[API] Added callback binding for InputText (#156)

* Added callback binding for InputText

* Add JavaDoc

* Change

* Add Javadoc

* Fix Import

* Teaks and improvements

- Extended example;
- Added input text callback ImGuiInputTextFlags#CallbackEdit;
- Minor code improvements.

---------

Co-authored-by: SpaiR <klimbetoo@gmail.com>

example/src/main/java/ExampleInputTextCallback.java

@@ -0,0 +1,44 @@
+import imgui.ImGui;
+import imgui.ImGuiInputTextCallbackData;
+import imgui.callback.ImGuiInputTextCallback;
+import imgui.flag.ImGuiCond;
+import imgui.flag.ImGuiInputTextFlags;
+import imgui.type.ImBoolean;
+import imgui.type.ImString;
+
+import java.time.LocalDateTime;
+import java.time.format.DateTimeFormatter;
+
+public class ExampleInputTextCallback {
+    private static final ImString STR = new ImString();
+    private static final StringBuilder OUTPUT = new StringBuilder();
+    private static final DateTimeFormatter DATE_FORMAT = DateTimeFormatter.ofPattern("yyyy/MM/dd HH:mm:ss");
+
+    private static final ImGuiInputTextCallback CALLBACK = new ImGuiInputTextCallback() {
+        @Override
+        public void accept(final ImGuiInputTextCallbackData data) {
+            final char c = (char) data.getEventChar();
+            if (c == 'h' || c == 'H') {
+                data.setEventChar('!');
+                OUTPUT.append(DATE_FORMAT.format(LocalDateTime.now())).append(" :: Replaced!\n");
+            } else if (c == 'w' || c == 'W') {
+                data.setEventChar(0);
+                OUTPUT.append(DATE_FORMAT.format(LocalDateTime.now())).append(" :: Discarded!\n");
+            } else {
+                OUTPUT.append(DATE_FORMAT.format(LocalDateTime.now())).append(" :: Typed: ").append(c).append('\n');
+            }
+        }
+    };
+
+    public static void show(final ImBoolean showInputTextCallback) {
+        ImGui.setNextWindowSize(400, 300, ImGuiCond.Once);
+        if (ImGui.begin("Input Text Callback Demo", showInputTextCallback)) {
+            ImGui.alignTextToFramePadding();
+            ImGui.text("Try to input \"Hello World!\":");
+            ImGui.sameLine();
+            ImGui.inputText("##input", STR, ImGuiInputTextFlags.CallbackCharFilter, CALLBACK);
+            ImGui.text(OUTPUT.toString());
+        }
+        ImGui.end();
+    }
+}

example/src/main/java/Extra.java

@@ -13,6 +13,7 @@ public class Extra {
     private static final ImBoolean SHOW_IMGUI_FILE_DIALOG_WINDOW = new ImBoolean(false);
     private static final ImBoolean SHOW_IMGUI_MEMORY_EDITOR_WINDOW = new ImBoolean(false);
     private static final ImBoolean SHOW_IMGUI_CANVAS_EDITOR_WINDOW = new ImBoolean(false);
+    private static final ImBoolean SHOW_IMGUI_INPUT_CALLBACK_WINDOW = new ImBoolean(false);
 
     private static final Graph GRAPH = new Graph();
 
@@ -28,6 +29,7 @@ public class Extra {
         ImGui.checkbox("Show ImGuiFileDialog Demo Window", SHOW_IMGUI_FILE_DIALOG_WINDOW);
         ImGui.checkbox("Show ImGui MemoryEditor Demo Window", SHOW_IMGUI_MEMORY_EDITOR_WINDOW);
         ImGui.checkbox("Show ImGui Canvas Demo Window", SHOW_IMGUI_CANVAS_EDITOR_WINDOW);
+        ImGui.checkbox("Show Imgui InputText Callback Window", SHOW_IMGUI_INPUT_CALLBACK_WINDOW);
 
         if (SHOW_DEMO_WINDOW.get()) {
             ImGui.showDemoWindow(SHOW_DEMO_WINDOW);
@@ -68,5 +70,9 @@ public class Extra {
         if (SHOW_IMGUI_CANVAS_EDITOR_WINDOW.get()) {
             ExampleCanvasEditor.show(SHOW_IMGUI_CANVAS_EDITOR_WINDOW);
         }
+
+        if (SHOW_IMGUI_INPUT_CALLBACK_WINDOW.get()) {
+            ExampleInputTextCallback.show(SHOW_IMGUI_INPUT_CALLBACK_WINDOW);
+        }
     }
 }

