diff --git a/platform/imgui/imgui.go b/platform/imgui/imgui.go
index a0c4a0c..8658545 100644
--- a/platform/imgui/imgui.go
+++ b/platform/imgui/imgui.go
@@ -4,6 +4,7 @@ package imgui
 // #include "native.h"
 import "C"
 import (
+	"fmt"
 	"unsafe"
 
 	"github.com/FooSoft/lazarus/graphics"
@@ -54,7 +55,8 @@ func SliderInt(label string, value *int, min, max int) bool {
 	return result
 }
 
-func Text(label string) {
+func Text(format string, args ...interface{}) {
+	label := fmt.Sprintf(format, args...)
 	labelStartC := C.CString(label)
 	labelEndC := (*C.char)(unsafe.Pointer(uintptr(unsafe.Pointer(labelStartC)) + uintptr(len(label))))
 	defer C.free(unsafe.Pointer(labelStartC))
diff --git a/tools/viewer/viewer.go b/tools/viewer/viewer.go
index 772eba4..7400e06 100644
--- a/tools/viewer/viewer.go
+++ b/tools/viewer/viewer.go
@@ -77,11 +77,11 @@ func (s *scene) Advance() error {
 	imgui.Columns(2)
 	imgui.Text("Size")
 	imgui.NextColumn()
-	imgui.Text(fmt.Sprintf("%+v", frame.Size))
+	imgui.Text("%+v", frame.Size)
 	imgui.NextColumn()
 	imgui.Text("Offset")
 	imgui.NextColumn()
-	imgui.Text(fmt.Sprintf("%+v", frame.Offset))
+	imgui.Text("%+v", frame.Offset)
 	imgui.Columns(1)
 	if imgui.Button("Exit") {
 		platform.WindowSetScene(nil)