Documentation

image_processing.php

Image processing functions

Functions to allow upload and resizing of images.

Table of Contents

Functions

upload_file()  : bool
Upload a file from the provided path to the given resource
extract_exif_comment()  : bool
Extract and process EXIF, IPTC, and FITS metadata for a resource.
iptc_return_utf8()  : string
Convert IPTC metadata text to UTF-8 encoding.
create_previews()  : bool
Generate previews for a resource, including thumbnails and alternative image sizes.
extract_mean_colour()  : void
Calculate and update the mean color values for a resource image.
update_portrait_landscape_field()  : void
Update the portrait or landscape orientation field for a resource.
get_colour_key()  : string
Generate a color key for an image based on dominant colors.
tweak_preview_images()  : bool
Apply rotation and gamma adjustments to all preview images of a resource.
tweak_wm_preview_images()  : bool
Apply rotation and gamma adjustments to all watermarked preview images of a resource.
AltImageRotate()  : resource
Rotate an image resource by a specified angle without using built-in rotation functions.
base64_to_jpeg()  : void
Convert a base64-encoded image to a JPEG file.
extract_indd_pages()  : array<string|int, mixed>|bool
Extracts JPG previews from INDD files when these have been set with a preview Note: it requires ExifTool >= 9.50
generate_file_checksum()  : bool
Generate or update the checksum for a resource file.
clear_file_checksum()  : bool
Clear the checksum value for a specified resource.
check_duplicate_checksum()  : array<string|int, mixed>
Check for duplicate files based on checksum.
upload_preview()  : bool
Upload and generate previews for a resource.
extract_text()  : bool
Extract text from the resource and save to the configured field
get_image_orientation()  : int
Get the orientation of an image file using ExifTool.
AutoRotateImage()  : bool
Automatically rotate an image based on its orientation metadata.
extract_icc_profile()  : bool
Provides ability to extract the ICC profile for a specified resource/ alternative file
extract_icc()  : bool
Extracts the ICC profile from an image file using ImageMagick.
get_imagemagick_version()  : mixed
Retrieves the version of ImageMagick installed on the system.
calculate_image_dimensions()  : array<string|int, mixed>
Function used to get new width & height for an image in order to maintain aspect ratio while it will fit within a desired dimension.
upload_file_by_url()  : bool
Upload file from a URL and add it to a resource.
delete_previews()  : mixed
Delete all preview files for specified resource id or resource data array
getFileDimensions()  : array<string|int, mixed>
Get dimensions of image file
getSvgSize()  : array<string|int, mixed>
Get SVG size by reading the file and looking for dimensions at either width and height OR at Viewbox attribute(s)
convertSvgLengthToPx()  : int|null
Convert SVG length/width dimension to px size at 96DPI
replace_preview_from_resource()  : bool
Replace preview image with preview image from another resource/alternaive file
get_preview_source_file()  : string
Get the source file to use for creating a preview
compute_tiles_at_scale_factor()  : array<string|int, mixed>
Compute image tile regions based on a scale factor.
transform_file()  : bool
Perform the requested action on the original file to create a new file
remove_video_previews()  : void
For a given resource reference, remove the video pre size and all snapshots.
start_previews()  : int
Create preview sizes via create_previews() and/or generate jobs as necessary
get_sizes_to_generate()  : array<string|int, mixed>|bool
Get an array of preview size IDs to generate
create_image_alternatives()  : bool
Generates alternative image files for a specified resource.
is_valid_imagemagick_color()  : bool
Input validation helper function for ImageMagick's color values (e.g. blue, #ddddff and rgb(255,255,255))
can_apply_icc_profile()  : bool
With $icc_extraction enabled, determine whether we should apply the icc profile that has been found.
transform_apply_icc_profile()  : array<string|int, mixed>
Check if system is using ICC profiles and prepare ImageMagick command for use by transform_file() to enable system wide configuration for $icc_extraction to be applied when transforming a file, such as by format chooser or image tools.
create_previews_using_im()  : bool
Generate previews for a resource using ImageMagick.

