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# Gdk::Drawable Class Reference

Inheritance diagram for Gdk::Drawable:

[legend]
List of all members.

## Detailed Description

Drawing Primitives.

Gdk::Drawable is the base class for all of the objects that accept drawing commands. The available drawables include pixmaps, windows, and bitmaps. Drawable is abstract as there is no such type on the server side.

To use a drawable, create a concrete Drawable of the type you wish to use and a Gdk::GC (graphics context) for that Drawable. With the GC you can draw lines, text, arcs and such.

An alternative is to create a Cairo::Context with get_cairo_context() while you handle the 'exposed' event of the drawable. For more about this, please see "Using cairo with GTK+" in the "Common questions" section of the GTK+ Reference Manual.

## Public Member Functions
void | copy_to_image (const Glib::RefPtr<Image>& image, int src_x, int src_y, int dest_x, int dest_y, int width, int height) const
Cairo::RefPtr<Cairo::Context> | create_cairo_context ()
| Creates a Cairo context for drawing to drawable .
void | draw_arc (const Glib::RefPtr<const GC>& gc, bool filled, int x, int y, int width, int height, int angle1, int angle2)
| Draws an arc or a filled 'pie slice'.
void | draw_drawable (const Glib::RefPtr<const GC>& gc, const Glib::RefPtr<const Drawable>& src, int xsrc, int ysrc, int xdest, int ydest, int width=-1, int height=-1)
| Copies the width x height region of src at coordinates ( xsrc , ysrc ) to coordinates ( xdest , ydest ) in drawable .
void | draw_glyphs (const Glib::RefPtr<const GC>& gc, const Glib::RefPtr<const Pango::Font>& font, int x, int y, const Pango::GlyphString& glyphs)
| This is a low-level function; 99% of text rendering should be done using gdk_draw_layout() instead.
void | draw_gray_image (const Glib::RefPtr<const GC>& gc, int x, int y, int width, int height, RgbDither dith, const guchar* rgb_buf, int rowstride)
void | draw_image (const Glib::RefPtr<const GC>& gc, const Glib::RefPtr<const Image>& image, int xsrc, int ysrc, int xdest, int ydest, int width=-1, int height=-1)
| Draws a Gdk::Image onto a drawable.
void | draw_indexed_image (const Glib::RefPtr<const GC>& gc, int x, int y, int width, int height, RgbDither dith, const guchar* rgb_buf, int rowstride, const RgbCmap& cmap)
void | draw_layout (const Glib::RefPtr<const GC>& gc, int x, int y, const Glib::RefPtr<const Pango::Layout>& layout, const Color& foreground, const Color& background)
| Render a Pango::Layout onto a Gdk::Drawable, overriding the layout's normal colors with foreground and/or background .
void | draw_layout (const Glib::RefPtr<const GC>& gc, int x, int y, const Glib::RefPtr<const Pango::Layout>& layout)
| Render a Pango::Layout onto a GDK drawable.
void | draw_layout_line (const Glib::RefPtr<const GC>& gc, int x, int y, const Glib::RefPtr<const Pango::LayoutLine>& line, const Color& foreground, const Color& background)
| Render a Pango::LayoutLine onto a Gdk::Drawable, overriding the layout's normal colors with foreground and/or background .
void | draw_layout_line (const Glib::RefPtr<const GC>& gc, int x, int y, const Glib::RefPtr<const Pango::LayoutLine>& line)
| Render a Pango::LayoutLine onto an GDK drawable.
void | draw_line (const Glib::RefPtr<const GC>& gc, int x1, int y1, int x2, int y2)
| Draws a line, using the foreground color and other attributes of the Gdk::GC.
void | draw_lines (const Glib::RefPtr<const GC>& gc, const Glib::ArrayHandle<Point>& points)
