholder: "Email",
successmessage: "Email is valid.",
prependIcon: "mdi-at",
value: ""
},
{
name: "Password",
rules: [
v => !!v || "You must enter a password.",
v => (v && v.length >= 8) || "Minimum 8 characters."
],
placeholder: "Password",
successmessage: "Password is valid.",
prependIcon: "mdi-lock",
appendIconShow: "mdi-eye",
appendIconHide: "mdi-eye-off",
showIconData: false,
value: "",
password: true
}
]
}
```
This is the data object in the `<script>`. Here we define everything we need for the form, and specify all props needed for the form to work.
### Validation
Validating a form is done on the inputs that make up the form with the `rules` prop.
This prop takes an array where each one of them must resolve to `true` in order for the form to be valid. We use arrow functions as the value of the input field is passed into the rules in order to check whether or not it is valud.
### Submitting and check
You should create a `<v-btn>` component and a method that will be called with `@click`.
```html
<v-btn
depressed
large
color="primary"
class="lighten-3"
:loading="load"
@click="submit"
>Submit</v-btn
>
```
```javascript
async submit() {
this.load = !this.load;
console.log("loading");
if (this.$refs.form.validate()) {
console.log("Success");
} else {
console.log("Not valid");
this.load = !this.load;
}
}
```
Here we are checking the validity of the form, and enabling/disabling the loading prop based on whether or not the form is correct.
### Hints
The following is a codepen showing how you can dynamically populate a hint to show if the form is submitted with empty values. This can be useful if don't want to show an error message, but you still want the form to provide feedback on what to fill in.
<https://codepen.io/anon/pen/GeVQLG>
## Triangle backgrounds
### Designs
Dual image: <https://codepen.io/eddyerburgh/pen/EPYVVX>
background-image: linear-gradient( 109.6deg, rgba(113,14,51,0.83) 15.2%, rgba(217,43,23,0.95) 96.8% );
## Animations
Vue Animations: <https://css-tricks.com/intro-to-vue-5-animations/>
### transitions
You can use Animista css animations with Vue's transition element:
<https://serversideup.net/animista-css-with-vuejs-transitions/>
### Router Animations
<https://github.com/Orlandster/vue-page-transition>
`yarn add vue-page-transition`
```javascript
import VuePageTransition from "vue-page-transition";
Vue.use(VuePageTransition);
```
You should wrap the `<router-view>`:
```html
<vue-page-transition name="fade-in-right">
<router-view />
</vue-page-transition>
```
A list of all transitions is here: <https://orlandster.github.io/vue-page-transition/#/>
### Animate on scroll
You can use vue transitions or you can use a helper library.
<https://michalsnik.github.io/aos/> can be used to quickly apply animations on scroll.
To use install with yarn:
`yarn add aos@next`
Then, in `main.js` add:
```javascript
import AOS from "aos";
import "aos/dist/aos.css";
```
And then add to the Vue instance the `AOS.init`:
```javascript
new Vue({
created() {
AOS.init();
},
router,
store,
vuetify,
render: h => h(App)
}).$mount("#app");
```
You can then in any component add any of the animations from the documentation:
`data-aos="zoom-in"`
To use with nuxt install as a plugin:
<https://www.yasminzy.com/nuxt/aos.html#steps>
#### Custom animations with AOS library
Custom Cubic-bezier easings: <https://cubic-bezier.com>
Custom easings: <https://easings.net/en>
You can use custom animations with the AOS library. For example, we can use Animista.
The base template is:
```scss
[data-aos="test-roll"] {
// initial here
transition-property: transform, opacity, filter;
&.aos-animate {
// final here
}
}
```
In Animista you should copy the keyframes. Take the 0% content and put it as the intitial content in the above template.
The the 100% content and place it in the final content in the above template.
You need to update the `transition-property` with the elements you are animating from one state to another.
Using custom easings is straightforward.
Create the scss:
```scss
[data-aos] {
body[data-aos-easing="new-easing"] &,
&[data-aos][data-aos-easing="new-easing"] {
transition-timing-function: cubic-bezier(0.25, 1, 0.57, 0.55);
}
}
```
Then apply in the html:
```html
<v-card
flat
color="rgb(0, 0, 0, 0)"
class="d-flex align-center justify-center flex-column pa-6"
data-aos="test-roll"
data-aos-duration="3000"
data-aos-easing="new-easing"
></v-card>
```
## Alternative to fill-height
Using `fill-height` prop on a `<v-container>` can result in a bug where the width of the container doesn't reach all the way to the right hand side.
