debugui: use strings for control IDs

Author: hajimehoshi

control.go

@@ -55,7 +55,7 @@ func (c *Context) mouseOver(bounds image.Rectangle) bool {
 }
 
 func (c *Context) updateControl(id controlID, bounds image.Rectangle, opt option) (wasFocused bool) {
-	if id == 0 {
+	if id == emptyControlID {
 		return false
 	}
 
@@ -73,11 +73,11 @@ func (c *Context) updateControl(id controlID, bounds image.Rectangle, opt option
 
 	if c.focus == id {
 		if inpututil.IsMouseButtonJustPressed(ebiten.MouseButtonLeft) && !mouseover {
-			c.setFocus(0)
+			c.setFocus(emptyControlID)
 			wasFocused = true
 		}
 		if !ebiten.IsMouseButtonPressed(ebiten.MouseButtonLeft) && (^opt&optionHoldFocus) != 0 {
-			c.setFocus(0)
+			c.setFocus(emptyControlID)
 			wasFocused = true
 		}
 	}
@@ -86,7 +86,7 @@ func (c *Context) updateControl(id controlID, bounds image.Rectangle, opt option
 		if inpututil.IsMouseButtonJustPressed(ebiten.MouseButtonLeft) {
 			c.setFocus(id)
 		} else if !mouseover {
-			c.hover = 0
+			c.hover = emptyControlID
 		}
 	}
 
@@ -129,7 +129,7 @@ func (c *Context) Text(text string) {
 			var endIdx, p int
 			c.SetGridLayout([]int{-1}, []int{lineHeight()})
 			for endIdx < len(text) {
-				if _, err := c.control(0, 0, func(bounds image.Rectangle, wasFocused bool) (bool, error) {
+				if _, err := c.control(emptyControlID, 0, func(bounds image.Rectangle, wasFocused bool) (bool, error) {
 					w := 0
 					endIdx = p
 					startIdx := endIdx
@@ -180,7 +180,7 @@ func (c *Context) button(label string, opt option, callerPC uintptr) (controlID,
 		return res, nil
 	})
 	if err != nil {
-		return 0, false, err
+		return emptyControlID, false, err
 	}
 	return id, res, nil
 }
@@ -484,5 +484,5 @@ func (c *Context) isCapturingInput() bool {
 		return false
 	}
 
-	return c.hoverRoot != nil || c.focus != 0
+	return c.hoverRoot != nil || c.focus != emptyControlID
 }

debugui_test.go

@@ -18,19 +18,19 @@ func TestMultipleButtonsInForLoop(t *testing.T) {
 			var id debugui.ControlID
 			for range 10 {
 				id2 := ctx.ButtonID("a")
-				if id2 == 0 {
+				if id2 == debugui.EmptyControlID {
 					t.Errorf("Caller() returned 0")
 					continue
 				}
-				if id == 0 {
+				if id == debugui.EmptyControlID {
 					id = id2
 					continue
 				}
 				if id != id2 {
-					t.Errorf("Caller() returned different values: %d and %d", id, id2)
+					t.Errorf("Caller() returned different values: %q and %q", id, id2)
 				}
 			}
-			if id == 0 {
+			if id == debugui.EmptyControlID {
 				t.Errorf("Caller() returned 0")
 			}
 		})
@@ -47,11 +47,11 @@ func TestMultipleButtonsOnOneLine(t *testing.T) {
 			idA1 := ctx.ButtonID("a")
 			idA2 := ctx.ButtonID("a")
 			if idA1 == idA2 {
-				t.Errorf("Button() returned the same value twice: %d", idA1)
+				t.Errorf("Button() returned the same value twice: %q", idA1)
 			}
 			idB1, idB2 := ctx.ButtonID("b"), ctx.ButtonID("b")
 			if idB1 == idB2 {
-				t.Errorf("Button() returned the same value twice: %d", idB1)
+				t.Errorf("Button() returned the same value twice: %q", idB1)
 			}
 		})
 		return nil

