Docs: added more detailed information about UTF-8 encoding.

+ Revert mistakenly committed Win32+DX11 main.cpp from last commit.
This commit is contained in:
ocornut 2023-05-10 12:54:51 +02:00
parent 513af1efc9
commit 430c05991c
5 changed files with 104 additions and 64 deletions

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@ -628,10 +628,11 @@ builder.BuildRanges(&ranges); // Build the final result
io.Fonts->AddFontFromFileTTF("myfontfile.ttf", 16.0f, nullptr, ranges.Data);
```
All your strings need to use UTF-8 encoding. In C++11 you can encode a string literal in UTF-8
by using the u8"hello" syntax. Specifying literal in your source code using a local code page
(such as CP-923 for Japanese or CP-1251 for Cyrillic) will NOT work!
Otherwise, you can convert yourself to UTF-8 or load text data from a file already saved as UTF-8.
All your strings need to use UTF-8 encoding.
You need to tell your compiler to use UTF-8, or in C++11 you can encode a string literal in UTF-8 by using the u8"hello" syntax.
Specifying literal in your source code using a local code page (such as CP-923 for Japanese or CP-1251 for Cyrillic) will NOT work!
See [About UTF-8 Encoding](https://github.com/ocornut/imgui/blob/master/docs/FONTS.md#about-utf-8-encoding) section
of [FONTS.md](https://github.com/ocornut/imgui/blob/master/docs/FONTS.md) for details about UTF-8 Encoding.
Text input: it is up to your application to pass the right character code by calling `io.AddInputCharacter()`.
The applications in examples/ are doing that.

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@ -12,41 +12,118 @@ In the [misc/fonts/](https://github.com/ocornut/imgui/tree/master/misc/fonts) fo
## Index
- [Readme First](#readme-first)
- [About Filenames](#about-filenames)
- [About UTF-8 Encoding](#about-utf-8-encoding)
- [Debug Tools](#debug-tools)
- [How should I handle DPI in my application?](#how-should-i-handle-dpi-in-my-application)
- [Fonts Loading Instructions](#font-loading-instructions)
- [Fonts Loading Instructions](#fonts-loading-instructions)
- [Using Icon Fonts](#using-icon-fonts)
- [Using FreeType Rasterizer (imgui_freetype)](#using-freetype-rasterizer-imgui_freetype)
- [Using Colorful Glyphs/Emojis](#using-colorful-glyphsemojis)
- [Using Custom Glyph Ranges](#using-custom-glyph-ranges)
- [Using Custom Colorful Icons](#using-custom-colorful-icons)
- [Using Font Data Embedded In Source Code](#using-font-data-embedded-in-source-code)
- [About filenames](#about-filenames)
- [Credits/Licenses For Fonts Included In Repository](#creditslicenses-for-fonts-included-in-repository)
- [Font Links](#font-links)
---------------------------------------
## Readme First
- 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.
## Readme First
**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()`.
##### [Return to Index](#index)
## About Filenames
**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.**
Two things to watch for:
(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.
```cpp
io.Fonts->AddFontFromFileTTF("MyFiles\MyImage01.jpg", ...); // This is INCORRECT!!
io.Fonts->AddFontFromFileTTF("MyFiles\\MyImage01.jpg", ...); // This is CORRECT
```
In some situations, you may also use `/` path separator under Windows.
(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
```
##### [Return to Index](#index)
## About UTF-8 Encoding
**For non-ASCII characters display, a common user issue is not passing correctly UTF-8 encoded strings.**
(1) We provide a function `ImGui::DebugTextEncoding(const char* text)` which you can call to verify the content of your UTF-8 strings.
This is a convenient way to confirm that your encoding is correct.
```cpp
ImGui::SeparatorText("CORRECT");
ImGui::DebugTextEncoding(u8"こんにちは");
ImGui::SeparatorText("INCORRECT");
ImGui::DebugTextEncoding("こんにちは");
```
![UTF-8 Encoding viewer](https://github.com/ocornut/imgui/assets/8225057/61c1696a-9a94-46c5-9627-cf91211111f0)
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.
![Fonts debugging](https://user-images.githubusercontent.com/8225057/135429892-0e41ef8d-33c5-4991-bcf6-f997a0bcfd6b.png)
- 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.
#### UTF-8 Encoding Viewer**
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.
![UTF-8 Encoding viewer](https://user-images.githubusercontent.com/8225057/166505963-8a0d7899-8ee8-4558-abb2-1ae523dc02f9.png)
- 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.
- Make sure your font ranges data are persistent (available during the calls to `GetTexDataAsAlpha8()`/`GetTexDataAsRGBA32()/`Build()`.
- Use C++11 u8"my text" syntax to encode literal strings as UTF-8. e.g.:
```cpp
u8"hello"
u8"こんにちは" // this will be encoded as UTF-8
```
##### [Return to Index](#index)
## How should I handle DPI in my application?
See [FAQ entry](https://github.com/ocornut/imgui/blob/master/docs/FAQ.md#q-how-should-i-handle-dpi-in-my-application).
@ -54,7 +131,7 @@ See [FAQ entry](https://github.com/ocornut/imgui/blob/master/docs/FAQ.md#q-how-s
##### [Return to Index](#index)
## Font Loading Instructions
## Fonts Loading Instructions
**Load default font:**
```cpp
@ -62,7 +139,6 @@ ImGuiIO& io = ImGui::GetIO();
io.Fonts->AddFontDefault();
```
**Load .TTF/.OTF file with:**
```cpp
ImGuiIO& io = ImGui::GetIO();
@ -70,7 +146,6 @@ io.Fonts->AddFontFromFileTTF("font.ttf", size_pixels);
```
If you get an assert stating "Could not load font file!", your font filename is likely incorrect. Read "[About filenames](#about-filenames)" carefully.
**Load multiple fonts:**
```cpp
// Init
@ -86,7 +161,6 @@ ImGui::Text("Hello with another font");
ImGui::PopFont();
```
**For advanced options create a ImFontConfig structure and pass it to the AddFont() function (it will be copied internally):**
```cpp
ImFontConfig config;
@ -96,7 +170,6 @@ config.GlyphExtraSpacing.x = 1.0f;
ImFont* font = io.Fonts->AddFontFromFileTTF("font.ttf", size_pixels, &config);
```
**Combine multiple fonts into one:**
```cpp
// Load a first font
@ -311,28 +384,6 @@ ImFont* font = io.Fonts->AddFontFromMemoryCompressedBase85TTF(compressed_data_ba
##### [Return to Index](#index)
## About filenames
**Please note that many new C/C++ users have issues loading their files _because the filename they provide is wrong_.**
Two things to watch for:
- Make sure your IDE/debugger settings starts your executable from the right working 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
// 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
io.Fonts->AddFontFromFileTTF("../MyImage01.jpg", ...);
```
- 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.
```cpp
io.Fonts->AddFontFromFileTTF("MyFiles\MyImage01.jpg", ...); // This is INCORRECT!!
io.Fonts->AddFontFromFileTTF("MyFiles\\MyImage01.jpg", ...); // This is CORRECT
```
In some situations, you may also use `/` path separator under Windows.
##### [Return to Index](#index)
## Credits/Licenses For Fonts Included In Repository
Some fonts files are available in the `misc/fonts/` folder:

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@ -1,4 +1,4 @@
// Dear ImGui: standalone example application for DirectX 11
// Dear ImGui: standalone example application for DirectX 11
// If you are new to Dear ImGui, read documentation from the docs/ folder + read the top of imgui.cpp.
// Read online: https://github.com/ocornut/imgui/tree/master/docs
@ -26,7 +26,7 @@ LRESULT WINAPI WndProc(HWND hWnd, UINT msg, WPARAM wParam, LPARAM lParam);
int main(int, char**)
{
// Create application window
ImGui_ImplWin32_EnableDpiAwareness();
//ImGui_ImplWin32_EnableDpiAwareness();
WNDCLASSEXW wc = { sizeof(wc), CS_CLASSDC, WndProc, 0L, 0L, GetModuleHandle(nullptr), nullptr, nullptr, nullptr, nullptr, L"ImGui Example", nullptr };
::RegisterClassExW(&wc);
HWND hwnd = ::CreateWindowW(wc.lpszClassName, L"Dear ImGui DirectX11 Example", WS_OVERLAPPEDWINDOW, 100, 100, 1280, 800, nullptr, nullptr, wc.hInstance, nullptr);
@ -71,7 +71,7 @@ int main(int, char**)
//io.Fonts->AddFontFromFileTTF("../../misc/fonts/DroidSans.ttf", 16.0f);
//io.Fonts->AddFontFromFileTTF("../../misc/fonts/Roboto-Medium.ttf", 16.0f);
//io.Fonts->AddFontFromFileTTF("../../misc/fonts/Cousine-Regular.ttf", 15.0f);
ImFont* font = io.Fonts->AddFontFromFileTTF("c:\\Windows\\Fonts\\ArialUni.ttf", 18.0f, nullptr, io.Fonts->GetGlyphRangesJapanese());
//ImFont* font = io.Fonts->AddFontFromFileTTF("c:\\Windows\\Fonts\\ArialUni.ttf", 18.0f, nullptr, io.Fonts->GetGlyphRangesJapanese());
//IM_ASSERT(font != nullptr);
// Our state
@ -114,12 +114,6 @@ int main(int, char**)
if (show_demo_window)
ImGui::ShowDemoWindow(&show_demo_window);
ImGui::SeparatorText("CORRECT");
ImGui::DebugTextEncoding(u8"こんにちは");
ImGui::SeparatorText("INCORRECT");
ImGui::DebugTextEncoding("こんにちは");
// 2. Show a simple window that we create ourselves. We use a Begin/End pair to create a named window.
{
static float f = 0.0f;
@ -127,13 +121,6 @@ int main(int, char**)
ImGui::Begin("Hello, world!"); // Create a window called "Hello, world!" and append into it.
#define U8(_S) (const char*)u8##_S
ImGui::Text(U8("こんにちは"));
//#pragma execution_character_set("utf-8")
ImGui::Text("日本語");
ImGui::Text("This is some useful text."); // Display some text (you can use a format strings too)
ImGui::Checkbox("Demo Window", &show_demo_window); // Edit bools storing our window open/close state
ImGui::Checkbox("Another Window", &show_another_window);

