GDBackend
class GDBackend extends SS_Object implements Image_Backend (View source)
A wrapper class for GD-based images, with lots of manipulation functions.
Properties
| public | string | $class | from SS_Object | |
| protected | array | $extension_instances | from SS_Object | |
| protected | $beforeExtendCallbacks | List of callbacks to call prior to extensions having extend called on them, each grouped by methodName. |
from SS_Object | |
| protected | $afterExtendCallbacks | List of callbacks to call after extensions having extend called on them, each grouped by methodName. |
from SS_Object | |
| protected | $gd | |||
| protected | $width | |||
| protected | $height | |||
| protected | $quality | |||
| protected | $interlace | |||
| protected | $cache | |||
| protected | $cacheKey | |||
| protected | $manipulation |
Methods
Get a configuration accessor for this class. Short hand for Config::inst()->get($this->class, .....).
Allows user code to hook into Object::extend prior to control being delegated to extensions. Each callback will be reset once called.
Allows user code to hook into Object::extend after control being delegated to extensions. Each callback will be reset once called.
An implementation of the factory method, allows you to create an instance of a class
Creates a class instance by the "singleton" design pattern.
Create an object from a string representation. It treats it as a PHP constructor without the 'new' keyword. It also manages to construct the object without the use of eval().
Parses a class-spec, such as "Versioned('Stage','Live')", as passed to create_from_string().
Similar to Object::create(), except that classes are only overloaded if you set the $strong parameter to TRUE when using Object::useCustomClass()
This class allows you to overload classes with other classes when they are constructed using the factory method Object::create()
If a class has been overloaded, get the class name it has been overloaded with - otherwise return the class name
Get the value of a static property of a class, even in that property is declared protected (but not private), without any inheritance, merging or parent lookup if it doesn't exist on the given class.
Return TRUE if a class has a specified extension.
Add an extension to a specific class.
No description
Attemps to locate and call a method dynamically added to a class at runtime if a default cannot be located
Return the names of all the methods available on this object
Adds any methods from Extension instances attached to this object.
Add all the methods from an object property (which is an Extension) to this object.
Add all the methods from an object property (which is an Extension) to this object.
Add a wrapper method - a method which points to another method with a different name. For example, Thumbnail(x) can be wrapped to generateThumbnail(x)
Add an extra method using raw PHP code passed as a string
Check if this class is an instance of a specific class, or has that class as one of its parents
Calls a method if available on both this object and all applied Extensions, and then attempts to merge all results into an array
Run the given function on all of this object's extensions. Note that this method originally returned void, so if you wanted to return results, you're hosed
Get an extension instance attached to this object by name.
Returns TRUE if this object instance has a specific extension applied in $extension_instances. Extension instances are initialized at constructor time, meaning if you use add_extension() afterwards, the added extension will just be added to new instances of the extended class. Use the static method has_extension() to check if a class (not an instance) has a specific extension.
Get all extension instances for this specific object instance.
Cache the results of an instance method in this object to a file, or if it is already cache return the cached results
Clears the cache for the given cacheToFile call
Loads a cache from the filesystem if a valid on is present and within the specified lifetime
Save a piece of cached data to the file system
Strip a file name of special characters so it is suitable for use as a cache file name
Check if we've got enough memory available for resampling this image. This check is rough, so it will not catch all images that are too large - it also won't work accurately on large, animated GIFs as bits per pixel can't be calculated for an animated GIF with a global color table.
Check if this image has previously crashed GD when attempting to open it - if it's opened successfully, the manipulation's cache key is removed.
Resize an image to cover the given width/height completely, and crop off any overhanging edges.
Rotates image by given angle. It's slow because makes it pixel by pixel rather than using built-in function. Used when imagerotate function is not available(i.e. Ubuntu)
Resize the image by preserving aspect ratio. By default, it will keep the image inside the maxWidth and maxHeight. Passing useAsMinimum will make the smaller dimension equal to the maximum corresponding dimension
Resize to fit fully within the given box, without resizing. Extra space left around the image will be padded with the background color.
Details
static Config_ForClass|null
config()
Get a configuration accessor for this class. Short hand for Config::inst()->get($this->class, .....).
protected
beforeExtending(string $method, callable $callback)
Allows user code to hook into Object::extend prior to control being delegated to extensions. Each callback will be reset once called.
protected
afterExtending(string $method, callable $callback)
Allows user code to hook into Object::extend after control being delegated to extensions. Each callback will be reset once called.
static SS_Object
create()
An implementation of the factory method, allows you to create an instance of a class
This method first for strong class overloads (singletons & DB interaction), then custom class overloads. If an overload is found, an instance of this is returned rather than the original class. To overload a class, use Object::useCustomClass()
This can be called in one of two ways - either calling via the class directly, or calling on Object and passing the class name as the first parameter. The following are equivalent: $list = DataList::create('SiteTree'); $list = SiteTree::get();
static SS_Object
singleton()
Creates a class instance by the "singleton" design pattern.
