UsageLast updated: 10 December 2022

The most common form of template tag used: all the parameters required to identify the source image and the manipulations and transformations required are included within the tag itself. 

To avoid any parsing confusion within the EE parse system, JCOGS Image single tags can use either image or single as the opening / closing tag element as required.

Illustration

{exp:jcogs_img:image width='300px' save_type='webp' aspect_ratio='16_9' crop='y' max='400' class='kittens' add_dims="yes" flip='v'}

The example tag given above will generate the image shown, via this HTML img tag:

<img src="https://domain.com/images/jcogs_img/cache/local_cache_image_file_name.webp" class="kittens" width="300" height="168">

Note that options chosen for the JCOGS Image tag parameters have resulted in output from the tag which comprises: 

• a well formed HTML img tag
• the img tag includes image dimensions
• the img tag includes the attribute class='kittens'

Also, the chosen JCOGS Image parameters have resulted in the image referenced in the img tag being:

• a cached copy of a local image file which in turn is a modified version of the source file
• cropped to give version of the original image shrunk to 300px wide
• with a 16x9 aspect ratio
• an image content which is the source image flipped vertically, and
• saved in the webp format.

JCOGS Image's default 'smart scale' crop means the image height has was reduced to maintian the requested 16x9 aspect ratio (over-riding both the height and max parameters included in the example).

JCOGS Image can also be accessed via the tag-pair form where a tag has an opening element (similar to the single-tag form described above) and also a closing element. Information can be passed to the add-on both from parameters placed within the opening tag and from the information enclosed between the opening and closing tag elements.

When a closing tag is defined JCOGS Image will process any parameters specified in the opening tag and replace any Image variables specified within the enclosed content with information relevant to the processed image. This approach allows you to create your own customised HTML output, and is particularly useful for creating the image content required by complex HTML image tags such as <figure> and <picture>.

For example:

{exp:jcogs_img:pair 
    src='{images}' 
    width='500px' 
    height='700px' 
    max_height="350px" 
    min="240px" 
    aspect_ratio='16_9' 
    crop='y' 
    save_type='webp' 
    allow_scale_larger='y' 
    class='cats' 
    rotate="35"
    flip='h'}
<figure>
    <img src="{made}" {attributes}="" width="{width}" height="{height}">
    <figcaption>This picture is called {name}.{extension}</figcaption>
</figure>
{/exp:jcogs_img:pair}

will generate this HTML output:

And this picture:

Note: the dimensions reported for the processed image are not those specified in the opening tag - this is because of the rotation, and the width / height reported in the img tag are the dimensions required for the bounding box such that the rotated image can be placed on the page without distortion.

As is the case with single tag version of JCOGS Image, tag pairs can use any of  image single or pair as the method name in the opening / closing tag element as required.

Sometimes developers have to design templates to work with blocks of content that may contain one or more images added by content editors: the JCOGS Image bulk tag offers a way to apply some image processing to these images to (for example) ensure that they are optimally sized and in the ideal image format.

The bulk tag uses the tag-pair format, and searchs the template content enclosed by its opening / closing tags for <img> tags; any tags found are processed by JCOGS Image using the parameters found in the opening bulk tag. 

The bulk tag is most often used to apply 'standard' modifications to all the images within a content block (e.g. making all the images the same size / aspect ratio, applying a standard filter to each, converting all to a preferred image format etc.). JCOGS Image's intelligent handling of class, style and pass-through attributes also makes it easy for the developer to add a range of attributes to the <img> tags - for example adding one or more classes or inline styles to each <img>, or adding implementation specific attributes (such as data-* attributes) or the inlining of javascript events (such as onclick=). 

Illustration

For example:

{exp:jcogs_img:bulk 
    width='300px' 
    aspect_ratio='16_9' 
    crop='y' 
    save_type='webp' 
    allow_scale_larger='y' 
    class='cats' 
    flip='h'}
<p>
    Macavity, Macavity, there’s no one like Macavity,
    There never was a Cat of such deceitfulness and suavity.
</p>
<img src="{images}" width="700px">
<p>
    He always has an alibi, and one or two to spare:
    At whatever time the deed took place—MACAVITY WASN’T THERE!
</p>
    <img src="https://placekitten.com/400/600">
{/exp:jcogs_img:bulk}

will generate HTML output like this:

<p>
    Macavity, Macavity, there’s no one like Macavity,
    There never was a Cat of such deceitfulness and suavity.
</p>
<img src="/media/jcogs_img/50802526853_0c0cdb05d0_c_42139d0677052065d989980f2e73fd284d253c87.webp" class="cats">
<p>
    He always has an alibi, and one or two to spare:
    At whatever time the deed took place—MACAVITY WASN’T THERE!
</p>
<img src="/media/jcogs_img/600_42139d0677052065d989980f2e73fd284d253c87.webp" class="cats">

This in turn will create output that looks like this: 

The palette pair type tag that gives you access to an analysis of the colours that appear in a processed image. It is broadly similar in function to the CE-Image ‘top_colors’ parameter.

