gtk2/gdk/gdkmemorytexture.h

/*
 * Copyright © 2018 Benjamin Otte
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library. If not, see <http://www.gnu.org/licenses/>.
 *
 * Authors: Benjamin Otte <otte@gnome.org>
 */

#ifndef __GDK_MEMORY_TEXTURE__H__
#define __GDK_MEMORY_TEXTURE__H__

#if !defined (__GDK_H_INSIDE__) && !defined (GTK_COMPILATION)
#error "Only <gdk/gdk.h> can be included directly."
#endif

#include <gdk/gdktexture.h>

G_BEGIN_DECLS

/**
 * GdkMemoryFormat:
 * @GDK_MEMORY_B8G8R8A8_PREMULTIPLIED: 4 bytes; for blue, green, red, alpha.
 *     The color values are premultiplied with the alpha value.
 * @GDK_MEMORY_A8R8G8B8_PREMULTIPLIED: 4 bytes; for alpha, red, green, blue.
 *     The color values are premultiplied with the alpha value.
 * @GDK_MEMORY_R8G8B8A8_PREMULTIPLIED: 4 bytes; for red, green, blue, alpha
 *     The color values are premultiplied with the alpha value.
 * @GDK_MEMORY_B8G8R8A8: 4 bytes; for blue, green, red, alpha.
 * @GDK_MEMORY_A8R8G8B8: 4 bytes; for alpha, red, green, blue.
 * @GDK_MEMORY_R8G8B8A8: 4 bytes; for red, green, blue, alpha.
 * @GDK_MEMORY_A8B8G8R8: 4 bytes; for alpha, blue, green, red.
 * @GDK_MEMORY_R8G8B8: 3 bytes; for red, green, blue. The data is opaque.
 * @GDK_MEMORY_B8G8R8: 3 bytes; for blue, green, red. The data is opaque.
 * @GDK_MEMORY_N_FORMATS: The number of formats. This value will change as
 *     more formats get added, so do not rely on its concrete integer.
 *
 * #GdkMemoryFormat describes a format that bytes can have in memory.
 *
 * It describes formats by listing the contents of the memory passed to it.
 * So GDK_MEMORY_A8R8G8B8 will be 1 byte (8 bits) of alpha, followed by a
 * byte each of red, green and blue. It is not endian-dependent, so
 * CAIRO_FORMAT_ARGB32 is represented by different #GdkMemoryFormats on
 * architectures with different endiannesses.
 * 
 * Its naming is modelled after VkFormat (see
 * https://www.khronos.org/registry/vulkan/specs/1.0/html/vkspec.html#VkFormat
 * for details).
 */
typedef enum {
  GDK_MEMORY_B8G8R8A8_PREMULTIPLIED,
  GDK_MEMORY_A8R8G8B8_PREMULTIPLIED,
  GDK_MEMORY_R8G8B8A8_PREMULTIPLIED,
  GDK_MEMORY_B8G8R8A8,
  GDK_MEMORY_A8R8G8B8,
  GDK_MEMORY_R8G8B8A8,
  GDK_MEMORY_A8B8G8R8,
  GDK_MEMORY_R8G8B8,
  GDK_MEMORY_B8G8R8,

  GDK_MEMORY_N_FORMATS
} GdkMemoryFormat;

/**
 * GDK_MEMORY_DEFAULT:
 *
 * This is the default memory format used by GTK and is the format
 * provided by gdk_texture_download(). It is equal to
 * %CAIRO_FORMAT_ARGB32.
 *
 * Be aware that unlike the #GdkMemoryFormat values, this format is
 * different for different endianness.
 */
#if G_BYTE_ORDER == G_LITTLE_ENDIAN
#define GDK_MEMORY_DEFAULT GDK_MEMORY_B8G8R8A8_PREMULTIPLIED
#elif G_BYTE_ORDER == G_BIG_ENDIAN
#define GDK_MEMORY_DEFAULT GDK_MEMORY_A8R8G8B8_PREMULTIPLIED
#else
#error "Unknown byte order for GDK_MEMORY_DEFAULT"
#endif

#define GDK_TYPE_MEMORY_TEXTURE (gdk_memory_texture_get_type ())

#define GDK_MEMORY_TEXTURE(obj)             (G_TYPE_CHECK_INSTANCE_CAST ((obj), GDK_TYPE_MEMORY_TEXTURE, GdkMemoryTexture))
#define GDK_IS_MEMORY_TEXTURE(obj)          (G_TYPE_CHECK_INSTANCE_TYPE ((obj), GDK_TYPE_MEMORY_TEXTURE))

/**
 * GdkMemoryTexture:
 *
 * A #GdkTexture representing image data in memory.
 */
typedef struct _GdkMemoryTexture        GdkMemoryTexture;
typedef struct _GdkMemoryTextureClass   GdkMemoryTextureClass;

G_DEFINE_AUTOPTR_CLEANUP_FUNC(GdkMemoryTexture, g_object_unref)


GDK_AVAILABLE_IN_ALL
GType                   gdk_memory_texture_get_type         (void) G_GNUC_CONST;

GDK_AVAILABLE_IN_ALL
GdkTexture *            gdk_memory_texture_new              (int                width,
                                                             int                height,
                                                             GdkMemoryFormat    format,
                                                             GBytes            *bytes,
                                                             gsize              stride);


G_END_DECLS

#endif /* __GDK_MEMORY_TEXTURE_H__ */