feat(api): make FreeType optional and disabled by default

FreeType renderer is still included in the final build.
Its usage is toggleable and DISABLED by default.

buildSrc/src/main/groovy/tool/generator/GenerateLibs.groovy

@@ -85,7 +85,15 @@ class GenerateLibs extends DefaultTask {
                 spec.from(project.rootProject.file('include/imgui/misc/freetype')) { CopySpec it -> it.include('*.h', '*.cpp') }
                 spec.into("$jniDir/misc/freetype")
             }
-            enableDefine('IMGUI_ENABLE_FREETYPE')
+
+            // Since we give a possibility to build library without enabled freetype - define should be set like that.
+            replaceSourceFileContent("imconfig.h", "//#define IMGUI_ENABLE_FREETYPE", "#define IMGUI_ENABLE_FREETYPE")
+
+            // Binding specific behavior to handle FreeType.
+            // By defining IMGUI_ENABLE_FREETYPE, Dear ImGui will default to using the FreeType font renderer.
+            // However, we modify the source code to ensure that, even with this, the STB_TrueType renderer is used instead.
+            // To use the FreeType font renderer, it must be explicitly forced on the atlas manually.
+            replaceSourceFileContent("imgui_draw.cpp", "ImGuiFreeType::GetBuilderForFreeType()", "ImFontAtlasGetBuilderForStbTruetype()")
         }
 
         // Copy dirent for ImGuiFileDialog
@@ -181,7 +189,13 @@ class GenerateLibs extends DefaultTask {
         target.libraries += ' -lfreetype'
     }
 
-    void enableDefine(String define) {
-        new File("$jniDir/imconfig.h").text += "#define $define"
+    void replaceSourceFileContent(String fileName, String replaceWhat, String replaceWith) {
+        def sourceFile = new File("$jniDir/$fileName")
+        def sourceTxt = sourceFile.text
+        def sourceTxtModified = sourceTxt.replace(replaceWhat, replaceWith)
+        if (sourceTxt == sourceTxtModified) {
+            throw new IllegalStateException("Unable to replace [$fileName] with content [$replaceWith]!")
+        }
+        sourceFile.text = sourceTxtModified
     }
 }

example/src/main/java/Main.java

@@ -43,7 +43,11 @@ protected void initImGui(final Configuration config) {
      * For more information read: https://github.com/ocornut/imgui/blob/33cdbe97b8fd233c6c12ca216e76398c2e89b0d8/docs/FONTS.md
      */
     private void initFonts(final ImGuiIO io) {
-        io.getFonts().addFontDefault(); // Add default font for latin glyphs
+        // This enables FreeType font renderer, which is disabled by default.
+        io.getFonts().setFreeTypeRenderer(true);
+
+        // Add default font for latin glyphs
+        io.getFonts().addFontDefault();
 
         // You can use the ImFontGlyphRangesBuilder helper to create glyph ranges based on text input.
         // For example: for a game where your script is known, if you can feed your entire script to it (using addText) and only build the characters the game needs.

imgui-binding/src/generated/java/imgui/ImFontAtlas.java

@@ -460,6 +460,32 @@ public void clear() {
     // Building in RGBA32 format is provided for convenience and compatibility, but note that unless you manually manipulate or copy color data into
     // the texture (e.g. when using the AddCustomRect*** api), then the RGB pixels emitted will always be white (~75% of memory/bandwidth waste.
 
+    /*JNI
+        #ifdef IMGUI_ENABLE_FREETYPE
+        #include "misc/freetype/imgui_freetype.h"
+        #endif
+     */
+
+    /**
+     * <b>BINDING NOTICE:</b> This method is specific to the imgui-java binding.
+     * <p>
+     * Since FreeType is included in the final build, it's possible to use both font renderers (STB_TrueType and FreeType) simultaneously without needing to rebuild the library.
+     * By default, we use small hacks to set STB_TrueType as the default font renderer. However, this method allows you to enforce the use of the FreeType renderer.
+     * <p>
+     * This method MUST be called before invoking the "#build" or "#getTexData*" methods.
+     *
+     * @param enabled true to enable the FreeType font renderer
+     */
+    public native void setFreeTypeRenderer(boolean enabled); /*
+        #ifdef IMGUI_ENABLE_FREETYPE
+        if (enabled) {
+            THIS->FontBuilderIO = ImGuiFreeType::GetBuilderForFreeType();
+        } else {
+            THIS->FontBuilderIO = NULL;
+        }
+        #endif
+    */
+
     /**
      * Build pixels data. This is called automatically for you by the GetTexData*** functions.
      */

imgui-binding/src/main/java/imgui/ImFontAtlas.java

@@ -137,6 +137,32 @@ protected long create() {
     // Building in RGBA32 format is provided for convenience and compatibility, but note that unless you manually manipulate or copy color data into
     // the texture (e.g. when using the AddCustomRect*** api), then the RGB pixels emitted will always be white (~75% of memory/bandwidth waste.
 
+    /*JNI
+        #ifdef IMGUI_ENABLE_FREETYPE
+        #include "misc/freetype/imgui_freetype.h"
+        #endif
+     */
+
+    /**
+     * <b>BINDING NOTICE:</b> This method is specific to the imgui-java binding.
+     * <p>
+     * Since FreeType is included in the final build, it's possible to use both font renderers (STB_TrueType and FreeType) simultaneously without needing to rebuild the library.
+     * By default, we use small hacks to set STB_TrueType as the default font renderer. However, this method allows you to enforce the use of the FreeType renderer.
+     * <p>
+     * This method MUST be called before invoking the "#build" or "#getTexData*" methods.
+     *
+     * @param enabled true to enable the FreeType font renderer
+     */
+    public native void setFreeTypeRenderer(boolean enabled); /*
+        #ifdef IMGUI_ENABLE_FREETYPE
+        if (enabled) {
+            THIS->FontBuilderIO = ImGuiFreeType::GetBuilderForFreeType();
+        } else {
+            THIS->FontBuilderIO = NULL;
+        }
+        #endif
+    */
+
     /**
      * Build pixels data. This is called automatically for you by the GetTexData*** functions.
      */

imgui-binding/src/main/native/imconfig.h

@@ -13,6 +13,7 @@
 //-----------------------------------------------------------------------------
 
 #pragma once
+
 #include "jni_assertion.h"
 
 //---- Define assertion handler. Defaults to calling assert().
@@ -30,6 +31,7 @@
 
 //---- Don't define obsolete functions/enums/behaviors. Consider enabling from time to time after updating to avoid using soon-to-be obsolete function/names.
 #define IMGUI_DISABLE_OBSOLETE_FUNCTIONS
+//#define IMGUI_DISABLE_OBSOLETE_KEYIO                      // 1.87: disable legacy io.KeyMap[]+io.KeysDown[] in favor io.AddKeyEvent(). This will be folded into IMGUI_DISABLE_OBSOLETE_FUNCTIONS in a few versions.
 
 //---- Disable all of Dear ImGui or don't implement standard windows.
 // It is very strongly recommended to NOT disable the demo windows during development. Please read comments in imgui_demo.cpp.
@@ -77,7 +79,7 @@
 
 //---- Use stb_truetype to build and rasterize the font atlas (default)
 // The only purpose of this define is if you want force compilation of the stb_truetype backend ALONG with the FreeType backend.
-//#define IMGUI_ENABLE_STB_TRUETYPE
+#define IMGUI_ENABLE_STB_TRUETYPE
 
 //---- Define constructor and implicit cast operators to convert back<>forth between your math types and ImVec2/ImVec4.
 // This will be inlined as part of ImVec2 and ImVec4 class declarations.