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

@@ -1,6 +1,7 @@
 package imgui;
 
 import imgui.assertion.ImAssertCallback;
+import imgui.callback.ImGuiInputTextCallback;
 import imgui.flag.ImGuiCond;
 import imgui.flag.ImGuiDragDropFlags;
 import imgui.flag.ImGuiInputTextFlags;
@@ -2988,11 +2989,13 @@ public class ImGui {
 
     /*JNI
         jmethodID jImStringResizeInternalMID;
+        jmethodID jInputTextCallbackMID;
 
         jfieldID inputDataSizeID;
         jfieldID inputDataIsDirtyID;
         jfieldID inputDataIsResizedID;
 
+
         struct InputTextCallbackUserData {
             JNIEnv* env;
             jobject* imString;
@@ -3001,6 +3004,7 @@ public class ImGui {
             char* resizedBuf;
             jobject* textInputData;
             char* allowedChars;
+            jobject* handler;
         };
 
         static int TextEditCallbackStub(ImGuiInputTextCallbackData* data) {
@@ -3033,6 +3037,11 @@ public class ImGui {
                 }
             }
 
+            if (userData->handler != NULL) {
+                JNIEnv* env = userData->env;
+                env->CallObjectMethod(*userData->handler, jInputTextCallbackMID, data);
+            }
+
             return 0;
         }
     */
@@ -3045,41 +3054,68 @@ public class ImGui {
 
         jclass jImString = env->FindClass("imgui/type/ImString");
         jImStringResizeInternalMID = env->GetMethodID(jImString, "resizeInternal", "(I)[B");
+
+        jclass jCallback = env->FindClass("imgui/callback/ImGuiInputTextCallback");
+        jInputTextCallbackMID = env->GetMethodID(jCallback, "accept", "(J)V");
     */
 
     public static boolean inputText(String label, ImString text) {
-        return preInputText(false, label, null, text, 0, 0, ImGuiInputTextFlags.None);
+        return preInputText(false, label, null, text);
     }
 
     public static boolean inputText(String label, ImString text, int imGuiInputTextFlags) {
         return preInputText(false, label, null, text, 0, 0, imGuiInputTextFlags);
     }
 
+    public static boolean inputText(String label, ImString text, int imGuiInputTextFlags, ImGuiInputTextCallback callback) {
+        return preInputText(false, label, null, text, 0, 0, imGuiInputTextFlags, callback);
+    }
+
     public static boolean inputTextMultiline(String label, ImString text) {
-        return preInputText(true, label, null, text, 0, 0, ImGuiInputTextFlags.None);
+        return preInputText(true, label, null, text);
     }
 
     public static boolean inputTextMultiline(String label, ImString text, float width, float height) {
-        return preInputText(true, label, null, text, width, height, ImGuiInputTextFlags.None);
+        return preInputText(true, label, null, text, width, height);
     }
 
     public static boolean inputTextMultiline(String label, ImString text, int imGuiInputTextFlags) {
         return preInputText(true, label, null, text, 0, 0, imGuiInputTextFlags);
     }
 
+    public static boolean inputTextMultiline(String label, ImString text, int imGuiInputTextFlags, ImGuiInputTextCallback callback) {
+        return preInputText(true, label, null, text, 0, 0, imGuiInputTextFlags, callback);
+    }
+
     public static boolean inputTextMultiline(String label, ImString text, float width, float height, int imGuiInputTextFlags) {
         return preInputText(true, label, null, text, width, height, imGuiInputTextFlags);
     }
 
+    public static boolean inputTextMultiline(String label, ImString text, float width, float height, int imGuiInputTextFlags, ImGuiInputTextCallback callback) {
+        return preInputText(true, label, null, text, width, height, imGuiInputTextFlags, callback);
+    }
+
     public static boolean inputTextWithHint(String label, String hint, ImString text) {
-        return preInputText(false, label, hint, text, 0, 0, ImGuiInputTextFlags.None);
+        return preInputText(false, label, hint, text);
     }
 
     public static boolean inputTextWithHint(String label, String hint, ImString text, int imGuiInputTextFlags) {
         return preInputText(false, label, hint, text, 0, 0, imGuiInputTextFlags);
     }
 