It will always return the same instance for this class, which can be used for performance reasons and as a simple way to access instance methods which don't rely on instance data (e.g. the custom SilverStripe static handling).
static
create_from_string($classSpec, $firstArg = null)
Create an object from a string representation. It treats it as a PHP constructor without the 'new' keyword. It also manages to construct the object without the use of eval().
Construction itself is done with Object::create(), so that Object::useCustomClass() calls are respected.
Object::create_from_string("Versioned('Stage','Live')") will return the result of
Versioned::create('Stage', 'Live);
It is designed for simple, clonable objects. The first time this method is called for a given string it is cached, and clones of that object are returned.
If you pass the $firstArg argument, this will be prepended to the constructor arguments. It's impossible to pass null as the firstArg argument.
Object::create_from_string("Varchar(50)", "MyField") will return the result of
Vachar::create('MyField', '50');
Arguments are always strings, although this is a quirk of the current implementation rather than something that can be relied upon.
static
parse_class_spec($classSpec)
Parses a class-spec, such as "Versioned('Stage','Live')", as passed to create_from_string().
Returns a 2-elemnent array, with classname and arguments
static SS_Object
strong_create()
Similar to Object::create(), except that classes are only overloaded if you set the $strong parameter to TRUE when using Object::useCustomClass()
static
useCustomClass(string $oldClass, string $newClass, bool $strong = false)
This class allows you to overload classes with other classes when they are constructed using the factory method Object::create()
static string
getCustomClass(string $class)
If a class has been overloaded, get the class name it has been overloaded with - otherwise return the class name
static any
static_lookup($class, $name, null $default = null)
Get the value of a static property of a class, even in that property is declared protected (but not private), without any inheritance, merging or parent lookup if it doesn't exist on the given class.
static
get_static($class, $name, $uncached = false)
deprecated
deprecated
No description
static
set_static($class, $name, $value)
deprecated
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static
uninherited_static($class, $name, $uncached = false)
deprecated
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static
combined_static($class, $name, $ceiling = false)
deprecated
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static
addStaticVars($class, $properties, $replace = false)
deprecated
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static
add_static_var($class, $name, $value, $replace = false)
deprecated
deprecated
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static
has_extension(string $classOrExtension, string $requiredExtension = null, bool $strict = false)
Return TRUE if a class has a specified extension.
This supports backwards-compatible format (static Object::has_extension($requiredExtension)) and new format ($object->has_extension($class, $requiredExtension))
static
add_extension(string $classOrExtension, string $extension = null)
Add an extension to a specific class.
The preferred method for adding extensions is through YAML config, since it avoids autoloading the class, and is easier to override in more specific configurations.
As an alternative, extensions can be added to a specific class directly in the Object::$extensions array. See SiteTree::$extensions for examples. Keep in mind that the extension will only be applied to new instances, not existing ones (including all instances created through singleton()).
static
remove_extension(string $extension)
Remove an extension from a class.
Keep in mind that this won't revert any datamodel additions of the extension at runtime, unless its used before the schema building kicks in (in your _config.php). Doesn't remove the extension from any Object instances which are already created, but will have an effect on new extensions. Clears any previously created singletons through singleton() to avoid side-effects from stale extension information.
static array
get_extensions(string $class, bool $includeArgumentString = false)
No description
static
get_extra_config_sources($class = null)
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__construct($filename = null, $args = array())
No description
mixed
__call(string $method, array $arguments)
Attemps to locate and call a method dynamically added to a class at runtime if a default cannot be located
You can add extra methods to a class using Extensions}, {@link Object::createMethod() or Object::addWrapperMethod()
bool
hasMethod(string $method)
Return TRUE if a method exists on this object
This should be used rather than PHP's inbuild method_exists() as it takes into account methods added via extensions
array
allMethodNames(bool $custom = false)
Return the names of all the methods available on this object
protected
defineMethods()
Adds any methods from Extension instances attached to this object.
All these methods can then be called directly on the instance (transparently mapped through __call()}), or called explicitly through {@link extend().
protected array
findMethodsFromExtension(object $extension)
No description
protected
addMethodsFrom(string $property, string|int $index = null)
Add all the methods from an object property (which is an Extension) to this object.
protected
removeMethodsFrom(string $property, string|int $index = null)
Add all the methods from an object property (which is an Extension) to this object.
protected
addWrapperMethod(string $method, string $wrap)
Add a wrapper method - a method which points to another method with a different name. For example, Thumbnail(x) can be wrapped to generateThumbnail(x)
protected
createMethod(string $method, string $code)
Add an extra method using raw PHP code passed as a string
stat($name, $uncached = false)
No description
set_stat($name, $value)
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uninherited($name)
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bool
exists()
Return true if this object "exists" i.e. has a sensible value
This method should be overriden in subclasses to provide more context about the classes state. For example, a DataObject class could return false when it is deleted from the database
string
parentClass()
No description
bool
is_a(string $class)
Check if this class is an instance of a specific class, or has that class as one of its parents
string
__toString()
No description
mixed
invokeWithExtensions(string $method, mixed $argument = null)
Calls a method if available on both this object and all applied Extensions, and then attempts to merge all results into an array
array
extend(string $method, mixed $a1 = null, mixed $a2 = null, mixed $a3 = null, mixed $a4 = null, mixed $a5 = null, mixed $a6 = null, mixed $a7 = null)
Run the given function on all of this object's extensions. Note that this method originally returned void, so if you wanted to return results, you're hosed
Currently returns an array, with an index resulting every time the function is called. Only adds returns if they're not NULL, to avoid bogus results from methods just defined on the parent extension. This is important for permission-checks through extend, as they use min() to determine if any of the returns is FALSE. As min() doesn't do type checking, an included NULL return would fail the permission checks.
