widget

package
Version: v0.0.0-...-dee53b3 Latest Latest
Warning

This package is not in the latest version of its module.

Go to latest
Published: Nov 22, 2022 License: MIT, Unlicense Imports: 32 Imported by: 281

Documentation

Overview

Package widget implements state tracking and event handling of common user interface controls. To draw widgets, use a theme packages such as package gioui.org/widget/material.

Index

Examples

Constants

This section is empty.

Variables

This section is empty.

Functions

This section is empty.

Types

type Bool

type Bool struct {
	Value bool
	// contains filtered or unexported fields
}

func (*Bool) Changed

func (b *Bool) Changed() bool

Changed reports whether Value has changed since the last call to Changed.

func (*Bool) Focused

func (b *Bool) Focused() bool

Focused reports whether b has focus.

func (*Bool) History

func (b *Bool) History() []Press

func (*Bool) Hovered

func (b *Bool) Hovered() bool

Hovered reports whether pointer is over the element.

func (*Bool) Layout

func (b *Bool) Layout(gtx layout.Context, w layout.Widget) layout.Dimensions

func (*Bool) Pressed

func (b *Bool) Pressed() bool

Pressed reports whether pointer is pressing the element.

type Border

type Border struct {
	Color        color.NRGBA
	CornerRadius unit.Dp
	Width        unit.Dp
}

Border lays out a widget and draws a border inside it.

func (Border) Layout

func (b Border) Layout(gtx layout.Context, w layout.Widget) layout.Dimensions

type ChangeEvent

type ChangeEvent struct{}

A ChangeEvent is generated for every user change to the text.

type Click

type Click struct {
	Modifiers key.Modifiers
	NumClicks int
}

Click represents a click.

type Clickable

type Clickable struct {
	// contains filtered or unexported fields
}

Clickable represents a clickable area.

Example (Passthrough)
package main

import (
	"fmt"
	"image"

	"gioui.org/f32"
	"gioui.org/io/pointer"
	"gioui.org/io/router"
	"gioui.org/layout"
	"gioui.org/op"
	"gioui.org/widget"
)

func main() {
	// When laying out clickable widgets on top of each other,
	// pointer events can be passed down for the underlying
	// widgets to pick them up.
	var button1, button2 widget.Clickable
	var r router.Router
	gtx := layout.Context{
		Ops:         new(op.Ops),
		Constraints: layout.Exact(image.Pt(100, 100)),
		Queue:       &r,
	}

	// widget lays out two buttons on top of each other.
	widget := func() {
		content := func(gtx layout.Context) layout.Dimensions { return layout.Dimensions{Size: gtx.Constraints.Min} }
		button1.Layout(gtx, content)
		// button2 completely covers button1, but pass-through allows pointer
		// events to pass through to button1.
		defer pointer.PassOp{}.Push(gtx.Ops).Pop()
		button2.Layout(gtx, content)
	}

	// The first layout and call to Frame declare the Clickable handlers
	// to the input router, so the following pointer events are propagated.
	widget()
	r.Frame(gtx.Ops)
	// Simulate one click on the buttons by sending a Press and Release event.
	r.Queue(
		pointer.Event{
			Source:   pointer.Mouse,
			Buttons:  pointer.ButtonPrimary,
			Type:     pointer.Press,
			Position: f32.Pt(50, 50),
		},
		pointer.Event{
			Source:   pointer.Mouse,
			Buttons:  pointer.ButtonPrimary,
			Type:     pointer.Release,
			Position: f32.Pt(50, 50),
		},
	)
	// The second layout ensures that the click event is registered by the buttons.
	widget()

	if button1.Clicked() {
		fmt.Println("button1 clicked!")
	}
	if button2.Clicked() {
		fmt.Println("button2 clicked!")
	}

}
Output:

button1 clicked!
button2 clicked!

func (*Clickable) Click

func (b *Clickable) Click()

Click executes a simple programmatic click

func (*Clickable) Clicked

func (b *Clickable) Clicked() bool

Clicked reports whether there are pending clicks as would be reported by Clicks. If so, Clicked removes the earliest click.

