> ## Documentation Index
> Fetch the complete documentation index at: https://mintlify.com/ocornut/imgui/llms.txt
> Use this file to discover all available pages before exploring further.

# Fonts

> Loading, customizing, and using fonts in Dear ImGui including TTF/OTF files, icon fonts, and multilingual text support

## Overview

Dear ImGui embeds default fonts for convenience, but you can load custom TTF/OTF fonts to match your application's design and support various languages.

<Note>
  **Since v1.92 (June 2025):** Font system has been significantly improved with dynamic font sizing and automatic glyph loading.
</Note>

## Default Fonts

Dear ImGui embeds two default fonts:

* **ProggyClean.ttf** - 13px pixel-perfect monospace font (doesn't scale well)
* **ProggyForever.ttf** - New scalable font mimicking ProggyClean

```cpp theme={null}
ImGuiIO& io = ImGui::GetIO();

// Load scalable default font (recommended)
io.Fonts->AddFontDefaultVector();

// Load bitmap default font (legacy)
io.Fonts->AddFontDefaultBitmap();

// Auto-select based on size (uses ProggyForever if size >= 15)
io.Fonts->AddFontDefault();
```

<Note>
  Define `IMGUI_DISABLE_DEFAULT_FONT` in `imconfig.h` to disable embedded fonts and save \~26 KB.
</Note>

## Loading Custom Fonts

### Basic Font Loading

**Since v1.92 (with updated backend):**

```cpp theme={null}
ImGuiIO& io = ImGui::GetIO();

// Size parameter is optional
io.Fonts->AddFontFromFileTTF("Roboto-Medium.ttf");
```

**Before v1.92 or without updated backend:**

```cpp theme={null}
ImGuiIO& io = ImGui::GetIO();

// Size parameter required
io.Fonts->AddFontFromFileTTF("Roboto-Medium.ttf", 18.0f);
```

### Setting Base Font Size

```cpp theme={null}
ImGuiStyle& style = ImGui::GetStyle();
style.FontSizeBase = 20.0f;
```

### Loading Multiple Fonts

```cpp theme={null}
ImGuiIO& io = ImGui::GetIO();

ImFont* font_default = io.Fonts->AddFontDefaultVector();
ImFont* font_large = io.Fonts->AddFontFromFileTTF("Roboto-Bold.ttf");
ImFont* font_small = io.Fonts->AddFontFromFileTTF("Roboto-Regular.ttf");

// Use fonts in your UI
ImGui::Text("Default font");

ImGui::PushFont(font_large, 0.0f);
ImGui::Text("Large bold font");
ImGui::PopFont();

ImGui::PushFont(font_small, 0.0f);
ImGui::Text("Small regular font");
ImGui::PopFont();
```

### Dynamic Font Sizing (v1.92+)

```cpp theme={null}
// Change size without changing font
ImGui::PushFont(NULL, 42.0f);
ImGui::Text("Large text");
ImGui::PopFont();

// Change font and size
ImGui::PushFont(custom_font, 24.0f);
ImGui::Text("Custom font at 24px");
ImGui::PopFont();
```

## Font Configuration

### Advanced Options

```cpp theme={null}
ImFontConfig config;
config.OversampleH = 3;              // Horizontal oversampling (improves quality)
config.OversampleV = 1;              // Vertical oversampling
config.GlyphExtraSpacing.x = 1.0f;   // Extra horizontal spacing between glyphs
config.GlyphOffset.y = 0.0f;         // Vertical offset for glyphs
config.PixelSnapH = true;            // Snap to pixel (for pixel fonts)

ImFont* font = io.Fonts->AddFontFromFileTTF("font.ttf", 0.0f, &config);
```

### Monospace Icons

Make icons monospace for better alignment:

```cpp theme={null}
ImFontConfig config;
config.GlyphMinAdvanceX = 13.0f;  // Make glyphs at least 13px wide

io.Fonts->AddFontFromFileTTF("fontawesome-webfont.ttf", 13.0f, &config);
```

## Merging Fonts

Combine multiple fonts into one for seamless multi-language or icon support.