void | draw_pixbuf (const Glib::RefPtr<const GC>& gc, const Glib::RefPtr<Pixbuf>& pixbuf, int src_x, int src_y, int dest_x, int dest_y, int width, int height, RgbDither dither, int x_dither, int y_dither)
| Renders a rectangular portion of a pixbuf to a drawable.
void | draw_point (const Glib::RefPtr<const GC>& gc, int x, int y)
| Draws a point, using the foreground color and other attributes of the Gdk::GC.
void | draw_points (const Glib::RefPtr<const GC>& gc, const Glib::ArrayHandle<Point>& points)
void | draw_polygon (const Glib::RefPtr<const GC>& gc, bool filled, const Glib::ArrayHandle<Point>& points)
void | draw_rectangle (const Glib::RefPtr<const GC>& gc, bool filled, int x, int y, int width, int height)
| Draws a rectangular outline or filled rectangle, using the foreground color and other attributes of the Gdk::GC.
void | draw_rgb_32_image (const Glib::RefPtr<const GC>& gc, int x, int y, int width, int height, RgbDither dith, const guchar* rgb_buf, int rowstride)
void | draw_rgb_32_image_dithalign (const Glib::RefPtr<const GC>& gc, int x, int y, int width, int height, RgbDither dith, const guchar* buf, int rowstride, int xdith, int ydith)
| Like gdk_draw_rgb_32_image(), but allows you to specify the dither offsets.
void | draw_rgb_image (const Glib::RefPtr<const GC>& gc, int x, int y, int width, int height, RgbDither dith, const guchar* rgb_buf, int rowstride)
void | draw_rgb_image_dithalign (const Glib::RefPtr<const GC>& gc, int x, int y, int width, int height, RgbDither dith, const guchar* rgb_buf, int rowstride, int xdith, int ydith)
void | draw_segments (const Glib::RefPtr<const GC>& gc, GdkSegment* segs, int nsegs)
| Draws a number of unconnected lines.
Region | get_clip_region () const
| Computes the region of a drawable that potentially can be written to by drawing primitives.
Glib::RefPtr<Colormap> | get_colormap ()
| Gets the colormap for drawable , if one is set; returns `0` otherwise.
int | get_depth () const
| Obtains the bit depth of the drawable, that is, the number of bits that make up a pixel in the drawable's visual.
Glib::RefPtr<const Display> | get_display () const
| Gets the Gdk::Display associated with a Gdk::Drawable.
Glib::RefPtr<Display> | get_display ()
| Gets the Gdk::Display associated with a Gdk::Drawable.
Glib::RefPtr<Image> | get_image (int x, int y, int width, int height) const
| A Gdk::Image stores client-side image data (pixels).
Glib::RefPtr<const Screen> | get_screen () const
| Gets the Gdk::Screen associated with a Gdk::Drawable.
Glib::RefPtr<Screen> | get_screen ()
| Gets the Gdk::Screen associated with a Gdk::Drawable.
void | get_size (int& width, int& height)
| Fills * width and * height with the size of drawable .
Region | get_visible_region () const
| Computes the region of a drawable that is potentially visible.
Glib::RefPtr<Visual> | get_visual ()
| Gets the Gdk::Visual describing the pixel format of drawable .
const GdkDrawable* | gobj () const
| Provides access to the underlying C GObject.
GdkDrawable* | gobj ()
| Provides access to the underlying C GObject.
GdkDrawable* | gobj_copy ()
| Provides access to the underlying C instance. The caller is responsible for unrefing it. Use when directly setting fields in structs.
void | set_colormap (const Glib::RefPtr<Colormap>& colormap)
| Sets the colormap associated with drawable .
virtual | ~Drawable ()
## Static Public Member Functions
static Glib::RefPtr<Drawable> | create ()
## Protected Member Functions
| Drawable ()
## Related Functions
(Note that these are not member functions.)
Glib::RefPtr<Gdk::Drawable> | wrap (GdkDrawable* object, bool take_copy=false)
| A Glib::wrap() method for this object.

