diff --git a/tools/tui/graphics/command.go b/tools/tui/graphics/command.go
index 9b8fab835..65918d091 100644
--- a/tools/tui/graphics/command.go
+++ b/tools/tui/graphics/command.go
@@ -510,6 +510,13 @@ func compress_with_zlib(data []byte) []byte {
 	return b.Bytes()
 }
 
+func (self *GraphicsCommand) AsAPC(payload []byte) string {
+	buf := strings.Builder{}
+	buf.Grow(1024)
+	self.WriteWithPayloadTo(&buf, payload)
+	return buf.String()
+}
+
 func (self *GraphicsCommand) WriteWithPayloadTo(o io.StringWriter, payload []byte) (err error) {
 	const compression_threshold = 1024
 	if len(payload) == 0 {
@@ -526,16 +533,23 @@ func (self *GraphicsCommand) WriteWithPayloadTo(o io.StringWriter, payload []byt
 	}
 	gc.SetDataSize(uint64(len(payload)))
 	data := base64.StdEncoding.EncodeToString(payload)
-	for len(data) > 0 && err != nil {
-		chunk := data[:4096]
-		data = data[4096:]
+	for len(data) > 0 && err == nil {
+		chunk := data
+		if len(data) > 4096 {
+			chunk = data[:4096]
+			data = data[4096:]
+		} else {
+			data = ""
+		}
 		if len(data) > 0 {
 			gc.m = GRT_more_more
 		} else {
 			gc.m = GRT_more_nomore
 		}
 		err = gc.serialize_to(o, chunk)
-		gc = GraphicsCommand{}
+		if gc.DataSize() > 0 {
+			gc = GraphicsCommand{}
+		}
 	}
 	return
 }
@@ -664,6 +678,7 @@ func GraphicsCommandFromAPCPayload(raw []byte) *GraphicsCommand {
 			if state == expecting_value {
 				add_key(pos)
 			}
+			state = expecting_key
 			payload_start_at = pos + 1
 			break
 		}
@@ -685,6 +700,9 @@ func GraphicsCommandFromAPCPayload(raw []byte) *GraphicsCommand {
 			}
 		}
 	}
+	if state == expecting_value {
+		add_key(len(raw))
+	}
 	if payload_start_at > -1 {
 		payload := raw[payload_start_at:]
 		if len(payload) > 0 {
diff --git a/tools/tui/graphics/command_test.go b/tools/tui/graphics/command_test.go
new file mode 100644
index 000000000..90d7c3fb0
--- /dev/null
+++ b/tools/tui/graphics/command_test.go
@@ -0,0 +1,103 @@
+// License: GPLv3 Copyright: 2022, Kovid Goyal, <kovid at kovidgoyal.net>
+
+package graphics
+
+import (
+	"bytes"
+	"compress/zlib"
+	"encoding/base64"
+	"fmt"
+	"io"
+	"strings"
+	"testing"
+
+	"github.com/google/go-cmp/cmp"
+	"golang.org/x/exp/rand"
+)
+
+var _ = fmt.Print
+
+func from_full_apc_escape_code(raw string) *GraphicsCommand {
+	return GraphicsCommandFromAPC([]byte(raw[2 : len(raw)-2]))
+}
+
+func TestGraphicsCommandSerialization(t *testing.T) {
+	gc := &GraphicsCommand{}
+
+	test_serialize := func(payload string, vals ...string) {
+		expected := "\033_G" + strings.Join(vals, ",")
+		if payload != "" {
+			expected += ";" + base64.StdEncoding.EncodeToString([]byte(payload))
+		}
+		expected += "\033\\"
+		if diff := cmp.Diff(expected, gc.AsAPC([]byte(payload))); diff != "" {
+			t.Fatalf("Failed to write vals: %#v with payload: %#v\n%s", vals, payload, diff)
+		}
+	}
+
+	test_chunked_payload := func(payload []byte) {
+		c := &GraphicsCommand{}
+		data := c.AsAPC([]byte(payload))
+		encoded := strings.Builder{}
+		compressed := false
+		var data_size uint64
+		for {
+			idx := strings.Index(data, "\033_")
+			if idx < 0 {
+				break
+			}
+			l := strings.Index(data, "\033\\")
+			apc := data[idx+2 : l]
+			data = data[l+2:]
+			g := GraphicsCommandFromAPC([]byte(apc))
+			if data_size == 0 {
+				data_size = g.DataSize()
+				compressed = g.Compression() != 0
+			}
+			encoded.WriteString(g.ResponseMessage())
+			if g.m == GRT_more_nomore {
+				break
+			}
+		}
+		if len(data) > 0 {
+			t.Fatalf("Unparsed remnant: %#v", string(data))
+		}
+		decoded, err := base64.StdEncoding.DecodeString(encoded.String())
+		if err != nil {
+			t.Fatalf("Encoded data not valid base-64 with error: %v", err)
+		}
+		if data_size > 0 && uint64(len(decoded)) != data_size {
+			t.Fatalf("Data size %d != decoded size %d", data_size, len(decoded))
+		}
+		if compressed {
+			b := bytes.Buffer{}
+			b.Write(decoded)
+			r, _ := zlib.NewReader(&b)
+			o := bytes.Buffer{}
+			io.Copy(&o, r)
+			r.Close()
+			decoded = o.Bytes()
+		}
+		if diff := cmp.Diff(payload, decoded); diff != "" {
+			t.Fatalf("Decoded payload does not match original\nlen decoded=%d len payload=%d", len(decoded), len(payload))
+		}
+	}
+
+	test_serialize("")
+	gc.SetTransmission(GRT_transmission_sharedmem).SetAction(GRT_action_query).SetZIndex(-3).SetWidth(33).SetImageId(11)
+	test_serialize("abcd", "a=q", "t=s", "w=33", "i=11", "z=-3")
+	q := from_full_apc_escape_code(gc.AsAPC([]byte("abcd")))
+	if diff := cmp.Diff(gc.AsAPC(nil), q.AsAPC(nil)); diff != "" {
+		t.Fatalf("Parsing failed:\n%s", diff)
+	}
+	if diff := cmp.Diff(q.response_message, base64.StdEncoding.EncodeToString([]byte("abcd"))); diff != "" {
+		t.Fatalf("Failed to parse payload:\n%s", diff)
+	}
+
+	test_chunked_payload([]byte("abcd"))
+	data := make([]byte, 8111)
+	rand.Read(data)
+	test_chunked_payload(data)
+	test_chunked_payload([]byte(strings.Repeat("a", 8007)))
+
+}