export_test.go

@@ -7,6 +7,8 @@ import "github.com/ebitengine/debugui/internal/caller"
 
 type ControlID = controlID
 
+const EmptyControlID = emptyControlID
+
 func (c *Context) ButtonID(label string) ControlID {
 	pc := caller.Caller()
 	var id controlID

helpers.go

@@ -6,7 +6,6 @@ package debugui
 import (
 	"errors"
 	"fmt"
-	"hash/fnv"
 	"image"
 	"slices"
 	"sort"
@@ -21,33 +20,19 @@ func clamp[T int | float64](x, a, b T) T {
 }
 
 func (c *Context) idFromGlobalUniquePointer(pointer unsafe.Pointer) controlID {
-	return c.idFromBytes([]byte(fmt.Sprintf("!pointer:%p", pointer)))
+	return controlID(fmt.Sprintf("!pointer:%p", pointer))
 }
 
 func (c *Context) idFromGlobalUniqueString(str string) controlID {
-	return c.idFromBytes([]byte(fmt.Sprintf("!string:%s", str)))
+	return controlID(fmt.Sprintf("!string:%s", str))
 }
 
 // idFromCaller returns a hash value based on the caller's file and line number.
 func (c *Context) idFromCaller(callerPC uintptr, str string) controlID {
 	if len(str) > 0 {
-		return c.idFromBytes([]byte(fmt.Sprintf("!caller:%d:%s", callerPC, str)))
+		return controlID(fmt.Sprintf("!caller:%d:%s", callerPC, str))
 	}
-	return c.idFromBytes([]byte(fmt.Sprintf("!caller:%d", callerPC)))
-}
-
-func (c *Context) idFromBytes(data []byte) controlID {
-	if len(data) == 0 {
-		return 0
-	}
-
-	h := fnv.New64a()
-	if _, err := h.Write(data); err != nil {
-		panic(err)
-	}
-	id := controlID(h.Sum64())
-	c.lastID = id
-	return id
+	return controlID(fmt.Sprintf("!caller:%d", callerPC))
 }
 
 func (c *Context) popContainer() {
@@ -165,7 +150,7 @@ func (c *Context) end() error {
 
 	// unset focus if focus id was not touched this frame
 	if !c.keepFocus {
-		c.focus = 0
+		c.focus = emptyControlID
 	}
 	c.keepFocus = false
 

layout.go

@@ -87,7 +87,7 @@ func (c *Context) GridCell(f func()) {
 }
 
 func (c *Context) gridCell(f func() error) error {
-	_, err := c.control(0, 0, func(bounds image.Rectangle, wasFocused bool) (res bool, err error) {
+	_, err := c.control(emptyControlID, 0, func(bounds image.Rectangle, wasFocused bool) (res bool, err error) {
 		c.pushLayout(bounds, image.Pt(0, 0))
 		defer func() {
 			if err2 := c.popLayout(); err2 != nil && err == nil {

textfield.go

@@ -35,7 +35,7 @@ func (c *Context) TextField(buf *string) bool {
 }
 
 func (c *Context) textInputTextField(id controlID) *textinput.Field {
-	if id == 0 {
+	if id == emptyControlID {
 		return nil
 	}
 	if _, ok := c.textInputTextFields[id]; !ok {
@@ -198,7 +198,7 @@ func (c *Context) numberTextField(value *float64, id controlID) (bool, error) {
 				nval = 0
 			}
 			*value = float64(nval)
-			c.numberEdit = 0
+			c.numberEdit = emptyControlID
 		}
 		return true, nil
 	}

type.go

@@ -9,7 +9,9 @@ import (
 	"github.com/hajimehoshi/ebiten/v2/exp/textinput"
 )
 
-type controlID uint64
+type controlID string
+
+const emptyControlID controlID = ""
 
 type container struct {
 	layout    ContainerLayout