## Constructor & Destructor Documentation

virtual Gdk::Drawable::~Drawable | ( |  | ) | `[virtual]`

Gdk::Drawable::Drawable | ( |  | ) | `[protected]`

## Member Function Documentation

void Gdk::Drawable::copy_to_image | ( | const Glib::RefPtr<Image>& | image,
|  | int | src_x,
|  | int | src_y,
|  | int | dest_x,
|  | int | dest_y,
|  | int | width,
|  | int | height |
| ) |  |  | const

static Glib::RefPtr<Drawable> Gdk::Drawable::create | ( |  | ) | `[static]`

Cairo::RefPtr<Cairo::Context> Gdk::Drawable::create_cairo_context | ( |  | ) |

Creates a Cairo context for drawing to drawable .

Returns:
  A newly created Cairo context.

Since gtkmm 2.10:

void Gdk::Drawable::draw_arc | ( | const Glib::RefPtr<const GC>& | gc,
|  | bool | filled,
|  | int | x,
|  | int | y,
|  | int | width,
|  | int | height,
|  | int | angle1,
|  | int | angle2 |
| ) |  |  |

Draws an arc or a filled 'pie slice'.

The arc is defined by the bounding rectangle of the entire ellipse, and the start and end angles of the part of the ellipse to be drawn.

Parameters:

  | gc | A Gdk::GC.
  | filled | `true` if the arc should be filled, producing a 'pie slice'.
  | x | The x coordinate of the left edge of the bounding rectangle.
  | y | The y coordinate of the top edge of the bounding rectangle.
  | width | The width of the bounding rectangle.
  | height | The height of the bounding rectangle.
  | angle1 | The start angle of the arc, relative to the 3 o'clock position, counter-clockwise, in 1/64ths of a degree.
  | angle2 | The end angle of the arc, relative to angle1 , in 1/64ths of a degree.

void Gdk::Drawable::draw_drawable | ( | const Glib::RefPtr<const GC>& | gc,
|  | const Glib::RefPtr<const Drawable>& | src,
|  | int | xsrc,
|  | int | ysrc,
|  | int | xdest,
|  | int | ydest,
|  | int | width = `-1`,
|  | int | height = `-1` |
| ) |  |  |

Copies the width x height region of src at coordinates ( xsrc , ysrc ) to coordinates ( xdest , ydest ) in drawable .

width and/or height may be given as -1, in which case the entire src drawable will be copied.

Most fields in gc are not used for this operation, but notably the clip mask or clip region will be honored.

The source and destination drawables must have the same visual and colormap, or errors will result. (On X11, failure to match visual/colormap results in a BadMatch error from the X server.) A common cause of this problem is an attempt to draw a bitmap to a color drawable. The way to draw a bitmap is to set the bitmap as the stipple on the Gdk::GC, set the fill mode to Gdk::STIPPLED, and then draw the rectangle.

Parameters:

  | gc | A Gdk::GC sharing the drawable's visual and colormap.
  | src | The source Gdk::Drawable, which may be the same as drawable .
  | xsrc | X position in src of rectangle to draw.
  | ysrc | Y position in src of rectangle to draw.
  | xdest | X position in drawable where the rectangle should be drawn.
  | ydest | Y position in drawable where the rectangle should be drawn.
  | width | Width of rectangle to draw, or -1 for entire src width.
  | height | Height of rectangle to draw, or -1 for entire src height.

void Gdk::Drawable::draw_glyphs | ( | const Glib::RefPtr<const GC>& | gc,
|  | const Glib::RefPtr<const Pango::Font>& | font,
|  | int | x,
|  | int | y,
|  | const Pango::GlyphString& | glyphs |
| ) |  |  |

This is a low-level function; 99% of text rendering should be done using gdk_draw_layout() instead.

A glyph is a single image in a font. This function draws a sequence of glyphs. To obtain a sequence of glyphs you have to understand a lot about internationalized text handling, which you don't want to understand; thus, use gdk_draw_layout() instead of this function, gdk_draw_layout() handles the details.

Parameters:

  | gc | A Gdk::GC.
  | font | Font to be used.
  | x | X coordinate of baseline origin.
  | y | Y coordinate of baseline origin.
  | glyphs | The glyph string to draw.

void Gdk::Drawable::draw_gray_image | ( | const Glib::RefPtr<const GC>& | gc,
|  | int | x,
|  | int | y,
|  | int | width,
|  | int | height,
|  | RgbDither | dith,
|  | const guchar * | rgb_buf,
|  | int | rowstride |
| ) |  |  |

void Gdk::Drawable::draw_image | ( | const Glib::RefPtr<const GC>& | gc,
|  | const Glib::RefPtr<const Image>& | image,
|  | int | xsrc,
|  | int | ysrc,
|  | int | xdest,
|  | int | ydest,
|  | int | width = `-1`,
|  | int | height = `-1` |
| ) |  |  |

Draws a Gdk::Image onto a drawable.

The depth of the Gdk::Image must match the depth of the Gdk::Drawable.