Functions

upload_file()

Upload a file from the provided path to the given resource

upload_file(int $ref[, bool $no_exif = false ][, bool $revert = false ][, bool $autorotate = false ][, string $file_path = "" ][, bool $after_upload_processing = false ][, bool $deletesource = true ]) : bool
Parameters
$ref : int

Resource ID

$no_exif : bool = false

Do not extract embedded metadata. False by default so data will be extracted

$revert : bool = false

Delete all data and re-extract embedded data

$autorotate : bool = false

Autorotate images - alters embedded orientation data in uploaded file

$file_path : string = ""

Path to file

$after_upload_processing : bool = false

Set to true will create an offline job to process the file

$deletesource : bool = true

Delete resource after upload

Return values
bool

extract_exif_comment()

Extract and process EXIF, IPTC, and FITS metadata for a resource.

extract_exif_comment(int $ref[, string $extension = "" ]) : bool

This function retrieves metadata from an image file, including EXIF, IPTC, and FITS metadata, and updates the corresponding fields in the database. The process includes support for embedded geolocation data, handling character encoding, and applying user-configurable options for specific fields. If ExifTool is available, it is used for more comprehensive metadata extraction. Otherwise, the PHP exif_read_data function is used as a fallback.

Parameters
$ref : int

The resource reference ID.

$extension : string = ""

(optional) The file extension for the image, used to validate processing compatibility.

Return values
bool —

Returns false if the file does not exist; true on successful completion

iptc_return_utf8()

Convert IPTC metadata text to UTF-8 encoding.

iptc_return_utf8(string $text) : string

This function attempts to detect the character encoding of IPTC metadata text and converts it to UTF-8. If conversion is not possible due to missing libraries or if the encoding is unknown, the text is returned as-is. It uses a predefined list of character encodings for the conversion attempts.

Parameters
$text : string

The IPTC metadata text to be converted.

Return values
string —

The converted text in UTF-8 encoding, or the original text if conversion fails.

create_previews()

Generate previews for a resource, including thumbnails and alternative image sizes.

create_previews(int $ref[, bool $thumbonly = false ][, string $extension = "jpg" ][, bool $previewonly = false ][, bool $previewbased = false ][, int $alternative = -1 ][, bool $ignoremaxsize = false ][, bool $ingested = false ][, bool $checksum_required = true ][, array<string|int, mixed> $onlysizes = array() ][, bool $no_tiles = false ]) : bool

This function creates or updates image previews for a resource, such as thumbnails, based on the specified parameters. It supports a variety of configurations, including resizing with ImageMagick or GD library, generating checksums, and setting file attributes. If the file size exceeds a specified limit, it can queue the preview generation as an offline job.

Parameters
$ref : int

The resource ID for which previews are generated.

$thumbonly : bool = false

(optional) If true, only the thumbnail will be generated. Default is false.

$extension : string = "jpg"

(optional) The file extension for the resource. Default is "jpg".

$previewonly : bool = false

(optional) If true, only preview images will be generated. Default is false.

$previewbased : bool = false

(optional) If true, previews are generated based on existing previews rather than original files. Default is false.

$alternative : int = -1

(optional) If set, specifies an alternative file ID to generate previews for. Default is -1.

$ignoremaxsize : bool = false

(optional) If true, the file size limit for preview generation is ignored. Default is false.

$ingested : bool = false

(optional) If true, marks the resource as already ingested into the system. Default is false.

$checksum_required : bool = true

(optional) If true, generates a checksum for the file. Default is true.

$onlysizes : array<string|int, mixed> = array()

(optional) Specifies an array of preview sizes to generate. If empty, all sizes are generated.

$no_tiles : bool = false

(optional) Set to true to prevent creation of preview tiles (if enabled). Tiles would not be created where the preview source is a file created by preview_preprocessing.php.

