io/pointer: print all types in Type.String

Signed-off-by: Pierre Curto <pierre.curto@gmail.com>

io/pointer/pointer.go

@@ -265,6 +265,22 @@ func (op InputOp) Add(o *op.Ops) {
 }
 
 func (t Type) String() string {
+	if t == Cancel {
+		return "Cancel"
+	}
+	var buf strings.Builder
+	for tt := Type(1); tt > 0; tt <<= 1 {
+		if t&tt > 0 {
+			if buf.Len() > 0 {
+				buf.WriteByte('|')
+			}
+			buf.WriteString((t & tt).string())
+		}
+	}
+	return buf.String()
+}
+
+func (t Type) string() string {
 	switch t {
 	case Press:
 		return "Press"

io/pointer/pointer_test.go

@@ -8,6 +8,32 @@ import (
 	"gioui.org/op"
 )
 
+func TestTypeString(t *testing.T) {
+	for _, tc := range []struct {
+		typ Type
+		res string
+	}{
+		{Cancel, "Cancel"},
+		{Press, "Press"},
+		{Release, "Release"},
+		{Move, "Move"},
+		{Drag, "Drag"},
+		{Enter, "Enter"},
+		{Leave, "Leave"},
+		{Scroll, "Scroll"},
+		{Enter | Leave, "Enter|Leave"},
+		{Press | Release, "Press|Release"},
+		{Enter | Leave | Press | Release, "Press|Release|Enter|Leave"},
+		{Move | Scroll, "Move|Scroll"},
+	} {
+		t.Run(tc.res, func(t *testing.T) {
+			if want, got := tc.res, tc.typ.String(); want != got {
+				t.Errorf("got %q; want %q", got, want)
+			}
+		})
+	}
+}
+
 func TestTransformChecks(t *testing.T) {
 	defer func() {
 		if err := recover(); err == nil {