**Since v1.92 (with updated backend):**

```cpp theme={null}
// Load base font
ImFont* font = io.Fonts->AddFontDefaultVector();

// Merge additional fonts
ImFontConfig config;
config.MergeMode = true;

// Add Asian characters
io.Fonts->AddFontFromFileTTF("DroidSans.ttf", 0.0f, &config);

// Add icons
io.Fonts->AddFontFromFileTTF("fontawesome-webfont.ttf", 0.0f, &config);
```

**Before v1.92:**

```cpp theme={null}
ImFont* font = io.Fonts->AddFontDefault();

static const ImWchar icons_ranges[] = { 0xf000, 0xf3ff, 0 };
ImFontConfig config;
config.MergeMode = true;

io.Fonts->AddFontFromFileTTF("DroidSans.ttf", 18.0f, &config, 
                              io.Fonts->GetGlyphRangesJapanese());
io.Fonts->AddFontFromFileTTF("fontawesome-webfont.ttf", 18.0f, &config, 
                              icons_ranges);
io.Fonts->Build();
```

### Excluding Overlapping Ranges (v1.92+)

Prevent conflicts when merging fonts:

```cpp theme={null}
#include "IconsFontAwesome.h"

// Exclude icon range from first font
static ImWchar exclude_ranges[] = { ICON_MIN_FA, ICON_MAX_FA, 0 };
ImFontConfig cfg1;
cfg1.GlyphExcludeRanges = exclude_ranges;
io.Fonts->AddFontFromFileTTF("segoeui.ttf", 0.0f, &cfg1);

// Add icon font to fill the gap
ImFontConfig cfg2;
cfg2.MergeMode = true;
io.Fonts->AddFontFromFileTTF("FontAwesome5.ttf", 0.0f, &cfg2);
```

## Icon Fonts

Use icon fonts like FontAwesome for scalable icons in your UI.

### Setup with IconFontCppHeaders

**Since v1.92:**

```cpp theme={null}
#include "IconsFontAwesome.h"

ImGuiIO& io = ImGui::GetIO();
io.Fonts->AddFontDefaultVector();

ImFontConfig config;
config.MergeMode = true;
config.GlyphMinAdvanceX = 13.0f;  // Monospace icons
io.Fonts->AddFontFromFileTTF("fonts/fontawesome-webfont.ttf", 13.0f, &config);
```

### Using Icons

```cpp theme={null}
#include "IconsFontAwesome.h"

// In UI code
ImGui::Text("%s Search", ICON_FA_SEARCH);
ImGui::Button(ICON_FA_SAVE " Save");
ImGui::Button(ICON_FA_FOLDER_OPEN " Open");

// ICON_FA_SEARCH is a string literal that can be concatenated
if (ImGui::Button(ICON_FA_TRASH " Delete")) {
    // Handle delete
}
```

## Multilingual Text Support

### Loading Non-Latin Fonts

**Since v1.92:** Glyph ranges are unnecessary!

```cpp theme={null}
ImGuiIO& io = ImGui::GetIO();
io.Fonts->AddFontFromFileTTF("NotoSansCJKjp-Medium.otf");
```

**Before v1.92:**

```cpp theme={null}
ImGuiIO& io = ImGui::GetIO();

// Japanese
io.Fonts->AddFontFromFileTTF("NotoSansCJKjp-Medium.otf", 20.0f, nullptr,
                              io.Fonts->GetGlyphRangesJapanese());

// Chinese (Simplified)
io.Fonts->AddFontFromFileTTF("NotoSansSC.otf", 20.0f, nullptr,
                              io.Fonts->GetGlyphRangesChineseSimplifiedCommon());

// Cyrillic
io.Fonts->AddFontFromFileTTF("NotoSans.ttf", 20.0f, nullptr,
                              io.Fonts->GetGlyphRangesCyrillic());
```

### UTF-8 Encoding

All Dear ImGui strings must be UTF-8 encoded.

