Friday, October 2, 2015

CSS3 Gradients

CSS3 gradients let you display smooth transitions between two or more specified colors.
Earlier, you had to use images for these effects. However, by using CSS3 gradients you can reduce download time and bandwidth usage. In addition, elements with gradients look better when zoomed, because the gradient is generated by the browser.
CSS3 defines two types of gradients:
  • Linear Gradients (goes down/up/left/right/diagonally)
  • Radial Gradients (defined by their center)

Browser Support

The numbers in the table specify the first browser version that fully supports the property.
Numbers followed by -webkit-, -moz-, or -o- specify the first version that worked with a prefix.
Property
linear-gradient10.026.0
10.0 -webkit-
16.0
3.6 -moz-
6.1
5.1 -webkit-
12.1
11.1 -o-
radial-gradient10.026.0
10.0 -webkit-
16.0
3.6 -moz-
6.1
5.1 -webkit-
12.1
11.6 -o-
repeating-linear-gradient10.026.0
10.0 -webkit-
16.0
3.6 -moz-
6.1
5.1 -webkit-
12.1
11.1 -o-
repeating-radial-gradient10.026.0
10.0 -webkit-
16.0
3.6 -moz-
6.1
5.1 -webkit-
12.1
11.6 -o-

CSS3 Linear Gradients

To create a linear gradient you must define at least two color stops. Color stops are the colors you want to render smooth transitions among. You can also set a starting point and a direction (or an angle) along with the gradient effect.
Example of Linear Gradient:
Linear gradient

Syntax

background: linear-gradient(directioncolor-stop1color-stop2, ...);
Linear Gradient - Top to Bottom (this is default)
The following example shows a linear gradient that starts at the top. It starts red, transitioning to blue:

#grad {
  background: -webkit-linear-gradient(red, blue); /* For Safari 5.1 to 6.0 */
  background: -o-linear-gradient(red, blue); /* For Opera 11.1 to 12.0 */
  background: -moz-linear-gradient(red, blue); /* For Firefox 3.6 to 15 */
  background: linear-gradient(red, blue); /* Standard syntax */
}

Linear Gradient - Left to Right
The following example shows a linear gradient that starts from the left. It starts red, transitioning to blue:

#grad {
  background: -webkit-linear-gradient(left, red , blue); /* For Safari 5.1 to 6.0 */
  background: -o-linear-gradient(right, red, blue); /* For Opera 11.1 to 12.0 */
  background: -moz-linear-gradient(right, red, blue); /* For Firefox 3.6 to 15 */
  background: linear-gradient(to right, red , blue); /* Standard syntax */
}

Linear Gradient - Diagonal
You can make a gradient diagonally by specifying both the horizontal and vertical starting positions.
The following example shows a linear gradient that starts at top left (and goes to bottom right). It starts red, transitioning to blue:

#grad {
  background: -webkit-linear-gradient(left top, red , blue); /* For Safari 5.1 to 6.0 */
  background: -o-linear-gradient(bottom right, red, blue); /* For Opera 11.1 to 12.0 */
  background: -moz-linear-gradient(bottom right, red, blue); /* For Firefox 3.6 to 15 */
  background: linear-gradient(to bottom right, red , blue); /* Standard syntax */
}

Using Angles

If you want more control over the direction of the gradient, you can define an angle, instead of the predefined directions (to bottom, to top, to right, to left, to bottom right, etc.).

Syntax

background: linear-gradient(anglecolor-stop1color-stop2);
The angle is specified as an angle between a horizontal line and the gradient line, going counter-clockwise. In other words, 0deg creates a bottom to top gradient, while 90deg generates a left to right gradient.
The following example shows how to use angles on linear gradients:

#grad {
  background: -webkit-linear-gradient(180deg, red, blue); /* For Safari 5.1 to 6.0 */
  background: -o-linear-gradient(180deg, red, blue); /* For Opera 11.1 to 12.0 */
  background: -moz-linear-gradient(180deg, red, blue); /* For Firefox 3.6 to 15 */
  background: linear-gradient(180deg, red, blue); /* Standard syntax */
}

Using Multiple Color Stops

The following example shows how to set multiple color stops:

#grad {
  background: -webkit-linear-gradient(red, green, blue); /* For Safari 5.1 to 6.0 */
  background: -o-linear-gradient(red, green, blue); /* For Opera 11.1 to 12.0 */
  background: -moz-linear-gradient(red, green, blue); /* For Firefox 3.6 to 15 */
  background: linear-gradient(red, green, blue); /* Standard syntax */
}

The following example shows how to create a linear gradient with the color of the rainbow and some text:

#grad {
  /* For Safari 5.1 to 6.0 */
  background: -webkit-linear-gradient(left,red,orange,yellow,green,blue,indigo,violet);
  /* For Opera 11.1 to 12.0 */
  background: -o-linear-gradient(left,red,orange,yellow,green,blue,indigo,violet);
  /* For Fx 3.6 to 15 */
  background: -moz-linear-gradient(left,red,orange,yellow,green,blue,indigo,violet);
  /* Standard syntax */
  background: linear-gradient(to right, red,orange,yellow,green,blue,indigo,violet); 
}

