diff --git a/Context.go b/Context.go
index 736a756c..6c081aae 100644
--- a/Context.go
+++ b/Context.go
@@ -146,7 +146,7 @@ func GetState[T any, PT genericDisposable[T]](c *context, id string) PT {
 		c.m.Unlock()
 
 		data, isOk := s.data.(PT)
-		Assert(isOk, "Context", "GetState", fmt.Sprintf("got state of unexpected type: expected %T, instead found %T", new(T), s.data))
+		Assert(isOk, "Context", "GetState", "got state of unexpected type: expected %T, instead found %T", new(T), s.data)
 
 		return data
 	}
diff --git a/ExtraWidgets.go b/ExtraWidgets.go
index 31fe9649..1cbe0b50 100644
--- a/ExtraWidgets.go
+++ b/ExtraWidgets.go
@@ -535,7 +535,6 @@ func (d *DatePickerWidget) Build() {
 			var row []Widget
 
 			for _, day := range week {
-				day := day // hack for golang ranges
 				if day == 0 {
 					row = append(row, Label(" "))
 					continue
diff --git a/FontAtlasProsessor.go b/FontAtlasProsessor.go
index 008d009f..60a7a272 100644
--- a/FontAtlasProsessor.go
+++ b/FontAtlasProsessor.go
@@ -290,7 +290,7 @@ func (a *FontAtlas) rebuildFontAtlas() {
 			} else {
 				fontConfig.SetFontDataOwnedByAtlas(false)
 				fonts.AddFontFromMemoryTTFV(
-					uintptr(unsafe.Pointer(imgui.SliceToPtr(fontInfo.fontByte))), //nolint:gosec // we need this here
+					uintptr(unsafe.Pointer(imgui.SliceToPtr(fontInfo.fontByte))),
 					int32(len(fontInfo.fontByte)),
 					fontInfo.size,
 					fontConfig,
@@ -328,7 +328,7 @@ func (a *FontAtlas) rebuildFontAtlas() {
 			fontConfig := imgui.NewFontConfig()
 			fontConfig.SetFontDataOwnedByAtlas(false)
 			f = fonts.AddFontFromMemoryTTFV(
-				uintptr(unsafe.Pointer(imgui.SliceToPtr(fontInfo.fontByte))), //nolint:gosec // we need this here
+				uintptr(unsafe.Pointer(imgui.SliceToPtr(fontInfo.fontByte))),
 				int32(len(fontInfo.fontByte)),
 				fontInfo.size,
 				fontConfig,
diff --git a/FontAtlasProsessor.go~ b/FontAtlasProsessor.go~
new file mode 100644
index 00000000..bfe6b520
--- /dev/null
+++ b/FontAtlasProsessor.go~
@@ -0,0 +1,348 @@
+package giu
+
+import (
+	"fmt"
+	"log"
+	"runtime"
+	"strings"
+	"sync"
+	"unsafe"
+
+	"github.com/AllenDang/cimgui-go/imgui"
+	"github.com/AllenDang/go-findfont"
+)
+
+const (
+	preRegisterString = " \"#$%&'()*+,-./0123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\\]^_`abcdefghijklmnopqrstuvwxyz{|}~"
+	windows           = "windows"
+	defaultFontSize   = 14
+)
+
+// FontInfo represents a giu implementation of imgui font.
+type FontInfo struct {
+	fontName string
+	fontPath string
+	fontByte []byte
+	size     float32
+}
+
+func (f *FontInfo) String() string {
+	return fmt.Sprintf("%s:%.2f", f.fontName, f.size)
+}
+
+func (f *FontInfo) SetSize(size float32) *FontInfo {
+	result := *f
+	result.size = size
+
+	for _, i := range Context.FontAtlas.extraFonts {
+		if i.String() == result.String() {
+			return &result
+		}
+	}
+
+	Context.FontAtlas.extraFonts = append(Context.FontAtlas.extraFonts, result)
+	Context.FontAtlas.shouldRebuildFontAtlas = true
+
+	return &result
+}
+
+type FontAtlas struct {
+	shouldRebuildFontAtlas bool
+	stringMap              sync.Map // key is rune, value indicates whether it's a new rune.
+	defaultFonts           []FontInfo
+	extraFonts             []FontInfo
+	extraFontMap           map[string]*imgui.Font
+	fontSize               float32
+}
+
+func newFontAtlas() *FontAtlas {
+	result := FontAtlas{
+		extraFontMap: make(map[string]*imgui.Font),
+		fontSize:     defaultFontSize,
+	}
+
+	// Pre register numbers
+	result.RegisterString(preRegisterString)
+
+	// Pre-register fonts
+	switch runtime.GOOS {
+	case "darwin":
+		// English font
+		result.registerDefaultFont("Menlo", result.fontSize)
+		// Chinese font
+		result.registerDefaultFont("STHeiti", result.fontSize-1)
+		// Jananese font
+		result.registerDefaultFont("ヒラギノ角ゴシック W0", result.fontSize+3)
+		// Korean font
+		result.registerDefaultFont("AppleSDGothicNeo", result.fontSize+2)
+	case windows:
+		// English font
+		result.registerDefaultFont("Calibri", result.fontSize+2)
