Image toolkits

Functions for image file manipulations.

Drupal's image toolkits provide an abstraction layer for common image file manipulations like scaling, cropping, and rotating. The abstraction frees module authors from the need to support multiple image libraries, and it allows site administrators to choose the library that's best for them.

PHP includes the GD library by default so a GD toolkit is installed with Drupal. Other toolkits like ImageMagick are available from contrib modules. GD works well for small images, but using it with larger files may cause PHP to run out of memory. In contrast the ImageMagick library does not suffer from this problem, but it requires the ISP to have installed additional software.

Image toolkits are discovered based on the associated module's hook_image_toolkits. Additionally the image toolkit include file must be identified in the files array in the file. The toolkit must then be enabled using the admin/config/media/image-toolkit form.

Only one toolkit may be selected at a time. If a module author wishes to call a specific toolkit they can check that it is installed by calling image_get_available_toolkits(), and then calling its functions directly.

Functions & methods

image_cropincludes/image.incCrop an image to the rectangle specified by the given rectangle.
image_desaturateincludes/image.incConvert an image to grayscale.
image_dimensions_scaleincludes/image.incScales image dimensions while maintaining aspect ratio.
image_gd_check_settingsmodules/system/ GD2 settings (that the right version is actually installed).
image_gd_create_tmpmodules/system/ a truecolor image preserving transparency from a provided image.
image_gd_cropmodules/system/ an image using the GD toolkit.
image_gd_desaturatemodules/system/ an image resource to grayscale.
image_gd_get_infomodules/system/ details about an image.
image_gd_loadmodules/system/ helper function to create an image resource from a file.
image_gd_resizemodules/system/ an image to the specified size using GD.
image_gd_rotatemodules/system/ an image the given number of degrees.
image_gd_savemodules/system/ helper to write an image resource to a destination file.
image_gd_settingsmodules/system/ settings for the GD2 toolkit.
image_gd_settings_validatemodules/system/ the submitted GD settings.
image_get_available_toolkitsincludes/image.incReturn a list of available toolkits.
image_get_infoincludes/image.incGet details about an image.
image_get_toolkitincludes/image.incRetrieve the name of the currently used toolkit.
image_loadincludes/image.incLoad an image file and return an image object.
image_resizeincludes/image.incResize an image to the given dimensions (ignoring aspect ratio).
image_rotateincludes/image.incRotate an image by the given number of degrees.
image_saveincludes/image.incClose the image and save the changes to a file.
image_scaleincludes/image.incScales an image while maintaining aspect ratio.
image_scale_and_cropincludes/image.incScales an image to the exact width and height given.
image_toolkit_invokeincludes/image.incInvokes the given method using the currently selected toolkit.


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API for manipulating images.