package core import "image" import "image/color" import "git.tebibyte.media/sashakoshka/tomo" // Core is a struct that implements some core functionality common to most // widgets. It is meant to be embedded directly into a struct. type Core struct { canvas tomo.BasicCanvas parent tomo.Element metrics struct { minimumWidth int minimumHeight int } selectable bool selected bool hooks tomo.ParentHooks } // NewCore creates a new element core and its corresponding control. func NewCore (parent tomo.Element) (core *Core, control CoreControl) { core = &Core { parent: parent } control = CoreControl { core: core } return } func (core Core) ColorModel () (model color.Model) { return color.RGBAModel } func (core Core) At (x, y int) (pixel color.Color) { return core.canvas.At(x, y) } func (core Core) Bounds () (bounds image.Rectangle) { return core.canvas.Bounds() } func (core Core) Set (x, y int, c color.Color) () { core.canvas.Set(x, y, c) } func (core Core) Buffer () (data []color.RGBA, stride int) { return core.canvas.Buffer() } func (core Core) Selectable () (selectable bool) { return core.selectable } func (core Core) Selected () (selected bool) { return core.selected } func (core Core) AdvanceSelection (direction int) (ok bool) { return } func (core *Core) SetParentHooks (hooks tomo.ParentHooks) { core.hooks = hooks } func (core Core) MinimumSize () (width, height int) { return core.metrics.minimumWidth, core.metrics.minimumHeight } // CoreControl is a struct that can exert control over a control struct. It can // be used as a canvas. It must not be directly embedded into an element, but // instead kept as a private member. type CoreControl struct { tomo.BasicCanvas core *Core } func (control CoreControl) HasImage () (empty bool) { return !control.Bounds().Empty() } func (control CoreControl) Select () (granted bool) { return control.core.hooks.RunSelectionRequest() } func (control CoreControl) SetSelected (selected bool) { if !control.core.selectable { return } control.core.selected = selected } func (control CoreControl) SetSelectable (selectable bool) { if control.core.selectable == selectable { return } control.core.selectable = selectable if !selectable { control.core.selected = false } control.core.hooks.RunSelectabilityChange(selectable) } func (control CoreControl) PushRegion (bounds image.Rectangle) { control.core.hooks.RunDraw(tomo.Cut(control, bounds)) } func (control CoreControl) PushAll () { control.PushRegion(control.Bounds()) } func (control *CoreControl) AllocateCanvas (width, height int) { core := control.core width, height, _ = control.ConstrainSize(width, height) core.canvas = tomo.NewBasicCanvas(width, height) control.BasicCanvas = core.canvas } func (control CoreControl) SetMinimumSize (width, height int) { core := control.core if width == core.metrics.minimumWidth && height == core.metrics.minimumHeight { return } core.metrics.minimumWidth = width core.metrics.minimumHeight = height core.hooks.RunMinimumSizeChange(width, height) // if there is an image buffer, and the current size is less // than this new minimum size, send core.parent a resize event. bounds := control.Bounds() imageWidth, imageHeight, constrained := control.ConstrainSize ( bounds.Dx(), bounds.Dy()) if constrained { core.parent.Handle (tomo.EventResize { Width: imageWidth, Height: imageHeight, }) } } func (control CoreControl) ConstrainSize ( inWidth, inHeight int, ) ( outWidth, outHeight int, constrained bool, ) { core := control.core outWidth = inWidth outHeight = inHeight if outWidth < core.metrics.minimumWidth { outWidth = core.metrics.minimumWidth constrained = true } if outHeight < core.metrics.minimumHeight { outHeight = core.metrics.minimumHeight constrained = true } return }