+		// Chinese font
+		result.registerDefaultFont("MSYH", result.fontSize+2)
+		// Japanese font
+		result.registerDefaultFont("MSGOTHIC", result.fontSize+2)
+		// Korean font
+		result.registerDefaultFont("MALGUNSL", result.fontSize+2)
+	case "linux":
+		// English fonts
+		result.registerDefaultFonts([]FontInfo{
+			{
+				fontName: "FreeSans.ttf",
+				size:     result.fontSize + 1,
+			},
+			{
+				fontName: "FiraCode-Medium",
+				size:     result.fontSize + 1,
+			},
+			{
+				fontName: "sans",
+				size:     result.fontSize + 1,
+			},
+		})
+		// Chinese fonts
+		result.registerDefaultFonts([]FontInfo{
+			{
+				fontName: "wqy-microhei",
+				size:     result.fontSize + 1,
+			},
+			{
+				fontName: "SourceHanSansCN",
+				size:     result.fontSize + 3,
+			},
+		})
+	}
+
+	return &result
+}
+
+// SetDefaultFontSize sets the default font size. Invoke this before MasterWindow.NewMasterWindow(..).
+func (a *FontAtlas) SetDefaultFontSize(size float32) {
+	a.fontSize = size
+}
+
+// SetDefaultFont changes default font.
+func (a *FontAtlas) SetDefaultFont(fontName string, size float32) {
+	fontPath, err := findfont.Find(fontName)
+	if err != nil {
+		log.Fatalf("Cannot find font %s", fontName)
+		return
+	}
+
+	fontInfo := FontInfo{fontName: fontName, fontPath: fontPath, size: size}
+	a.defaultFonts = append([]FontInfo{fontInfo}, a.defaultFonts...)
+}
+
+// SetDefaultFontFromBytes changes default font by bytes of the font file.
+func (a *FontAtlas) SetDefaultFontFromBytes(fontBytes []byte, size float32) {
+	a.defaultFonts = append([]FontInfo{
+		{
+			fontByte: fontBytes,
+			size:     size,
+		},
+	}, a.defaultFonts...)
+}
+
+func (a *FontAtlas) GetDefaultFonts() []FontInfo {
+	return a.defaultFonts
+}
+
+// AddFont adds font by name, if the font is found, return *FontInfo, otherwise return nil.
+// To use added font, use giu.Style().SetFont(...).
+func (a *FontAtlas) AddFont(fontName string, size float32) *FontInfo {
+	fontPath, err := findfont.Find(fontName)
+	if err != nil {
+		fmt.Printf("[Warning]Cannot find font %s at system, related text will not be rendered.\n", fontName)
+		return nil
+	}
+
+	fi := FontInfo{
+		fontName: fontName,
+		fontPath: fontPath,
+		size:     size,
+	}
+
+	a.extraFonts = append(a.extraFonts, fi)
+
+	return &fi
+}
+
+// AddFontFromBytes does similar to AddFont, but using data from memory.
+func (a *FontAtlas) AddFontFromBytes(fontName string, fontBytes []byte, size float32) *FontInfo {
+	fi := FontInfo{
+		fontName: fontName,
+		fontByte: fontBytes,
+		size:     size,
+	}
+
+	a.extraFonts = append(a.extraFonts, fi)
+
+	return &fi
+}
+
+func (a *FontAtlas) registerDefaultFont(fontName string, size float32) {
+	fontPath, err := findfont.Find(fontName)
+	if err != nil {
+		return
+	}
+
+	fontInfo := FontInfo{fontName: fontName, fontPath: fontPath, size: size}
+	a.defaultFonts = append(a.defaultFonts, fontInfo)
+}
+
+func (a *FontAtlas) registerDefaultFonts(fontInfos []FontInfo) {
+	var firstFoundFont *FontInfo
+
+	for _, fi := range fontInfos {
+		fontPath, err := findfont.Find(fi.fontName)
+		if err == nil {
+			firstFoundFont = &FontInfo{fontName: fi.fontName, fontPath: fontPath, size: fi.size}
+			break
+		}
+	}
+
+	if firstFoundFont != nil {
+		a.defaultFonts = append(a.defaultFonts, *firstFoundFont)
+	}
+}
+
+// RegisterString register string to font atlas builder.
+// Note only register strings that will be displayed on the UI.
+func (a *FontAtlas) RegisterString(str string) string {
+	for _, s := range str {
+		if _, ok := a.stringMap.Load(s); !ok {
+			a.stringMap.Store(s, false)
+			a.shouldRebuildFontAtlas = true
+		}
+	}
+
+	return str
+}
+
+// RegisterStringPointer registers string pointer to font atlas builder.
+// Note only register strings that will be displayed on the UI.
+func (a *FontAtlas) RegisterStringPointer(str *string) *string {
+	a.RegisterString(*str)
+	return str
+}
+
+// RegisterStringSlice calls RegisterString for each slice element.
