content/public/android/java/src/org/chromium/content_public/browser/StylusWritingHandler.java

// Copyright 2022 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

package org.chromium.content_public.browser;

import android.content.Context;
import android.graphics.Point;
import android.graphics.Rect;
import android.view.MotionEvent;
import android.view.View;
import android.view.inputmethod.EditorInfo;

/**
 * Interface that provides Stylus handwriting to text input functionality in HTML edit fields. This
 * is implemented by a corresponding Stylus writing class that would handle the events and messages
 * in this interface outside of //content (i.e. //components/stylus_handwriting) and these are
 * called from the current WebContents related classes in //content.
 */
public interface StylusWritingHandler {
    /**
     * @return true if soft keyboard can be shown during stylus writing.
     */
    boolean canShowSoftKeyboard();

    /**
     * Requests to start stylus writing for input field in web page.
     *
     * @return true if writing can be started or if started successfully, false if writing cannot
     * be started.
     */
    boolean requestStartStylusWriting(StylusWritingImeCallback imeCallback);

    /**
     * Update current input state parameters to stylus writing system.
     *  @param text the input text
     * @param selectionStart the input selection start offset
     * @param selectionEnd the input selection end offset
     */
    default void updateInputState(String text, int selectionStart, int selectionEnd) {}

    /**
     * Notify focused node has changed in web page.
     *
     * @param editableBounds the Editable element bounds Rect in pix
     * @param isEditable     is true if focused node is of editable type.
     * @param currentView the {@link View} in which the focused node changed.
     */
    default void onFocusedNodeChanged(Rect editableBounds, boolean isEditable, View currentView) {}

    /**
     * Handle touch events if needed for stylus writing.
     *
     * @param event {@link MotionEvent} to be handled.
     * @param currentView the {@link View} which is receiving the events.
     * @return true if event is consumed by stylus writing system.
     */
    default boolean handleTouchEvent(MotionEvent event, View currentView) {
        return false;
    }

    /**
     * Handle hover events for Direct writing.
     *
     * @param event {@link MotionEvent} to be handled.
     * @param currentView the {@link View} which is receiving the events.
     */
    default void handleHoverEvent(MotionEvent event, View currentView) {}

    /**
     * Update the editor attributes corresponding to current input.
     *
     * @param editorInfo {@link EditorInfo} object
     */
    default void updateEditorInfo(EditorInfo editorInfo) {}

    /**
     * Notify the view is detached from window.
     *
     * @param context the current context
     */
    default void onDetachedFromWindow(Context context) {}

    /**
     * Notify current view focus has changed
     *
     * @param hasFocus whether view gained or lost focus
     */
    default void onFocusChanged(boolean hasFocus) {}

    /**
     * This message is sent when the stylus writable element has been focused.
     * @param focusedEditBounds the input field bounds in view
     * @param cursorPosition the input cursor Position point in pix
     */
    default void onEditElementFocusedForStylusWriting(
            Rect focusedEditBounds, Point cursorPosition) {}
}