**Verify encoding:**

```cpp theme={null}
ImGui::DebugTextEncoding(u8"こんにちは");  // Correct
ImGui::DebugTextEncoding("こんにちは");    // May be wrong depending on compiler
```

**Use u8 prefix:**

```cpp theme={null}
ImGui::Text(u8"こんにちは");        // Japanese
ImGui::Text(u8"你好");            // Chinese
ImGui::Text(u8"Привет");        // Russian
ImGui::Button(u8"保存");          // Save (Japanese)
```

**Compiler settings:**

* Visual Studio: Add `/utf-8` flag or `#pragma execution_character_set("utf-8")`
* Ensure source files are saved as UTF-8

**C++20 note:**

```cpp theme={null}
// C++20 changed u8"" to return const char8_t*
ImGui::Text((const char*)u8"こんにちは");

// Or disable with compiler flag: /Zc:char8_t- (MSVC) or -fno-char8_t (GCC/Clang)
```

### Example Japanese UI

```cpp theme={null}
ImGuiIO& io = ImGui::GetIO();
io.Fonts->AddFontFromFileTTF("NotoSansCJKjp-Medium.otf");

// In UI code
ImGui::Text(u8"こんにちは！テスト %d", 123);

if (ImGui::Button(u8"ロード")) {
    // Load
}

static char buf[256] = u8"こんにちは";
ImGui::InputText(u8"文字列", buf, IM_COUNTOF(buf));
```

## FreeType Rasterizer

For better quality at small sizes, use FreeType instead of stb\_truetype:

```cpp theme={null}
// In imconfig.h or build system
#define IMGUI_ENABLE_FREETYPE

// Compile with misc/freetype/imgui_freetype.cpp
```

### FreeType Options

```cpp theme={null}
#include "misc/freetype/imgui_freetype.h"

ImFontConfig config;
config.FontLoaderFlags |= ImGuiFreeTypeLoaderFlags_LoadColor;  // For emoji
config.FontLoaderFlags |= ImGuiFreeTypeLoaderFlags_Bold;        // Synthesize bold
config.FontLoaderFlags |= ImGuiFreeTypeLoaderFlags_Oblique;     // Synthesize italic

io.Fonts->AddFontFromFileTTF("font.ttf", 16.0f, &config);
```

### Colored Glyphs/Emoji

```cpp theme={null}
#define IMGUI_ENABLE_FREETYPE
#define IMGUI_USE_WCHAR32  // Support characters beyond U+FFFF

ImFontConfig config;
config.FontLoaderFlags |= ImGuiFreeTypeLoaderFlags_LoadColor;

io.Fonts->AddFontFromFileTTF("NotoSans-Regular.ttf", 16.0f);

config.MergeMode = true;
io.Fonts->AddFontFromFileTTF("seguiemj.ttf", 16.0f, &config);  // Windows emoji font
```

## Loading from Memory

```cpp theme={null}
// Load font data into memory
void* font_data = LoadFontDataFromFile("font.ttf", &font_size);

// Option 1: Transfer ownership to ImGui (default)
ImFont* font = io.Fonts->AddFontFromMemoryTTF(font_data, font_size, size_pixels);
// ImGui will free font_data

// Option 2: Keep ownership
ImFontConfig config;
config.FontDataOwnedByAtlas = false;
ImFont* font = io.Fonts->AddFontFromMemoryTTF(font_data, font_size, size_pixels, &config);
// You must free font_data yourself after ImGui::DestroyContext()
```

### Embedding Fonts in Source Code

```bash theme={null}
# Convert TTF to compressed C array
./binary_to_compressed_c font.ttf FontName > font_data.cpp
```

```cpp theme={null}
// In your code
extern const unsigned int FontName_compressed_size;
extern const unsigned int FontName_compressed_data[];

ImFont* font = io.Fonts->AddFontFromMemoryCompressedTTF(
    FontName_compressed_data,
    FontName_compressed_size,
    18.0f
);
```

