Is size of a pixel relative to the screen size? - css

I am creating a website that is mobile friendly. I've defined a fixed size for all buttons.
.btn
min-height:45px
When moving from a large screen to a small screen does the size of the pixel scale? For instance, if on a large desktop screen, 45px takes up 1% of screen height will it also take up 1% of screen height on a small mobile screen? It looks like it doesnt scale proportionally to the height of the screen. Should I be going about this a different way? Thanks!

No. It is not. If you want to scale your web app, you should use relative units like %, vw, or vh.
You can read more about it here.
And you can study how to view your web app on different sized viewports here.

No, pixels are not relative to screen size. If you want to use a relative suffix, use the % suffix. This will make the style relative to the parent element. For example, if the parent element is the <body> element, then width: 100% will make the element's width the size of the page.

No, a pixel does not scale. If you would like your html elements to scale, use vw (view width) and vh (view height) instead of px (pixels).

This varies from one device to another.
Px is in no way non-visually comparable to any relative units like vh, vw, % etc etc.
If you want to know what px means as exact as possible see here.

Related

How to maintain font size ratio based on screen size while using flex box

I was given a Figma design of a webpage. The Figma page width was 1825px. The width of my laptop is 1080px. Suppose a text in Figma page has font-size 20px. How do I convert it to my laptop so that the ratio is maintained?
I can't use a percentage because I'm using flexbox. And when I try using percentage what it does is takes the percentage of its parent container rather than the entire body.
I also tried using VW. Calculated the view width based on the 1825px breakpoint and implemented that. The issue is that the pixels are getting distorted in this approach.
Also, This answer Typography using VW got lots of upvotes means VW works, Then why am I facing the issue?
I'm using react and I don't want any javascript solution. Is there any way to solve this using CSS only?
Are you sure you need to do it? Font size usually changes when breakpoint is reached.
But if you really need to do it, you may set the font-size based on viewport width.
So if 20px font-size on 1825px width is desired ratio then you need to set font-size to 0,01vw to preserve the ratio across all screen sizes.
The easiest way would be to use media queries.
https://developer.mozilla.org/es/docs/CSS/Media_queries
You can also try other units like vw (view width), rem (relative to the font size of the root element), etc...
https://www.w3schools.com/cssref/css_units.asp