The palette for the image is determined using a well regarded algorithm called Modified Median Cut Quantization. The maximum number of colours in the palette can be controlled through the palette_size parameter, which must be at least 2.

The tag supports some special variables:

• {dominant_color} - the rgba() colour code for the image's dominant colour
• {colors}…{/colors} - a variable pair that loops through the palette values identified for the image. The values exposed by this variable pair are:
  • {color} returns the rgb() color value of a palette colour
  • {rank} returns the ordinal rank of the palette colour (#1 being the dominant colour)

Illustration

JCOGS Image has strong compatibility with the stalwart CE Image add-on, offering developers a simpler upgrade path to EE5, EE6 and EE7 for sites developed using the CE-Img add-on.

Drop-in compatibility

Although JCOGS Image is based on a completely new image processing code base, it is possible to upgrade an existing site to JCOGS Image without loss of function simply doing a search / replace on the CE Image tag name - so for example {exp:ce_img:single...} would change to {exp:jcogs_img:single...}. In most cases the templates will generate output similar to that produced with CE Image.

Note: Some CE Image functions are not replicated (e.g. ASCIIart) and for some advanced uses (e.g. filters) there are some differences in how some settings work. Sections later in this document for more complete compatibility information.

CE Image Parameter Compatibility Table

Parameter	CE Image Compatibility	Notes
add_dimensions	New feature
add_dims	Full
allow_scale_larger	Full
ascii_art	Not implemented	Unlikely to be replicated.
aspect_ratio	New feature
attributes	Full
auto_cache	N/A	File caching is handled differently by JCOGS Image - see separate notes
auto_sharpen	New feature
aws_auto_url	Not implemented	Could be implemented in a future version if demand for this exists
bg_color	Full
bg_color_default	Not implemented	Currently available via Control Panel option. Could be replicated as a parameter if demand for this exists.
border	Full	Added in version 1.1
bucket	Not implemented	File caching is handled differently by JCOGS Image - see separate notes
cache	New feature	This parameter allows the cache setting for an image to be set at the tag level.
cache_dir	Full
consolidate_class_style	New feature
create_tag	Full
crop	Full
debug	Not implemented	Deprecated in CE Image. Comprehensive debugging information available via Control Panel option.
default_img_width	New feature
disable_browser_checks	New feature
disable_xss_check	Not implemented	XSS checks on paths provided are not optional.
encode_urls	N/A	JCOGS Image uses a different approach to file names and so this is not needed
fallback_src	Full
filename	Full
filename_prefix	Full
filename_suffix	Full
filter	Full	Not all the filter options available in CE Image are currently implemented, see separate notes on this in the Filters section of this document.
flip	Full
force_remote	N/A	This behaviour is handled automatically, there is no equivalent operation
hash_filename	Full
height	Full
hide_relative_path	N/A	JCOGS Image uses a different approach to file names and paths and so this is not needed
image_path_prefix	New feature
interlace	Full
lazy	New feature	Implements automatic lazy-loading for tags generated by the add-on.
manipulate	Not implemented	Could be replicated if demand for this exists
max	Full
max_height	Full
max_width	Full
min	Full
min_height	Full
min_width	Full
output	Full
overwrite_cache	Full
png_quality	New feature
quality	Full
reflection	Full
remote_cache_time	N/A	File caching is handled differently by JCOGS Image - see separate notes
remote_dir	N/A	File caching is handled differently by JCOGS Image - see separate notes
rotate	Full
rounded_corners	Partial	Added in version 1.3. Separately specified colour backgrounds for each corner for non-transparent image formats not supported.
save_type	Full
src	Full
srcset	New feature	Automatically add responsive variants of the processed image to an <img> tag via the srcset= and sizes= parameters
svg_passthrough	New feature
text	Full	Added in version 1.1
top_colors	Partial	A broadly similar output is provided by JCOGS Image's palette method.
unique	N/A	File caching is handled differently by JCOGS Image - see separate notes
url_only	Full
use_image_path_prefix	New feature
watermark	Full	Added in version 1.1
width	Full

CE Image Filter Compatibility Table

CE Image Variable Compatibility Table