Return values
bool —

Returns true if previews were generated successfully; false otherwise.

extract_mean_colour()

Calculate and update the mean color values for a resource image.

extract_mean_colour(GdImage $image, int $ref) : void

Calculate and update the mean color values for a resource image.

This function calculates the mean red, green, and blue color values for a given image by sampling pixels in a grid pattern. It adjusts for brightness and excludes grayscale pixels to determine the dominant colors. Additionally, it updates the thumbnail dimensions and color key in the resource record.

Parameters
$image : GdImage

The image resource to analyze for mean color.

$ref : int

The resource ID for which the color data is updated.

update_portrait_landscape_field()

Update the portrait or landscape orientation field for a resource.

update_portrait_landscape_field(int $ref[, resource|null $image = null ]) : void

This function determines whether a resource image is in portrait, landscape, or square orientation and updates the specified field accordingly. If no image resource is provided, it attempts to load the thumbnail image for the resource.

Parameters
$ref : int

The resource ID to update.

$image : resource|null = null

(optional) An image resource for orientation analysis. If not provided, the function will load the resource thumbnail.

get_colour_key()

Generate a color key for an image based on dominant colors.

get_colour_key(GdImage $image) : string

This function extracts a color key that represents the dominant colors in an image, similar to a soundex code for colors. It maps the colors in the image to predefined color categories (e.g., black, white, red, etc.), calculates the closest match for each sampled pixel, and returns a five-character color key based on the most frequent colors.

Parameters
$image : GdImage

The image resource to analyze.

Return values
string —

A five-character string representing the dominant colors in the image.

tweak_preview_images()

Apply rotation and gamma adjustments to all preview images of a resource.

tweak_preview_images(int $ref, int $rotateangle, float $gamma[, string $extension = "jpg" ][, int $alternative = -1 ][, string $resource_ext = "" ]) : bool

This function adjusts the preview images of a resource by rotating or applying gamma correction. It primarily modifies the screen resolution preview, then scales and updates other preview sizes accordingly. For video resources, it also rotates snapshot images. Updates to rotation and gamma values are recorded in the database to allow future reconstruction of adjustments.

Parameters
$ref : int

The resource ID for which previews are tweaked.

$rotateangle : int

The angle in degrees to rotate the preview images.

$gamma : float

The gamma correction factor (values > 1 to lighten, values < 1 to darken).

$extension : string = "jpg"

(optional) The file extension for the preview images. Default is "jpg".

$alternative : int = -1

(optional) The ID of an alternative file to tweak previews for. Default is -1.

$resource_ext : string = ""

(optional) The file extension of the original resource, used for video snapshot rotation.

Return values
bool —

Returns false if the main preview file does not exist; otherwise, updates previews and returns true.

tweak_wm_preview_images()

Apply rotation and gamma adjustments to all watermarked preview images of a resource.

tweak_wm_preview_images(int $ref, int $rotateangle, float $gamma[, string $extension = "jpg" ][, int $alternative = -1 ]) : bool

This function modifies watermarked preview images by applying a specified rotation angle and gamma correction factor. Each preview size defined in the database is processed, adjusting the watermarked version accordingly. The function resizes and updates each adjusted preview image.

Parameters
$ref : int

The resource ID for which watermarked previews are tweaked.

$rotateangle : int

The angle in degrees to rotate the watermarked preview images.

$gamma : float

The gamma correction factor to apply (values > 1 to lighten, values < 1 to darken).

$extension : string = "jpg"

(optional) The file extension for the preview images. Default is "jpg".

$alternative : int = -1

(optional) The ID of an alternative file to tweak previews for. Default is -1.

Return values
bool —

Returns false if a watermarked file does not exist; otherwise, updates previews and returns true.

AltImageRotate()

Rotate an image resource by a specified angle without using built-in rotation functions.

AltImageRotate(GdImage $src_img, int $angle) : resource

This function manually rotates an image resource by 90, -90, or 180 degrees, creating a new image with the rotated pixels. If the angle is not one of these specified values, the original image is returned unmodified.

