content: /*
   * Copyright (C) 2006 The Android Open Source Project
   *
   * Licensed under the Apache License, Version 2.0 (the "License");
   * you may not use this file except in compliance with the License.
   * You may obtain a copy of the License at
   *
   *      http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  
  package android.view;
  
  import android.graphics.Canvas;
  import android.graphics.Rect;
  
  /**
   * Abstract interface to someone holding a display surface.  Allows you to
   * control the surface size and format, edit the pixels in the surface, and
   * monitor changes to the surface.  This interface is typically available
   * through the {@link SurfaceView} class.
   *
   * <p>When using this interface from a thread other than the one running
   * its {@link SurfaceView}, you will want to carefully read the
   * methods
   * {@link #lockCanvas} and {@link Callback#surfaceCreated Callback.surfaceCreated()}.
   */
  public interface SurfaceHolder {
  
      /** @deprecated this is ignored, this value is set automatically when needed. */
      @Deprecated
      public static final int SURFACE_TYPE_NORMAL = 0;
      /** @deprecated this is ignored, this value is set automatically when needed. */
      @Deprecated
      public static final int SURFACE_TYPE_HARDWARE = 1;
      /** @deprecated this is ignored, this value is set automatically when needed. */
      @Deprecated
      public static final int SURFACE_TYPE_GPU = 2;
      /** @deprecated this is ignored, this value is set automatically when needed. */
      @Deprecated
      public static final int SURFACE_TYPE_PUSH_BUFFERS = 3;
  
      /**
       * Exception that is thrown from {@link #lockCanvas} when called on a Surface
       * whose type is SURFACE_TYPE_PUSH_BUFFERS.
       */
      public static class BadSurfaceTypeException extends RuntimeException {
          public BadSurfaceTypeException() {
          }
  
          public BadSurfaceTypeException(String name) {
              super(name);
          }
      }
  
      /**
       * A client may implement this interface to receive information about
       * changes to the surface.  When used with a {@link SurfaceView}, the
       * Surface being held is only available between calls to
       * {@link #surfaceCreated(SurfaceHolder)} and
       * {@link #surfaceDestroyed(SurfaceHolder)}.  The Callback is set with
       * {@link SurfaceHolder#addCallback SurfaceHolder.addCallback} method.
       */
      public interface Callback {
          /**
           * This is called immediately after the surface is first created.
           * Implementations of this should start up whatever rendering code
           * they desire.  Note that only one thread can ever draw into
           * a {@link Surface}, so you should not draw into the Surface here
           * if your normal rendering will be in another thread.
           *
           * @param holder The SurfaceHolder whose surface is being created.
           */
          public void surfaceCreated(SurfaceHolder holder);
  
          /**
           * This is called immediately after any structural changes (format or
           * size) have been made to the surface.  You should at this point update
           * the imagery in the surface.  This method is always called at least
           * once, after {@link #surfaceCreated}.
           *
           * @param holder The SurfaceHolder whose surface has changed.
           * @param format The new PixelFormat of the surface.
           * @param width The new width of the surface.
           * @param height The new height of the surface.
           */
          public void surfaceChanged(SurfaceHolder holder, int format, int width,
                  int height);
  
          /**
           * This is called immediately before a surface is being destroyed. After
           * returning from this call, you should no longer try to access this
           * surface.  If you have a rendering thread that directly accesses
           * the surface, you must ensure that thread is no longer touching the
           * Surface before returning from this function.
           *
           * @param holder The SurfaceHolder whose surface is being destroyed.
           */
          public void surfaceDestroyed(SurfaceHolder holder);
      }
  