func (*Clickable) Clicks

func (b *Clickable) Clicks() []Click

Clicks returns and clear the clicks since the last call to Clicks.

func (*Clickable) Focused

func (b *Clickable) Focused() bool

Focused reports whether b has focus.

func (*Clickable) History

func (b *Clickable) History() []Press

History is the past pointer presses useful for drawing markers. History is retained for a short duration (about a second).

func (*Clickable) Hovered

func (b *Clickable) Hovered() bool

Hovered reports whether a pointer is over the element.

func (*Clickable) Layout

Layout and update the button state

func (*Clickable) Pressed

func (b *Clickable) Pressed() bool

Pressed reports whether a pointer is pressing the element.

type Decorations

type Decorations struct {
	// contains filtered or unexported fields
}

Decorations handles the states of window decorations.

func (*Decorations) Actions

func (d *Decorations) Actions() system.Action

Actions returns the set of actions activated by the user.

func (*Decorations) Clickable

func (d *Decorations) Clickable(action system.Action) *Clickable

Clickable returns the clickable for the given single action.

func (*Decorations) LayoutMove

func (d *Decorations) LayoutMove(gtx layout.Context, w layout.Widget) layout.Dimensions

LayoutMove lays out the widget that makes a window movable.

func (*Decorations) Maximized

func (d *Decorations) Maximized() bool

Maximized returns whether the window is maximized.

func (*Decorations) Perform

func (d *Decorations) Perform(actions system.Action)

Perform updates the decorations as if the specified actions were performed by the user.

type Draggable

type Draggable struct {
	// Type contains the MIME type and matches transfer.SourceOp.
	Type string
	// contains filtered or unexported fields
}

Draggable makes a widget draggable.

func (*Draggable) Dragging

func (d *Draggable) Dragging() bool

Dragging returns whether d is being dragged.

func (*Draggable) Layout

func (d *Draggable) Layout(gtx layout.Context, w, drag layout.Widget) layout.Dimensions
Example
package main

import (
	"fmt"
	"image"

	"gioui.org/f32"
	"gioui.org/io/pointer"
	"gioui.org/io/router"
	"gioui.org/io/transfer"
	"gioui.org/layout"
	"gioui.org/op"
	"gioui.org/op/clip"
	"gioui.org/widget"
)

func main() {
	var r router.Router
	gtx := layout.Context{
		Ops:         new(op.Ops),
		Constraints: layout.Exact(image.Pt(100, 100)),
		Queue:       &r,
	}
	// mime is the type used to match drag and drop operations.
	// It could be left empty in this example.
	mime := "MyMime"
	drag := &widget.Draggable{Type: mime}
	var drop int
	// widget lays out the drag and drop handlers and processes
	// the transfer events.
	widget := func() {
		// Setup the draggable widget.
		w := func(gtx layout.Context) layout.Dimensions {
			sz := image.Pt(10, 10) // drag area
			return layout.Dimensions{Size: sz}
		}
		drag.Layout(gtx, w, w)
		// drag must respond with an Offer event when requested.
		// Use the drag method for this.
		if m, ok := drag.Requested(); ok {
			drag.Offer(gtx.Ops, m, offer{Data: "hello world"})
		}

		// Setup the area for drops.
		ds := clip.Rect{
			Min: image.Pt(20, 20),
			Max: image.Pt(40, 40),
		}.Push(gtx.Ops)
		transfer.TargetOp{
			Tag:  &drop,
			Type: mime, // this must match the drag Type for the drop to succeed
		}.Add(gtx.Ops)
		ds.Pop()
		// Check for the received data.
		for _, ev := range gtx.Events(&drop) {
			switch e := ev.(type) {
			case transfer.DataEvent:
				data := e.Open()
				fmt.Println(data.(offer).Data)
			}
		}
	}
	// Register and lay out the widget.
	widget()
	r.Frame(gtx.Ops)

	// Send drag and drop gesture events.
	r.Queue(
		pointer.Event{
			Type:     pointer.Press,
			Position: f32.Pt(5, 5), // in the drag area
		},
		pointer.Event{
			Type:     pointer.Move,
			Position: f32.Pt(5, 5), // in the drop area
		},
		pointer.Event{
			Type:     pointer.Release,
			Position: f32.Pt(30, 30), // in the drop area
		},
	)
	// Let the widget process the events.
	widget()
	r.Frame(gtx.Ops)

