Half circle with css

Draw Half Circle with CSS or Svg

You need first to get the values for the points where the arc begins and where it ends. You are working with lowercase (relative) commands so everything is relative to the previous command.

The starting point for the arc is X: -39.1875 + 78.375 = 39.1875 and y: -40

The end point uses the same x (0) and the y is -40 + 100.31399917602539 = 140.31399917602539

140.31399917602539 is also the height of your first path, so the radius for the arc is 140.31399917602539 / 2 = 70.1569995880127

Putting it all together your second path should be:

M39.1875,-40 a70.1569995880127,70.1569995880127 0 0 1 0,140.31399917602539

M39.1875,-40 A70.1569995880127,70.1569995880127 0 0 1 39.1875,100.31399917602539

SVG Half Circle: Why is it rotated?

When using the lineto command, uppercase-L ( L ) specifies an absolute coordinate while lowercase-L ( l ) specifies a relative move. It seems like you wanted to use the relative command.

As far as an example, the pie-chart-like one on the W3 path’s page uses a single path:

 fill="red" stroke="blue" stroke-width="5" />

produces the red part in this image:

Note the liberal use of lowercase (relative) commands.

SVG semi-arc clockwise animation over 180 degrees (half of a circle) with pure CSS/JS

A possible solution would be animating a very thick stroke (the double of the radius of the circle).

In this case the radius of the circle is 20 so the stroke-width=»40″

In the next example I’m animating the stroke-dasharray of the path from: 62.84,0 (stroke length = 62.84, gap = 0) to 0, 62.4 (stroke length = 0, gap = 62.84) where 62.84 is the length of the path.

Please read about how How SVG Line Animation Works

path stroke-dasharray: 62.84,0; 
animation: anim 5s linear infinite;
>

@keyframes anim to stroke-dasharray: 0, 62.84; 
>
>

Drawing half a circle in CSS

Something like this would probably work:

Cutting out half a circle header with an SVG

Your SVG background needs to be a rectangle with a circular hole cut out of it.

If you don’t want to draw this shape in a vector editor, then you’ll need to use a to make a circular hole in a rectangle.

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CSS Half Circle

CSS provides a very useful property for borders — Border Radius. With radius provided, the borders are rounded and the degree of rounding depends on the value of radius. And just like border style and width, the radii of all four vertices are independent of each other.

Following is how a box would like with a small border-radius .

What would happen if the radius of borders was equal to or more than half of the box’s width? You likely guessed it right. We get a circle.

Now, if we want to draw a semi-circle, how can we achieve it? One may think that reducing the height to half the value would solve the issue. Let’s give it a shot.

What we need to do, alongside reducing the height to half, is to have a radius only for top corners.

Use Cases

You can use the half-circle to build informational widgets like this one:

You may need to build a theme element, say a logo, that is comprised of half circles:

You could also be building a loader which comprises of animated half-circles:

See the Pen CSS Half Circle by Steve Marx (@xram) on CodePen.

You may be building a widget that requires circular transitions/animations effect:

Conclusion

CSS provides a very powerful property of border-radius . Applied with element dimensions and border widths, it helps us achieve shapes that are not provided out-of-the-box. One such example is a half-circle. By applying only top radii to a circle and halving its height, we can create a half-circle.

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How to create a half circle with CSS?

With CSS we can easily create the most commonly used shapes like circles, half circles, triangles, etc. In this tutorial, I will walk you through the simple steps of creating a half circle with pure CSS.

From the CSS point of view, a half circle is nothing but a rectangle with any of its two corners rounded. So, in simple words, to create a half circle using CSS all we need to do is make the element’s corners rounded.

To create rounded corners in CSS, we could use the border-radius and its constituents properties.

Here an important question arises, can we make any size element a half circle? Well, the answer is No. If you want to make an element a perfect half circle, its width should be 2 times its height and its individual corner’s border radius should be same as its height value.

Let’s understand it with examples.

Create a top half circle with CSS

To create a top half circle, we could use the border-top-left-radius and border-top-right-radius properties to make its top corners rounded.

Remember that the element’s width should be two times its height and the top corners radius should be same as its height.

Here is a working example:

Example:

Create a bottom half circle with CSS

To create a bottom half circle, we could use the border-bottom-left-radius and border-bottom-right-radius properties to make its bottom corners rounded. Other rules will remain the same.

Here is a working example:

Example:

Create a left half circle with CSS

If you want to create a left half or a right half-circle, the rules get reversed. Now the height of the element must be two times its width and the border radius of respective corners must be same as the width value.

To create a left half circle, we could use the border-top-left-radius and border-bottom-left-radius properties to make the left corners rounded.

Here is a working example:

Example:

Create a right half circle with CSS

If you want to create a right half circle, the rules will be same as creating a left half circle.

