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tomo-old/entity.go

130 lines
4.1 KiB
Go

package tomo
import "image"
import "git.tebibyte.media/sashakoshka/tomo/canvas"
// Entity is a handle given to elements by the backend. Different types of
// entities may be assigned to elements that support different capabilities.
type Entity interface {
// Invalidate marks the element's current visual as invalid. At the end
// of every event, the backend will ask all invalid entities to redraw
// themselves.
Invalidate ()
// Bounds returns the bounds of the element to be used for drawing and
// layout.
Bounds () image.Rectangle
// Window returns the window that the element is in.
Window () Window
// SetMinimumSize reports to the system what the element's minimum size
// can be. The minimum size of child elements should be taken into
// account when calculating this.
SetMinimumSize (width, height int)
// DrawBackground asks the parent element to draw its background pattern
// to a canvas. This should be used for transparent elements like text
// labels. If there is no parent element (that is, the element is
// directly inside of the window), the backend will draw a default
// background pattern.
DrawBackground (canvas.Canvas)
}
// LayoutEntity is given to elements that support the Layoutable interface.
type LayoutEntity interface {
Entity
// InvalidateLayout marks the element's layout as invalid. At the end of
// every event, the backend will ask all invalid elements to recalculate
// their layouts.
InvalidateLayout ()
}
// ContainerEntity is given to elements that support the Container interface.
type ContainerEntity interface {
Entity
LayoutEntity
// Adopt adds an element as a child.
Adopt (child Element)
// Insert inserts an element in the child list at the specified
// location.
Insert (index int, child Element)
// Disown removes the child at the specified index.
Disown (index int)
// IndexOf returns the index of the specified child.
IndexOf (child Element) int
// Child returns the child at the specified index.
Child (index int) Element
// CountChildren returns the amount of children the element has.
CountChildren () int
// PlaceChild sets the size and position of the child at the specified
// index to a bounding rectangle.
PlaceChild (index int, bounds image.Rectangle)
// SelectChild marks a child as selected or unselected, if it is
// selectable.
SelectChild (index int, selected bool)
// ChildMinimumSize returns the minimum size of the child at the
// specified index.
ChildMinimumSize (index int) (width, height int)
}
// FocusableEntity is given to elements that support the Focusable interface.
type FocusableEntity interface {
Entity
// Focused returns whether the element currently has input focus.
Focused () bool
// Focus sets this element as focused. If this succeeds, the element will
// recieve a HandleFocus call.
Focus ()
// FocusNext causes the focus to move to the next element. If this
// succeeds, the element will recieve a HandleUnfocus call.
FocusNext ()
// FocusPrevious causes the focus to move to the next element. If this
// succeeds, the element will recieve a HandleUnfocus call.
FocusPrevious ()
}
// SelectableEntity is given to elements that support the Selectable interface.
type SelectableEntity interface {
Entity
// Selected returns whether this element is currently selected.
Selected () bool
}
// FlexibleEntity is given to elements that support the Flexible interface.
type FlexibleEntity interface {
Entity
// NotifyFlexibleHeightChange notifies the system that the parameters
// affecting the element's flexible height have changed. This method is
// expected to be called by flexible elements when their content changes.
NotifyFlexibleHeightChange ()
}
// ScrollableEntity is given to elements that support the Scrollable interface.
type ScrollableEntity interface {
Entity
// NotifyScrollBoundsChange notifies the system that the element's
// scroll content bounds or viewport bounds have changed. This is
// expected to be called by scrollable elements when they change their
// supported scroll axes, their scroll position (either autonomously or
// as a result of a call to ScrollTo()), or their content size.
NotifyScrollBoundsChange ()
}