	// Process the transfer.DataEvent.
	widget()

}

type offer struct {
	Data string
}

func (offer) Read([]byte) (int, error) { return 0, nil }
func (offer) Close() error             { return nil }
Output:

hello world

func (*Draggable) Offer

func (d *Draggable) Offer(ops *op.Ops, mime string, data io.ReadCloser)

Offer the data ready for a drop. Must be called after being Requested. The mime must be one in the requested list.

func (*Draggable) Pos

func (d *Draggable) Pos() f32.Point

Pos returns the drag position relative to its initial click position.

func (*Draggable) Requested

func (d *Draggable) Requested() (mime string, requested bool)

Requested returns the MIME type, if any, for which the Draggable was requested to offer data.

type Editor

type Editor struct {
	Alignment text.Alignment
	// SingleLine force the text to stay on a single line.
	// SingleLine also sets the scrolling direction to
	// horizontal.
	SingleLine bool
	// Submit enabled translation of carriage return keys to SubmitEvents.
	// If not enabled, carriage returns are inserted as newlines in the text.
	Submit bool
	// Mask replaces the visual display of each rune in the contents with the given rune.
	// Newline characters are not masked. When non-zero, the unmasked contents
	// are accessed by Len, Text, and SetText.
	Mask rune
	// InputHint specifies the type of on-screen keyboard to be displayed.
	InputHint key.InputHint
	// MaxLen limits the editor content to a maximum length. Zero means no limit.
	MaxLen int
	// Filter is the list of characters allowed in the Editor. If Filter is empty,
	// all characters are allowed.
	Filter string
	// contains filtered or unexported fields
}

Editor implements an editable and scrollable text area.

func (*Editor) CaretCoords

func (e *Editor) CaretCoords() f32.Point

CaretCoords returns the coordinates of the caret, relative to the editor itself.

func (*Editor) CaretPos

func (e *Editor) CaretPos() (line, col int)

CaretPos returns the line & column numbers of the caret.

func (*Editor) ClearSelection

func (e *Editor) ClearSelection()

ClearSelection clears the selection, by setting the selection end equal to the selection start.

func (*Editor) Delete

func (e *Editor) Delete(runes int)

Delete runes from the caret position. The sign of runes specifies the direction to delete: positive is forward, negative is backward.

If there is a selection, it is deleted and counts as a single rune.

func (*Editor) Events

func (e *Editor) Events() []EditorEvent

Events returns available editor events.

func (*Editor) Focus

func (e *Editor) Focus()

Focus requests the input focus for the Editor.

func (*Editor) Focused

func (e *Editor) Focused() bool

Focused returns whether the editor is focused or not.

func (*Editor) Insert

func (e *Editor) Insert(s string)

Insert inserts text at the caret, moving the caret forward. If there is a selection, Insert overwrites it.

func (*Editor) Layout

func (e *Editor) Layout(gtx layout.Context, sh text.Shaper, font text.Font, size unit.Sp, content layout.Widget) layout.Dimensions

Layout lays out the editor. If content is not nil, it is laid out on top.

func (*Editor) Len

func (e *Editor) Len() int

Len is the length of the editor contents, in runes.

func (*Editor) MoveCaret

func (e *Editor) MoveCaret(startDelta, endDelta int)

MoveCaret moves the caret (aka selection start) and the selection end relative to their current positions. Positive distances moves forward, negative distances moves backward. Distances are in runes.

func (*Editor) NumLines

func (e *Editor) NumLines() int

NumLines returns the number of lines in the editor.

func (*Editor) PaintCaret

func (e *Editor) PaintCaret(gtx layout.Context)

func (*Editor) PaintSelection

func (e *Editor) PaintSelection(gtx layout.Context)

PaintSelection paints the contrasting background for selected text.

func (*Editor) PaintText

func (e *Editor) PaintText(gtx layout.Context)

func (*Editor) Read

func (e *Editor) Read(p []byte) (int, error)