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@ -13394,7 +13394,7 @@ void ImGui::DebugRenderKeyboardPreview(ImDrawList* draw_list)
void ImGui::DebugTextEncoding(const char* str)
{
Text("Text: \"%s\"", str);
if (!BeginTable("list", 4, ImGuiTableFlags_Borders | ImGuiTableFlags_RowBg | ImGuiTableFlags_SizingFixedFit))
if (!BeginTable("##DebugTextEncoding", 4, ImGuiTableFlags_Borders | ImGuiTableFlags_RowBg | ImGuiTableFlags_SizingFixedFit | ImGuiTableFlags_Resizable))
return;
TableSetupColumn("Offset");
TableSetupColumn("UTF-8");

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@ -2832,7 +2832,8 @@ struct ImFontAtlas
//-------------------------------------------
// Helpers to retrieve list of common Unicode ranges (2 value per range, values are inclusive, zero-terminated list)
// NB: Make sure that your string are UTF-8 and NOT in your local code page. In C++11, you can create UTF-8 string literal using the u8"Hello world" syntax. See FAQ for details.
// NB: Make sure that your string are UTF-8 and NOT in your local code page.
// Read https://github.com/ocornut/imgui/blob/master/docs/FONTS.md/#about-utf-8-encoding for details.
// NB: Consider using ImFontGlyphRangesBuilder to build glyph ranges from textual data.
IMGUI_API const ImWchar* GetGlyphRangesDefault(); // Basic Latin, Extended Latin
IMGUI_API const ImWchar* GetGlyphRangesGreek(); // Default + Greek and Coptic