[wpigui] Add font selector (#7134)

wpigui/src/main/native/cpp/wpigui.cpp

@@ -17,6 +17,8 @@
 #include <GLFW/glfw3.h>
 #include <IconsFontAwesome6.h>
 #include <imgui.h>
+#include <imgui_DroidSans.h>
+#include <imgui_FiraCodeRetina.h>
 #include <imgui_FontAwesomeSolid.h>
 #include <imgui_ProggyDotted.h>
 #include <imgui_impl_glfw.h>
@@ -94,6 +96,8 @@ static void IniReadLine(ImGuiContext* ctx, ImGuiSettingsHandler* handler,
     impl->userScale = num;
   } else if (std::strncmp(lineStr, "style=", 6) == 0) {
     impl->style = num;
+  } else if (std::strncmp(lineStr, "font=", 5) == 0) {
+    impl->defaultFontName = &lineStr[5];
   } else if (std::strncmp(lineStr, "fps=", 4) == 0) {
     impl->fps = num;
   }
@@ -106,23 +110,26 @@ static void IniWriteAll(ImGuiContext* ctx, ImGuiSettingsHandler* handler,
   }
   out_buf->appendf(
       "[MainWindow][GLOBAL]\nwidth=%d\nheight=%d\nmaximized=%d\n"
-      "xpos=%d\nypos=%d\nuserScale=%d\nstyle=%d\nfps=%d\n\n",
+      "xpos=%d\nypos=%d\nuserScale=%d\nstyle=%d\nfont=%s\nfps=%d\n\n",
       gContext->width, gContext->height, gContext->maximized ? 1 : 0,
       gContext->xPos, gContext->yPos, gContext->userScale, gContext->style,
-      gContext->fps);
+      gContext->defaultFontName.c_str(), gContext->fps);
 }
 
 void gui::CreateContext() {
   gContext = new Context;
-  AddFont("ProggyDotted", [](ImGuiIO& io, float size, const ImFontConfig* cfg) {
-    auto font = ImGui::AddFontProggyDotted(io, size, cfg);
-    static const ImWchar icons_ranges[] = {ICON_MIN_FA, ICON_MAX_16_FA, 0};
-    ImFontConfig icons_cfg;
-    icons_cfg.MergeMode = true;
-    icons_cfg.PixelSnapH = true;
-    ImGui::AddFontFontAwesomeSolid(io, size, &icons_cfg, icons_ranges);
-    return font;
-  });
+  AddDefaultFont("Proggy Dotted",
+                 [](ImGuiIO& io, float size, const ImFontConfig* cfg) {
+                   return ImGui::AddFontProggyDotted(io, size, cfg);
+                 });
+  AddDefaultFont("Droid Sans",
+                 [](ImGuiIO& io, float size, const ImFontConfig* cfg) {
+                   return ImGui::AddFontDroidSans(io, size, cfg);
+                 });
+  AddDefaultFont("Fira Code Retina",
+                 [](ImGuiIO& io, float size, const ImFontConfig* cfg) {
+                   return ImGui::AddFontFiraCodeRetina(io, size, cfg);
+                 });
   PlatformCreateContext();
 }
 
@@ -158,17 +165,25 @@ static void ReloadFonts() {
   io.Fonts->Clear();
   gContext->fonts.clear();
   float size = 7.0f + gContext->fontScale * 3.0f;
-  bool first = true;
   for (auto&& makeFont : gContext->makeFonts) {
-    if (makeFont.second) {
+    if (makeFont.func) {
       ImFontConfig cfg;
-      std::snprintf(cfg.Name, sizeof(cfg.Name), "%s", makeFont.first);
-      ImFont* font = makeFont.second(io, size, &cfg);
-      if (first) {
-        ImGui::GetIO().FontDefault = font;
-        first = false;
+      std::snprintf(cfg.Name, sizeof(cfg.Name), "%s", makeFont.name.c_str());
+      bool isDefault = makeFont.name == gContext->defaultFontName;
+      if (!makeFont.defaultOnly || isDefault) {
+        ImFont* font = makeFont.func(io, size, &cfg);
+        if (isDefault) {
+          // Merge font awesome solid into default font
+          static const ImWchar icons_ranges[] = {ICON_MIN_FA, ICON_MAX_16_FA,
+                                                 0};
+          ImFontConfig icons_cfg;
+          icons_cfg.MergeMode = true;
+          icons_cfg.PixelSnapH = true;
+          ImGui::AddFontFontAwesomeSolid(io, size, &icons_cfg, icons_ranges);
+          ImGui::GetIO().FontDefault = font;
+        }
+        gContext->fonts.emplace_back(font);
       }
-      gContext->fonts.emplace_back(font);
     }
   }
 }
@@ -479,11 +494,20 @@ int gui::AddFont(
     std::function<ImFont*(ImGuiIO& io, float size, const ImFontConfig* cfg)>
         makeFont) {
   if (makeFont) {
-    gContext->makeFonts.emplace_back(name, std::move(makeFont));
+    gContext->makeFonts.emplace_back(name, false, std::move(makeFont));
   }
   return gContext->makeFonts.size() - 1;
 }
 