Parameters
$src_img : GdImage

The source image resource to rotate.

$angle : int

The angle in degrees to rotate the image (90, -90, or 180).

Return values
resource —

The rotated image resource, or the original if the angle is unsupported.

base64_to_jpeg()

Convert a base64-encoded image to a JPEG file.

base64_to_jpeg(string $imageData, string $outputfile) : void

This function decodes a base64-encoded image string and saves it as a JPEG file.

Parameters
$imageData : string

The base64-encoded image data.

$outputfile : string

The path to save the decoded JPEG file.

Tags
throws
Exception

if the output file cannot be opened for writing.

extract_indd_pages()

Extracts JPG previews from INDD files when these have been set with a preview Note: it requires ExifTool >= 9.50

extract_indd_pages(string $filename) : array<string|int, mixed>|bool
Parameters
$filename : string
Return values
array<string|int, mixed>|bool

generate_file_checksum()

Generate or update the checksum for a resource file.

generate_file_checksum(int $resource, string $extension[, bool $anyway = false ]) : bool

This function calculates a unique checksum for a specified resource file. It either generates the checksum based on file contents and updates the resource record, or clears any existing checksum if the file does not exist. It also sets metadata indicating the checksum's last verification date and integrity status.

Parameters
$resource : int

The ID of the resource for which the checksum is generated.

$extension : string

The file extension of the resource.

$anyway : bool = false

(optional) If true, forces checksum generation regardless of configuration settings.

Return values
bool —

Returns true if the checksum was generated; false if the file does not exist or was not generated.

clear_file_checksum()

Clear the checksum value for a specified resource.

clear_file_checksum(int $resource) : bool
Parameters
$resource : int

The ID of the resource to clear the checksum for.

Return values
bool —

Returns true if the checksum was cleared successfully; false if the resource ID is invalid.

check_duplicate_checksum()

Check for duplicate files based on checksum.

check_duplicate_checksum(string $filepath, int $replace_resource) : array<string|int, mixed>

This function calculates the checksum of a file and checks if any existing resources have the same checksum, indicating a possible duplicate. If a duplicate is found and the resource is not marked for replacement, the function returns the list of duplicate resource IDs.

Parameters
$filepath : string

The file path of the file to check.

$replace_resource : int

The resource ID to replace, if applicable, to avoid detecting it as a duplicate.

Return values
array<string|int, mixed> —

An array of duplicate resource IDs, or an empty array if no duplicates are found.

upload_preview()

Upload and generate previews for a resource.

upload_preview(int $ref) : bool

This function uploads a user-provided preview image for a specified resource, ensuring the file is in JPEG format. After moving the file to its temporary location, it generates previews and cleans up the temporary file if not in use for transcoding.

Parameters
$ref : int

The resource ID for which the preview is uploaded.

Return values
bool —

Returns true if the preview upload and processing are successful, false if the file is not in JPEG format.

extract_text()

Extract text from the resource and save to the configured field

extract_text(int $ref, string $extension[, string $path = "" ]) : bool
Parameters
$ref : int

Resource ref

$extension : string

File extension

$path : string = ""

Path can be set to use an alternate file, for example, in the case of unoconv

Tags
uses
resource_log()
get_resource_path()
debug()
run_command()
hook()
update_field()
Return values
bool —

Returns false on error else true.

get_image_orientation()

Get the orientation of an image file using ExifTool.

get_image_orientation(string $file) : int

This function retrieves the orientation metadata of an image file. If orientation information is not available, it attempts to retrieve the rotation metadata. The function uses ExifTool for the extraction and processes the result to return the orientation angle in degrees.

Parameters
$file : string

The path to the image file.

Return values
int —

The orientation angle in degrees (0, 90, 180, 270), or 0 if no orientation information is available.

AutoRotateImage()

Automatically rotate an image based on its orientation metadata.

