refaneed.blogg.se - Imagemagick rotate

Colored source: actionpack/lib/action_controller/macro/image_magick.rb ( download).

Subversion: actionpack/lib/action_controller/macro/image_magick.rb.

There is currently no demo of the 'filter' method, but there are examples in the documentation.

A (static) demonstration of the 'action' approach.

You can use many other ImageMagick commands in the same way. Request the view, and ta-da: the image first_photo.jpg is displayed, and it is resized to fit within 100x100 pixels. Now, if you want to generate and display thumbnails, you'd do this: The image files are stored in the directory '/var/lib/photos'. Suppose that you have an image gallery, with a controller Photo to display the images. The basic idea is this: you have a directory with images, and want to process them with ImageMagick (because you want to resize them, or crop them, or rotate them etc.). This extension provides an easy way to use ImageMagick commands to process images from a Rails template. It’ll give me the freedom to write more technical content.ImageMagick for Rails ImageMagick for Rails If you’ve found this tutorial or blog post interesting, or it's helped you solve a particular issue, then please consider buying me a virtual coffee as a way of saying thanks.

ImageMagick - Get the 5 most prominent colours within an image.

ImageMagick - Convert JPG image to WebP format.

ImageMagick - Resize an image maintaining aspect ratio.

This ImageMagick command lists out the top five most prominent colours. To get the best effect, it’s best to use one of the prominent colours from the target image. It also adds colour to the placeholder as the image is downloaded and decoded. When defining an img element within your web pages, it’s sometimes a good idea to define a background colour as a fallback if the image fails to load. ↓ ImageMagick - Get the 5 most prominent colours within an image. Therefore it makes sense to use ImageMagick to convert the JPG version of your file: convert input.jpg output.webp By using WebP in HTML picture elements, developers can gain an overall performance boost my serving up the WebP version of the file to those browsers that can support it.

WebP is an image format that provides superior lossless and lossy compression. ↓ ImageMagick - Convert JPG image to WebP format. To convert a JPG image to a greyscale black and white photo use the following command: jpegtran -greyscale input.jpg > grey.jpg jpegtran -copy none -progressive -optimize input.jpg > output.jpg The progressive encoding can make the image appear to load faster over slow internet connections, as it renders the image in stages to make it appear it’s being streamed in. The command below does this, while also converting the JPG to use a progressive encoding. To prepare a JPG image which is as small as possible for website performance we should remove all the EXIF data and remove the embedded thumbnail that many cameras generate. Th convert -geometry x400 input.jpg -quality 80 output.jpg In this example we’re resizing the image to a fixed height of 400 pixels. You can also resize the image by fixing the height and maintaining the aspect ration. convert -geometry 700x input.jpg -quality 80 output.jpg We also reduce the quality of the JPG compression to 80%. In this example, we resize the input image to a maximum width of 700 pixels. You can use the convert command from the ImageMagic library to resize an image to a specific width while maintaining the aspect ration for the images height. ↓ ImageMagick - Resize an image maintaining aspect ratio You can rotate an image through 90 or 180 degrees by using the jpegtran command: jpegtran -rotate 90 input.jpg > output.jpg Which will return the dimensions like: input.jpg JPEG 3264x2448 3264x2448+0+0 8-bit sRGB ↓ Get dimensions of an image identify input.jpg

Here is a list of the commands I use on a regular basis. With ImageMagick and other command line tools, such as jpegtran, you can accomplish a lot from the terminal. In most cases, you’ll not need a fully blown image editor like Gimp installed on your machine.

Maybe you need to rotate or resize an image before posting it to your web site. Recipes for manipulating images from the command lineĪs a web developer there are many instances in which you need to interact with images. Fiction Technical Drawings Contact ImageMagick - resize, rotate and convert images from the Linux command-line