Parameters:

  | gc | A Gdk::GC.
  | image | The Gdk::Image to draw.
  | xsrc | The left edge of the source rectangle within image .
  | ysrc | The top of the source rectangle within image .
  | xdest | The x coordinate of the destination within drawable .
  | ydest | The y coordinate of the destination within drawable .
  | width | The width of the area to be copied, or -1 to make the area extend to the right edge of image .
  | height | The height of the area to be copied, or -1 to make the area extend to the bottom edge of image .

void Gdk::Drawable::draw_indexed_image | ( | const Glib::RefPtr<const GC>& | gc,
|  | int | x,
|  | int | y,
|  | int | width,
|  | int | height,
|  | RgbDither | dith,
|  | const guchar * | rgb_buf,
|  | int | rowstride,
|  | const RgbCmap& | cmap |
| ) |  |  |

void Gdk::Drawable::draw_layout | ( | const Glib::RefPtr<const GC>& | gc,
|  | int | x,
|  | int | y,
|  | const Glib::RefPtr<const Pango::Layout>& | layout,
|  | const Color& | foreground,
|  | const Color& | background |
| ) |  |  |

Render a Pango::Layout onto a Gdk::Drawable, overriding the layout's normal colors with foreground and/or background .

foreground and background need not be allocated.

If the layout's Pango::Context has a transformation matrix set, then x and y specify the position of the top left corner of the bounding box (in device space) of the transformed layout.

If you're using GTK+, the ususal way to obtain a Pango::Layout is gtk_widget_create_pango_layout().

Parameters:

  | gc | Base graphics context to use.
  | x | The X position of the left of the layout (in pixels).
  | y | The Y position of the top of the layout (in pixels).
  | layout | A Pango::Layout.
  | foreground | Foreground override color, or `0` for none.
  | background | Background override color, or `0` for none.

void Gdk::Drawable::draw_layout | ( | const Glib::RefPtr<const GC>& | gc,
|  | int | x,
|  | int | y,
|  | const Glib::RefPtr<const Pango::Layout>& | layout |
| ) |  |  |

Render a Pango::Layout onto a GDK drawable.

If the layout's Pango::Context has a transformation matrix set, then x and y specify the position of the top left corner of the bounding box (in device space) of the transformed layout.

If you're using GTK+, the usual way to obtain a Pango::Layout is gtk_widget_create_pango_layout().

Parameters:

  | gc | Base graphics context to use.
  | x | The X position of the left of the layout (in pixels).
  | y | The Y position of the top of the layout (in pixels).
  | layout | A Pango::Layout.

void Gdk::Drawable::draw_layout_line | ( | const Glib::RefPtr<const GC>& | gc,
|  | int | x,
|  | int | y,
|  | const Glib::RefPtr<const Pango::LayoutLine>& | line,
|  | const Color& | foreground,
|  | const Color& | background |
| ) |  |  |

Render a Pango::LayoutLine onto a Gdk::Drawable, overriding the layout's normal colors with foreground and/or background .

foreground and background need not be allocated.

If the layout's Pango::Context has a transformation matrix set, then x and y specify the position of the left edge of the baseline (left is in before-tranform user coordinates) in after-transform device coordinates.

Parameters:

  | gc | Base graphics to use.
  | x | The x position of start of string (in pixels).
  | y | The y position of baseline (in pixels).
  | line | A Pango::LayoutLine.
  | foreground | Foreground override color, or `0` for none.
  | background | Background override color, or `0` for none.

void Gdk::Drawable::draw_layout_line | ( | const Glib::RefPtr<const GC>& | gc,
|  | int | x,
|  | int | y,
|  | const Glib::RefPtr<const Pango::LayoutLine>& | line |
| ) |  |  |

Render a Pango::LayoutLine onto an GDK drawable.

If the layout's Pango::Context has a transformation matrix set, then x and y specify the position of the left edge of the baseline (left is in before-tranform user coordinates) in after-transform device coordinates.

Parameters:

  | gc | Base graphics to use.
  | x | The x position of start of string (in pixels).
  | y | The y position of baseline (in pixels).
  | line | A Pango::LayoutLine.

void Gdk::Drawable::draw_line | ( | const Glib::RefPtr<const GC>& | gc,
|  | int | x1,
|  | int | y1,
|  | int | x2,
|  | int | y2 |
| ) |  |  |

Draws a line, using the foreground color and other attributes of the Gdk::GC.