Read implements io.Reader.

func (*Editor) Seek

func (e *Editor) Seek(offset int64, whence int) (int64, error)

Seek implements io.Seeker.

func (*Editor) SelectedText

func (e *Editor) SelectedText() string

SelectedText returns the currently selected text (if any) from the editor.

func (*Editor) Selection

func (e *Editor) Selection() (start, end int)

Selection returns the start and end of the selection, as rune offsets. start can be > end.

func (*Editor) SelectionLen

func (e *Editor) SelectionLen() int

SelectionLen returns the length of the selection, in runes; it is equivalent to utf8.RuneCountInString(e.SelectedText()).

func (*Editor) SetCaret

func (e *Editor) SetCaret(start, end int)

SetCaret moves the caret to start, and sets the selection end to end. start and end are in runes, and represent offsets into the editor text.

func (*Editor) SetText

func (e *Editor) SetText(s string)

SetText replaces the contents of the editor, clearing any selection first.

func (*Editor) Text

func (e *Editor) Text() string

Text returns the contents of the editor.

func (*Editor) WriteTo

func (e *Editor) WriteTo(w io.Writer) (int64, error)

WriteTo implements io.WriterTo.

type EditorEvent

type EditorEvent interface {
	// contains filtered or unexported methods
}

type Enum

type Enum struct {
	Value string
	// contains filtered or unexported fields
}

func (*Enum) Changed

func (e *Enum) Changed() bool

Changed reports whether Value has changed by user interaction since the last call to Changed.

func (*Enum) Focused

func (e *Enum) Focused() (string, bool)

Focused reports the focused key, or false if no key is focused.

func (*Enum) Hovered

func (e *Enum) Hovered() (string, bool)

Hovered returns the key that is highlighted, or false if none are.

func (*Enum) Layout

func (e *Enum) Layout(gtx layout.Context, k string, content layout.Widget) layout.Dimensions

Layout adds the event handler for the key k.

type Fit

type Fit uint8

Fit scales a widget to fit and clip to the constraints.

const (
	// Unscaled does not alter the scale of a widget.
	Unscaled Fit = iota
	// Contain scales widget as large as possible without cropping
	// and it preserves aspect-ratio.
	Contain
	// Cover scales the widget to cover the constraint area and
	// preserves aspect-ratio.
	Cover
	// ScaleDown scales the widget smaller without cropping,
	// when it exceeds the constraint area.
	// It preserves aspect-ratio.
	ScaleDown
	// Fill stretches the widget to the constraints and does not
	// preserve aspect-ratio.
	Fill
)

type Float

type Float struct {
	Value float32
	Axis  layout.Axis
	// contains filtered or unexported fields
}

Float is for selecting a value in a range.

func (*Float) Changed

func (f *Float) Changed() bool

Changed reports whether the value has changed since the last call to Changed.

func (*Float) Dragging

func (f *Float) Dragging() bool

Dragging returns whether the value is being interacted with.

func (*Float) Layout

func (f *Float) Layout(gtx layout.Context, pointerMargin int, min, max float32) layout.Dimensions

Layout updates the value according to drag events along the f's main axis.

The range of f is set by the minimum constraints main axis value.

func (*Float) Pos

func (f *Float) Pos() float32

Pos reports the selected position.

type Icon

type Icon struct {
	// contains filtered or unexported fields
}

func NewIcon

func NewIcon(data []byte) (*Icon, error)

NewIcon returns a new Icon from IconVG data.

func (*Icon) Layout

func (ic *Icon) Layout(gtx layout.Context, color color.NRGBA) layout.Dimensions

Layout displays the icon with its size set to the X minimum constraint.

type Image

type Image struct {
	// Src is the image to display.
	Src paint.ImageOp
	// Fit specifies how to scale the image to the constraints.
	// By default it does not do any scaling.
	Fit Fit
	// Position specifies where to position the image within
	// the constraints.
	Position layout.Direction
	// Scale is the ratio of image pixels to
	// dps. If Scale is zero Image falls back to
	// a scale that match a standard 72 DPI.
	Scale float32
}