      /**
       * Additional callbacks that can be received for {@link Callback}.
       */
      public interface Callback2 extends Callback {
          /**
           * Called when the application needs to redraw the content of its
           * surface, after it is resized or for some other reason.  By not
           * returning from here until the redraw is complete, you can ensure that
           * the user will not see your surface in a bad state (at its new
           * size before it has been correctly drawn that way).  This will
           * typically be preceeded by a call to {@link #surfaceChanged}.
           *
           * As of O, {@link #surfaceRedrawNeededAsync} may be implemented
           * to provide a non-blocking implementation. If {@link #surfaceRedrawNeededAsync}
           * is not implemented, then this will be called instead.
           *
           * @param holder The SurfaceHolder whose surface has changed.
           */
          void surfaceRedrawNeeded(SurfaceHolder holder);
  
          /**
           * An alternative to surfaceRedrawNeeded where it is not required to block
           * until the redraw is complete. You should initiate the redraw, and return,
           * later invoking drawingFinished when your redraw is complete.
           *
           * This can be useful to avoid blocking your main application thread on rendering.
           *
           * As of O, if this is implemented {@link #surfaceRedrawNeeded} will not be called.
           * However it is still recommended to implement {@link #surfaceRedrawNeeded} for
           * compatibility with older versions of the platform.
           *
           * @param holder The SurfaceHolder which needs redrawing.
           * @param drawingFinished A runnable to signal completion. This may be invoked
           * from any thread.
           *
           */
          default void surfaceRedrawNeededAsync(SurfaceHolder holder, Runnable drawingFinished) {
              surfaceRedrawNeeded(holder);
              drawingFinished.run();
          }
      }
  
      /**
       * Add a Callback interface for this holder.  There can several Callback
       * interfaces associated with a holder.
       *
       * @param callback The new Callback interface.
       */
      public void addCallback(Callback callback);
  
      /**
       * Removes a previously added Callback interface from this holder.
       *
       * @param callback The Callback interface to remove.
       */
      public void removeCallback(Callback callback);
  
      /**
       * Use this method to find out if the surface is in the process of being
       * created from Callback methods. This is intended to be used with
       * {@link Callback#surfaceChanged}.
       *
       * @return true if the surface is in the process of being created.
       */
      public boolean isCreating();
  
      /**
       * Sets the surface's type.
       *
       * @deprecated this is ignored, this value is set automatically when needed.
       */
      @Deprecated
      public void setType(int type);
  
      /**
       * Make the surface a fixed size.  It will never change from this size.
       * When working with a {@link SurfaceView}, this must be called from the
       * same thread running the SurfaceView's window.
       *
       * @param width The surface's width.
       * @param height The surface's height.
       */
      public void setFixedSize(int width, int height);
  
      /**
       * Allow the surface to resized based on layout of its container (this is
       * the default).  When this is enabled, you should monitor
       * {@link Callback#surfaceChanged} for changes to the size of the surface.
       * When working with a {@link SurfaceView}, this must be called from the
       * same thread running the SurfaceView's window.
       */
      public void setSizeFromLayout();
  
      /**
       * Set the desired PixelFormat of the surface.  The default is OPAQUE.
       * When working with a {@link SurfaceView}, this must be called from the
       * same thread running the SurfaceView's window.
       *
       * @param format A constant from PixelFormat.
       *
       * @see android.graphics.PixelFormat
       */
      public void setFormat(int format);
  
      /**
       * Enable or disable option to keep the screen turned on while this
       * surface is displayed.  The default is false, allowing it to turn off.
       * This is safe to call from any thread.
       *
       * @param screenOn Set to true to force the screen to stay on, false
       * to allow it to turn off.
       */
      public void setKeepScreenOn(boolean screenOn);
  
