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diff --git a/3rdparty/imgui/misc/freetype/README.md b/3rdparty/imgui/misc/freetype/README.md new file mode 100644 index 00000000..ba633f69 --- /dev/null +++ b/3rdparty/imgui/misc/freetype/README.md @@ -0,0 +1,133 @@ +# 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. + +**Usage** +1. Get latest FreeType binaries or build yourself. +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): + +```cpp +// See ImGuiFreeType::RasterizationFlags +unsigned int flags = ImGuiFreeType::NoHinting; +ImGuiFreeType::BuildFontAtlas(io.Fonts, flags); +io.Fonts->GetTexDataAsRGBA32(&pixels, &width, &height); +``` + +**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** +```cpp +#include "misc/freetype/imgui_freetype.h" +#include "misc/freetype/imgui_freetype.cpp" + +// 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 + // e.g ImGui_ImplGlfwGL3_InvalidateDeviceObjects() + ImGui_ImplGlfwGL3_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; + unsigned int FontsFlags; + + FreeTypeTest() + { + BuildMode = FontBuildMode_FreeType; + WantRebuild = true; + FontsMultiply = 1.0f; + FontsFlags = 0; + } + + // Call _BEFORE_ NewFrame() + bool UpdateRebuild() + { + if (!WantRebuild) + return false; + ImGuiIO& io = ImGui::GetIO(); + for (int n = 0; n < io.Fonts->Fonts.Size; n++) + { + io.Fonts->Fonts[n]->ConfigData->RasterizerMultiply = FontsMultiply; + io.Fonts->Fonts[n]->ConfigData->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); + 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); + } + ImGui::End(); + } +}; +``` + +**Known issues** +- Output texture has excessive resolution (lots of vertical waste). +- 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+. + + + |