Add paste support to entry widget (fyne-io#89)

* Add initial paste support to entry

* Add Clipboard interface, implement for Gl driver

* Add Shortcut interface and default handler

* Allow adding of shortcuts to canvas

canvas.go

@@ -17,4 +17,5 @@ type Canvas interface {
 	SetOnTypedRune(func(rune))
 	OnTypedKey() func(*KeyEvent)
 	SetOnTypedKey(func(*KeyEvent))
+	AddShortcut(shortcut Shortcut, handler func(shortcut Shortcut))
 }

canvasobject.go

@@ -53,3 +53,8 @@ type Focusable interface {
 	TypedRune(rune)
 	TypedKey(*KeyEvent)
 }
+
+// Shortcutable describes any CanvasObject that can respond to shortcut commands (quit, cut, copy, and paste).
+type Shortcutable interface {
+	TypedShortcut(shortcut Shortcut) bool
+}

clipboard.go

@@ -0,0 +1,9 @@
+package fyne
+
+// Clipboard represents the system clipboard interface
+type Clipboard interface {
+	// Content returns the clipboard content
+	Content() string
+	// SetContent sets the clipboard content
+	SetContent(content string)
+}

driver/desktop/key.go

@@ -1,6 +1,8 @@
 package desktop
 
-import "fyne.io/fyne"
+import (
+	"fyne.io/fyne"
+)
 
 const (
 	// KeyShift represents the left or right shift key
@@ -14,3 +16,17 @@ const (
 	// KeyMenu represents the left or right menu / application key
 	KeyMenu fyne.KeyName = "Menu"
 )
+
+// Modifier captures any key modifiers (shift etc) pressed during this key event
+type Modifier int
+
+const (
+	// ShiftModifier represents a shift key being held
+	ShiftModifier Modifier = 1 << iota
+	// ControlModifier represents the ctrl key being held
+	ControlModifier
+	// AltModifier represents either alt keys being held
+	AltModifier
+	// SuperModifier represents either super keys being held
+	SuperModifier
+)

driver/desktop/shortcut.go

@@ -0,0 +1,40 @@
+package desktop
+
+import (
+	"strings"
+
+	"fyne.io/fyne"
+)
+
+// CustomShortcut describes a shortcut desktop event.
+type CustomShortcut struct {
+	fyne.KeyName
+	Modifier
+}
+
+// ShortcutName returns the shortcut name associated to the event
+func (cs *CustomShortcut) ShortcutName() string {
+	id := &strings.Builder{}
+	id.WriteString("CustomDesktop:")
+	id.WriteString(modifierToString(cs.Modifier))
+	id.WriteString("+")
+	id.WriteString(string(cs.KeyName))
+	return id.String()
+}
+
+func modifierToString(mods Modifier) string {
+	s := []string{}
+	if (mods & ShiftModifier) != 0 {
+		s = append(s, string(KeyShift))
+	}
+	if (mods & ControlModifier) != 0 {
+		s = append(s, string(KeyControl))
+	}
+	if (mods & AltModifier) != 0 {
+		s = append(s, string(KeyAlt))
+	}
+	if (mods & SuperModifier) != 0 {
+		s = append(s, string(KeySuper))
+	}
+	return strings.Join(s, "+")
+}

driver/desktop/shortcut_test.go

@@ -0,0 +1,80 @@
+package desktop
+
+import (
+	"testing"
+
+	"fyne.io/fyne"
+)
+
+func TestCustomShortcut_Shortcut(t *testing.T) {
+	type fields struct {
+		KeyName  fyne.KeyName
+		Modifier Modifier
+	}
+	tests := []struct {
+		name   string
+		fields fields
+		want   string
+	}{
+		{
+			name: "Ctrl+C",
+			fields: fields{
+				KeyName:  fyne.KeyC,
+				Modifier: ControlModifier,
+			},
+			want: "CustomDesktop:Control+C",
+		},
+		{
+			name: "Ctrl+Alt+Esc",
+			fields: fields{
+				KeyName:  fyne.KeyEscape,
+				Modifier: ControlModifier + AltModifier,
+			},
+			want: "CustomDesktop:Control+Alt+Escape",
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			cs := &CustomShortcut{
+				KeyName:  tt.fields.KeyName,
+				Modifier: tt.fields.Modifier,
+			}
+			if got := cs.ShortcutName(); got != tt.want {
+				t.Errorf("CustomShortcut.ShortcutName() = %v, want %v", got, tt.want)
+			}
+		})
+	}
+}
+
+func Test_modifierToString(t *testing.T) {
+	type args struct {
+	}
+	tests := []struct {
+		name string
+		mods Modifier
+		want string
+	}{
+		{
+			name: "None",
+			mods: 0,
+			want: "",
+		},
+		{
+			name: "Ctrl",
+			mods: ControlModifier,
+			want: "Control",
+		},
+		{
+			name: "Shift+Ctrl",
+			mods: ShiftModifier + ControlModifier,
+			want: "Shift+Control",
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			if got := modifierToString(tt.mods); got != tt.want {
+				t.Errorf("modifierToString() = %v, want %v", got, tt.want)
+			}
+		})
+	}
+}

driver/gl/canvas.go

@@ -17,6 +17,7 @@ type glCanvas struct {
 
 	onTypedRune func(rune)
 	onTypedKey  func(*fyne.KeyEvent)
+	shortcut    fyne.ShortcutHandler
 
 	program uint32
 	scale   float32
@@ -130,6 +131,10 @@ func (c *glCanvas) SetOnTypedKey(typed func(*fyne.KeyEvent)) {
 	c.onTypedKey = typed
 }
 
+func (c *glCanvas) AddShortcut(shortcut fyne.Shortcut, handler func(shortcut fyne.Shortcut)) {
+	c.shortcut.AddShortcut(shortcut, handler)
+}
+
 func (c *glCanvas) paint(size fyne.Size) {
 	if c.Content() == nil {
 		return

driver/gl/clipboard.go

@@ -0,0 +1,27 @@
+package gl
+
+import (
+	"log"
+
+	"github.com/go-gl/glfw/v3.2/glfw"
+)
+
+// clipboard represents the system clipboard
+type clipboard struct {
+	window *glfw.Window
+}
+
+// Content returns the clipboard content
+func (c *clipboard) Content() string {
+	content, err := c.window.GetClipboardString()
+	if err != nil {
+		log.Printf("unable to get clipboard string: %v", err)
+		return ""
+	}
+	return content
+}
+
+// SetContent sets the clipboard content
+func (c *clipboard) SetContent(content string) {
+	c.window.SetClipboardString(content)
+}