## DPI Handling

### Scaling Fonts

```cpp theme={null}
ImGuiStyle& style = ImGui::GetStyle();

// Set base size
style.FontSizeBase = 16.0f;

// Apply DPI scaling
style.FontScaleDpi = 2.0f;  // 2x for high-DPI displays

// Fonts will automatically scale
```

### In Docking Branch

```cpp theme={null}
ImGuiIO& io = ImGui::GetIO();

// Automatically scale fonts when moving between monitors with different DPI
io.ConfigDpiScaleFonts = true;

// Also scale UI elements
io.ConfigDpiScaleViewports = true;
```

## Debugging Fonts

### Metrics Window

```cpp theme={null}
ImGui::ShowMetricsWindow();
// Navigate to: Fonts section
// Shows: Atlas texture, loaded fonts, glyph information
```

### UTF-8 Encoding Viewer

```cpp theme={null}
ImGui::ShowMetricsWindow();
// Navigate to: Tools > UTF-8 Encoding viewer
// Or call directly:
ImGui::DebugTextEncoding("Test string");
```

### Check Glyph Coverage

In Metrics window:

1. Expand "Fonts" section
2. Select your font
3. View loaded glyphs and coverage

## Common Font Resources

### Monospace Fonts

* **Proggy Fonts** - [https://github.com/bluescan/proggyfonts](https://github.com/bluescan/proggyfonts)
* **JetBrains Mono** - [https://www.jetbrains.com/lp/mono/](https://www.jetbrains.com/lp/mono/)
* **Fira Code** - [https://github.com/tonsky/FiraCode](https://github.com/tonsky/FiraCode)
* **Source Code Pro** - [https://github.com/adobe-fonts/source-code-pro](https://github.com/adobe-fonts/source-code-pro)
* **Inconsolata** - [http://www.levien.com/type/myfonts/inconsolata.html](http://www.levien.com/type/myfonts/inconsolata.html)

### Icon Fonts

* **Font Awesome** - [https://fontawesome.com](https://fontawesome.com)
* **IconFontCppHeaders** - [https://github.com/juliettef/IconFontCppHeaders](https://github.com/juliettef/IconFontCppHeaders)
* **Material Design Icons** - [https://material.io/icons/](https://material.io/icons/)
* **IcoMoon** - [https://icomoon.io/app](https://icomoon.io/app) (custom icon builder)

### Multilingual Fonts

* **Google Noto Fonts** - [https://www.google.com/get/noto/](https://www.google.com/get/noto/) (all languages)
* **M+ Fonts** - [http://mplus-fonts.sourceforge.jp/](http://mplus-fonts.sourceforge.jp/) (Japanese)
* **Droid Sans** - [https://www.fontsquirrel.com/fonts/droid-sans](https://www.fontsquirrel.com/fonts/droid-sans)

## Best Practices

<Steps>
  1. **Load fonts at initialization** - Font atlas building can be slow
  2. **Use merged fonts** - For multi-language and icon support
  3. **Test with real content** - Ensure all needed glyphs are available
  4. **Consider file size** - Loading many fonts increases memory usage
  5. **Use UTF-8 everywhere** - Ensure source files and strings are UTF-8
  6. **Test on target hardware** - Font rendering quality varies by platform
</Steps>

<Note>
  The `misc/fonts/` folder contains example fonts for reference. See [FONTS.md](https://github.com/ocornut/imgui/blob/master/docs/FONTS.md) for credits and licenses.
</Note>

## See Also

* [Troubleshooting](/guides/troubleshooting) - Font-related issues
* [Performance](/guides/performance) - Font atlas optimization
* [FONTS.md](https://github.com/ocornut/imgui/blob/master/docs/FONTS.md) - Complete font documentation