AutoRotateImage(string $src_image[, int|bool $ref = false ]) : bool

This function uses ImageMagick to rotate an image to the correct orientation. If the image's orientation is determined using ExifTool, the function will rotate the image accordingly. It preserves custom metadata when applicable.

Parameters
$src_image : string

The path to the source image that needs to be rotated.

$ref : int|bool = false

The resource ID for the image; used to fetch orientation data if needed. Pass false if no resource ID is available.

Return values
bool —

Returns true if the image was successfully rotated and saved, or false on failure.

extract_icc_profile()

Provides ability to extract the ICC profile for a specified resource/ alternative file

extract_icc_profile(int $ref, string $extension[, int $alternative = -1 ]) : bool
Parameters
$ref : int

Resource ref

$extension : string

Extension of the file

$alternative : int = -1

Resource alternative ref. Default -1 as per get_resource_path() defintion

Tags
uses
get_resource_path()
extract_icc()
Return values
bool

extract_icc()

Extracts the ICC profile from an image file using ImageMagick.

extract_icc(string $infile[, string $ref = '' ]) : bool

This function attempts to extract the ICC profile from the specified image file and saves it as a separate file with the .icc extension. It checks if the ICC profile already exists and will remove it before extraction. The function is compatible with both Windows and non-Windows environments.

Parameters
$infile : string

The path to the input image file from which to extract the ICC profile.

$ref : string = ''

Optional. The resource ID associated with the image file. Used to determine the output path for the extracted ICC profile.

Tags
used-by
extract_icc_profile()
Return values
bool —

Returns true if the ICC profile was successfully extracted and saved, or false on failure.

get_imagemagick_version()

Retrieves the version of ImageMagick installed on the system.

get_imagemagick_version([bool $array = true ]) : mixed

This function checks the version of ImageMagick by executing the convert command. It can return the version information as either an array or a string, depending on the value of the $array parameter.

Parameters
$array : bool = true

Optional. If set to true, the function returns an array containing the major, minor, revision, and patch version numbers. If false, it returns a version string in the format "major.minor.revision-patch".

Return values
mixed —

Returns an array with version numbers if $array is true, a version string if false, or false if ImageMagick is not installed or the version cannot be determined.

calculate_image_dimensions()

Function used to get new width & height for an image in order to maintain aspect ratio while it will fit within a desired dimension.

calculate_image_dimensions(string $image_path, int $target_width, int $target_height[, bool $enlarge_image = false ]) : array<string|int, mixed>
Parameters
$image_path : string

The full path to the image (can be physical / URL)

$target_width : int
$target_height : int
$enlarge_image : bool = false

Specify whether images smaller than our target should be enlarged or not. Default is FALSE

Return values
array<string|int, mixed> —

New dimensions which can be used to resize the image and offset values client code can use for consistent visual display

upload_file_by_url()

Upload file from a URL and add it to a resource.

upload_file_by_url(int $ref[, bool $no_exif = false ][, bool $revert = false ][, bool $autorotate = false ][, string $url = "" ][, string $key = "" ]) : bool
Parameters
$ref : int

Resource ID

$no_exif : bool = false

=false Don't extract exif data - true to disable extraction

$revert : bool = false

=false Delete all data and re-extract embedded data

$autorotate : bool = false

=false Autorotate images - alters embedded orientation data in uploaded file

$url : string = ""

="" File URL

$key : string = ""

="" Optional key to distinguish betweeen simultaneous requests from same user with same filename

Return values
bool

delete_previews()

Delete all preview files for specified resource id or resource data array

delete_previews(mixed $resource[, mixed $alternative = -1 ]) : mixed
Parameters
$resource : mixed

array|integer Resource array or resource ID to delete preview files for

$alternative : mixed = -1

getFileDimensions()

