Images

Images — A client-side area for bit-mapped graphics

Functions

GdkImage * gdk_image_new ()
GdkImage * gdk_image_new_bitmap ()
GdkImage * gdk_image_get ()
GdkImage * gdk_image_ref ()
void gdk_image_unref ()
GdkColormap * gdk_image_get_colormap ()
void gdk_image_set_colormap ()
guint16 gdk_image_get_bits_per_pixel ()
guint16 gdk_image_get_bytes_per_pixel ()
guint16 gdk_image_get_bytes_per_line ()
GdkByteOrder gdk_image_get_byte_order ()
guint16 gdk_image_get_depth ()
gint gdk_image_get_height ()
GdkImageType gdk_image_get_image_type ()
GdkVisual * gdk_image_get_visual ()
gint gdk_image_get_width ()
gpointer gdk_image_get_pixels ()
void gdk_image_put_pixel ()
guint32 gdk_image_get_pixel ()

Types and Values

  GdkImage
enum GdkImageType
#define gdk_image_destroy

Includes

#include <gdk/gdk.h>

Description

The GdkImage type represents an area for drawing graphics. It has now been superceded to a large extent by the much more flexible GdkRGB functions.

To create an empty GdkImage use gdk_image_new(). To create a GdkImage from bitmap data use gdk_image_new_bitmap(). To create an image from part of a GdkWindow use gdk_drawable_get_image().

The image can be manipulated with gdk_image_get_pixel() and gdk_image_put_pixel(), or alternatively by changing the actual pixel data. Though manipulating the pixel data requires complicated code to cope with the different formats that may be used.

To draw a GdkImage in a GdkWindow or GdkPixmap use gdk_draw_image().

To destroy a GdkImage use gdk_image_destroy().

Functions

gdk_image_new ()

GdkImage *
gdk_image_new (GdkImageType type,
               GdkVisual *visual,
               gint width,
               gint height);

gdk_image_new is deprecated and should not be used in newly-written code.

Creates a new GdkImage.

Parameters

type

the type of the GdkImage, one of GDK_IMAGE_NORMAL, GDK_IMAGE_SHARED and GDK_IMAGE_FASTEST. GDK_IMAGE_FASTEST is probably the best choice, since it will try creating a GDK_IMAGE_SHARED image first and if that fails it will then use GDK_IMAGE_NORMAL.

  

visual

the GdkVisual to use for the image.

  

width

the width of the image in pixels.

  

height

the height of the image in pixels.

  

Returns

a new GdkImage, or NULL if the image could not be created.

gdk_image_new_bitmap ()

GdkImage *
gdk_image_new_bitmap (GdkVisual *visual,
                      gpointer data,
                      gint width,
                      gint height);

gdk_image_new_bitmap is deprecated and should not be used in newly-written code.

Creates a new GdkImage with a depth of 1 from the given data.

THIS FUNCTION IS INCREDIBLY BROKEN. The passed-in data must be allocated by malloc() (NOT g_malloc()) and will be freed when the image is freed.

Parameters

visual

the GdkVisual to use for the image.

  

data

the pixel data.

 

width

the width of the image in pixels.

 

height

the height of the image in pixels.

 

Returns

a new GdkImage.

gdk_image_get ()

GdkImage *
gdk_image_get (GdkDrawable *drawable,
               gint x,
               gint y,
               gint width,
               gint height);

gdk_image_get is deprecated and should not be used in newly-written code.

This is a deprecated wrapper for gdk_drawable_get_image(); gdk_drawable_get_image() should be used instead. Or even better: in most cases gdk_pixbuf_get_from_drawable() is the most convenient choice.

Parameters

drawable

a GdkDrawable

  

x

x coordinate in window

 

y

y coordinate in window

 

width

width of area in window

 

height

height of area in window

 

Returns

a new GdkImage or NULL

gdk_image_ref ()

GdkImage *
gdk_image_ref (GdkImage *image);

gdk_image_ref has been deprecated since version 2.0 and should not be used in newly-written code.

