Embedded padding/margin in fonts

问题:

It seems that all fonts have some sort of embedded padding or margin. By setting:

margin: 0px;
padding: 0px;

You never get what you want. Does anybody know why this is?

回答1:

It sounds like the issue you are having is not with the CSS but the font itself. Most fonts define a baseline, x-height and line-height out-of-the-box. Your specific issue is likely with the font's leading, the space between lines. Sometimes these values can be wildly inconsistent. If you are really trying to get a specific font to line up correctly, I would recommend taking a look at FontLab and editing the glyphs/baseline/line-height for the specific font you are working with.

You can also look at a web-safe version of the font. These types of fonts usually have been specifically spaced to render best on the web. This isn't always the case, but it might get you the results you are looking for. Check out Google's library of web fonts here.

Update

This answer has received enough attention that I decided to add the first comment below to the answer and expound on it.

Browser Reset: Every browser will set default states for many of the reserved HTML tags like a and strong. There are other things defined by default including fonts, line-heights, weights and sizes. This could have an affect on the rendering of a font. Generally this is localized to specific browsers. So, by using a CSS reset, you can eliminate default rendering issues in browsers. Eric Meyers Reset is a good reset, but there are definitely others. Try using different ones to see which works best for you.

However, CSS resets work by targeting all browsers and setting them to all be the same. Some people prefer to use something that, instead, targets only the issues with each browser. That is were Normalize will be better.

There are also issues that a CSS reset will not fix. Such as font aliasing (making the fonts seem smooth rather than jagged). Since some browsers and operating systems do not add anti-aliasing to fonts, you will also see glyph width differences. This, unfortunately, is unavoidable in most cases. Some people go the route of using a flash font replacement tool like Cufon or Sifr. This too has it's own list of issues (such as the FOUC).

Another Update

One other issue that is still out there is the problem with kerning, or the space between glyphs. There is a CSS property letter-spacing that will allow you to do a global kern on a block of text, but it lacks the ability to target individual glyphs like Photoshop or InDesign. The kerning is also based on whole-pixels, so you are limited by what you can achieve. It also has issues with IE and is not as reliable as one would hope. There is a javascript called kerningjs that is pretty decent but it, too, is whole-pixel based and therefore not as accurate as rasterized text.

On the whole, fonts on the web have gotten better over the past few years. Sadly, we are still dealing with issues from the past, when fonts were only intended to be printed or rasterized. There is hope on the horizon for us font enthusiasts, though. As @allcaps said, the CSS3 specification for linebox is out there, so it's only a matter of time until it is widely accepted!

回答2:

The reasons of this pecularity of the computer fonts are mostly historical. In the past, fonts were the sets of small metal blocks with one character on each, and the height of these blocks had to be enough to contain all the elements of any character, including descendants, ascendants and diacritical marks. The typographic tradition has defined the font size as the height of such metal blocks. That's why almost all actual characters are usually much smaller visually than the font size set for the text and there is some white space above and below them.

Here is a good article explaining the historical roots of the main typographic measurements: http://www.dev-archive.net/articles/typograph1-en.html#Ch22

回答3:

x ov gjqpy bdfhklt CAPS ÂÊÁËÈ

A glyph is designed on a two dimensional canvas. For the latin writing system the height of this canvas is consistent and width may vary. Glyphs are placed on a baseline. x is on the baseline and the top of x defines x-height. Round and pointy shapes appear smaller so are optically corrected. Descenders extend below the baseline. Ascenders, capitals go above x-height. Browsers align text with different fonts (in the same paragraph) by baseline.

So why is the build in margin? Glyphs need whitespace around to be aligned to each other.

What can we do to influence these margins?

1. Choose your fonts wisely.
2. Specify line-height p { line-height:0.5EM;}.
3. Baseline shift .shift { top:-.5em; position:relative; }
4. And wait for CSS3 module: line.

General advice: do not adjust a font yourself unless you are absolutely sure what you are doing. One of the many things you'll encounter is hinting. Windows needs hinted fonts and hinting is hard to get right. Also the way fonts are loaded (@font-face) will load a local copy if it exists. You can disable local fonts by a hack. Your mileage may vary.

回答4:

you can use line-height and letter-spacing padding/margin in fonts... otherwise use custom css for each heading........

/*use line-height*/
.font{
line-height: 1px; 
letter-spacing: 1px;
}

or use custom css......

  h1{margin:1px 0;}
    h2{margin:1px 0;}
    h3{margin:1px 0;}
    h4{margin:1px 0;}

using these css before use reset css .......

回答5:

The "padding" at the top and bottom of fonts is essentially reserved space for diacritics (https://en.wikipedia.org/wiki/Diacritic). Some scripts stack multiple diacritics on some letters, including capitals (for example, Vietnamese https://en.wikipedia.org/wiki/Vietnamese_alphabet) so a font designer that forgets to reserve some place for them won't be able to extend his font later. Also, horizontal scripts require some separation (leading) between lines to be readable.

Only very specific glyphs like box drawing elements extend to the limits of a glyph box http://www.unicode.org/charts/PDF/U2500.pdf That's also why the "padding" is built-in each glyph. If it was an external property it would not be possible to differentiate between glyphs intended to be jointive and glyphs that need some separation (in other words the amount of padding is a glyph property no a whole-font property).

The following example requires a good font with decent Unicode coverage (http://dejavu-fonts.org/ works)

Jointive box drawing elements
↓
┃ÇŖŞ
┃ẤỄǛȰ┃U ← You really need to include the "padding" to align with box drawings
  ↑
 Latin capitals with multiple diacritics (really crowded)

Lastly fonts stem from very old technology (movable type), and the conventions used to describe them still refer to fifteenth century habits, which makes them quite un-obvious to laymen.

