_(You may browse this at https://github.com/ocornut/imgui/blob/master/docs/FONTS.md or view this file with any Markdown viewer)_
## Dear ImGui: Using Fonts
The code in imgui.cpp embeds a copy of 'ProggyClean.ttf' (by Tristan Grimmer),
a 13 pixels high, pixel-perfect font used by default. We embed it in the source code so you can use Dear ImGui without any file system access. ProggyClean does not scale smoothly, therefore it is recommended that you load your own file when using Dear ImGui in an application aiming to look nice and wanting to support multiple resolutions.
You may also load external .TTF/.OTF files.
In the [misc/fonts/](https://github.com/ocornut/imgui/tree/master/misc/fonts) folder you can find a few suggested fonts, provided as a convenience.
**A vast majority of font and text related issues encountered comes from 3 things:**
- Invalid filename due to use of `\` or unexpected working directory. See [About Filenames](#about-filenames). AddFontXXX functions should assert if the filename is incorrect.
- Invalid UTF-8 encoding of your non-ASCII strings. See [About UTF-8 Encoding](#about-utf-8-encoding). Use the encoding viewer to confirm yours is correct.
- You need to load a font with explicit glyph ranges if you want to use non-ASCII characters. See [Fonts Loading Instructions](#fonts-loading-instructions). Use Metrics/Debugger->Fonts to confirm loaded fonts and loaded glyph ranges.
The third point is a current constraint of Dear ImGui (which we will lift in the future): when loading a font you need to specify which characters glyphs to load.
All loaded fonts glyphs are rendered into a single texture atlas ahead of time. Calling either of `io.Fonts->GetTexDataAsAlpha8()`, `io.Fonts->GetTexDataAsRGBA32()` or `io.Fonts->Build()` will build the atlas. This is generally called by the Renderer backend, e.g. `ImGui_ImplDX11_NewFrame()` calls it.
**If you use custom glyphs ranges, make sure the array is persistent** and available during the calls to `GetTexDataAsAlpha8()/GetTexDataAsRGBA32()/Build()`.
**Please note that many new C/C++ users have issues loading their files _because the filename they provide is wrong_ due to incorrect assumption of what is the current directory.**
(1) In C/C++ and most programming languages if you want to use a backslash `\` within a string literal, you need to write it double backslash `\\`. At it happens, Windows uses backslashes as a path separator, so be mindful.
(2) Make sure your IDE/debugger settings starts your executable from the right working (current) directory. In Visual Studio you can change your working directory in project `Properties > General > Debugging > Working Directory`. People assume that their execution will start from the root folder of the project, where by default it often starts from the folder where object or executable files are stored.
```cpp
io.Fonts->AddFontFromFileTTF("MyImage01.jpg", ...); // Relative filename depends on your Working Directory when running your program!
io.Fonts->AddFontFromFileTTF("../MyImage01.jpg", ...); // Load from the parent folder of your Working Directory
You can also find this tool under `Metrics/Debuggers->Tools->UTF-8 Encoding viewer` if you want to paste from clipboard, but this won't validate the UTF-8 encoding done by your compiler.
(2) To encode in UTF-8:
There are also compiler-specific ways to enforce UTF-8 encoding by default:
- Visual Studio compiler: `/utf-8` command-line flag.
- Visual Studio compiler: `#pragma execution_character_set("utf-8")` inside your code.
- Since May 2023 we have changed the Visual Studio projects of all our examples to use `/utf-8` ([see commit](https://github.com/ocornut/imgui/commit/513af1efc9080857bbd10000d98f98f2a0c96803)).
Or, since C++11, you can use the `u8"my text"` syntax to encode literal strings as UTF-8. e.g.:
```cpp
ImGui::Text(u8"hello");
ImGui::Text(u8"こんにちは"); // this will always be encoded as UTF-8
ImGui::Text("こんにちは"); // the encoding of this is depending on compiler settings/flags and may be incorrect.
```
Since C++20, because the C++ committee hate its users, they decided to change the `u8""` syntax to not return `const char*` but a new type `const char_t*` which doesn't cast to `const char*`.
