| description |
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You can apply transformations conditionally based on certain properties of the input asset. |
Transformations can be applied conditionally i.e. only if certain properties of the input asset satisfy a given condition. To accomplish this, you can create if-else - like constructs within an asset URL.
The syntax to build and specify a conditional transformation block is:
if-{condition},{transformations_on_true},if-else,{transformations_on_false},if-end
For example, you can resize all landscape images to a certain width, say 200, while resizing portrait images to width 300. The value of the ar (aspect ratio) property of an image helps determine whether it has a landscape (> 1) or portrait (< 1) orientation.
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https://ik.imagekit.io/demo/tr:if-ar_gt_1,w-200,if-else,w-300,if-end/default-image.jpg
- condition: A condition based on a property of the image that evaluates to either true or false. It has the format
if-{property}_{operator}_{value}. Read more - transformations_on_true: Transformations that are applied only if the preceeding condition evaluates to true. This can be a chain of transformations as well.
- transformations_on_false (optional): Transformations that are applied only if the preceeding condition evaluates to false. This can be a chain of transformations as well. This part along with the preceeding
if-elseare optional and can be skipped.
The condition part in the above syntax can be built using a predefined set of image properties, comparison operators, and logical operators. A singular condition follows the {property}_{operator}_{value} syntax. For example, if-h_gt_100 evaluates to true if the height of the image is greater than 100.
You can combine multiple conditions using the and and or logical operators. For example, if-h_gte_100_and_h_lte_400_or_ar_lt_4-3 evaluates to true only if the image height is between 100 and 400, or the aspect ratio is less than 4:3.
{% hint style="info" %}
and operator has precedence over or operator during condition evaluation.
{% endhint %}
| Property | Allowed values | Description |
|---|---|---|
h |
|
Height of the image at the current step in a chain of transforms. eg. 100, 200.55 |
w |
|
Width of the image at the current step in a chain of transforms. eg. 100, 200.55 |
ar |
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Aspect ratio of the image at the current step in a chain of transforms. eg. 100, 200.55, 4-3 |
ih |
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Height of the original, untransformed image. eg. 100, 200.55 |
iw |
|
Width of the original, untransformed image. eg. 100, 200.55 |
iar |
|
Aspect ratio of the original, untransformed image. eg. 100, 200.55, 4-3 |
| Operator | Description |
|---|---|
| eq | h_eq_100 evaluates to true if the image height is equal to 100 |
| ne | h_ne_100 evaluates to true if the image height is not equal to 100 |
| gt | h_gt_100 evaluates to true if the image height is greater than 100 |
| gte | h_gte_100 evaluates to true if the image height is greater than or equal to 100 |
| lt | h_lt_100 evaluates to true if the image height is less than 100 |
| lte | h_lte_100 evaluates to true if the image height is less than or equal to 100 |
You can specify a set of any supported transformations, or a chain of transformations, in place of the transformations_on_true and transformations_on_false parts. The former will be applied if the condition evaluates to true. The latter will be applied if the condition evaluates to false. The if-else and the succeeding transformations are optional.
For example, if-ar_gt_1,w-200,if-else,w-300,if-end and if-ar_gt_1,w-200,if-end are both valid.
{% hint style="info" %} Conditional transformations are not supported for gif files yet. {% endhint %}
An if block can be one of the steps in a chain of transformations. For example, in h-200,c-pad_resize:if-h_eq_200,w-100,if-end:rt-90, the if block is the second step in a chain of three steps. The height value that this, if block receives for evaluating the h_eq_100 condition, will be 200 since the previous step in the chain resizes the image to a height of 200. Hence, the condition will evaluate to true.
{% hint style="warning" %}
A step containing an if block cannot contain any other comma-separated transform within that step. For example, h-400:rt-90,if-h_eq_200,w-100,if-end:rt-90 or h-400:if-h_eq_200,w-100,if-end,bl-10:rt-90 or h-100,if-h_eq_200,w-100,if-end are all invalid.
{% endhint %}