      /**
       * Start editing the pixels in the surface.  The returned Canvas can be used
       * to draw into the surface's bitmap.  A null is returned if the surface has
       * not been created or otherwise cannot be edited.  You will usually need
       * to implement {@link Callback#surfaceCreated Callback.surfaceCreated}
       * to find out when the Surface is available for use.
       *
       * <p>The content of the Surface is never preserved between unlockCanvas() and
       * lockCanvas(), for this reason, every pixel within the Surface area
       * must be written. The only exception to this rule is when a dirty
       * rectangle is specified, in which case, non-dirty pixels will be
       * preserved.
       *
       * <p>If you call this repeatedly when the Surface is not ready (before
       * {@link Callback#surfaceCreated Callback.surfaceCreated} or after
       * {@link Callback#surfaceDestroyed Callback.surfaceDestroyed}), your calls
       * will be throttled to a slow rate in order to avoid consuming CPU.
       *
       * <p>If null is not returned, this function internally holds a lock until
       * the corresponding {@link #unlockCanvasAndPost} call, preventing
       * {@link SurfaceView} from creating, destroying, or modifying the surface
       * while it is being drawn.  This can be more convenient than accessing
       * the Surface directly, as you do not need to do special synchronization
       * with a drawing thread in {@link Callback#surfaceDestroyed
       * Callback.surfaceDestroyed}.
       *
       * @return Canvas Use to draw into the surface.
       */
      public Canvas lockCanvas();
  
  
      /**
       * Just like {@link #lockCanvas()} but allows specification of a dirty rectangle.
       * Every
       * pixel within that rectangle must be written; however pixels outside
       * the dirty rectangle will be preserved by the next call to lockCanvas().
       *
       * @see android.view.SurfaceHolder#lockCanvas
       *
       * @param dirty Area of the Surface that will be modified.
       * @return Canvas Use to draw into the surface.
       */
      public Canvas lockCanvas(Rect dirty);
  
      /**
       * <p>Just like {@link #lockCanvas()} but the returned canvas is hardware-accelerated.
       *
       * <p>See the <a href="{@docRoot}guide/topics/graphics/hardware-accel.html#unsupported">
       * unsupported drawing operations</a> for a list of what is and isn't
       * supported in a hardware-accelerated canvas.
       *
       * @return Canvas Use to draw into the surface.
       * @throws IllegalStateException If the canvas cannot be locked.
       */
      default Canvas lockHardwareCanvas() {
          throw new IllegalStateException("This SurfaceHolder doesn't support lockHardwareCanvas");
      }
  
      /**
       * Finish editing pixels in the surface.  After this call, the surface's
       * current pixels will be shown on the screen, but its content is lost,
       * in particular there is no guarantee that the content of the Surface
       * will remain unchanged when lockCanvas() is called again.
       *
       * @see #lockCanvas()
       *
       * @param canvas The Canvas previously returned by lockCanvas().
       */
      public void unlockCanvasAndPost(Canvas canvas);
  
      /**
       * Retrieve the current size of the surface.  Note: do not modify the
       * returned Rect.  This is only safe to call from the thread of
       * {@link SurfaceView}'s window, or while inside of
       * {@link #lockCanvas()}.
       *
       * @return Rect The surface's dimensions.  The left and top are always 0.
       */
      public Rect getSurfaceFrame();
  
      /**
       * Direct access to the surface object.  The Surface may not always be
       * available -- for example when using a {@link SurfaceView} the holder's
       * Surface is not created until the view has been attached to the window
       * manager and performed a layout in order to determine the dimensions
       * and screen position of the Surface.    You will thus usually need
       * to implement {@link Callback#surfaceCreated Callback.surfaceCreated}
       * to find out when the Surface is available for use.
       *
       * <p>Note that if you directly access the Surface from another thread,
       * it is critical that you correctly implement
       * {@link Callback#surfaceCreated Callback.surfaceCreated} and
       * {@link Callback#surfaceDestroyed Callback.surfaceDestroyed} to ensure
       * that thread only accesses the Surface while it is valid, and that the
       * Surface does not get destroyed while the thread is using it.
       *
       * <p>This method is intended to be used by frameworks which often need
       * direct access to the Surface object (usually to pass it to native code).
       *
       * @return Surface The surface.
       */
      public Surface getSurface();
  }
  