CSS Percentages And Pixels

I like to think of myself as having some serious CSS swagger(I am also a PHP hack, and pretty good at Javascript), but today I was chatting with a designer about a specific situation, and honestly I just did not know the answer to it. I was hoping someone could elaborate on the problem.
Scenario:
I hear many a people say, "Oh I use percentages for everything because of responsive design", but then you go and look at their css, and they are using px all over the place for margins, padding etc.
My problem is that should I be using pixels at all? I'd say the main pain point I have in understanding this, is when it comes to high resolution screens.
For example, I was creating a pretty simple "hero" in which I set the height of my container to 700px tall with a background image and some text, while setting the width of it to 100%. On my screen I was creating it on, it displayed full height of my screen(which was the intention), but when I had someone else view it on a higher resolution laptop screen, the picture was significantly shorter in height, with white space underneath it, failing to fill the whole height of the screen.
I am looking for someone to explain exactly how pixels values are affected on higher resolution screens, and if you should always use percentages.
For example, If I set a container to be 300px wide on a "normal" resolution screen, will that same container be 150px wide on the higher resolution screen, and also look shrunken and terrible?
Say I start using percentages for things like margin and padding, I am curious as to how css would calculate that? For example, say I have a contact form with many inputs stacked on top of eachother, and I do something like the following:
input {
margin-bottom: 2.5%;
}
Where would the css be calculating that 2.5% from? Does it say, "Make that margin-bottom 2.5% of the height of it's parent? I am just confused as what it would be based off of.
Any input is greatly appreciated. Thank you.
First of all, I want to refer to an answer given on SO that explains the percentage property really good: https://stackoverflow.com/a/31032477/4459695
So should I use pixels?
Using pixels should indeed be avoided in modern Web Design, for a few simple reasons:
Pixels are fixed. They do not adapt to different screen sizes or viewports, scalings or layouts. Since mobile first is a goto pattern and responsive Web Design relies on adaptable units, and since pixels are avoidable, - avoid them.
High resolution screens are getting more and more mainstream, and if you do not want to adapt to even more media queries (for the larger screens), you should not be using pixels.
There are better, more dynamic alternatives. These include vw, vh, em, rem and of course %.
But when to use which unit?
em and rem are really good for font sizes or anything like that. They will easily scale and can be used for margins and paddings too, depending on content size.
% are best used in relative object positioning, not so much in margins, paddings or font-sizes, although they can (margins and paddings are okay, I guess). What I mean by this is that percentages work best when combining them with width, height or anything like that (they work great in flex-layouts, for example).
vw and vh are allrounders - I personally do not use them in specific cases, but they are quite handy sometimes. Best example would be an overlay which should fill the complete viewport.
All those units are dynamic and depend on the viewport. This is great, because this allows for flexible styling. Pixels do not.
% value in margin and padding is always % of the parent's width.
So say you have a <div> with margin-bottom: 25%;, inside another <div> which is 1000px wide, then the bottom margin of the <div> is 1000*25% = 250px.
.container {
width: 100px;
background: green;
}
.child25,
.child45,
.child-none{
background: yellow;
}
.child25 {
margin-bottom: 25%;
}
.child45 {
margin-bottom: 45%;
}
<div class="container">
<div class="child25">This one should have 25px margin bottom.</div>
<div class="child45">This one should have 45px margin bottom.</div>
<div class="child-none">This one has no margin</div>
</div>
As for your hero problem, if you want the hero's height to be full screen's height, use height: 100vh;, which mean 100% of the viewport's height.
A 700px height element will always be 700px high on any screen. The different in real-life perceived size is because of the screen's ppi (pixel per inch), or dpi (dot per inch) as they are usually called on mobile devices. The value refer to the number of pixel/dot that fill each real-life inch on that screen.

How do I make my image appear in relation to the size of a user's screen?

I have an image of that has a height of 480px. On my Macbook it looks OK but when I go to my 30 inch monitor obviously there is a huge space in the bottom.
What can I do to make sure that the 480px will always be in relation so the size of the user's screen?
I did some searches and it seems that using background-image: cover or background position I can do some stuff but highly likely it's not what I am looking for. What can I do tackle this issue?
One way to achieve this is to place the image in a container that can scale with the page.
Height is a hard attribute to scale, but you can achieve it as long as all of the parent elements have a specified height as well.
You can use CSS code such as
height:40%;
to scale elements.
Scale the page's height here to see for yourself: http://jsfiddle.net/L7uWd/
Try with the width in percentage to set the image size as per the browser width. It's always preferable to set the width in percentage(instead of pixel) while re-sizing the element based on window re-sizing.
Set the image height to some percentage instead of pixel, that will automatically handle with the size of the screen.

Where is the small row width defined in Zurb Foundation 4?

While I see the $row-width: emCalc(1000px); in _variables.css, I can't find where the small width is defined for mobile devices. I'm assuming it's just set to 100% but I'd like to play around with changing this.
Your assumption is correct : The row-width variable just sets the maximum width.
The width of the .row is always 100%
When it's a large screen, the width is constrained by the max-width variable, so it's by default 1000px
When it's a small screen (as a mobile device), the .row width is 100%.
I'm assuming it's just set to 100% but I'd like to play around with
changing this.
You may consider to change the breakpoint width, or using different structure (columns?).

Resizing images based on their original size with CSS

I'm making a responsive blog for both mobile and desktop users (all in one). With respect to image resizing, I understand that I can use width:100%; height:100%; so that they scale proportionally depending on the page size, but I've noticed that smaller images upscale to fit the width of the DIV that it is in. Let's say my DIV has a max-width of 640px but an image I include within it in 500px.
What CSS can I use to keep the image at 500px and then scale down proportionally if the resolution width falls below 500px?
The reason I'm asking this is because not all images in posts may be 640px wide.
Set your image max-width property to the actual image size.
Why don't you just set max-width:100% and leave width off.

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