+    private static boolean preInputText(boolean multiline, String label, String hint, ImString text) {
+        return preInputText(multiline, label, hint, text, 0, 0);
+    }
+
+    private static boolean preInputText(boolean multiline, String label, String hint, ImString text, float width, float height) {
+        return preInputText(multiline, label, hint, text, width, height, ImGuiInputTextFlags.None);
+    }
+
     private static boolean preInputText(boolean multiline, String label, String hint, ImString text, float width, float height, int flags) {
+        return preInputText(multiline, label, hint, text, width, height, flags, null);
+    }
+
+    private static boolean preInputText(boolean multiline, String label, String hint, ImString text, float width, float height, int flags, ImGuiInputTextCallback callback) {
         final ImString.InputData inputData = text.inputData;
 
         if (inputData.isResizable) {
@@ -3095,10 +3131,10 @@ public class ImGui {
             hintLabel = "";
         }
 
-        return nInputText(multiline, hint != null, label, hintLabel, text, text.getData(), text.getData().length, width, height, flags, inputData, inputData.allowedChars);
+        return nInputText(multiline, hint != null, label, hintLabel, text, text.getData(), text.getData().length, width, height, flags, inputData, inputData.allowedChars, callback);
     }
 
-    private static native boolean nInputText(boolean multiline, boolean hint, String label, String hintLabel, ImString imString, byte[] buf, int maxSize, float width, float height, int flags, ImString.InputData textInputData, String allowedChars); /*
+    private static native boolean nInputText(boolean multiline, boolean hint, String label, String hintLabel, ImString imString, byte[] buf, int maxSize, float width, float height, int flags, ImString.InputData textInputData, String allowedChars, ImGuiInputTextCallback callback); /*
         InputTextCallbackUserData userData;
         userData.imString = &imString;
         userData.maxSize = maxSize;
@@ -3107,6 +3143,7 @@ public class ImGui {
         userData.textInputData = &textInputData;
         userData.env = env;
         userData.allowedChars = allowedChars;
+        userData.handler = &callback;
 
         bool valueChanged;
 

