Refactor ImDrawList

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

@@ -11,16 +11,16 @@ package imgui;
  * but you are totally free to apply whatever transformation matrix to want to the data (if you apply such transformation you'll want to apply it to ClipRect as well)
  * Important: Primitives are always added to the list and not culled (culling is done at higher-level by ImGui:: functions), if you use this API a lot consider coarse culling your drawn objects.
  */
-public final class ImDrawList {
+public final class ImDrawList implements ImDestroyable {
-    public static final int TYPE_WINDOW = 0;
+    final long ptr;
-    public static final int TYPE_BACKGROUND = 1;
-    public static final int TYPE_FOREGROUND = 2;
 
-    @SuppressWarnings({"FieldCanBeLocal", "unused"})
+    ImDrawList(final long ptr) {
-    private final int drawListType;
+        this.ptr = ptr;
+    }
 
-    ImDrawList(final int drawListType) {
+    @Override
-        this.drawListType = drawListType;
+    public void destroy() {
+        nDestroy(ptr);
     }
 
     /*JNI
@@ -28,31 +28,18 @@ public final class ImDrawList {
         #include <imgui.h>
         #include "jni_common.h"
 
-        const static int DRAWLIST_TYPE_WINDOW     = 0;
+        jfieldID imDrawListPtrID;
-        const static int DRAWLIST_TYPE_BACKGROUND = 1;
-        const static int DRAWLIST_TYPE_FOREGROUND = 2;
 
-        ImDrawList* getDrawList(int drawListType) {
+        #define IM_DRAW_LIST ((ImDrawList*)env->GetLongField(object, imDrawListPtrID))
-            switch (drawListType) {
-                case DRAWLIST_TYPE_WINDOW:
-                    return ImGui::GetWindowDrawList();
-                case DRAWLIST_TYPE_BACKGROUND:
-                    return ImGui::GetBackgroundDrawList();
-                case DRAWLIST_TYPE_FOREGROUND:
-                    return ImGui::GetForegroundDrawList();
-                default:
-                    return NULL;
-            }
-        }
-
-        jfieldID drawListTypeID;
-
-        #define IM_DRAW_LIST getDrawList(env->GetIntField(object, drawListTypeID))
      */
 
     static native void nInit(); /*
         jclass jImDrawListClass = env->FindClass("imgui/ImDrawList");
-        drawListTypeID = env->GetFieldID(jImDrawListClass, "drawListType", "I");
+        imDrawListPtrID = env->GetFieldID(jImDrawListClass, "ptr", "J");
+    */
+
+    private native void nDestroy(long ptr); /*
+        delete (ImDrawList*)ptr;
     */
 
     /**

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

@@ -18,13 +18,12 @@ public final class ImGui {
 
     private static final ImGuiIO IMGUI_IO;
 
-    private static final ImDrawList IM_DRAW_LIST_WINDOW = new ImDrawList(ImDrawList.TYPE_WINDOW);
-    private static final ImDrawList IM_DRAW_LIST_BACKGROUND = new ImDrawList(ImDrawList.TYPE_BACKGROUND);
-    private static final ImDrawList IM_DRAW_LIST_FOREGROUND = new ImDrawList(ImDrawList.TYPE_FOREGROUND);
-
     private static ImDrawData drawData;
     private static ImFont font;
     private static ImGuiStyle style;
+    private static ImDrawList windowDrawList;
+    private static ImDrawList backgroundDrawList;
+    private static ImDrawList foregroundDrawList;
 
     static {
         final String libPath = System.getProperty(LIB_PATH_PROP);
@@ -465,9 +464,16 @@ public final class ImGui {
      * Get draw list associated to the current window, to append your own drawing primitives
      */
     public static ImDrawList getWindowDrawList() {
-        return IM_DRAW_LIST_WINDOW;
+        if (windowDrawList == null) {
+            windowDrawList = new ImDrawList(nGetWindowDrawList());
+        }
+        return windowDrawList;
     }
 
+    private static native long nGetWindowDrawList(); /*
+        return (intptr_t)ImGui::GetWindowDrawList();
+    */
+
     /**
      * Get current window position in screen space (useful if you want to do your own drawing via the DrawList API)
      */
@@ -4412,16 +4418,30 @@ public final class ImGui {
      * This draw list will be the first rendering one. Useful to quickly draw shapes/text behind dear imgui contents.
      */
     public static ImDrawList getBackgroundDrawList() {
-        return IM_DRAW_LIST_BACKGROUND;
+        if (backgroundDrawList == null) {
+            backgroundDrawList = new ImDrawList(nGetBackgroundDrawList());
+        }
+        return backgroundDrawList;
     }
 
+    private static native long nGetBackgroundDrawList(); /*
+        return (intptr_t)ImGui::GetBackgroundDrawList();
+    */
+
     /**
      * This draw list will be the last rendered one. Useful to quickly draw shapes/text over dear imgui contents.
      */
     public static ImDrawList getForegroundDrawList() {
-        return IM_DRAW_LIST_FOREGROUND;
+        if (foregroundDrawList == null) {
+            foregroundDrawList = new ImDrawList(nGetForegroundDrawList());
+        }
+        return foregroundDrawList;
     }
 
+    private static native long nGetForegroundDrawList(); /*
+        return (intptr_t)ImGui::GetForegroundDrawList();
+    */
+
     // TODO GetDrawListSharedData
 
     /**

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

@@ -199,15 +199,13 @@ public final class ImGuiIO {
      * Font atlas: load, rasterize and pack one or more fonts into a single texture.
      */
     public ImFontAtlas getFonts() {
-        // on demand instantiation
-        // will throw native exception if Dear ImGui context isn't created (like in the original library)
         if (imFontAtlas == null) {
-            imFontAtlas = new ImFontAtlas(nGetFontsPtr());
+            imFontAtlas = new ImFontAtlas(nGetFonts());
         }
         return imFontAtlas;
     }
 
-    private native long nGetFontsPtr(); /*
+    private native long nGetFonts(); /*
         return (intptr_t)ImGui::GetIO().Fonts;
     */