Instance Method

setDataRetained:

Sets whether the receiver retains its source image data.

Declaration

- (void)setDataRetained:(BOOL)flag;

Parameters

flag

YES if you want the source image data to be retained; otherwise NO.

Discussion

Retention of the source image data is important if the source of the image data could change, be moved, or be deleted. Data retention is also useful if you plan to resize an image frequently; otherwise, resizing occurs on a cached copy of the image, which can lose image quality during successive scaling operations. With data retention enabled, the image is resized from the original source data.

If the responsibility for drawing the image is delegated to another object, there is no reason to retain the image data. Similarly, if the source of the image data is not expected to change or you do not plan to resize the image, you do not need to retain the data. In fact, retaining the data leads to increased memory usage, which could have a negative impact on performance.

If you create your image object using the initByReferencingFile: method, the only data retained is the name of the source file.

See Also

Deprecated Symbols

+ imageFileTypes

Returns an array of strings identifying the image types supported by the registered image representation objects.

Deprecated
+ imageUnfilteredFileTypes

Returns an array of strings identifying the file types supported directly by the registered image representation objects.

Deprecated
+ imagePasteboardTypes

Returns an array of strings identifying the pasteboard types supported directly by the registered image representation objects.

Deprecated
+ imageUnfilteredPasteboardTypes

Returns an array of strings identifying the pasteboard types supported directly by the registered image representation objects.

Deprecated
- lockFocusOnRepresentation:

Prepares the specified image representation to receive drawing commands.

Deprecated
- bestRepresentationForDevice:

Returns the best representation for the device with the specified characteristics.

Deprecated
- compositeToPoint:operation:

Composites the entire image to the specified point in the current coordinate system.

Deprecated
- compositeToPoint:fromRect:operation:

Composites a portion of the image to the specified point in the current coordinate system.

Deprecated
- compositeToPoint:fromRect:operation:fraction:

Composites a portion of the image at the specified opacity to the current coordinate system.

Deprecated
- compositeToPoint:operation:fraction:

Composites the entire image at the specified opacity in the current coordinate system.

Deprecated
- dissolveToPoint:fraction:

Composites the entire image to the specified location using the source-over operator.

Deprecated
- dissolveToPoint:fromRect:fraction:

Composites a portion of the image to the specified location using the source-over operator.

Deprecated
- setScalesWhenResized:

Sets whether to scale different-sized image representations to fit the image's size.

Deprecated
- scalesWhenResized

Returns a Boolean value indicating whether to scale image representations to fit the image's size.

Deprecated
- isDataRetained

Returns a Boolean value indicating whether the receiver retains its source image data.

Deprecated
- setCachedSeparately:

Sets whether each image representation uses a separate offscreen window to cache its contents.

Deprecated
- isCachedSeparately

Returns a Boolean value indicating whether each image representation caches its contents in a separate offscreen window.

Deprecated
- setCacheDepthMatchesImageDepth:

Sets whether the receiver's offscreen window caches use the same bit depth as the image data itself.

Deprecated
- cacheDepthMatchesImageDepth

Returns a Boolean value indicating whether an image's offscreen window caches use the same bit depth as the image data itself.

Deprecated
- setFlipped:

Sets whether the polarity of the y axis is inverted when drawing an image.

Deprecated
- isFlipped

Returns a Boolean value indicating whether the image uses a flipped coordinate system.

Deprecated