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

@@ -0,0 +1,182 @@
+package imgui;
+
+import imgui.binding.ImGuiStruct;
+
+/**
+ * Shared state of InputText(), passed as an argument to your callback when a ImGuiInputTextFlags_Callback* flag is used.<p>
+ * The callback function should return 0 by default.<p>
+ * Callbacks (follow a flag name and see comments in ImGuiInputTextFlags_ declarations for more details)<p>
+ * - ImGuiInputTextFlags_CallbackEdit:        Callback on buffer edit (note that InputText() already returns true on edit, the callback is useful mainly to manipulate the underlying buffer while focus is active)<p>
+ * - ImGuiInputTextFlags_CallbackAlways:      Callback on each iteration<p>
+ * - ImGuiInputTextFlags_CallbackCompletion:  Callback on pressing TAB<p>
+ * - ImGuiInputTextFlags_CallbackHistory:     Callback on pressing Up/Down arrows<p>
+ * - ImGuiInputTextFlags_CallbackCharFilter:  Callback on character inputs to replace or discard them. Modify 'EventChar' to replace or discard, or return 1 in callback to discard.<p>
+ * - ImGuiInputTextFlags_CallbackResize:      Callback on buffer capacity changes request (beyond 'buf_size' parameter value), allowing the string to grow.<p>
+ */
+public class ImGuiInputTextCallbackData extends ImGuiStruct {
+    public ImGuiInputTextCallbackData(final long ptr) {
+        super(ptr);
+    }
+
+    /*JNI
+        #include "_common.h"
+
+        #define IMGUI_CALLBACK_DATA ((ImGuiInputTextCallbackData*)STRUCT_PTR)
+     */
+
+    /**
+     * One ImGuiInputTextFlags_Callback*
+     *
+     * @return ImGuiInputTextFlags
+     */
+    public native int getEventFlag(); /*
+        return IMGUI_CALLBACK_DATA->EventFlag;
+    */
+
+    /**
+     * What user passed to InputText()
+     *
+     * @return ImGuiInputTextFlags
+     */
+    public native int getFlags(); /*
+        return IMGUI_CALLBACK_DATA->Flags;
+    */
+
+    /**
+     * [CharFilter] Character input;
+     *
+     * @return Character input
+     */
+    public native int getEventChar(); /*
+        return IMGUI_CALLBACK_DATA->EventChar;
+    */
+
+    /**
+     * [CharFilter] Replace character with another one, or set to zero to drop. return 1 is equivalent to setting EventChar=0;
+     *
+     * @param c Replaced characters
+     */
+    public void setEventChar(final char c) {
+        setEventChar((int) c);
+    }
+
+    /**
+     * [CharFilter] Replace character with another one, or set to zero to drop. return 1 is equivalent to setting EventChar=0;
+     *
+     * @param c Replaced characters
+     */
+    public native void setEventChar(int c); /*
+        IMGUI_CALLBACK_DATA->EventChar = c;
+    */
+
+    /**
+     * [Completion,History]
+     *
+     * @return Key pressed (Up/Down/TAB)
+     */
+    public native int getEventKey(); /*
+        return IMGUI_CALLBACK_DATA->EventKey;
+    */
+
+    /**
+     * [Resize] Can replace pointer <p>
+     * [Completion,History,Always] Only write to pointed data, don't replace the actual pointer!
+     *
+     * @return Buf
+     */
+    public native String getBuf(); /*
+        return env->NewStringUTF(IMGUI_CALLBACK_DATA->Buf);
+    */
+
+    /**
+     * Set if you modify Buf/BufTextLen!
+     *
+     * @return Dirty
+     */
+    public native boolean getBufDirty(); /*
+        return IMGUI_CALLBACK_DATA->BufDirty;
+    */
+
+    /**
+     * Set if you modify Buf/BufTextLen!
+     *
+     * @param dirty Dirty
+     */
+    public native void setBufDirty(boolean dirty); /*
+        IMGUI_CALLBACK_DATA->BufDirty = dirty;
+    */
+
+    /**
+     * Current cursor position
+     *
+     * @return Current cursor position
+     */
+    public native int getCursorPos(); /*
+        return IMGUI_CALLBACK_DATA->CursorPos;
+    */
+
+    /**
+     * Set the current cursor position
+     *
+     * @param pos Set the current cursor position
+     */
+    public native void setCursorPos(int pos); /*
+        IMGUI_CALLBACK_DATA->CursorPos = pos;
+    */
+
+    /**
+     * Selection Start
+     *
+     * @return Selection Start
+     */
+    public native int getSelectionStart(); /*
+        return IMGUI_CALLBACK_DATA->SelectionStart;
+    */
+
+    /**
+     * Set Selection Start
+     *
+     * @param pos Selection Start
+     */
+    public native void setSelectionStart(int pos); /*
+        IMGUI_CALLBACK_DATA->SelectionStart = pos;
+    */
+
+    /**
+     * Selection End
+     *
+     * @return Selection End
+     */
+    public native int getSelectionEnd(); /*
+        return IMGUI_CALLBACK_DATA->SelectionEnd;
+    */
+
+    /**
+     * Set Selection End
+     *
+     * @param pos Selection End
+     */
+    public native void setSelectionEnd(int pos); /*
+        IMGUI_CALLBACK_DATA->SelectionEnd = pos;
+    */
+
+    /**
+     * Delete Chars
+     *
+     * @param pos        Start Delete Pos
+     * @param bytesCount Delete Char Count
+     */
+    public native void deleteChars(int pos, int bytesCount); /*
+        IMGUI_CALLBACK_DATA->DeleteChars(pos, bytesCount);
+    */
+
+    /**
+     * Insert Chars
+     *
+     * @param pos insert Psos
+     * @param str insert String
+     */
+    public native void insertChars(int pos, String str); /*
+        IMGUI_CALLBACK_DATA->InsertChars(pos, str);
+    */
+}

imgui-binding/src/main/java/imgui/callback/ImGuiInputTextCallback.java

@@ -0,0 +1,17 @@
+package imgui.callback;
+
+import imgui.ImGuiInputTextCallbackData;
+
+import java.util.function.Consumer;
+
+/**
+ * Callback to use in {@link imgui.ImGui#inputText(String, imgui.type.ImString, int, ImGuiInputTextCallback)}.
+ */
+public abstract class ImGuiInputTextCallback implements Consumer<ImGuiInputTextCallbackData> {
+    /**
+     * This function will be called by the native Callback and wrapped.
+     */
+    public final void accept(final long ptr) {
+        accept(new ImGuiInputTextCallbackData(ptr));
+    }
+}

imgui-binding/src/main/java/imgui/flag/ImGuiInputTextFlags.java

@@ -86,4 +86,8 @@ public final class ImGuiInputTextFlags {
      * You will be provided a new BufSize in the callback and NEED to honor it. (see misc/cpp/imgui_stdlib.h for an example of using this)
      */
     public static final int CallbackResize = 1 << 18;
+    /**
+     * Callback on any edit (note that InputText() already returns true on edit, the callback is useful mainly to manipulate the underlying buffer while focus is active).
+     */
+    public static final int CallbackEdit = 1 << 19;
 }