Using Transparency

CSS3 gradients also support transparency, which can be used to create fading effects.
To add transparency, we use the rgba() function to define the color stops. The last parameter in the rgba() function can be a value from 0 to 1, and it defines the transparency of the color: 0INDICATES full transparency, 1 indicates full color (no transparency).
The following example shows a linear gradient that starts from the left. It starts fully transparent, transitioning to full color red:

#grad {
  background: -webkit-linear-gradient(left,rgba(255,0,0,0),rgba(255,0,0,1)); /*Safari 5.1-6*/
  background: -o-linear-gradient(right,rgba(255,0,0,0),rgba(255,0,0,1)); /*Opera 11.1-12*/
  background: -moz-linear-gradient(right,rgba(255,0,0,0),rgba(255,0,0,1)); /*Fx 3.6-15*/
  background: linear-gradient(to right, rgba(255,0,0,0), rgba(255,0,0,1)); /*Standard*/
}

Repeating a linear-gradient

The repeating-linear-gradient() function is used to repeat linear gradients:

#grad {
  /* Safari 5.1 to 6.0 */
  background: -webkit-repeating-linear-gradient(red, yellow 10%, green 20%);
  /* Opera 11.1 to 12.0 */
  background: -o-repeating-linear-gradient(red, yellow 10%, green 20%);
  /* Firefox 3.6 to 15 */
  background: -moz-repeating-linear-gradient(red, yellow 10%, green 20%);
  /* Standard syntax */
  background: repeating-linear-gradient(red, yellow 10%, green 20%);
}

CSS3 Radial Gradients

A radial gradient is defined by its center.
To create a radial gradient you must also define at least two color stops.
Example of Radial Gradient:
Radial gradient

Syntax

background: radial-gradient(shape size at position, start-color, ..., last-color);
By default, shape is ellipse, size is farthest-corner, and position is center.
Radial Gradient - Evenly Spaced Color Stops (this is default)

#grad {
  background: -webkit-radial-gradient(red, green, blue); /* Safari 5.1 to 6.0 */
  background: -o-radial-gradient(red, green, blue); /* For Opera 11.6 to 12.0 */
  background: -moz-radial-gradient(red, green, blue); /* For Firefox 3.6 to 15 */
  background: radial-gradient(red, green, blue); /* Standard syntax */
}

Radial Gradient - Differently Spaced Color Stops

#grad {
  background: -webkit-radial-gradient(red 5%, green 15%, blue 60%); /* Safari 5.1-6.0 */
  background: -o-radial-gradient(red 5%, green 15%, blue 60%); /* For Opera 11.6-12.0 */
  background: -moz-radial-gradient(red 5%, green 15%, blue 60%); /* For Firefox 3.6-15 */
  background: radial-gradient(red 5%, green 15%, blue 60%); /* Standard syntax */
}

Set Shape

The shape parameter defines the shape. It can take the value circle or ellipse. The default value is ellipse.

#grad {
  background: -webkit-radial-gradient(circle, red, yellow, green); /* Safari */
  background: -o-radial-gradient(circle, red, yellow, green); /* Opera 11.6 to 12.0 */
  background: -moz-radial-gradient(circle, red, yellow, green); /* Firefox 3.6 to 15 */
  background: radial-gradient(circle, red, yellow, green); /* Standard syntax */
}

Use of Different Size Keywords

The size parameter defines the size of the gradient. It can take four values:
  • closest-side
  • farthest-side
  • closest-corner
  • farthest-corner
#grad1 {
  /* Safari 5.1 to 6.0 */
  background: -webkit-radial-gradient(60% 55%, closest-side,blue,green,yellow,black); 
  /* For Opera 11.6 to 12.0 */
  background: -o-radial-gradient(60% 55%, closest-side,blue,green,yellow,black);
  /* For Firefox 3.6 to 15 */
  background: -moz-radial-gradient(60% 55%, closest-side,blue,green,yellow,black);
  /* Standard syntax */
  background: radial-gradient(closest-side at 60% 55%,blue,green,yellow,black);
}

#grad2 {
  /* Safari 5.1 to 6.0 */
  background: -webkit-radial-gradient(60% 55%, farthest-side,blue,green,yellow,black);
  /* Opera 11.6 to 12.0 */ 
  background: -o-radial-gradient(60% 55%, farthest-side,blue,green,yellow,black);
  /* For Firefox 3.6 to 15 */
  background: -moz-radial-gradient(60% 55%, farthest-side,blue,green,yellow,black);
  /* Standard syntax */
  background: radial-gradient(farthest-side at 60% 55%,blue,green,yellow,black);
}

Repeating a radial-gradient

The repeating-radial-gradient() function is used to repeat radial gradients:

#grad {
  /* For Safari 5.1 to 6.0 */
  background: -webkit-repeating-radial-gradient(red, yellow 10%, green 15%);
  /* For Opera 11.6 to 12.0 */
  background: -o-repeating-radial-gradient(red, yellow 10%, green 15%);
  /* For Firefox 3.6 to 15 */
  background: -moz-repeating-radial-gradient(red, yellow 10%, green 15%);
  /* Standard syntax */
  background: repeating-radial-gradient(red, yellow 10%, green 15%);
}




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