Because of type usage of `u8""` in C++20 is a little more tedious:
```cpp
ImGui::Text((const char*)u8"こんにちは");
```
We suggest using a macro in your codebase:
```cpp
#define U8(_S) (const char*)u8##_S
ImGui::Text(U8("こんにちは"));
```
##### [Return to Index](#index)
## Debug Tools
#### Metrics/Debugger->Fonts
You can use the `Metrics/Debugger` window (available in `Demo>Tools`) to browse your fonts and understand what's going on if you have an issue. You can also reach it in `Demo->Tools->Style Editor->Fonts`. The same information are also available in the Style Editor under Fonts.
You can use the `UTF-8 Encoding viewer` in `Metrics/Debugger` to verify the content of your UTF-8 strings. From C/C++ code, you can call `ImGui::DebugTextEncoding("my string");` function to verify that your UTF-8 encoding is correct.
If you get an assert stating "Could not load font file!", your font filename is likely incorrect. Read "[About filenames](#about-filenames)" carefully.
- If you have very large number of glyphs or multiple fonts, the texture may become too big for your graphics API. The typical result of failing to upload a texture is if every glyph appears as a white rectangle.
- Mind the fact that some graphics drivers have texture size limitation. If you are building a PC application, mind the fact that your users may use hardware with lower limitations than yours.
Some solutions:
1. Reduce glyphs ranges by calculating them from source localization data.
You can use the `ImFontGlyphRangesBuilder` for this purpose and rebuilding your atlas between frames when new characters are needed. This will be the biggest win!
2. You may reduce oversampling, e.g. `font_config.OversampleH = 2`, this will largely reduce your texture size.
Note that while OversampleH = 2 looks visibly very close to 3 in most situations, with OversampleH = 1 the quality drop will be noticeable.
3. Set `io.Fonts.TexDesiredWidth` to specify a texture width to minimize texture height (see comment in `ImFontAtlas::Build()` function).
4. Set `io.Fonts.Flags |= ImFontAtlasFlags_NoPowerOfTwoHeight;` to disable rounding the texture height to the next power of two.
5. Read about oversampling [here](https://github.com/nothings/stb/blob/master/tests/oversample).
6. To support the extended range of unicode beyond 0xFFFF (e.g. emoticons, dingbats, symbols, shapes, ancient languages, etc...) add `#define IMGUI_USE_WCHAR32`in your `imconfig.h`.
##### [Return to Index](#index)
## Using Icon Fonts
Using an icon font (such as [FontAwesome](http://fontawesome.io) or [OpenFontIcons](https://github.com/traverseda/OpenFontIcons)) is an easy and practical way to use icons in your Dear ImGui application.
A common pattern is to merge the icon font within your main font, so you can embed icons directly from your strings without having to change fonts back and forth.
To refer to the icon UTF-8 codepoints from your C++ code, you may use those headers files created by Juliette Foucaut: https://github.com/juliettef/IconFontCppHeaders.
So you can use `ICON_FA_SEARCH` as a string that will render as a "Search" icon.
Example Setup:
```cpp
// Merge icons into default tool font
#include "IconsFontAwesome.h"
ImGuiIO& io = ImGui::GetIO();
io.Fonts->AddFontDefault();
ImFontConfig config;
config.MergeMode = true;
config.GlyphMinAdvanceX = 13.0f; // Use if you want to make the icon monospaced
- Dear ImGui uses imstb\_truetype.h to rasterize fonts (with optional oversampling). This technique and its implementation are not ideal for fonts rendered at small sizes, which may appear a little blurry or hard to read.
- There is an implementation of the ImFontAtlas builder using FreeType that you can use in the [misc/freetype/](https://github.com/ocornut/imgui/tree/master/misc/freetype) folder.
- FreeType supports auto-hinting which tends to improve the readability of small fonts.
- Read documentation in the [misc/freetype/](https://github.com/ocornut/imgui/tree/master/misc/freetype) folder.
- Correct sRGB space blending will have an important effect on your font rendering quality.
##### [Return to Index](#index)
## Using Colorful Glyphs/Emojis
- Rendering of colored emojis is only supported by imgui_freetype with FreeType 2.10+.
- You will need to load fonts with the `ImGuiFreeTypeBuilderFlags_LoadColor` flag.