+func (a *FontAtlas) RegisterStringSlice(str []string) []string {
+	for _, s := range str {
+		a.RegisterString(s)
+	}
+
+	return str
+}
+
+// Rebuild font atlas when necessary.
+func (a *FontAtlas) rebuildFontAtlas() {
+	if !a.shouldRebuildFontAtlas {
+		return
+	}
+
+	fonts := Context.IO().Fonts()
+	fonts.Clear()
+
+	var sb strings.Builder
+
+	a.stringMap.Range(func(k, v any) bool {
+		a.stringMap.Store(k, true)
+
+		if ks, ok := k.(rune); ok {
+			sb.WriteRune(ks)
+		}
+
+		return true
+	})
+
+	ranges := imgui.NewGlyphRange()
+	builder := imgui.NewFontGlyphRangesBuilder()
+
+	// Because we pre-registered numbers, so default string map's length should greater then 11.
+	if sb.Len() > len(preRegisterString) {
+		builder.AddText(sb.String())
+	} else {
+		builder.AddRanges(fonts.GlyphRangesDefault())
+	}
+
+	builder.BuildRanges(ranges)
+
+	if len(a.defaultFonts) > 0 {
+		fontConfig := imgui.NewFontConfig()
+		fontConfig.SetOversampleH(2)
+		fontConfig.SetOversampleV(2)
+		fontConfig.SetRasterizerMultiply(1.5)
+
+		for i, fontInfo := range a.defaultFonts {
+			if i > 0 {
+				fontConfig.SetMergeMode(true)
+			}
+
+			// Scale font size with DPI scale factor
+			if runtime.GOOS == windows {
+				xScale, _ := Context.backend.ContentScale()
+				fontInfo.size *= xScale
+			}
+
+			if len(fontInfo.fontByte) == 0 {
+				fonts.AddFontFromFileTTFV(fontInfo.fontPath, fontInfo.size, fontConfig, ranges.Data())
+			} else {
+				fontConfig.SetFontDataOwnedByAtlas(false)
+				fonts.AddFontFromMemoryTTFV(
+					uintptr(unsafe.Pointer(imgui.SliceToPtr(fontInfo.fontByte))), //nolint:gosec // we need this here
+					int32(len(fontInfo.fontByte)),                                // nolint:gosec // no risk heree I think, its cimgui-go API
+					fontInfo.size,
+					fontConfig,
+					ranges.Data(),
+				)
+			}
+		}
+
+		// Fall back if no font is added
+		if fonts.FontCount() == 0 {
+			fonts.AddFontDefault()
+		}
+	} else {
+		fonts.AddFontDefault()
+	}
+
+	// Add extra fonts
+	for _, fontInfo := range a.extraFonts {
+		// Scale font size with DPI scale factor
+		if runtime.GOOS == windows {
+			xScale, _ := Context.backend.ContentScale()
+			fontInfo.size *= xScale
+		}
+
+		// Store imgui.Font for PushFont
+		var f *imgui.Font
+		if len(fontInfo.fontByte) == 0 {
+			f = fonts.AddFontFromFileTTFV(
+				fontInfo.fontPath,
+				fontInfo.size,
+				imgui.NewFontConfig(),
+				ranges.Data(),
+			)
+		} else {
+			fontConfig := imgui.NewFontConfig()
+			fontConfig.SetFontDataOwnedByAtlas(false)
+			f = fonts.AddFontFromMemoryTTFV(
+				uintptr(unsafe.Pointer(imgui.SliceToPtr(fontInfo.fontByte))), //nolint:gosec // we need this here
+				int32(len(fontInfo.fontByte)),                                // nolint:gosec // no risk heree I think, its cimgui-go API
+				fontInfo.size,
+				fontConfig,
+				ranges.Data(),
+			)
+		}
+
+		a.extraFontMap[fontInfo.String()] = f
+	}
+
+	fontTextureImg, w, h, _ := fonts.GetTextureDataAsRGBA32()
+	tex := Context.backend.CreateTexture(fontTextureImg, int(w), int(h))
+	fonts.SetTexID(tex)
+	fonts.SetTexReady(true)
+
+	a.shouldRebuildFontAtlas = false
+}
diff --git a/MasterWindow.go b/MasterWindow.go
index 10670f2b..afa7e363 100644
--- a/MasterWindow.go
+++ b/MasterWindow.go
@@ -81,6 +81,7 @@ type MasterWindow struct {
 // see examples/helloworld/.
 func NewMasterWindow(title string, width, height int, flags MasterWindowFlags) *MasterWindow {
 	imGuiContext := imgui.CreateContext()
+
 	implot.PlotCreateContext()
 	imnodes.ImNodesCreateContext()
 
diff --git a/Widgets.go b/Widgets.go
index a61c316e..15cde5f0 100644
--- a/Widgets.go
+++ b/Widgets.go
@@ -206,7 +206,6 @@ func (c *ComboWidget) Build() {
 
 	if imgui.BeginComboV(Context.FontAtlas.RegisterString(c.label.String()), c.previewValue, imgui.ComboFlags(c.flags)) {
 		for i, item := range c.items {
-			i := i
 			if imgui.SelectableBool(fmt.Sprintf("%s##%d", item, i)) {
 				*c.selected = int32(i)
 				if c.onChange != nil {