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# QImageReader Class Reference
[com.trolltech.qt.gui module]

The `QImageReader` class provides a format independent interface for reading images from files or other devices. More...

## Detailed Description

The `QImageReader` class provides a format independent interface for reading images from files or other devices.

The most common way to read images is through `QImage` and `QPixmap`'s constructors, or by calling QImage::load() and QPixmap::load(). `QImageReader` is a specialized class which gives you more control when reading images. For example, you can read an image into a specific size by calling `setScaledSize`, and you can select a clip rect, effectively loading only parts of an image, by calling `setClipRect`. Depending on the underlying support in the image format, this can save memory and speed up loading of images.

To read an image, you start by constructing a `QImageReader` object. Pass either a file name or a device pointer, and the image format to `QImageReader`'s constructor. You can then set several options, such as the clip rect (by calling `setClipRect`) and scaled size (by calling `setScaledSize`). `canRead` returns the image if the `QImageReader` can read the image (i.e., the image format is supported and the device is open for reading). Call `read` to read the image.

If any error occurs when reading the image, `read` will return a null `QImage`. You can then call `error` to find the type of error that occurred, or `errorString` to get a human readable description of what went wrong.

Call `supportedImageFormats` for a list of formats that `QImageReader` can read. `QImageReader` supports all built-in image formats, in addition to any image format plugins that support reading.

See also `QImageWriter`, `QImageIOHandler`, and `QImageIOPlugin`.