An alternative is to use `d-flex` on the `<v-container>`:
```html
<v-container
fluid
class="d-flex align-center"
style="height: 100vh;"
></v-container>
```
document usign align with viewport
set a default which applies to all, set the one you want to apply for upwards
document setting a default cols (check this with triangle)
## Dynamic Mobile Layouts
### Cols
<!-- TODO Screenshot of firebase tutorial login page -->
<https://git.panaetius.co.uk/web-development/savvy-firebase/src/branch/base-template/src/views/forms/LoginForm.vue>
You can control how items are rendered based on the viewport width. For example, you can have a page appear across 2 columns on desktop, but display a single column on mobile : <http://localhost:8080/triangle>
One way is to use the the viewport cols props for `<v-col>`:
```html
<v-col
sm="6"
cols="12"
align-self="stretch"
class="d-flex justify-sm-end justify-center pb-10 pb-sm-0 pr-sm-10"
></v-col>
```
This will set a default of 12, and then use 6 on sm and anything above it.
You can find all props for the dynamic cols in <https://vuetifyjs.com/en/components/grids/#api>
If you set a row to use more than 12 columns, it will overfill on to the next line.
<!-- ? should this be merged with the previous section on mobile layouts -->
Using the cards to create dynamic rows filling the space in each column, you can go even further and control how this should render on different viewports.
For example, if we wanted to center content on a mobile, but have it align to the right on larger screens we can do the following:
```html
<div
class="d-flex flex-column align-sm-end align-center justify-center"
:class="alignOnViewport"
>
```
Here we are using `align-center`. This will set the content to center itself by default. We can then use `align-sm-end` to align the content to the right on anything sm and above. Combinations of these can be used to create dynamic and fluid layouts for all devices.
You can also use dynamically created classes to apply css to the content depending on the viewport.
<!-- ! create the trilium note link here -->
## CSS Spacing
<https://vuetifyjs.com/en/styles/spacing/>
You can use the helper classes `pa-10` to control padding/margins.
You can also viewport widths in these too:
`pb-xs-10 pr-sm-10`
When wanting to use a default value and only apply another one on a certain viewport:
`class="d-flex justify-sm-end justify-center pb-10 pb-sm-0 pr-sm-10"`
This will set a padding on the bottom of 10 for xs and then 0 for anything higher.
## Dynamically Apply Classes
<https://michaelnthiessen.com/dynamically-add-class-name/>
### Apply classes based on viewport
You can use the breakpoint variables:
<https://vuetifyjs.com/en/customization/breakpoints/#breakpoint-service-object>
In javascript to determine what the breakpoint/size/dimension etc is. You should prepend:
`$vuetify.breakpoint`
before each breakpoint service object.
You can also use a neat javascript check with `switch` and `case` to create a computed variable:
```javascript
computed: {
imageHeight () {
switch (this.$vuetify.breakpoint.name) {
case 'xs': return '220px'
case 'sm': return '400px'
case 'md': return '500px'
case 'lg': return '600px'
case 'xl': return '800px'
}
},
}
```
Alternatively, you can create a normal computed variable and reference it in your props:
```javascript
computed: {
isXSmall() {
return this.$vuetify.breakpoint.xsOnly;
}
}
```
You can then dynamically set classes with the `:class` prop:
```html
<div
class="d-flex flex-column align-sm-end align-center justify-center"
:class="[isXSmall ? 'text-align-center' : 'text-align-right']"
></div>
```
You can use both `class` and the prop `:class` together. You can use different methods to do this, here we used an array, but you can also use a javascript object.
<https://michaelnthiessen.com/dynamically-add-class-name/>
A cleaner way to do this is to use computed properties exclusively, either returning a single value, or an array as above:
```javascript
computed: {
alignOnViewport() {
return this.$vuetify.breakpoint.xsOnly
? "text-align-center"
: "text-align-right";
}
}
```
Using the `:class` prop:
```html
<div
class="d-flex flex-column align-sm-end align-center justify-center"
:class="alignOnViewport"
></div>
```
## SVG
### Viewbox
<https://css-tricks.com/scale-svg/>
Viewbox is an attribute on the `<svg>` element and has 4 components: x, y, height, width.