Parameters:

  | gc | A Gdk::GC.
  | x1 | The x coordinate of the start point.
  | y1 | The y coordinate of the start point.
  | x2 | The x coordinate of the end point.
  | y2 | The y coordinate of the end point.

void Gdk::Drawable::draw_lines | ( | const Glib::RefPtr<const GC>& | gc,
|  | const Glib::ArrayHandle<Point>& | points |
| ) |  |  |

void Gdk::Drawable::draw_pixbuf | ( | const Glib::RefPtr<const GC>& | gc,
|  | const Glib::RefPtr<Pixbuf>& | pixbuf,
|  | int | src_x,
|  | int | src_y,
|  | int | dest_x,
|  | int | dest_y,
|  | int | width,
|  | int | height,
|  | RgbDither | dither,
|  | int | x_dither,
|  | int | y_dither |
| ) |  |  |

Renders a rectangular portion of a pixbuf to a drawable.

The destination drawable must have a colormap. All windows have a colormap, however, pixmaps only have colormap by default if they were created with a non-`0` window argument. Otherwise a colormap must be set on them with Gdk::Drawable::set_colormap().

On older X servers, rendering pixbufs with an alpha channel involves round trips to the X server, and may be somewhat slow.

The clip mask of gc is ignored, but clip rectangles and clip regions work fine.

If GDK is built with the Sun mediaLib library, the gdk_draw_pixbuf function is accelerated using mediaLib, which provides hardware acceleration on Intel, AMD, and Sparc chipsets. If desired, mediaLib support can be turned off by setting the GDK_DISABLE_MEDIALIB environment variable.

Since gtkmm 2.2:

Parameters:

  | gc | A Gdk::GC, used for clipping, or `0`.
  | pixbuf | A Gdk::Pixbuf.
  | src_x | Source X coordinate within pixbuf.
  | src_y | Source Y coordinates within pixbuf.
  | dest_x | Destination X coordinate within drawable.
  | dest_y | Destination Y coordinate within drawable.
  | width | Width of region to render, in pixels, or -1 to use pixbuf width.
  | height | Height of region to render, in pixels, or -1 to use pixbuf height.
  | dither | Dithering mode for Gdk::RGB.
  | x_dither | X offset for dither.
  | y_dither | Y offset for dither.

void Gdk::Drawable::draw_point | ( | const Glib::RefPtr<const GC>& | gc,
|  | int | x,
|  | int | y |
| ) |  |  |

Draws a point, using the foreground color and other attributes of the Gdk::GC.

Parameters:

  | gc | A Gdk::GC.
  | x | The x coordinate of the point.
  | y | The y coordinate of the point.

void Gdk::Drawable::draw_points | ( | const Glib::RefPtr<const GC>& | gc,
|  | const Glib::ArrayHandle<Point>& | points |
| ) |  |  |

void Gdk::Drawable::draw_polygon | ( | const Glib::RefPtr<const GC>& | gc,
|  | bool | filled,
|  | const Glib::ArrayHandle<Point>& | points |
| ) |  |  |

void Gdk::Drawable::draw_rectangle | ( | const Glib::RefPtr<const GC>& | gc,
|  | bool | filled,
|  | int | x,
|  | int | y,
|  | int | width,
|  | int | height |
| ) |  |  |

Draws a rectangular outline or filled rectangle, using the foreground color and other attributes of the Gdk::GC.

A rectangle drawn filled is 1 pixel smaller in both dimensions than a rectangle outlined. Calling `gdk_draw_rectangle (window, gc, `true`, 0, 0, 20, 20)` results in a filled rectangle 20 pixels wide and 20 pixels high. Calling `gdk_draw_rectangle (window, gc, `false`, 0, 0, 20, 20)` results in an outlined rectangle with corners at (0, 0), (0, 20), (20, 20), and (20, 0), which makes it 21 pixels wide and 21 pixels high.