Get dimensions of image file

getFileDimensions(string $identify_fullpath, string $prefix, string $file, string $extension) : array<string|int, mixed>
Parameters
$identify_fullpath : string

path to IM identify command

$prefix : string

prefix - used by camera RAW files

$file : string

path to file

$extension : string

file extension

Return values
array<string|int, mixed> —

width and height of image, elements are null if not possible e.g. not an image file

getSvgSize()

Get SVG size by reading the file and looking for dimensions at either width and height OR at Viewbox attribute(s)

getSvgSize(string $file_path) : array<string|int, mixed>
Parameters
$file_path : string

Path to SVG file (should work with both a physical path and a URL)

Return values
array<string|int, mixed> —

where first element is width and second is height represented as strings

convertSvgLengthToPx()

Convert SVG length/width dimension to px size at 96DPI

convertSvgLengthToPx(string $length) : int|null
Parameters
$length : string

dimension to be converted

Return values
int|null —

dimension in pixels, or null if cannot be converted

replace_preview_from_resource()

Replace preview image with preview image from another resource/alternaive file

replace_preview_from_resource(int $ref, int $previewresource, int $previewalt) : bool
Parameters
$ref : int

Resource to replace preview image for

$previewresource : int

Preview source resource ref

$previewalt : int

Preview source resource alternative ref

Return values
bool

get_preview_source_file()

Get the source file to use for creating a preview

get_preview_source_file(int $ref, string $extension, bool $previewonly, bool $previewbased, int $alternative, bool $ingested) : string
Parameters
$ref : int

Resource ID

$extension : string

Resource extension

$previewonly : bool

Create previews only

$previewbased : bool

Use existing preview as source

$alternative : int

Alternative file reference

$ingested : bool

Has file been ingested?

Return values
string

compute_tiles_at_scale_factor()

Compute image tile regions based on a scale factor.

compute_tiles_at_scale_factor(int $sf, int $sw, int $sh) : array<string|int, mixed>

IMPORTANT: Please note that the origin position (0,0) is the upper left-most pixel of the image

Parameters
$sf : int

Scale factor

$sw : int

Source image width

$sh : int

Source image height

Tags
see
https://iiif.io/api/image/2.1/#region
https://iiif.io/api/image/2.1/#size
Return values
array<string|int, mixed> —

Returns array of tile data:

  • id -> tile region identifier. Usually used as the size argument with get_resource_path()
  • x -> represents the number of pixels from the origin (ie. position zero) on the horizontal axis
  • y -> represents the number of pixels from the origin (ie. position zero) on the vertical axis
  • w -> width of the region in pixels
  • h -> height of the region in pixels
  • row -> represents the row grid position of the region (used with DZI compliant systems)
  • column -> represents the column grid position of the region (used with DZI compliant systems)

transform_file()

Perform the requested action on the original file to create a new file

transform_file(string $sourcepath, string $outputpath, array<string|int, mixed> $actions) : bool
Parameters
$sourcepath : string

Path to source file

$outputpath : string
$actions : array<string|int, mixed>

Array of actions to perform

Return values
bool —

Image created successfully?

remove_video_previews()

For a given resource reference, remove the video pre size and all snapshots.

remove_video_previews(int $resource) : void
Parameters
$resource : int

Resource to remove video previews.

start_previews()

Create preview sizes via create_previews() and/or generate jobs as necessary

start_previews(int $ref[, string $extension = "" ]) : int
Parameters
$ref : int

Resource ID

$extension : string = ""

File extension

Return values
int —

0 Preview creation failed 1 All previews have been created 2 Minimal previews created and offline jobs/scripts are required to create the full set of previews/image/video $alternatives

get_sizes_to_generate()

Get an array of preview size IDs to generate

get_sizes_to_generate(string $extension, array<string|int, mixed> $dimensions[, bool $thumbonly = false ][, bool $previewonly = false ][, array<string|int, mixed> $onlysizes = [] ][, bool $no_tiles = false ]) : array<string|int, mixed>|bool
Parameters
$extension : string

File extension ('hpr' is only required for non-JPG images)

$dimensions : array<string|int, mixed>

Image source dimensions in format [width,height]

$thumbonly : bool = false

Generate 'thm' and 'col' only

$previewonly : bool = false

Generate 'scr', 'pre', 'thm' and 'col' only

$onlysizes : array<string|int, mixed> = []

Array of requested size IDs to generate

$no_tiles : bool = false

Set to true to prevent creation of preview tiles (if enabled). Tiles would not be created where the preview source is a file created by preview_preprocessing.php.

