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linux/flutter/ephemeral/flutter_linux/fl_pixel_buffer_texture.h

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+// Copyright 2013 The Flutter Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef FLUTTER_SHELL_PLATFORM_LINUX_PUBLIC_FLUTTER_LINUX_FL_PIXEL_BUFFER_TEXTURE_H_
+#define FLUTTER_SHELL_PLATFORM_LINUX_PUBLIC_FLUTTER_LINUX_FL_PIXEL_BUFFER_TEXTURE_H_
+
+#if !defined(__FLUTTER_LINUX_INSIDE__) && !defined(FLUTTER_LINUX_COMPILATION)
+#error "Only <flutter_linux/flutter_linux.h> can be included directly."
+#endif
+
+#include <gmodule.h>
+
+#include "fl_texture.h"
+
+G_BEGIN_DECLS
+
+G_MODULE_EXPORT
+G_DECLARE_DERIVABLE_TYPE(FlPixelBufferTexture,
+                         fl_pixel_buffer_texture,
+                         FL,
+                         PIXEL_BUFFER_TEXTURE,
+                         GObject)
+
+/**
+ * FlPixelBufferTexture:
+ *
+ * #FlPixelBufferTexture represents an OpenGL texture generated from a pixel
+ * buffer.
+ *
+ * The following example shows how to implement an #FlPixelBufferTexture.
+ * ![<!-- language="C" -->
+ *   struct _MyTexture {
+ *     FlPixelBufferTexture parent_instance;
+ *
+ *     uint8_t *buffer;  // your pixel buffer.
+ *   }
+ *
+ *   G_DEFINE_TYPE(MyTexture,
+ *                 my_texture,
+ *                 fl_pixel_buffer_texture_get_type ())
+ *
+ *   static gboolean
+ *   my_texture_copy_pixels (FlPixelBufferTexture* texture,
+ *                           const uint8_t** out_buffer,
+ *                           uint32_t* width,
+ *                           uint32_t* height,
+ *                           GError** error) {
+ *     // This method is called on Render Thread. Be careful with your
+ *     // cross-thread operation.
+ *
+ *     // @width and @height are initially stored the canvas size in Flutter.
+ *
+ *     // You must prepare your pixel buffer in RGBA format.
+ *     // So you may do some format conversion first if your original pixel
+ *     // buffer is not in RGBA format.
+ *     manage_your_pixel_buffer_here ();
+ *
+ *     if (your_operations_are_successfully_finished) {
+ *       // Directly return pointer to your pixel buffer here.
+ *       // Flutter takes content of your pixel buffer after this function
+ *       // is finished. So you must make the buffer live long enough until
+ *       // next tick of Render Thread.
+ *       // If it is hard to manage lifetime of your pixel buffer, you should
+ *       // take look into #FlTextureGL.
+ *
+ *       *out_buffer = buffer;
+ *       *width = real_width_of_buffer;
+ *       *height = real_height_of_buffer;
+ *       return TRUE;
+ *     } else {
+ *       // set @error to report failure.
+ *       return FALSE;
+ *     }
+ *   }
+ *
+ *   static void my_texture_class_init(MyTextureClass* klass) {
+ *     FL_PIXEL_BUFFER_TEXTURE_CLASS(klass)->copy_pixels =
+ * my_texture_copy_pixels;
+ *   }
+ *
+ *   static void my_texture_init(MyTexture* self) {}
+ * ]|
+ */
+
+struct _FlPixelBufferTextureClass {
+  GObjectClass parent_class;
+
+  /**
+   * FlPixelBufferTexture::copy_pixels:
+   * @texture: an #FlPixelBufferTexture.
+   * @buffer: (out): pixel data.
+   * @width: (inout): width of the texture in pixels.
+   * @height: (inout): height of the texture in pixels.
+   * @error: (allow-none): #GError location to store the error occurring, or
+   * %NULL to ignore.
+   *
+   * Retrieve pixel buffer in RGBA format.
+   *
+   * As this method is usually invoked from the render thread, you must
+   * take care of proper synchronization. It also needs to be ensured that
+   * the returned buffer is not released prior to unregistering this texture.
+   *
+   * Returns: %TRUE on success.
+   */
+  gboolean (*copy_pixels)(FlPixelBufferTexture* texture,
+                          const uint8_t** buffer,
+                          uint32_t* width,
+                          uint32_t* height,
+                          GError** error);
+};
+
+G_END_DECLS
+
+#endif  // FLUTTER_SHELL_PLATFORM_LINUX_PUBLIC_FLUTTER_LINUX_FL_PIXEL_BUFFER_TEXTURE_H_