The extension methods are defined during __construct()} in {@link defineMethods().
Extension
getExtensionInstance(string $extension)
Get an extension instance attached to this object by name.
bool
hasExtension(string $extension)
Returns TRUE if this object instance has a specific extension applied in $extension_instances. Extension instances are initialized at constructor time, meaning if you use add_extension() afterwards, the added extension will just be added to new instances of the extended class. Use the static method has_extension() to check if a class (not an instance) has a specific extension.
Caution: Don't use singleton(
array
getExtensionInstances()
Get all extension instances for this specific object instance.
See get_extensions() to get all applied extension classes for this class (not the instance).
mixed
cacheToFile(string $method, int $lifetime = 3600, string $ID = false, array $arguments = array())
Cache the results of an instance method in this object to a file, or if it is already cache return the cached results
clearCache($method, $ID = false, $arguments = array())
Clears the cache for the given cacheToFile call
protected mixed
loadCache(string $cache, int $lifetime = 3600)
Loads a cache from the filesystem if a valid on is present and within the specified lifetime
protected
saveCache(string $cache, mixed $data)
Save a piece of cached data to the file system
protected string
sanitiseCachename(string $name)
Strip a file name of special characters so it is suitable for use as a cache file name
static
set_default_quality($quality)
deprecated
deprecated
Set the default image quality.
void
setImageResource(mixed $resource)
setImageResource
Set the backend-specific resource handling the manipulations. Replaces Image::setGD()
setGD($gd)
deprecated
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No description
mixed
getImageResource()
getImageResource
Get the backend-specific resource handling the manipulations. Replaces Image::getGD()
getGD()
deprecated
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bool
imageAvailable(string $filename, string $manipulation)
No description
bool
checkAvailableMemory(string $filename)
Check if we've got enough memory available for resampling this image. This check is rough, so it will not catch all images that are too large - it also won't work accurately on large, animated GIFs as bits per pixel can't be calculated for an animated GIF with a global color table.
bool
failedResample(string $filename, $manipulation)
Check if this image has previously crashed GD when attempting to open it - if it's opened successfully, the manipulation's cache key is removed.
void
setQuality(int $quality)
Set the image quality, used when saving JPEGs.
Image_Backend
croppedResize(int $width, int $height)
Resize an image to cover the given width/height completely, and crop off any overhanging edges.
fittedResize($width, $height)
Resizes the image to fit within the given region.
Behaves similarly to paddedResize but without the padding.
bool
hasImageResource()
hasImageResource
hasGD()
deprecated
deprecated
No description
Image_Backend
resize(int $width, int $height)
Resize an image, skewing it as necessary.
GD
rotate($angle)
Rotates image by given angle.
GD
rotatePixelByPixel($angle)
Rotates image by given angle. It's slow because makes it pixel by pixel rather than using built-in function. Used when imagerotate function is not available(i.e. Ubuntu)
GD
crop($top, $left, $width, $height)
Crop's part of image.
int
getWidth()
Method return width of image.
int
getHeight()
Method return height of image.
Image_Backend
resizeByWidth(int $width)
Resize an image by width. Preserves aspect ratio.
Image_Backend
resizeByHeight(int $height)
Resize an image by height. Preserves aspect ratio
Image_Backend
resizeRatio($maxWidth, $maxHeight, $useAsMinimum = false)
Resize the image by preserving aspect ratio. By default, it will keep the image inside the maxWidth and maxHeight. Passing useAsMinimum will make the smaller dimension equal to the maximum corresponding dimension
static
color_web2gd($image, $webColor, $transparencyPercent = 0)
No description
Image_Backend
paddedResize(int $width, int $height, $backgroundColor = "FFFFFF", $transparencyPercent = 0)
Resize to fit fully within the given box, without resizing. Extra space left around the image will be padded with the background color.
greyscale($R = 299, $G = 587, $B = 114, $brightness = 100)
Make the image greyscale.
Default color weights are based on standard BT.601 (those used in PAL, NTSC and many software packages, also see https://en.wikipedia.org/wiki/Grayscale#Luma_coding_in_video_systems )
$R = red weight, defaults to 299 $G = green weight, defaults to 587 $B = blue weight, defaults to 114 $brightness = brightness in percentage, defaults to 100
makeDir($dirname)
No description
void
writeTo($filename)
writeTo
void
onBeforeDelete(Image $frontend)
No description