Parameters:

  | gc | A Gdk::GC.
  | filled | `true` if the rectangle should be filled.
  | x | The x coordinate of the left edge of the rectangle.
  | y | The y coordinate of the top edge of the rectangle.
  | width | The width of the rectangle.
  | height | The height of the rectangle.

void Gdk::Drawable::draw_rgb_32_image | ( | const Glib::RefPtr<const GC>& | gc,
|  | int | x,
|  | int | y,
|  | int | width,
|  | int | height,
|  | RgbDither | dith,
|  | const guchar * | rgb_buf,
|  | int | rowstride |
| ) |  |  |

void Gdk::Drawable::draw_rgb_32_image_dithalign | ( | const Glib::RefPtr<const GC>& | gc,
|  | int | x,
|  | int | y,
|  | int | width,
|  | int | height,
|  | RgbDither | dith,
|  | const guchar * | buf,
|  | int | rowstride,
|  | int | xdith,
|  | int | ydith |
| ) |  |  |

Like gdk_draw_rgb_32_image(), but allows you to specify the dither offsets.

See gdk_draw_rgb_image_dithalign() for more details.

Parameters:

  | gc | A Gdk::GC.
  | x | X coordinate on drawable where image should go.
  | y | Y coordinate on drawable where image should go.
  | width | Width of area of image to draw.
  | height | Height of area of image to draw.
  | dith | Dithering mode.
  | buf | RGB image data.
  | rowstride | Rowstride of RGB image data.
  | xdith | X dither offset.
  | ydith | Y dither offset.

void Gdk::Drawable::draw_rgb_image | ( | const Glib::RefPtr<const GC>& | gc,
|  | int | x,
|  | int | y,
|  | int | width,
|  | int | height,
|  | RgbDither | dith,
|  | const guchar * | rgb_buf,
|  | int | rowstride |
| ) |  |  |

void Gdk::Drawable::draw_rgb_image_dithalign | ( | const Glib::RefPtr<const GC>& | gc,
|  | int | x,
|  | int | y,
|  | int | width,
|  | int | height,
|  | RgbDither | dith,
|  | const guchar * | rgb_buf,
|  | int | rowstride,
|  | int | xdith,
|  | int | ydith |
| ) |  |  |

void Gdk::Drawable::draw_segments | ( | const Glib::RefPtr<const GC>& | gc,
|  | GdkSegment * | segs,
|  | int | nsegs |
| ) |  |  |

Draws a number of unconnected lines.

Parameters:

  | gc | A Gdk::GC.
  | segs | An array of Gdk::Segment structures specifying the start and end points of the lines to be drawn.
  | nsegs | The number of line segments to draw, i.e. the size of the segs array.

Region Gdk::Drawable::get_clip_region | ( |  | ) | const

Computes the region of a drawable that potentially can be written to by drawing primitives.

This region will not take into account the clip region for the GC, and may also not take into account other factors such as if the window is obscured by other windows, but no area outside of this region will be affected by drawing primitives.

Returns:
  A Gdk::Region. This must be freed with gdk_region_destroy() when you are done.

Glib::RefPtr<Colormap> Gdk::Drawable::get_colormap | ( |  | ) |

Gets the colormap for drawable , if one is set; returns `0` otherwise.

Returns:
  The colormap, or `0`.

int Gdk::Drawable::get_depth | ( |  | ) | const

Obtains the bit depth of the drawable, that is, the number of bits that make up a pixel in the drawable's visual.

Examples are 8 bits per pixel, 24 bits per pixel, etc.

Returns:
  Number of bits per pixel.

Glib::RefPtr<const Display> Gdk::Drawable::get_display | ( |  | ) | const

Gets the Gdk::Display associated with a Gdk::Drawable.

Returns:
  The Gdk::Display associated with drawable

Since gtkmm 2.2:

Glib::RefPtr<Display> Gdk::Drawable::get_display | ( |  | ) |

Gets the Gdk::Display associated with a Gdk::Drawable.

Returns:
  The Gdk::Display associated with drawable

Since gtkmm 2.2:

Glib::RefPtr<Image> Gdk::Drawable::get_image | ( | int | x,
|  | int | y,
|  | int | width,
|  | int | height |
| ) |  |  | const

A Gdk::Image stores client-side image data (pixels).

