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Fonts: (Breaking) Rename ImGuiFreeType:: flags to ImGuiFreeTypeBuilderFlags_XXX. Remove ImGuiFreeType::BuildFontAtlas() flags. Rename ImFontConfig::RasterizerFlags to FontBuilderFlags. Add ImFontBuilderIO (opaque). Amend 53d59f3 with a dozen of small fixes.

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ocornut
2021-01-26 17:25:09 +01:00
parent 9417acc20f
commit 3867c6c5f0
9 changed files with 194 additions and 235 deletions
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misc/freetype/README.md
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# imgui_freetype
Build font atlases using FreeType instead of stb_truetype (which is the default font rasterizer in Dear ImGui).
Build font atlases using FreeType instead of stb_truetype (which is the default font rasterizer).
<br>by @vuhdo, @mikesart, @ocornut.
### Usage
1. Get latest FreeType binaries or build yourself (under Windows you may use vcpkg with `vcpkg install freetype`, `vcpkg integrate install`).
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):
2. Add imgui_freetype.h/cpp alongside your project files.
3. Add `#define IMGUI_ENABLE_FREETYPE` in your [imconfig.h](https://github.com/ocornut/imgui/blob/master/imconfig.h) file
```cpp
// See ImGuiFreeType::RasterizationFlags
unsigned int flags = ImGuiFreeType::NoHinting;
ImGuiFreeType::BuildFontAtlas(io.Fonts, flags);
io.Fonts->GetTexDataAsRGBA32(&pixels, &width, &height);
```
### Gamma Correct Blending
### About 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 Dear ImGui styles will be impacted by this change (alpha values will need tweaking).
### Test code Usage
```cpp
#include "misc/freetype/imgui_freetype.h"
#include "misc/freetype/imgui_freetype.cpp"
### Testbed for toying with settings (for developers)
// Load various small fonts
ImGuiIO& io = ImGui::GetIO();
io.Fonts->AddFontFromFileTTF("../../misc/fonts/Roboto-Medium.ttf", 13.0f);
io.Fonts->AddFontFromFileTTF("../../misc/fonts/Cousine-Regular.ttf", 13.0f);
io.Fonts->AddFontDefault();
FreeTypeTest freetype_test;
// Main Loop
while (true)
{
if (freetype_test.UpdateRebuild())
{
// REUPLOAD FONT TEXTURE TO GPU
ImGui_ImplXXX_DestroyDeviceObjects();
ImGui_ImplXXX_CreateDeviceObjects();
}
ImGui::NewFrame();
freetype_test.ShowFreetypeOptionsWindow();
...
}
```
### Test code
```cpp
#include "misc/freetype/imgui_freetype.h"
#include "misc/freetype/imgui_freetype.cpp"
struct FreeTypeTest
{
enum FontBuildMode
{
FontBuildMode_FreeType,
FontBuildMode_Stb
};
FontBuildMode BuildMode;
bool WantRebuild;
float FontsMultiply;
int FontsPadding;
unsigned int FontsFlags;
FreeTypeTest()
{
BuildMode = FontBuildMode_FreeType;
WantRebuild = true;
FontsMultiply = 1.0f;
FontsPadding = 1;
FontsFlags = 0;
}
// Call _BEFORE_ NewFrame()
bool UpdateRebuild()
{
if (!WantRebuild)
return false;
ImGuiIO& io = ImGui::GetIO();
io.Fonts->TexGlyphPadding = FontsPadding;
for (int n = 0; n < io.Fonts->ConfigData.Size; n++)
{
ImFontConfig* font_config = (ImFontConfig*)&io.Fonts->ConfigData[n];
font_config->RasterizerMultiply = FontsMultiply;
font_config->RasterizerFlags = (BuildMode == FontBuildMode_FreeType) ? FontsFlags : 0x00;
}
if (BuildMode == FontBuildMode_FreeType)
ImGuiFreeType::BuildFontAtlas(io.Fonts, FontsFlags);
else if (BuildMode == FontBuildMode_Stb)
io.Fonts->Build();
WantRebuild = false;
return true;
}
// Call to draw interface
void ShowFreetypeOptionsWindow()
{
ImGui::Begin("FreeType Options");
ImGui::ShowFontSelector("Fonts");
WantRebuild |= ImGui::RadioButton("FreeType", (int*)&BuildMode, FontBuildMode_FreeType);
ImGui::SameLine();
WantRebuild |= ImGui::RadioButton("Stb (Default)", (int*)&BuildMode, FontBuildMode_Stb);
WantRebuild |= ImGui::DragFloat("Multiply", &FontsMultiply, 0.001f, 0.0f, 2.0f);
WantRebuild |= ImGui::DragInt("Padding", &FontsPadding, 0.1f, 0, 16);
if (BuildMode == FontBuildMode_FreeType)
{
WantRebuild |= ImGui::CheckboxFlags("NoHinting", &FontsFlags, ImGuiFreeType::NoHinting);
WantRebuild |= ImGui::CheckboxFlags("NoAutoHint", &FontsFlags, ImGuiFreeType::NoAutoHint);
WantRebuild |= ImGui::CheckboxFlags("ForceAutoHint", &FontsFlags, ImGuiFreeType::ForceAutoHint);
WantRebuild |= ImGui::CheckboxFlags("LightHinting", &FontsFlags, ImGuiFreeType::LightHinting);
WantRebuild |= ImGui::CheckboxFlags("MonoHinting", &FontsFlags, ImGuiFreeType::MonoHinting);
WantRebuild |= ImGui::CheckboxFlags("Bold", &FontsFlags, ImGuiFreeType::Bold);
WantRebuild |= ImGui::CheckboxFlags("Oblique", &FontsFlags, ImGuiFreeType::Oblique);
WantRebuild |= ImGui::CheckboxFlags("Monochrome", &FontsFlags, ImGuiFreeType::Monochrome);
}
ImGui::End();
}
};
```
See https://gist.github.com/ocornut/b3a9ecf13502fd818799a452969649ad
### Known issues
- `cfg.OversampleH`, `OversampleV` are ignored (but perhaps not so necessary with this rasterizer).