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Class Gtk::Preview

A widget to display RGB or grayscale data.
Contained in: Gtk
Derived from: Widget
Derived by: none

#include <gtk--/preview.h>


public function member index:

explicit Preview(GtkPreviewType type);
void draw_row(const guchar* data, gint x, gint y, gint w);
static Gdk_Colormap get_cmap();
static GtkPreviewInfo* get_info();
static Gdk_Visual get_visual();
GtkPreview* gtkobj();
const GtkPreview* gtkobj() const;
static bool isA(Object* object);
void put(Gdk_Window& window, Gdk_GC& gc, gint srcx, gint srcy, gint destx, gint desty, gint width, gint height);
static void reset();
static void set_color_cube(guint nred_shades, guint ngreen_shades, guint nblue_shades, guint ngray_shades);
void set_dither(GdkRgbDither dither);
void set_expand(bool expand);
static void set_gamma(double gamma);
static void set_install_cmap(bool install_cmap);
static void set_reserved(gint nreserved);
void size(gint width, gint height);
static void uninit();
virtual ~Preview();
 

Description:



Function Member Descriptions:

Gtk::Preview::draw_row - Sets the data for a portion of a row.

void draw_row(const guchar* data, gint x, gint y, gint w);
data: The new data for the portion. It should contain w bytes of data if the preview is of type GTK_TYPE_GRAYSCALE, and 3*w bytes of data if the preview is of type GTK_TYPE_COLOR.

x: The starting value on the row to set.

y: The row to change.

w: The number of pixels in the row to change.



Gtk::Preview::gtkobj - Returns the underlaying gtk+ object.

GtkPreview* gtkobj();

Gtk::Preview::isA - Returns true if object is this type.

static bool isA(Object* object);

Gtk::Preview::reset - This function is deprecated and does nothing. It was once used for changing the colormap and visual on the fly.

static void reset();

Gtk::Preview::set_color_cube - This function is deprecated and does nothing. Gdk:::RGB automatically picks an optimium color cube for the display.

static void set_color_cube(guint nred_shades, guint ngreen_shades, guint nblue_shades, guint ngray_shades);

Gtk::Preview::set_dither - Set the dithering mode for the display.

void set_dither(GdkRgbDither dither);
dither: The dithering mode. There are three values:

GDK_RGB_DITHER_NONE: Never use dithering.

GDK_RGB_DITHER_NORMAL: Use dithering in 8 bits per pixel (and below) only.

GDK_RGB_DITHER_MAX: Use dithering in 16 bits per pixel and below.



Gtk::Preview::set_expand - Determines the way that the the preview widget behaves when the size it is allocated is larger than the requested size.

void set_expand(bool expand);
If expand is FALSE, then the preview's window and buffer will be no larger than the size set with size, and the data set will be centered in the allocation if it is larger. If expand is TRUE then the window and buffer will expand with the allocation; the application is responsible for catching the "size_allocate" signal and providing the data appropriate for this size.

expand: Whether the preview's window should expand or not.



Gtk::Preview::set_gamma - Set the gamma-correction value for all preview widgets. (This function

static void set_gamma(double gamma);
will eventually be replaced with a function that sets a per-preview-widget gamma value). The resulting intensity is given by: destination_value * pow (source_value/255, 1/gamma). The gamma value is applied when the data is set with draw_row so changing this value will not affect existing data in preview widgets.

gamma: The new gamma value.



Gtk::Preview::set_install_cmap - This function is deprecated and does nothing. Gdk::RGB will automatically pick a private colormap if it cannot allocate sufficient colors.

static void set_install_cmap(bool install_cmap);

Gtk::Preview::set_reserved - This function is deprecated and does nothing.

static void set_reserved(gint nreserved);

Gtk::Preview::size - Set the size that the preview widget will request in response to a "size_request"

void size(gint width, gint height);
signal. The drawing area may actually be allocated a size larger than this depending on how it is packed within the enclosing containers. The effect of this is determined by whether the preview is set to expand or not (see set_expand).

width: The new width.

height: The new height.



Gtk::Preview::uninit - This function is deprecated and does nothing.

static void uninit();