Initial commit

tomo.go

@@ -0,0 +1,114 @@
+package tomo
+
+import "image"
+import "errors"
+import "image/draw"
+import "image/color"
+// import "git.tebibyte.media/sashakoshka/tomo/iterator"
+
+// Image represents a simple image buffer that fulfills the image.Image
+// interface while also having methods that do away with the use of the
+// color.Color interface to facilitate more efficient drawing. This interface
+// can be easily satisfied using an image.RGBA struct.
+type Image interface {
+	image.Image
+	RGBAAt (x, y int) (c color.RGBA)
+}
+
+// Canvas is like Image but also requires a SetRGBA method. This interface can
+// be easily satisfied using an image.RGBA struct.
+type Canvas interface {
+	draw.Image
+	RGBAAt (x, y int) (c color.RGBA)
+	SetRGBA (x, y int, c color.RGBA)
+}
+
+// Element represents a basic on-screen object.
+type Element interface {
+	// Element must implement the Image interface. Elements should start out
+	// with a completely blank image buffer, and only set its size and draw
+	// on it for the first time when sent an EventResize event.
+	Image
+
+	// Handle handles an event, propagating it to children if necessary.
+	Handle (event Event)
+
+	// Selectable returns whether this element can be selected. If this
+	// element contains other selectable elements, it must return true.
+	Selectable () (bool)
+
+	// SetDrawCallback sets a function to be called when a part of the
+	// element's surface is updated. The updated region will be passed to
+	// the callback as a sub-image.
+	SetDrawCallback (draw func (region Image))
+
+	// SetMinimumSizeChangeCallback sets a function to be called when the
+	// element's minimum width and/or height changes. When this function is
+	// called, the element will have already been resized and there is no
+	// need to send it a resize event.
+	SetMinimumSizeChangeCallback (notify func (width, height int))
+
+	// MinimumWidth specifies the minimum amount of pixels this element's
+	// width may be set to. If the element is resized to an amount smaller
+	// that MinimumWidth, it will instead set its width to MinimumWidth.
+	MinimumWidth () (minimum int)
+
+	// MinimumHeight specifies the minimum amount of pixels this element's
+	// height may be set to. If the element is resized to an amount smaller
+	// that MinimumHeight, it will instead set its height to MinimumHeight.
+	MinimumHeight () (minimum int)
+}
+
+// Window represents a top-level container generated by the currently running
+// backend. It can contain a single element. It is hidden by default, and must
+// be explicitly shown with the Show() method. If it contains no element, it
+// displays a black (or transprent) background.
+type Window interface {
+	Element
+	Adopt (child Element)
+	Child () (child Element)
+	SetTitle (title string)
+	SetIcon  (sizes []image.Image)
+	Show     ()
+	Hide     ()
+	Close    ()
+	OnClose  (func ())
+}
+
+var backend Backend
+
+// Run initializes a backend, calls the callback function, and begins the event
+// loop in that order. This function does not return until Stop() is called, or
+// the backend experiences a fatal error.
+func Run (callback func ()) (err error) {
+	backend, err = instantiateBackend()
+	if callback != nil { callback() }
+	err = backend.Run()
+	backend = nil
+	return
+}
+
+// Stop gracefully stops the event loop and shuts the backend down. Call this
+// before closing your application.
+func Stop () {
+	if backend != nil { backend.Stop() }
+}
+
+// Do executes the specified callback within the main thread as soon as
+// possible. This function can be safely called from other threads.
+func Do (callback func ()) {
+	
+}
+
+// NewWindow creates a new window using the current backend, and returns it as a
+// Window. If the window could not be created, an error is returned explaining
+// why. If this function is called without a running backend, an error is
+// returned as well.
+func NewWindow (width, height int) (window Window, err error) {
+	if backend == nil {
+		err = errors.New("no backend is running.")
+		return
+	}
+	window, err = backend.NewWindow(width, height)
+	return
+}