+void gui::AddDefaultFont(
+    const char* name,
+    std::function<ImFont*(ImGuiIO& io, float size, const ImFontConfig* cfg)>
+        makeFont) {
+  if (makeFont) {
+    gContext->makeFonts.emplace_back(name, true, std::move(makeFont));
+  }
+}
+
 void gui::SetStyle(Style style) {
   gContext->style = static_cast<int>(style);
   switch (style) {
@@ -553,6 +577,17 @@ void gui::EmitViewMenu() {
       ImGui::EndMenu();
     }
 
+    if (ImGui::BeginMenu("Font")) {
+      for (auto&& makeFont : gContext->makeFonts) {
+        bool selected = gContext->defaultFontName == makeFont.name;
+        if (ImGui::MenuItem(makeFont.name.c_str(), nullptr, &selected)) {
+          gContext->defaultFontName = makeFont.name;
+          gContext->reloadFonts = true;
+        }
+      }
+      ImGui::EndMenu();
+    }
+
     if (ImGui::BeginMenu("Zoom")) {
       for (int i = 0; i < kFontScaledLevels && (25 * (i + 2)) <= 200; ++i) {
         char label[20];

wpigui/src/main/native/include/wpigui.h

@@ -144,6 +144,21 @@ int AddFont(
     std::function<ImFont*(ImGuiIO& io, float size, const ImFontConfig* cfg)>
         makeFont);
 
+/**
+ * Adds a default font option.  This is the font used for menus, etc.  If the
+ * font is selected by the user as the default font, the passed function is
+ * called during initialization as many times as necessary to create a range of
+ * sizes.  If not selected, the font is not loaded (to always load a font,
+ * use AddFont() instead).
+ *
+ * @param name font name
+ * @param makeFont font creation / loader function
+ */
+void AddDefaultFont(
+    const char* name,
+    std::function<ImFont*(ImGuiIO& io, float size, const ImFontConfig* cfg)>
+        makeFont);
+
 /**
  * Gets a font added with AddFont() with the appropriate font size for
  * the current scaling of the GUI.

wpigui/src/main/native/include/wpigui_internal.h

@@ -25,6 +25,7 @@ struct SavedSettings {
   int userScale = 2;
   int style = 0;
   int fps = 120;
+  std::string defaultFontName = "Proggy Dotted";
 };
 
 constexpr int kFontScaledLevels = 9;
@@ -44,10 +45,21 @@ struct Context : public SavedSettings {
   std::function<void(bool exiting)> saveSettings;
   std::vector<std::function<void()>> initializers;
   std::vector<std::function<void(float scale)>> windowScalers;
-  std::vector<std::pair<
-      const char*,
-      std::function<ImFont*(ImGuiIO& io, float size, const ImFontConfig* cfg)>>>
-      makeFonts;
+  struct FontMaker {
+    FontMaker(
+        std::string name, bool defaultOnly,
+        std::function<ImFont*(ImGuiIO& io, float size, const ImFontConfig* cfg)>
+            func)
+        : name{std::move(name)},
+          defaultOnly{defaultOnly},
+          func{std::move(func)} {}
+
+    std::string name;
+    bool defaultOnly;
+    std::function<ImFont*(ImGuiIO& io, float size, const ImFontConfig* cfg)>
+        func;
+  };
+  std::vector<FontMaker> makeFonts;
 
   ImVec4 clearColor = ImVec4(0.45f, 0.55f, 0.60f, 1.00f);
   std::vector<std::function<void()>> earlyExecutors;