Clip-Path and border

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The clip-path() property

Clip-path() is a CSS property to cut a geometrical region from a region:

circle()

We use circle( radius, center ):

//we can use % and px for the center, 50% takes the entire space
.circolo{
    background-color: red;
    clip-path: circle(40% at 20% 75% );
}

clip circle on different center

ellipse()

inset()

We can have border-radius on inset clips:

Border radius examples

Unlike inset() that can take 2 values max, we can use up to 4 with border-radius:

.commo{
    background-color: crimson;
    clip-path: inset( 5% 15% round 50% 50% 0 0 );
}

.pizza{
    background-color: goldenrod;
    clip-path: inset( 15% 5% round 50% 50% );
}

.tower{
    background-color: dodgerblue;
    clip-path: inset( 10% round 50% 0 50% 0 );
}

.quarto{
    background-color: rosybrown;
    clip-path: inset( 15% round 0 50% 0 0 );
}

inset with border radius

We can clip entire polygon(), you can use this as a guide:

Star polygon clip

We draw (X,Y) points for each point of the polygon:

//remember to NOT put a (,) for the last point
.stalle{
    background-color: white;
    clip-path: polygon(
        50% 0%, 
        61% 35%, 
        98% 35%, 
        68% 57%, 
        79% 91%, 
        50% 70%, 
        21% 91%, 
        32% 57%, 
        2% 35%, 
        39% 35%
    );
}

star polygon on gradient

Slice polygon

CSS borders and border-box

Using the border property we can specify width, color and style of a border

Borders guide

About border-style:

.dot{
    border: dotted 5px brown;
}

.dash{
    border: dashed 5px brown;
}

.solid{
    border: solid 5px brown;
}

//all get a complementary darker border-color 
.groove{
    border: groove 10px red;
}

.ridge{
    border: ridge 10px red;
}

.inset{
    border: inset  10px red;
}

.outset{
    border: outset 10px red;
}

We can style/width each side of the border

//order being top/right/bottom/left
.chiuso{
    border: outset red;
    border-width: 8px 4px 2px 20px;
}

border examples

We can use border-style: double or the outline property for a double border:

Border: double and Outline guide

The width of border-style: double is equally divided:

//between the external border, the offset, and the internal
.dou{
    border: double 10px red;    //3px red, 3px white, 3px red
}

The outline property draws a line outside the border.

It shared properties with border but can't use border-radius, it can conflict with margin:

//outline-style: dotted, dashed, solid, double, groove, ridge, inset, outset
.groove{
    background-color: darkorange;
    border: 5px dotted brown;
    outline: 5px dashed lightskyblue;
    outline-offset: 5px;
}

Outline-offset is not in the shortcut and can be negative:

//calculate outline width when setting offset
.dash{
    background-color: darkorange;

    border: 5px dashed lightskyblue;
    outline: 5px dotted brown;
    outline-offset: -15px;
}

border-style double and outlines

For an internal border, we can use :before:after, box-shadow, or background-clip:

Absolute position

We space each side:

//relative>absolute needed 
.tasti{
    position: relative;
    border: 8px solid red;
}

.tasti::after{
    content: " ";
    position: absolute;

    top: 5px;
    left: 5px;
    right: 5px;
    bottom: 5px;
    border: 3px solid green;
}

after layer on the relative

Display flex

box-shadow

background-clip

The border width sets the difference between content-box and border-box:

//box-sizing: content-box is set by default, it adds border and padding to the width
//border-box sums border and padding to the set width
.come{
    background-color: pink;
    box-sizing: content-box;
    
    padding: 20px;
    border: 10px blue solid;
}

.cane{
    background-color: pink;

    border: 10px blue solid;
    box-sizing: content-box;
}

border-box and content-box

We use border-images to use gradients or url images for our borders:

Border-image guide

We can't use the shorthand for images/gradients:

.lineare{
    border-style: solid;
    border-width: 15px;
    border-image: linear-gradient(90deg, rgb(0,143,104), rgb(250,224,66));
    border-image-slice: 1;
}

.gradiale{
    border-image: radial-gradient(rgb(0,143,104), rgb(250,224,66)) 1;
}

.conico{
    border-image: conic-gradient(red, yellow, lime, aqua, blue, magenta, red) 1;
}

//border-image-slice is needed in border-image
//it's X,Y and can use px/%, for how the image will be cut
.test{
  border-style: solid;
  border-width: 15px;
  border-image: url( https://live.staticflickr.com/65535/49927594376_d7c5d1d0e6_c.jpg );
  border-image-slice: 60 30;
}

.grand{
  border-style: solid;
  border-width: 15px;
  border-image: url(https://live.staticflickr.com/65535/49927594376_d7c5d1d0e6_c.jpg);
  border-image-slice: 80 fill;
}
//fill will use the image as background+border

background-images

We can't use border-radius not border-left/right/top/bottom for border-image but:

Border image radius guide

We can use padding-box and border-box background:

//we need to use a gradient in the padding-box only to keep the border colored
.granola{
    padding: 15px;

    border: 8px solid transparent;
    border-radius: 15px;
    background: 
        linear-gradient(white 0 0) padding-box,
        linear-gradient(to left, blue, pink) border-box;
}

We could use border-image-slice to cut borders:

//we need % for that
.meta{
    border-style: solid;
    border-width: 15px;

    border-image: linear-gradient(to left, pink, blue);
    border-image-slice: 100% 1;
}

Or cut specific border-width:

.chris{
    padding: 5px;

    border-width: 10px 0 10px 0;
    border-style: solid;
    border-color: transparent;
    
    background: 
        linear-gradient(white 0 0) padding-box,
        linear-gradient(to right, blue, pink) border-box;
}

It works the same for border-radius:

//you will need +1 radius on width
.vas{
    padding: 5px;

    border-width: 0 0 10px 20px;
    border-radius: 50% 0 50% 50%;
    border-style: solid;
    border-color: transparent;

    background: 
        linear-gradient(white 0 0) padding-box,
        linear-gradient(to right, blue, pink) border-box;
}

different border-image styles

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