47 lines
958 B
Go
47 lines
958 B
Go
package stone
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import "image"
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import "errors"
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type Backend interface {
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Run ()
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SetTitle (title string) (err error)
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SetIcon (icons []image.Image) (err error)
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Draw ()
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CellMetrics () (width, height int)
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}
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type BackendFactory func (
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application *Application,
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callbackManager *CallbackManager,
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imageManager *ImageManager,
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) (
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backend Backend,
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err error,
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)
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var factories []BackendFactory
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func RegisterBackend (factory BackendFactory) {
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factories = append(factories, factory)
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}
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func instantiateBackend (application *Application) (backend Backend, err error) {
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// find a suitable backend
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for _, factory := range factories {
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backend, err = factory (
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application,
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&application.callbackManager,
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&application.imageManager)
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if err == nil && backend != nil { return }
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}
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// if none were found, but there was no error produced, produce an
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// error
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if err == nil {
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err = errors.New("no available backends")
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}
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return
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}
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