Use g_object_ref() instead.

Deprecated function; use g_object_ref() instead.

Parameters

image

a GdkImage

  

Returns

the image

gdk_image_unref ()

void
gdk_image_unref (GdkImage *image);

gdk_image_unref has been deprecated since version 2.0 and should not be used in newly-written code.

Use g_object_unref() instead.

Deprecated function; use g_object_unref() instead.

Parameters

image

a GdkImage

  

gdk_image_get_colormap ()

GdkColormap *
gdk_image_get_colormap (GdkImage *image);

gdk_image_get_colormap has been deprecated since version 2.22 and should not be used in newly-written code.

GdkImage should not be used anymore.

Retrieves the colormap for a given image, if it exists. An image will have a colormap if the drawable from which it was created has a colormap, or if a colormap was set explicitely with gdk_image_set_colormap().

Parameters

image

a GdkImage

  

Returns

colormap for the image

gdk_image_set_colormap ()

void
gdk_image_set_colormap (GdkImage *image,
                        GdkColormap *colormap);

gdk_image_set_colormap has been deprecated since version 2.22 and should not be used in newly-written code.

GdkImage should not be used anymore.

Sets the colormap for the image to the given colormap. Normally there's no need to use this function, images are created with the correct colormap if you get the image from a drawable. If you create the image from scratch, use the colormap of the drawable you intend to render the image to.

Parameters

image

a GdkImage

  

colormap

a GdkColormap

  

gdk_image_get_bits_per_pixel ()

guint16
gdk_image_get_bits_per_pixel (GdkImage *image);

gdk_image_get_bits_per_pixel has been deprecated since version 2.22 and should not be used in newly-written code.

GdkImage should not be used anymore.

Determines the number of bits per pixel of the image.

Parameters

image

a GdkImage

  

Returns

the bits per pixel

Since 2.22

gdk_image_get_bytes_per_pixel ()

guint16
gdk_image_get_bytes_per_pixel (GdkImage *image);

gdk_image_get_bytes_per_pixel has been deprecated since version 2.22 and should not be used in newly-written code.

GdkImage should not be used anymore.

Determines the number of bytes per pixel of the image.

Parameters

image

a GdkImage

  

Returns

the bytes per pixel

Since 2.22

gdk_image_get_bytes_per_line ()

guint16
gdk_image_get_bytes_per_line (GdkImage *image);

gdk_image_get_bytes_per_line has been deprecated since version 2.22 and should not be used in newly-written code.

GdkImage should not be used anymore.

Determines the number of bytes per line of the image.

Parameters

image

a GdkImage

  

Returns

the bytes per line

Since 2.22

gdk_image_get_byte_order ()

GdkByteOrder
gdk_image_get_byte_order (GdkImage *image);

gdk_image_get_byte_order has been deprecated since version 2.22 and should not be used in newly-written code.

GdkImage should not be used anymore.

Determines the byte order of the image.

Parameters

image

a GdkImage

  

Returns

a GdkVisual

Since 2.22

gdk_image_get_depth ()

guint16
gdk_image_get_depth (GdkImage *image);

gdk_image_get_depth has been deprecated since version 2.22 and should not be used in newly-written code.

GdkImage should not be used anymore.

Determines the depth of the image.

Parameters

image

a GdkImage

  

Returns

the depth

Since 2.22

gdk_image_get_height ()

gint
gdk_image_get_height (GdkImage *image);

gdk_image_get_height has been deprecated since version 2.22 and should not be used in newly-written code.

GdkImage should not be used anymore.

Determines the height of the image.

Parameters

image

a GdkImage

  

Returns

the height

Since 2.22

gdk_image_get_image_type ()

GdkImageType
gdk_image_get_image_type (GdkImage *image);

gdk_image_get_image_type has been deprecated since version 2.22 and should not be used in newly-written code.

GdkImage should not be used anymore.

Determines the type of a given image.

