Drezil/imgui
1
0
Fork 0
mirror of https://github.com/Drezil/imgui.git synced 2025-07-16 01:33:14 +02:00
Code Issues Packages Projects Releases Wiki Activity

ImFontAtlas: Rewrote FreeType based builder.

Browse Source 
- Fixed abnormally high atlas height. (#618)
- Fixed support for any values of TexGlyphPadding (not just only 1). (#618)
- Atlas width is now properly based on total surface rather than glyph count (unless overridden with TexDesiredWidth). (#618)
- Fixed atlas builder so missing glyphs won't influence the atlas texture width. (#2233, #618)
- Fixed atlas builder so duplicate glyphs (when merging fonts) won't be included in the rasterized atlas. (#618)
This commit is contained in:
omar
2019-01-10 22:11:27 +01:00
parent 9a9712807e
commit 21828b08a0
3 changed files with 397 additions and 192 deletions
Download Patch File Download Diff File Expand all files Collapse all files

33
misc/freetype/README.md
View File

@ -1,14 +1,14 @@
# imgui_freetype
This is an attempt to replace stb_truetype (the default imgui's font rasterizer) with FreeType.
Currently not optimal and probably has some limitations or bugs.
By [Vuhdo](https://github.com/Vuhdo) (Aleksei Skriabin). Improvements by @mikesart. Maintained by @ocornut.
Build font atlases using FreeType instead of stb_truetype (the default imgui's font rasterizer).
<br>by @vuhdo, @mikesart, @ocornut.
**Usage**
1. Get latest FreeType binaries or build yourself.
### Usage
1. Get latest FreeType binaries or build yourself (under Windows you may use vcpkg with `vcpkg install freetype`).
2. Add imgui_freetype.h/cpp alongside your imgui sources.
3. Include imgui_freetype.h after imgui.h.
4. Call ImGuiFreeType::BuildFontAtlas() *BEFORE* calling ImFontAtlas::GetTexDataAsRGBA32() or ImFontAtlas::Build() (so normal Build() won't be called):
4. Call `ImGuiFreeType::BuildFontAtlas()` *BEFORE* calling `ImFontAtlas::GetTexDataAsRGBA32()` or `ImFontAtlas::Build()` (so normal Build() won't be called):
```cpp
// See ImGuiFreeType::RasterizationFlags
@ -17,13 +17,14 @@ ImGuiFreeType::BuildFontAtlas(io.Fonts, flags);
io.Fonts->GetTexDataAsRGBA32(&pixels, &width, &height);
```
**Gamma Correct Blending**
### Gamma Correct Blending
FreeType assumes blending in linear space rather than gamma space.
See FreeType note for [FT_Render_Glyph](https://www.freetype.org/freetype2/docs/reference/ft2-base_interface.html#FT_Render_Glyph).
For correct results you need to be using sRGB and convert to linear space in the pixel shader output.
The default imgui styles will be impacted by this change (alpha values will need tweaking).
**Test code Usage**
### Test code Usage
```cpp
#include "misc/freetype/imgui_freetype.h"
#include "misc/freetype/imgui_freetype.cpp"
@ -42,16 +43,15 @@ while (true)
if (freetype_test.UpdateRebuild())
{
// REUPLOAD FONT TEXTURE TO GPU
// e.g ImGui_ImplGlfwGL3_InvalidateDeviceObjects() + ImGui_ImplGlfwGL3_CreateDeviceObjects()
// e.g ImGui_ImplOpenGL3_DestroyDeviceObjects() + ImGui_ImplOpenGL3_CreateDeviceObjects()
}
ImGui::NewFrame();
freetype_test.ShowFreetypeOptionsWindow();
...
}
}
```
**Test code**
### Test code
```cpp
#include "misc/freetype/imgui_freetype.h"
#include "misc/freetype/imgui_freetype.cpp"
@ -61,7 +61,7 @@ struct FreeTypeTest
enum FontBuildMode
{
FontBuildMode_FreeType,
FontBuildMode_Stb,
FontBuildMode_Stb
};
FontBuildMode BuildMode;
@ -120,14 +120,7 @@ struct FreeTypeTest
};
```
**Known issues**
- Output texture has excessive resolution (lots of vertical waste).
### Known issues
- FreeType's memory allocator is not overridden.
- `cfg.OversampleH`, `OversampleV` are ignored (but perhaps not so necessary with this rasterizer).
**Obligatory comparison screenshots**
Using Windows built-in segoeui.ttf font. Open in new browser tabs, view at 1080p+.
![freetype rasterizer](https://raw.githubusercontent.com/wiki/ocornut/imgui_club/images/freetype_20170817.png)