Here, we could use the border-top-right-radius and border-bottom-right-radius properties to make the right corners rounded.

Here is a working example;

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CSS Half Circle

Cascading style sheet plays an important role in designing and adding effects to the HTML content. Along with HTML tags, CSS is an essential tag to create any webpage either static or dynamic. Moreover, all the custom websites we see on the internet are developed by using HTML and its building block CSS. This styling may be of different types either inline, internal, or external. But in this article, we will be following the internal styling. A semi-circle will be created and will be designed by following the piece of HTML, and CSS tags. The user must be aware of the basics of HTML opening and closing tags and also the CSS declaration by classes and ids. With that, it becomes easier to understand the creation of a circle.

Implementation of half circle

A simple implementation sequence of HTML and CSS tags is applied along with the border-radius property of CSS. Open the text editor and use the following code to draw a half circle on a webpage. For the implementation of a half circle in HTML and CSS, we have used internal CSS that is declared inside the tag with the opening and closing tags. Start with the HTML tags, open the head tag. Then in the first step, we have given the title to the page. This title name will be appearing on the top of the tab in the browser at the time of execution. After closing the title tag, we will declare the style tag. First, we will declare the margin and padding of the shape.

Difference b/w margin and padding

Margin is the space around the object you want to create. This property is used for the object adjustment on the page, either to move on left or right, etc. It is a transparent area having no background color. A margin surrounds the shape from all 4 sides.

Padding is the portion that is present between the created object and the content inside the object. This content can be a shape, text, etc. The padding property specifies how an object looks inside the container. This container also contains a background color. Increasing or decreasing the size of padding affects the size of the content inside it.

So, here inside the style code, we have declared both margin and padding as 0. This means we will use the adjusting codes manually by declaring the height and width property of the shape. It is necessary to declare these properties as 0 instead of eliminating them from the code because it is considered auto if not declared as zero.

The third property related to shape is the background color white. This is the default color. If you do not mention it, it will always be white. Next, we will use the styling of the Div. Div is a container to contains some elements inside it. It does not have any effect on the layout nor the content until we provide any style to it. Here, we have used much effect for the div container. All the effects of the shape are applied to the div container for the adjustments. The position of the container is taken as absolute.

The two basic properties of shape are the location and direction of the shape. To adjust the shape, we will use the top and left attributes. ‘Top’ will decide the distance of the shape from the top border of the webpage. The left portion shows the distance of the shape from the left border of the page. Both properties are taken in percent.

Transform feature is a powerful property that is used to rotate, skew, bend, or translate the object. One of the most used features is the ‘translate’ feature which is used to move the object from one place to the other. In creating a half circle, we have used two values of displacement from the left and the top in percent. We have taken both values with the negative sign for the adjustment.

Now, we will use some effects on the shape creating a property like its height and the width. Both properties are taken in pixels.

What is the Border-radius property and why is it used?

Border radius is the backbone of creating a circle, or a semi-circle in HTML. This property plays a vital role to round the corners of the edges of the border of an object. Playing with the border and turning them towards the center makes a perfect circle. The parameters can be of 4 values. The border-radius property is used to give the value of the radius of the border. The 4 values are the length, percentage, initial, and inherit properties.

These 4 values are specified in a specific order to form a radius of a border:

The border radius can contain all of these values or the customized one by removing any one value. If the value of the bottom left is removed, then the value will be the value of the top-right of the shape.

To make a half circle, we have taken 2 values as 150px, and the other two are declared as zero. If we take all the values like 150 or any other number closer to it, then the resultant shape would be a full circle or an oval. After that alignment of the radius, we have assigned the color to the red shape. Now, we will close the style section and the head section as well.

Inside the body section of the code, we declare a div, only the opening and the closing tags for div are used here. All the styling is declared in the style section of CSS.

Now, we will save the code in the text editor. Make sure that the file formed must be saved with the name having an extension of html. For example, sample.html is the file, on which we are working.

To execute the text file, open the file by selecting the option of ‘open-with’ and selecting any browser of your choice. By doing this, the file icon will be replaced with the browser icon.

You will see that a half circle is formed with red color and the same alignments are performed that we had declared.

Conclusion

An implementation of a half circle in CSS is conducted by giving a brief introduction to HTML and CSS. A simple text editor and a browser are responsible for the execution of HTML and CSS tags in the file. We have used internal CSS for this purpose. Furthermore, an important CSS property that is border-radius property is also defined here. By following this feature a circle is formed, we just need to customize some values of it. All the effects are declared in the CSS section, the body section only contains the div container.

About the author

Aqsa Yasin

I am a self-motivated information technology professional with a passion for writing. I am a technical writer and love to write for all Linux flavors and Windows.

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