- Emojis are frequently encoded in upper Unicode layers (character codes >0x10000) and will need dear imgui compiled with `IMGUI_USE_WCHAR32`.
- Not all types of color fonts are supported by FreeType at the moment.
- Stateful Unicode features such as skin tone modifiers are not supported by the text renderer.
You can use the `ImFontGlyphRangesBuilder` helper to create glyph ranges based on text input. For example: for a game where your script is known, if you can feed your entire script to it and only build the characters the game needs.
io.Fonts->Build(); // Build the atlas while 'ranges' is still in scope and not deleted.
```
##### [Return to Index](#index)
## Using Custom Colorful Icons
As an alternative to rendering colorful glyphs using imgui_freetype with `ImGuiFreeTypeBuilderFlags_LoadColor`, you may allocate your own space in the texture atlas and write yourself into it. **(This is a BETA api, use if you are familiar with dear imgui and with your rendering backend)**
- You can use the `ImFontAtlas::AddCustomRect()` and `ImFontAtlas::AddCustomRectFontGlyph()` api to register rectangles that will be packed into the font atlas texture. Register them before building the atlas, then call Build()`.
- You can then use `ImFontAtlas::GetCustomRectByIndex(int)` to query the position/size of your rectangle within the texture, and blit/copy any graphics data of your choice into those rectangles.
- This API is beta because it is likely to change in order to support multi-dpi (multiple viewports on multiple monitors with varying DPI scale).
#### Pseudo-code:
```cpp
// Add font, then register two custom 13x13 rectangles mapped to glyph 'a' and 'b' of this font
- Compile and use [binary_to_compressed_c.cpp](https://github.com/ocornut/imgui/blob/master/misc/fonts/binary_to_compressed_c.cpp) to create a compressed C style array that you can embed in source code.
- See the documentation in [binary_to_compressed_c.cpp](https://github.com/ocornut/imgui/blob/master/misc/fonts/binary_to_compressed_c.cpp) for instructions on how to use the tool.
- You may find a precompiled version binary_to_compressed_c.exe for Windows inside the demo binaries package (see [README](https://github.com/ocornut/imgui/blob/master/docs/README.md)).
- The tool can optionally output Base85 encoding to reduce the size of _source code_ but the read-only arrays in the actual binary will be about 20% bigger.
Then load the font with:
```cpp
ImFont* font = io.Fonts->AddFontFromMemoryCompressedTTF(compressed_data, compressed_data_size, size_pixels, ...);
```
or
```cpp
ImFont* font = io.Fonts->AddFontFromMemoryCompressedBase85TTF(compressed_data_base85, size_pixels, ...);
```
##### [Return to Index](#index)
## Credits/Licenses For Fonts Included In Repository
Some fonts files are available in the `misc/fonts/` folder:
**Roboto-Medium.ttf**, by Christian Robetson
<br>Apache License 2.0
<br>https://fonts.google.com/specimen/Roboto
**Cousine-Regular.ttf**, by Steve Matteson
<br>Digitized data copyright (c) 2010 Google Corporation.
<br>Licensed under the SIL Open Font License, Version 1.1
- Google Icon Fonts https://design.google.com/icons/
- Kenney Icon Font (Game Controller Icons) https://github.com/nicodinh/kenney-icon-font
- IcoMoon - Custom Icon font builder https://icomoon.io/app
#### REGULAR FONTS
- Google Noto Fonts (worldwide languages) https://www.google.com/get/noto/
- Open Sans Fonts https://fonts.google.com/specimen/Open+Sans
- (Japanese) M+ fonts by Coji Morishita http://mplus-fonts.sourceforge.jp/mplus-outline-fonts/index-en.html
#### MONOSPACE FONTS
Pixel Perfect:
- Proggy Fonts, by Tristan Grimmer http://www.proggyfonts.net or http://upperbounds.net
- Sweet16, Sweet16 Mono, by Martin Sedlak (Latin + Supplemental + Extended A) https://github.com/kmar/Sweet16Font (also include an .inl file to use directly in dear imgui.)
Regular:
- Google Noto Mono Fonts https://www.google.com/get/noto/
- Typefaces for source code beautification https://github.com/chrissimpkins/codeface