Return values
array<string|int, mixed>|bool —

Array of size IDs or false on failure.

create_image_alternatives()

Generates alternative image files for a specified resource.

create_image_alternatives(int $ref, array<string|int, mixed> $params[, bool $force = false ]) : bool

This function checks the existing alternative files and creates new ones based on the specified parameters. It can also force the creation of alternatives even if they already exist. It uses ImageMagick to process the images according to the specified configurations.

Parameters
$ref : int

The resource ID for which alternatives are being generated.

$params : array<string|int, mixed>

An associative array containing the following keys:

  • file: The file path of the original image.
  • extension: The extension of the original image (default is "jpg").
  • previewonly: A boolean indicating if only previews should be created.
  • previewbased: A boolean indicating if the alternatives are based on previews.
  • ingested: A boolean indicating if the resource has been ingested (default is true).
$force : bool = false

Optional. If set to true, will force the generation of alternative files even if they exist.

Return values
bool —

Returns true if alternatives were generated successfully, false otherwise.

can_apply_icc_profile()

With $icc_extraction enabled, determine whether we should apply the icc profile that has been found.

can_apply_icc_profile(string $original_file_path) : bool

Note: This doesn't prevent ICC profile extraction.

Parameters
$original_file_path : string

Path to the original file from which the ICC profile was extracted.

Return values
bool

transform_apply_icc_profile()

Check if system is using ICC profiles and prepare ImageMagick command for use by transform_file() to enable system wide configuration for $icc_extraction to be applied when transforming a file, such as by format chooser or image tools.

transform_apply_icc_profile(int $ref, string $original_file_path) : array<string|int, mixed>
Parameters
$ref : int

Resource id.

$original_file_path : string

Path to the original file for the resource.

Return values
array<string|int, mixed>

create_previews_using_im()

Generate previews for a resource using ImageMagick.

create_previews_using_im(int $ref[, bool $thumbonly = false ][, string $extension = "jpg" ][, bool $previewonly = false ][, bool $previewbased = false ][, int $alternative = -1 ][, bool $ingested = false ][, array<string|int, mixed> $onlysizes = [] ][, bool $no_tiles = false ]) : bool

This function creates image previews for a resource by leveraging ImageMagick to handle resizing and generating thumbnails, medium, large, and custom-sized previews. It provides flexible options to control the generation process, such as limiting previews to specific sizes, applying watermarks, handling color profiles, and managing alternative files. The function includes extensive support for non-standard image formats and configurations.

Parameters
$ref : int

The resource ID for which previews are generated.

$thumbonly : bool = false

(optional) If true, only the thumbnail will be generated. Default is false.

$extension : string = "jpg"

(optional) The file extension for the resource. Default is "jpg".

$previewonly : bool = false

(optional) If true, only preview images will be generated. Default is false.

$previewbased : bool = false

(optional) If true, previews are generated based on existing previews rather than original files. Default is false.

$alternative : int = -1

(optional) Specifies an alternative file ID to generate previews for, if any. Default is -1.

$ingested : bool = false

(optional) If true, marks the resource as already ingested into the system. Default is false.

$onlysizes : array<string|int, mixed> = []

(optional) Specifies an array of preview sizes to generate. If empty, all sizes are generated.

$no_tiles : bool = false

(optional) Set to true to prevent creation of preview tiles (if enabled). Tiles would not be created where the preview source is a file created by preview_preprocessing.php.

Return values
bool —

Returns true if previews were generated successfully; false otherwise.

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