(See also http://www.webfonts.info/node/330 for info on complications added by computer font formats)

fonts opentype text-rendering

回答6:

If you want use space between lines in a paragraph, you can use:

line-height: 3px; /*3px is an example*/

Or, if you use space between letters, you can use:

letter-spacing: -2px;

Hugs, Vin.

回答7:

Its not a problem with the font as such. Yes, as @matthew said, the font design itself has some character built in. For example, check out difference between say "Segoe" family and "Verdana" family. You will keep on resetting your css if you need to use both. One style just won't work.

The larger part of the problem lies in the way different browsers render even on the same OS. Heck, even different versions of IE render differently. ClearType, Anti-aliasing, font smoothing, software rendering instead of GPU rendering, rendering engine itself, etc. etc. all play their role to make sure you don't end up with pixel-perfect design across all browsers across all OSs.

ClearType tries to align with pixel-grid causing another set of problems with subtle differences in height.

This link is very old, but still very relevant: http://www.joelonsoftware.com/items/2007/06/12.html

See Also: http://www.codinghorror.com/blog/2007/06/whats-wrong-with-apples-font-rendering.html

See Also: https://webmasters.stackexchange.com/questions/9972/how-can-i-make-fonts-render-the-same-way-across-different-web-browsers

See Also: CSS font differences between browsers

Your best bet would be to keep tinkering with css until you get close enough.

回答8:

Here is my Opinion

• The margin is the distance from each side to the neighboring element and the margin property can be set for the top, left, right and bottom of an element
• padding is the distance between the border of an HTML element and the content within it.

But in your case you dont really need these both you , as you are interested in font spacing , there is one css property called letter-spacing

• The letter-spacing property increases or decreases the space between characters in a text

Try

 h2 {letter-spacing:-3px}

The letter-spacing property is supported in all major browsers.

Note: The value "inherit" is not supported in IE7 and earlier. IE8 requires a !DOCTYPE. IE9 supports "inherit".

回答9:

The native margins for text elements are as follows (at least in Firefox and Chrome):

Working Example

 p{margin:16px 0;}
h1{margin:21px 0;}
h2{margin:19px 0;}
h3{margin:18px 0;}
h4{margin:21px 0;}
h5{margin:22px 0;}
h5{margin:24px 0;}

To remove them you'll have to re-set the margin like so:

p, h1, h2, h3, h4, h5, h6{margin:0;}

回答10:

After looking at the html source of a html document found out that after the normal margin/padding added by all the browsers, chrome by default adds its own webkit's margin/padding properties.

-webkit-margin-before: 1em;
-webkit-margin-after: 1em;
-webkit-margin-start: 0px;
-webkit-margin-end: 0px;

Solution is instead of normal

*{
margin:0;
padding:0;
}

Append the style with

*{
margin:0;
padding:0;
-webkit-margin-before:0;    
-webkit-margin-after:0;
}

As -webkit-margin-start and -webkit-margin-end are already set to 0px, there is no use of setting them in here.

Tell me if that works! :)

回答11:

I think is kerning what you intend to describe

take a look to this library

http://kerningjs.com/

CSS, meet kerning. Kerning, meet CSS. Kern, style, transform, and scale your web type with real CSS rules, automatically.

Print designers have had it easy for way too long. This is 2012; the web has been around for over two decades, yet web designers don’t get full control over their typography? Forget that, use Kerning.js!

it's free

回答12:

The fonts itself has problems it seems. CSS can be used as shown above to solve the problem but still it should be said that it is better in your scenario to fix up the font files itself.

Check out this page as it will give you better insight on how to edit a font: http://mashable.com/2011/11/17/free-font-creation-tools/

回答13:

I often run into the same issue, especially when trying to get text to top-align with something beside it that isn't text, such as an image.

Here's a technique I've had some success with. Select a portion of the text so that a colored background appears behind it. The top of the selection highlight will reveal what the font considers the "top" and "bottom" of the letter. Take screenshots of the font at various sizes and across multiple browsers. Zoom in on the screen capture in Photoshop and count the number of pixels from what you believe "should" be the top and the actual top. Calculate the percentage that number of pixels represents within the entire selection height.

Then set a negative top margin on the text in ems that is equal to the percentage of the "overflow." So if the text should be 10px tall and it's actually 12px tall, then give it a negative top margin of -0.2em.

Then wherever you assign the font-family that's causing the problem, also include this negative top margin as well. You can use the same technique for bottom and side overflow as well, but I typically find it's the top that causes the biggest headaches.

回答14:

What's about resetting the margin and padding value to zero in all

*{
  margin: 0;
  padding: 0;
}

回答15:

I have run into this pain a couple of times when using some webfonts for icons and gained better control by placing them in an absolute positioned container.

HTML

 <div class="relative">
     <div class="webfont">&#10004</div>
 </div>

CSS

 .relative { position:relative; }
 .webfont {  position: absolute;

             top: -5px; 
             left: -5px; /* easier control with these values */
           }

This felt like a better way to control things cross browser, rather than say, using positive/negative margins and paddings.

Giving the text block a container and class we have much more cleaner ability to tweak it's position cross browser. ( IMO ).

Might be something there.

Cheers,

Rob

回答16:

You can do it with line-height

I know it's not too common in HTML5, and is more HTML4.1, but...

<font style="line-height: 5px;">

and if it's really that important:

<font style="padding: 5px;">L</font>
<font style="padding: 5px;">o/font>
<font style="padding: 5px;">r</font>
<font style="padding: 5px;">e</font>
<font style="padding: 5px;">m</font>