Image Manipulation

Package diskfs implements methods for creating and manipulating disks and filesystems methods for creating and manipulating disks and filesystems, whether block devices in /dev or direct disk images. This does **not** mount any disks or filesystems, neither directly locally nor via a VM. Instead, it manipulates the bytes directly. This is not intended as a replacement for operating system filesystem and disk drivers. Instead, it is intended to make it easy to work with partitions, partition tables and filesystems directly without requiring operating system mounts. Some examples: 1. Create a disk image of size 10MB with a FAT32 filesystem spanning the entire disk.

Package imaging provides basic image manipulation functions (resize, rotate, flip, crop, etc.). This package is based on the standard Go image package and works best along with it. Image manipulation functions provided by the package take any image type that implements `image.Image` interface as an input, and return a new image of `*image.NRGBA` type (32bit RGBA colors, not premultiplied by alpha). Imaging package uses parallel goroutines for faster image processing. To achieve maximum performance, make sure to allow Go to utilize all CPU cores: Here is the complete example that loades several images, makes thumbnails of them and joins them together.

Package diskfs implements methods for creating and manipulating disks and filesystems methods for creating and manipulating disks and filesystems, whether block devices in /dev or direct disk images. This does **not** mount any disks or filesystems, neither directly locally nor via a VM. Instead, it manipulates the bytes directly. This is not intended as a replacement for operating system filesystem and disk drivers. Instead, it is intended to make it easy to work with partitions, partition tables and filesystems directly without requiring operating system mounts. Some examples: 1. Create a disk image of size 10MB with a FAT32 filesystem spanning the entire disk.

Package qml offers graphical QML application support for the Go language. This package is in an alpha stage, and still in heavy development. APIs may change, and things may break. At this time contributors and developers that are interested in tracking the development closely are encouraged to use it. If you'd prefer a more stable release, please hold on a bit and subscribe to the mailing list for news. It's in a pretty good state, so it shall not take too long. See http://github.com/go-qml/qml for details. The qml package enables Go programs to display and manipulate graphical content using Qt's QML framework. QML uses a declarative language to express structure and style, and supports JavaScript for in-place manipulation of the described content. When using the Go qml package, such QML content can also interact with Go values, making use of its exported fields and methods, and even explicitly creating new instances of registered Go types. A simple Go application that integrates with QML may perform the following steps for offering a graphical interface: Some of these topics are covered below, and may also be observed in practice in the following examples: The following logic demonstrates loading a QML file into a window: Any QML object may be manipulated by Go via the Object interface. That interface is implemented both by dynamic QML values obtained from a running engine, and by Go types in the qml package that represent QML values, such as Window, Context, and Engine. For example, the following logic creates a window and prints its width whenever it's made visible: Information about the methods, properties, and signals that are available for QML objects may be obtained in the Qt documentation. As a reference, the "visibleChanged" signal and the "width" property used in the example above are described at: When in doubt about what type is being manipulated, the Object.TypeName method provides the type name of the underlying value. The simplest way of making a Go value available to QML code is setting it as a variable of the engine's root context, as in: This logic would enable the following QML code to successfully run: While registering an individual Go value as described above is a quick way to get started, it is also fairly limited. For more flexibility, a Go type may be registered so that QML code can natively create new instances in an arbitrary position of the structure. This may be achieved via the RegisterType function, as the following example demonstrates: With this logic in place, QML code can create new instances of Person by itself: Independently from the mechanism used to publish a Go value to QML code, its methods and fields are available to QML logic as methods and properties of the respective QML object representing it. As required by QML, though, the Go method and field names are lowercased according to the following scheme when being accesed from QML: While QML code can directly read and write exported fields of Go values, as described above, a Go type can also intercept writes to specific fields by declaring a setter method according to common Go conventions. This is often useful for updating the internal state or the visible content of a Go-defined type. For example: In the example above, whenever QML code attempts to update the Person.Name field via any means (direct assignment, object declarations, etc) the SetName method is invoked with the provided value instead. A setter method may also be used in conjunction with a getter method rather than a real type field. A method is only considered a getter in the presence of the respective setter, and according to common Go conventions it must not have the Get prefix. Inside QML logic, the getter and setter pair is seen as a single object property. Custom types implemented in Go may have displayable content by defining a Paint method such as: A simple example is available at: Resource files (qml code, images, etc) may be packed into the Go qml application binary to simplify its handling and distribution. This is done with the genqrc tool: The following blog post provides more details: