You can write a regular bash script and save things to variables etc. I piped it into awk to do some simple division. This says, identify the width of image.jpg. This was my workaround to not being able to reference the attributes mentioned above. This is why the colors we chose mattered so much.īut I can hear you saying - “HEY! What the hell is with all that extra stuff with awk and backticks!!!” If it is passed a greyscale image with no opacity, it will treat it like a regular mask and only show the sections that are masked by WHITE areas. Why? Well, this is a special case of the copy_opacity composition mode. You will notice an extra argument now at the end, -alpha Off. Masks are greyscale images with no opacity, meaning no alpha channel. Next we draw the circle with a fill of white. We then use the -threshold switch set to -1 because that will turn it completely white. We will use the actual image we uploaded using +clone. So we work around this like so.įirst, when we create the canvas, we don’t use xc. And when I used them inside the circle declaration I received errors. When trying to draw a primitive shape like a circle, which required me to be inside parenthesis, the escapes where not recognized. In imagemagick, you can reference various attributes of an opened image using different escape sequences. ![]() It assumes you know the dimensions of the image you are processing. It looks like so.Ĭonvert goat.jpg \( +clone -threshold -1 -negate -fill white -draw "circle `identify -format %w goat.jpg | awk ''`, 0" \) -alpha Off -compose copy_opacity -composite goat_method_two.png Because the opacity is the cutout of a circle, when we choose to composite the images, you get a circular crop the size of your image. In this case, it should use copy_opacity. We compose these images by telling imagemagick what composition method it should use. The second is of a white circle on a transparent background. Next we choose to composite these two images. The first coordinate is the center of the circle, the second is the outer edge. Pay attention that the circle command goes INSIDE the quotes. Next we draw a circle using the draw command. We then set the fill of the circle we are about to draw. After the colon xc: we place the color the background should be, in this case none. We then initiate this canvas using xc:none. Inside the parenthesis we set the size of a new canvas using the -size switch. The parenthesis are escaped by backslashes and you MUST have a space after the opening paren and before the closing escape backslash. If this was another jpg, we could simply name it without the parenthesis. To add a second image to the image we are going to open parenthesis, we open parenthesis because we have some processes that are only meant for that image. IMPORTANT: The methods shown in this post are for a landscape image. Next we want to create another image that acts somewhat like a mask, but for all intents and purposes kind of is not as it isn’t a greyscale image and retains its alpha channel. All $ convert goat.jpg does is open that image. ![]() This takes an image of an adorable goat, whose dimensions are 960圆50. This post will show you a couple ways in which you can crop images using imagemagick and explain why somethings are the way they are.Ĭonvert goat.jpg \( -size 960圆50 xc:none -fill white -draw "circle 480,325 480,0" \) -compose copy_opacity -composite goat_method_one.png This is especially true when all you want to do is perform what should be a simple task. There is a plethora of documentation, and some of it can be quite confusing. However, it seems to make a lot of people crazy and understandably so. The default location for this is on the Linux desktop.I like imagemagick. You'll find the cropped images in the destination file, as explained above. When you're done, click Batch and wait for the files to be cropped. Phatch does the cropping at the directory level, so ensure your images have been gathered together in a single location. When you're ready, click the Execute button (the paper airplane) and browse for the images to be cropped. By default this is measured in pixels (px) but if you prefer this can be changed to % or cm, mm, or even inch.Ĭlick + again to select Save, and pay attention to the In: field, which displays the location of the cropped images. Here, click Mode to change the option to Custom and you'll be able to specify how many pixels from the Left, Right, Top, and Bottom edges of the images. ![]() Many options are available here, but to crop some files, begin by selecting Crop. You can install Phatch with: sudo apt-get install phatchĪfter installing, you'll need to launch Phatch from the menu, and click + to create a new batch process.
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