ImageMagick Tutorial: Crop

ImageMagick Tutorials

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Examples of what ImageMagick can do.

How to transparify images.

How to change image colors.

How to annotate (write on) images.

How to composite images.

How to add and remove image comments.

How to resize images.

How to make an animation.

How to change the speed of an animated gif.

How to change the number of repetitions (loop) of an animated gif.

How to remove a specific frame from an animated gif.

How to morph images.

How to crop images.

How to chop crop images.

How to rotate images.

*NOTE*

Image Magick only stores the rendered images on their system for a short while. Always transload the output to your homepage promptly.

How to Crop an Image Using ImageMagick

Put the URL of the image you want to crop into the text field where it asks for the URL: and click on the view button.

On the next page you will see your image as well as the width x height of the image in the status bar at the bottom of your screen. *Write these numbers down* Go to the top of the screen and click on the Transform tab.

On the next page you will see a Parameter box and some buttons.

In the Parameter box it wants to know the size of the image and how much to take off horizontally and vertically. Here's how it works:

HORIZONTALLY:	+ takes off from the left - takes off from the right
VERTICALLY:	+ takes off from the top - takes off from the bottom

Uncropped
Original Dimensions: 180w x 195h

So to take off 15 from the right and 10 from the bottom for the above image, these values are entered in the Parameter box.

Click on the crop button.

Next scroll to the bottom of the page and check the box for reset page geometry.

Now click where it says Press to (transform) your image or (reset) the form. Here's the result. The white areas are to illustrate the cropped off area and would not appear in an actual cropping job.

First Crop
New Dimensions: 165w x 185h

If the cropping was not right, hit back to recrop the original image.

Now to crop from the left side and the top, click on the Transform tag at the top of the screen again.

On the next page fill in the newly cropped image size, seen in the status bar, along with the cropping parameters. This example now takes off 70 from the right and 35 from the top.

180x195-15-10

165x185+70+35

Click on the crop button.

Then click where it says Press to (transform) your image or (reset) the form. Here is the result:

Second Crop
Final Dimensions: 95w x 150h

BEFORE AFTER

Go to the top of the screen and click on the Output tab.
On the next page select the following:
Format: Put a checkmark next to gif or jpg.
Storage Type: Click the single file button for a still image, or the multi-frame file button for an animated gif.
Click where it says Press to (output) your image or (reset) the form.

On the next page just click on the image and get the URL so you can transload it to your homepage account.

How to Chop Crop an Image Using ImageMagick
First Chop

Put the URL of the image you want to chop crop into the text field where it asks for the URL: and click on the view button.
Then click on the image and position the arrow on a bottom right corner point. To the right of and below that point image content will be chopped off by a later step.
Click the arrow and write down the two numbers at the bottom left below the image: 165,185 in the example above.
Now click on the Transform tag at the top of the screen.
On the next page enter the image size, seen in the status bar, and the numbers derived above.

180x195+165+185

Click on the chop button.

Now click where it says Press to (transform) your image or (reset) the form. The right side and bottom will be chopped.

Second Crop

Again click on the image and position the arrow on a top left corner point. To the left of and above that point image content will be cropped off by a later step.
Click the arrow and write down the two numbers at the bottom left below the image: 70,35 in the example above.
Now click on the Transform tag at the top of the screen.
On the next page enter the new image size, seen in the status bar, and the numbers derived above.

165x185+70+35

Click on the crop button.
Now click where it says Press to (transform) your image or (reset) the form. The image will be chop cropped on all four sides.
Click here for the rest of the steps to ouput the image.

How to Rotate an Image Using
Image Magick

Put the url of the image you want to rotate into the text field where it asks for the URL and hit the view button.

On the next page you will see the the image. Its width x height is shown in the status bar at the bottom of the screen. *Remember those dimensions.
Go to the top of the screen and click on the Transform tab.

On the next page either rotate left or rotate right buttons can be used without setting a value in the parameter box.
Rotate left will stand the image on its left side (-90°) and rotate right will stand the image on its right side (+90°).

To rotate the image a specific amount, click on the rotate button and input a parameter value using the formula:
{+ - }{# }{> < }

+
-
#
>
< =
=
=
=
= positive degrees
negative degrees
number of degrees
width is greater than height of image
width is less than height of image

If images width is greater than height, to rotate it positive 45 degrees use:
Parameter

+45>

If image width is less than height, to rotate it positive 45 degrees use:
Parameter

+45<

Then click where it says Press to (transform) your image or (reset) the form.
Click here for the rest of the steps to ouput the rotated image.

Basic Image Magick tutorials are a valuable resource. These will be actively maintained, updated, and improved. New information welcomed.

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