In contrast, Gdk::Pixmap and Gdk::Window are server-side objects. get_image() obtains the pixels from a server-side drawable as a client-side Gdk::Image. The format of a Gdk::Image depends on the Gdk::Visual of the current display, which makes manipulating Gdk::Image extremely difficult; therefore, in most cases you should use the Gdk::Pixbuf::create() method that takes a Gdk::Drawable, instead of this lower-level function. A Gdk::Pixbuf contains image data in a canonicalized RGB format, rather than a display-dependent format. Of course, there's a convenience vs. speed tradeoff here, so you'll want to think about what makes sense for your application.

x , y , width , and height define the region of drawable to obtain as an image.

You would usually copy image data to the client side if you intend to examine the values of individual pixels, for example to darken an image or add a red tint. It would be prohibitively slow to make a round-trip request to the windowing system for each pixel, so instead you get all of them at once, modify them, then copy them all back at once.

If the X server or other windowing system backend is on the local machine, this function may use shared memory to avoid copying the image data.

If the source drawable is a Gdk::Window and partially offscreen or obscured, then the obscured portions of the returned image will contain undefined data.

Parameters:

  | x | X coordinate on drawable .
  | y | Y coordinate on drawable .
  | width | Width of region to get.
  | height | Height or region to get.

Returns:
  A Gdk::Image containing the contents of drawable .

Glib::RefPtr<const Screen> Gdk::Drawable::get_screen | ( |  | ) | const

Gets the Gdk::Screen associated with a Gdk::Drawable.

Returns:
  The Gdk::Screen associated with drawable

Since gtkmm 2.2:

Glib::RefPtr<Screen> Gdk::Drawable::get_screen | ( |  | ) |

Gets the Gdk::Screen associated with a Gdk::Drawable.

Returns:
  The Gdk::Screen associated with drawable

Since gtkmm 2.2:

void Gdk::Drawable::get_size | ( | int & | width,
|  | int & | height |
| ) |  |  |

Fills * width and * height with the size of drawable .

width or height can be `0` if you only want the other one.

On the X11 platform, if drawable is a Gdk::Window, the returned size is the size reported in the most-recently-processed configure event, rather than the current size on the X server.

Parameters:

  | width | Location to store drawable's width, or `0`.
  | height | Location to store drawable's height, or `0`.

Region Gdk::Drawable::get_visible_region | ( |  | ) | const

Computes the region of a drawable that is potentially visible.

This does not necessarily take into account if the window is obscured by other windows, but no area outside of this region is visible.

Returns:
  A Gdk::Region. This must be freed with gdk_region_destroy() when you are done.

Glib::RefPtr<Visual> Gdk::Drawable::get_visual | ( |  | ) |

Gets the Gdk::Visual describing the pixel format of drawable .

Returns:
  A Gdk::Visual.

const GdkDrawable* Gdk::Drawable::gobj | ( |  | ) | const`[inline]`

Provides access to the underlying C GObject.

Reimplemented from Glib::ObjectBase.

Reimplemented in Gdk::Pixmap, and Gdk::Window.

GdkDrawable* Gdk::Drawable::gobj | ( |  | ) | `[inline]`

Provides access to the underlying C GObject.

Reimplemented from Glib::ObjectBase.

Reimplemented in Gdk::Pixmap, and Gdk::Window.

GdkDrawable* Gdk::Drawable::gobj_copy | ( |  | ) |

Provides access to the underlying C instance. The caller is responsible for unrefing it. Use when directly setting fields in structs.

Reimplemented in Gdk::Pixmap, and Gdk::Window.

void Gdk::Drawable::set_colormap | ( | const Glib::RefPtr<Colormap>& | colormap | ) |

Sets the colormap associated with drawable .

Normally this will happen automatically when the drawable is created; you only need to use this function if the drawable-creating function did not have a way to determine the colormap, and you then use drawable operations that require a colormap. The colormap for all drawables and graphics contexts you intend to use together should match. i.e. when using a Gdk::GC to draw to a drawable, or copying one drawable to another, the colormaps should match.

Parameters:

  | colormap | A Gdk::Colormap.

## Friends And Related Function Documentation

Glib::RefPtr<Gdk::Drawable> wrap | ( | GdkDrawable * | object,
|  | bool | take_copy = `false` |
| ) |  |  | `[related]`

A Glib::wrap() method for this object.

Parameters:

  | object | The C instance.
  | take_copy | False if the result should take ownership of the C instance. True if it should take a new copy or ref.

Returns:
  A C++ instance that wraps this C instance.

The documentation for this class was generated from the following file:

- drawable.h