The x and y set the coordinate system to use for the top left corner of the viewport. Simple scaling can be done by setting these to 0,0, but you could set them to something else (like central) to make drawing circles using radius easier, or for easier transforming/rotating.
Take for example `viewBox="-50 -50 100 100"` - this means the top left corner has coordinates -50,-50, so the bottom right corner has coordinates 50,50. Drawing a circle centered around 0,0 with radius 50 it will fill the screen.
Setting a viewbox allows you to set the box that the svg element should draw in. This will allow you to then control the width and height to scale the element properly.
## Triangle banners
### Method 1 - position: absolute
See <https://git.panaetius.co.uk/web-development/savvy-firebase/src/branch/base-template/src/views/Triangle.vue> for an example.
You should create a triangle banner css class:
```scss
.newtriangle {
width: 105vw;
height: 50vh;
background-image: radial-gradient(
circle farthest-corner at 7.5% 54.1%,
rgba(0, 0, 0, 1) 0%,
rgba(39, 0, 89, 1) 74.9%
);
-webkit-clip-path: polygon(0 0, 100% 35%, 100% 65%, 0% 100%);
clip-path: polygon(0 0, 100% 35%, 100% 65%, 0% 100%);
}
```
Then you should create a `<v-row>` with this class. This row should also set `position: absolute; z-index: 1;` in the style (or add this to the triangle class).
```html
<v-row class="d-flex newtriangle" style="position: absolute; z-index: 1;">
<v-col
class="d-flex align-center pt-0 ml-8"
style="position: relative; z-index: 10;"
>
<v-card flat color="rgb(0, 0, 0, 0)">
<h1 class="display" style="position: relative;">
Welcome to Savvy Firebox Tutorial
</h1>
<v-btn
x-large
color="primary"
style="position: relative; z-index: 10;"
class="lighten-1"
>Click Here</v-btn
>
</v-card>
</v-col>
</v-row>
```
Because the element has been set to position absolute, any content after this without absolute positioning will be on top of this element. You should create a blank row with `position: relative;` with a height matching the triangle banner above it. This will create blank space on top of the banner.
```html
<v-row class="d-flex" style="position: relative; height: 50vh;"> </v-row>
```
Any other content then be placed after this like normal.
### Method 2 - Without position: absolute
See <https://git.panaetius.co.uk/web-development/savvy-firebase/src/branch/base-template/src/views/Backgrounds.vue> for an example.
Add the css class for the banner:
```css
.newtriangle {
width: 105vw;
height: 50vh;
background-image: radial-gradient(
circle farthest-corner at 7.5% 54.1%,
rgba(0, 0, 0, 1) 0%,
rgba(39, 0, 89, 1) 74.9%
);
-webkit-clip-path: polygon(0 0, 100% 35%, 100% 65%, 0% 100%);
clip-path: polygon(0 0, 100% 35%, 100% 65%, 0% 100%);
}
```
Apply this class to a `<v-content>` and add any content to go inside it:
```html
<v-container fluid class="newtriangle">
<v-row class="fill-height d-flex align-center">
<v-col class="">
<h1 class="display-2 white--text">
CSS polygon background with clip-path.
</h1>
</v-col>
</v-row>
</v-container>
```
## Fullscreen backgrounds
You can use svg images as a fullsize background. These images can be obtained from envano web templates - use Pixelmator Pro and its extraction tools to extract the svg elements, upscale and export for web.
Create a `<v-img>` with the src as the svg image.
```html
<v-img
src="../assets/images/background.svg"
:height="this.currentHeight - 64"
width="auto"
contain="false"
position="bottom 0px right 0px"
></v-img>
```
Any content to go in the page should go inside the `<v-img>` tags.
The width should be auto - it will be set by the height.
The prop `contain` should be used to ensure the image fits the full height properly and isn't cropped.
To align the image in the bottom right, set the position prop:
```html
position="bottom 0px right 0px"
```
If you are using a appbar, you should dynamically get the viewport height, and substract the height of the appbar. The default height is `64px` - use the documentation to find the heights if using dense or extended props.
You should add a computed property that returns the current viewport height:
```javascript
computed: {
currentHeight() {
return window.innerHeight
}
}
```
Then, in the height of the `<v-img>` you should set a dynamic prop that sets the height of the image to this computed property minus the height of the appbar.
```html
:height="this.currentHeight - 64"
```