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 } // ColorModel fulfills the draw.Image interface. func (core *Core) ColorModel () (model color.Model) { return color.RGBAModel } // ColorModel fulfills the draw.Image interface. func (core *Core) At (x, y int) (pixel color.Color) { return core.canvas.At(x, y) } // ColorModel fulfills the draw.Image interface. func (core *Core) Bounds () (bounds image.Rectangle) { return core.canvas.Bounds() } // ColorModel fulfills the draw.Image interface. func (core *Core) Set (x, y int, c color.Color) () { core.canvas.Set(x, y, c) } // Buffer fulfills the tomo.Canvas interface. func (core *Core) Buffer () (data []color.RGBA, stride int) { return core.canvas.Buffer() } // MinimumSize fulfils the tomo.Element interface. This should not need to be // overridden. func (core *Core) MinimumSize () (width, height int) { return core.metrics.minimumWidth, core.metrics.minimumHeight } // SetParentHooks fulfils the tomo.Element interface. This should not need to be // overridden. func (core *Core) SetParentHooks (hooks tomo.ParentHooks) { core.hooks = hooks } // CoreControl is a struct that can exert control over a Core struct. It can be // used as a canvas. It must not be directly embedded into an element, but // instead kept as a private member. When a Core struct is created, a // corresponding CoreControl struct is linked to it and returned alongside it. type CoreControl struct { tomo.BasicCanvas core *Core } // RequestSelection requests that the element's parent send it a selection // event. If the request was granted, it returns true. If it was denied, it // returns false. func (control CoreControl) RequestSelection () (granted bool) { return control.core.hooks.RunSelectionRequest() } // RequestSelectionMotion requests that the element's parent deselect this // element and select the one to the left or right of it, depending on the // direction. If the requests was granted, it returns true. If it was denied, it // returns false. func (control CoreControl) RequestSelectionMotion ( direction tomo.SelectionDirection, ) ( granted bool, ) { return control.core.hooks.RunSelectionMotionRequest(direction) } // HasImage returns true if the core has an allocated image buffer, and false if // it doesn't. func (control CoreControl) HasImage () (has bool) { return !control.Bounds().Empty() } // PushRegion pushes the selected region of pixels to the parent element. This // does not need to be called when responding to a resize event. func (control CoreControl) PushRegion (bounds image.Rectangle) { control.core.hooks.RunDraw(tomo.Cut(control, bounds)) } // PushAll pushes all pixels to the parent element. This does not need to be // called when responding to a resize event. func (control CoreControl) PushAll () { control.PushRegion(control.Bounds()) } // AllocateCanvas resizes the canvas, constraining the width and height so that // they are not less than the specified minimum width and height. func (control *CoreControl) AllocateCanvas (width, height int) { control.core.canvas = tomo.NewBasicCanvas(width, height) control.BasicCanvas = control.core.canvas } // SetMinimumSize sets the minimum size of this element, notifying the parent // element in the process. 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. if control.HasImage() { bounds := control.Bounds() imageWidth, imageHeight, constrained := control.ConstrainSize(bounds.Dx(), bounds.Dy()) if constrained { core.parent.Resize(imageWidth, imageHeight) } } } // NotifyFlexibleHeightChange notifies the parent element that this element's // flexible height has changed. func (control CoreControl) NotifyFlexibleHeightChange () { control.core.hooks.RunFlexibleHeightChange() } // ConstrainSize contstrains the specified width and height to the minimum width // and height, and returns wether or not anything ended up being constrained. 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 }