52 lines
1.5 KiB
Go
52 lines
1.5 KiB
Go
package tomo
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import "image"
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// Backend represents a connection to a display server, or something similar.
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// It is capable of managing an event loop, and creating windows.
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type Backend interface {
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// Run runs the backend's event loop. It must block until the backend
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// experiences a fatal error, or Stop() is called.
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Run () error
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// Stop stops the backend's event loop.
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Stop ()
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// Do executes the specified callback within the main thread as soon as
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// possible. This method must be safe to call from other threads.
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Do (callback func ())
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// NewEntity creates a new entity for the specified element.
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NewEntity (owner Element) Entity
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// NewWindow creates a new window within the specified bounding
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// rectangle. The position on screen may be overridden by the backend or
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// operating system.
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NewWindow (bounds image.Rectangle) (MainWindow, error)
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// SetTheme sets the theme of all open windows.
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SetTheme (Theme)
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// SetConfig sets the configuration of all open windows.
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SetConfig (Config)
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}
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var backend Backend
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// GetBackend returns the currently running backend.
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func GetBackend () Backend {
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return backend
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}
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// SetBackend sets the currently running backend. The backend can only be set
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// once—if there already is one then this function will do nothing.
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func SetBackend (b Backend) {
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if backend != nil { return }
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backend = b
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}
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// Bounds creates a rectangle from an x, y, width, and height.
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func Bounds (x, y, width, height int) image.Rectangle {
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return image.Rect(x, y, x + width, y + height)
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}
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