Image is a widget that displays an image.

func (Image) Layout

func (im Image) Layout(gtx layout.Context) layout.Dimensions

type Label

type Label struct {
	// Alignment specify the text alignment.
	Alignment text.Alignment
	// MaxLines limits the number of lines. Zero means no limit.
	MaxLines int
}

Label is a widget for laying out and drawing text.

func (Label) Layout

func (l Label) Layout(gtx layout.Context, s text.Shaper, font text.Font, size unit.Sp, txt string) layout.Dimensions

type List

type List struct {
	Scrollbar
	layout.List
}

List holds the persistent state for a layout.List that has a scrollbar attached.

type Press

type Press struct {
	// Position of the press.
	Position image.Point
	// Start is when the press began.
	Start time.Time
	// End is when the press was ended by a release or cancel.
	// A zero End means it hasn't ended yet.
	End time.Time
	// Cancelled is true for cancelled presses.
	Cancelled bool
}

Press represents a past pointer press.

type Scrollbar

type Scrollbar struct {
	// contains filtered or unexported fields
}

Scrollbar holds the persistent state for an area that can display a scrollbar. In particular, it tracks the position of a viewport along a one-dimensional region of content. The viewport's position can be adjusted by drag operations along the display area, or by clicks within the display area.

Scrollbar additionally detects when a scroll indicator region is hovered.

func (*Scrollbar) AddDrag

func (s *Scrollbar) AddDrag(ops *op.Ops)

AddDrag configures the drag listener for the scrollbar to use the current clip area.

func (*Scrollbar) AddIndicator

func (s *Scrollbar) AddIndicator(ops *op.Ops)

AddIndicator configures the indicator click listener for the scrollbar to use the current clip area.

func (*Scrollbar) AddTrack

func (s *Scrollbar) AddTrack(ops *op.Ops)

AddTrack configures the track click listener for the scrollbar to use the current clip area.

func (*Scrollbar) Dragging

func (s *Scrollbar) Dragging() bool

Dragging reports whether the user is currently performing a drag gesture on the indicator. Note that this can return false while ScrollDistance is nonzero if the user scrolls using a different control than the scrollbar (like a mouse wheel).

func (*Scrollbar) IndicatorHovered

func (s *Scrollbar) IndicatorHovered() bool

IndicatorHovered reports whether the scroll indicator is currently being hovered by the pointer.

func (*Scrollbar) Layout

func (s *Scrollbar) Layout(gtx layout.Context, axis layout.Axis, viewportStart, viewportEnd float32) layout.Dimensions

Layout updates the internal state of the scrollbar based on events since the previous call to Layout. The provided axis will be used to normalize input event coordinates and constraints into an axis- independent format. viewportStart is the position of the beginning of the scrollable viewport relative to the underlying content expressed as a value in the range [0,1]. viewportEnd is the position of the end of the viewport relative to the underlying content, also expressed as a value in the range [0,1]. For example, if viewportStart is 0.25 and viewportEnd is .5, the viewport described by the scrollbar is currently showing the second quarter of the underlying content.

func (*Scrollbar) ScrollDistance

func (s *Scrollbar) ScrollDistance() float32

ScrollDistance returns the normalized distance that the scrollbar moved during the last call to Layout as a value in the range [-1,1].

func (*Scrollbar) TrackHovered

func (s *Scrollbar) TrackHovered() bool

TrackHovered reports whether the scroll track is being hovered by the pointer.

type SelectEvent

type SelectEvent struct{}

A SelectEvent is generated when the user selects some text, or changes the selection (e.g. with a shift-click), including if they remove the selection. The selected text is not part of the event, on the theory that it could be a relatively expensive operation (for a large editor), most applications won't actually care about it, and those that do can call Editor.SelectedText() (which can be empty).

type SubmitEvent

type SubmitEvent struct {
	Text string
}

A SubmitEvent is generated when Submit is set and a carriage return key is pressed.

Directories

Path Synopsis
Package material implements the Material design.
Package material implements the Material design.

Jump to

Keyboard shortcuts

? : This menu
/ : Search site
f or F : Jump to
y or Y : Canonical URL