Parameters

image

a GdkImage

  

Returns

the GdkImageType of the image

Since 2.22

gdk_image_get_visual ()

GdkVisual *
gdk_image_get_visual (GdkImage *image);

gdk_image_get_visual has been deprecated since version 2.22 and should not be used in newly-written code.

GdkImage should not be used anymore.

Determines the visual that was used to create the image.

Parameters

image

a GdkImage

  

Returns

a GdkVisual

Since 2.22

gdk_image_get_width ()

gint
gdk_image_get_width (GdkImage *image);

gdk_image_get_width has been deprecated since version 2.22 and should not be used in newly-written code.

GdkImage should not be used anymore.

Determines the width of the image.

Parameters

image

a GdkImage

  

Returns

the width

Since 2.22

gdk_image_get_pixels ()

gpointer
gdk_image_get_pixels (GdkImage *image);

gdk_image_get_pixels has been deprecated since version 2.22 and should not be used in newly-written code.

GdkImage should not be used anymore.

Returns a pointer to the pixel data of the image.

Parameters

image

a GdkImage

  

Returns

the pixel data of the image

Since 2.22

gdk_image_put_pixel ()

void
gdk_image_put_pixel (GdkImage *image,
                     gint x,
                     gint y,
                     guint32 pixel);

gdk_image_put_pixel is deprecated and should not be used in newly-written code.

Sets a pixel in a GdkImage to a given pixel value.

Parameters

image

a GdkImage.

  

x

the x coordinate of the pixel to set.

  

y

the y coordinate of the pixel to set.

  

pixel

the pixel value to set.

  

gdk_image_get_pixel ()

guint32
gdk_image_get_pixel (GdkImage *image,
                     gint x,
                     gint y);

gdk_image_get_pixel is deprecated and should not be used in newly-written code.

Gets a pixel value at a specified position in a GdkImage.

Parameters

image

a GdkImage.

  

x

the x coordinate of the pixel to get.

  

y

the y coordinate of the pixel to get.

  

Returns

the pixel value at the given position.

Types and Values

GdkImage

typedef struct {
  GObject parent_instance;

  
  GdkImageType GSEAL (type); /* read only. */
  GdkVisual    *GSEAL (visual);	    /* read only. visual used to create the image */
  GdkByteOrder GSEAL (byte_order); /* read only. */
  gint		GSEAL (width);  /* read only. */
  gint		GSEAL (height); /* read only. */
  guint16 GSEAL (depth);  /* read only. */
  guint16 GSEAL (bpp);    /* read only. bytes per pixel */
  guint16 GSEAL (bpl);    /* read only. bytes per line */
  guint16       GSEAL (bits_per_pixel); /* read only. bits per pixel */
  gpointer GSEAL (mem);

  GdkColormap  *GSEAL (colormap); /* read only. */
} GdkImage;

The GdkImage struct contains information on the image and the pixel data.

Members

GObject parent_instance;

the parent instance

  

enum GdkImageType

Specifies the type of a GdkImage.

Members

GDK_IMAGE_NORMAL

The original X image type, which is quite slow since the image has to be transferred from the client to the server to display it.

  

GDK_IMAGE_SHARED

A faster image type, which uses shared memory to transfer the image data between client and server. However this will only be available if client and server are on the same machine and the shared memory extension is supported by the server.

  

GDK_IMAGE_FASTEST

Specifies that GDK_IMAGE_SHARED should be tried first, and if that fails then GDK_IMAGE_NORMAL will be used.

  

gdk_image_destroy

#define gdk_image_destroy              g_object_unref

gdk_image_destroy is deprecated and should not be used in newly-written code.

Destroys a GdkImage, freeing any resources allocated for it.

See Also

Bitmaps and Pixmaps

Graphics which are stored on the X Windows server. Since these are stored on the server they can be drawn very quickly, and all of the Drawing Primitives can be used to draw on them. Their main disadvantage is that manipulating individual pixels can be very slow.

GdkRGB

Built on top of GdkImage, this provides much more functionality, including the dithering of colors to produce better output on low-color displays.

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