imgui_freetype_test.cpp

// Test helper for imgui_freetype

#include "misc/freetype/imgui_freetype.h"

struct FreeTypeTest
{
    enum FontBuildMode { FontBuildMode_FreeType, FontBuildMode_Stb };

    FontBuildMode   BuildMode = FontBuildMode_FreeType;
    bool            WantRebuild = true;
    float           RasterizerMultiply = 1.0f;
    unsigned int    FreeTypeBuilderFlags = 0;

    // Call _BEFORE_ NewFrame()
    bool PreNewFrame()
    {
        if (!WantRebuild)
            return false;

        ImFontAtlas* atlas = ImGui::GetIO().Fonts;
        for (int n = 0; n < atlas->ConfigData.Size; n++)
            ((ImFontConfig*)&atlas->ConfigData[n])->RasterizerMultiply = RasterizerMultiply;

        // Allow for dynamic selection of the builder. 
        // In real code you are likely to just define IMGUI_ENABLE_FREETYPE and never assign to FontBuilderIO.
#ifdef IMGUI_ENABLE_FREETYPE
        if (BuildMode == FontBuildMode_FreeType)
        {
            atlas->FontBuilderIO = ImGuiFreeType::GetBuilderForFreeType();
            atlas->FontBuilderFlags = FreeTypeBuilderFlags;
        }
#endif
#ifdef IMGUI_ENABLE_STB_TRUETYPE
        if (BuildMode == FontBuildMode_Stb)
        {
            atlas->FontBuilderIO = ImFontAtlasGetBuilderForStbTruetype();
            atlas->FontBuilderFlags = 0;
        }
#endif
        atlas->Build();
        WantRebuild = false;
        return true;
    }

    // Call to draw UI
    void ShowFontsOptionsWindow()
    {
        ImFontAtlas* atlas = ImGui::GetIO().Fonts;

        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::DragInt("TexGlyphPadding", &atlas->TexGlyphPadding, 0.1f, 1, 16);
        WantRebuild |= ImGui::DragFloat("RasterizerMultiply", &RasterizerMultiply, 0.001f, 0.0f, 2.0f);
        ImGui::Separator();

        if (BuildMode == FontBuildMode_FreeType)
        {
#ifndef IMGUI_ENABLE_FREETYPE
            ImGui::TextColored(ImVec4(1.0f, 0.5f, 0.5f, 1.0f), "Error: FreeType builder not compiled!");
#endif
            WantRebuild |= ImGui::CheckboxFlags("NoHinting", &FreeTypeBuilderFlags, ImGuiFreeTypeBuilderFlags_NoHinting);
            WantRebuild |= ImGui::CheckboxFlags("NoAutoHint", &FreeTypeBuilderFlags, ImGuiFreeTypeBuilderFlags_NoAutoHint);
            WantRebuild |= ImGui::CheckboxFlags("ForceAutoHint", &FreeTypeBuilderFlags, ImGuiFreeTypeBuilderFlags_ForceAutoHint);
            WantRebuild |= ImGui::CheckboxFlags("LightHinting", &FreeTypeBuilderFlags, ImGuiFreeTypeBuilderFlags_LightHinting);
            WantRebuild |= ImGui::CheckboxFlags("MonoHinting", &FreeTypeBuilderFlags, ImGuiFreeTypeBuilderFlags_MonoHinting);
            WantRebuild |= ImGui::CheckboxFlags("Bold", &FreeTypeBuilderFlags, ImGuiFreeTypeBuilderFlags_Bold);
            WantRebuild |= ImGui::CheckboxFlags("Oblique", &FreeTypeBuilderFlags, ImGuiFreeTypeBuilderFlags_Oblique);
            WantRebuild |= ImGui::CheckboxFlags("Monochrome", &FreeTypeBuilderFlags, ImGuiFreeTypeBuilderFlags_Monochrome);
        }

        if (BuildMode == FontBuildMode_Stb)
        {
#ifndef IMGUI_ENABLE_STB_TRUETYPE
            ImGui::TextColored(ImVec4(1.0f, 0.5f, 0.5f, 1.0f), "Error: stb_truetype builder not compiled!");
#endif
        }
        ImGui::End();
    }
};

[....]

// Application Init: Load various small fonts
ImGuiIO& io = ImGui::GetIO();
io.Fonts->AddFontFromFileTTF("NotoSans-Regular.ttf", 13.0f);
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;

[....]

// Application main loop
while (1)
{
   if (freetype_test.PreNewFrame())
   {
      // REUPLOAD FONT TEXTURE TO GPU
      ImGui_ImplXXX_DestroyDeviceObjects();
      ImGui_ImplXXX_CreateDeviceObjects();
   }
   ImGui::NewFrame();
   freetype_test.ShowFontsOptionsWindow();
   ...
}