GtkPreview

GtkPreview — A widget to display RGB or grayscale data

Functions

Properties

gboolean expand Read / Write

Types and Values

Object Hierarchy

    GObject
    ╰── GInitiallyUnowned
        ╰── GtkObject
            ╰── GtkWidget
                ╰── GtkPreview

Implemented Interfaces

GtkPreview implements AtkImplementorIface and GtkBuildable.

Includes

#include <gtk/gtk.h>

Description

The GtkPreview widget provides a simple interface used to display images as RGB or grayscale data. It's deprecated; just use a GdkPixbuf displayed by a GtkImage, or perhaps a GtkDrawingArea. GtkPreview has no advantage over those approaches.

Functions

gtk_preview_uninit ()

void
gtk_preview_uninit (void);

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

This function is deprecated and does nothing.


gtk_preview_new ()

GtkWidget *
gtk_preview_new (GtkPreviewType type);

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

Create a new preview widget.

Parameters

type

the type data contained by the widget. (Grayscale or RGB)

 

Returns

a new GtkPreview


gtk_preview_size ()

void
gtk_preview_size (GtkPreview *preview,
                  gint width,
                  gint height);

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

Set the size that the preview widget will request in response to a "size_request" 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 gtk_preview_expand())

Parameters

preview

a GtkPreview.

 

width

the new width.

 

height

the new height.

 

gtk_preview_put ()

void
gtk_preview_put (GtkPreview *preview,
                 GdkWindow *window,
                 GdkGC *gc,
                 gint srcx,
                 gint srcy,
                 gint destx,
                 gint desty,
                 gint width,
                 gint height);

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

Takes a portion of the contents of a preview widget and draws it onto the given drawable, window.

Parameters

preview

a GtkPreview.

 

window

a window or pixmap.

 

gc

The graphics context for the operation. Only the clip mask for this GC matters.

 

srcx

the x coordinate of the upper left corner in the source image.

 

srcy

the y coordinate of the upper left corner in the source image.

 

destx

the x coordinate of the upper left corner in the destination image.

 

desty

the y coordinate of the upper left corner in the destination image.

 

width

the width of the rectangular portion to draw.

 

height

the height of the rectangular portion to draw.

 

gtk_preview_draw_row ()

void
gtk_preview_draw_row (GtkPreview *preview,
                      guchar *data,
                      gint x,
                      gint y,
                      gint w);

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

Sets the data for a portion of a row.

Parameters

preview

a GtkPreview.

 

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_set_expand ()

void
gtk_preview_set_expand (GtkPreview *preview,
                        gboolean expand);

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

Determines the way that the the preview widget behaves when the size it is allocated is larger than the requested size. If expand is FALSE, then the preview's window and buffer will be no larger than the size set with gtk_preview_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.

Parameters

preview

a GtkPreview.

 

expand

whether the preview's window should expand or not.

 

gtk_preview_set_gamma ()

void
gtk_preview_set_gamma (double gamma_);

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

Set the gamma-correction value for all preview widgets. (This function 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 gtk_preview_draw_row() so changing this value will not affect existing data in preview widgets.

Parameters

gamma_

the new gamma value.

 

gtk_preview_set_color_cube ()

void
gtk_preview_set_color_cube (guint nred_shades,
                            guint ngreen_shades,
                            guint nblue_shades,
                            guint ngray_shades);

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

This function is deprecated and does nothing. GdkRGB automatically picks an optimium color cube for the display.

Parameters

nred_shades

ignored

 

ngreen_shades

ignored

 

nblue_shades

ignored

 

ngray_shades

ignored

 

gtk_preview_set_install_cmap ()

void
gtk_preview_set_install_cmap (gint install_cmap);

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

This function is deprecated and does nothing. GdkRGB will automatically pick a private colormap if it cannot allocate sufficient colors.

Parameters

install_cmap

ignored.

 

gtk_preview_set_reserved ()

void
gtk_preview_set_reserved (gint nreserved);

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

This function is deprecated and does nothing.

Parameters

nreserved

ignored.

 

gtk_preview_set_dither ()

void
gtk_preview_set_dither (GtkPreview *preview,
                        GdkRgbDither dither);

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

Set the dithering mode for the display.

Parameters

preview

a GtkPreview.

 

dither

the dithering mode.

 

gtk_preview_get_visual ()

GdkVisual *
gtk_preview_get_visual (void);

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

Returns the visual used by preview widgets. This function is deprecated, and you should use gdk_rgb_get_visual() instead.

Returns

the visual for previews.


gtk_preview_get_cmap ()

GdkColormap *
gtk_preview_get_cmap (void);

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

Returns the colormap used by preview widgets. This function is deprecated, and you should use gdk_rgb_get_cmap() instead.

Returns

the colormap for previews.


gtk_preview_get_info ()

GtkPreviewInfo *
gtk_preview_get_info (void);

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

Return a GtkPreviewInfo structure containing global information about preview widgets.

Returns

a GtkPreviewInfo structure. The return value belongs to GTK+ and must not be modified or freed.


gtk_preview_reset ()

void
gtk_preview_reset (void);

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

This function is deprecated and does nothing. It was once used for changing the colormap and visual on the fly.

Types and Values

struct GtkPreview

struct GtkPreview;

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

The GtkPreview struct contains private data only, and should be accessed using the functions below.


struct GtkPreviewInfo

struct GtkPreviewInfo {
  guchar *lookup;

  gdouble gamma;
};

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

Contains information about global properties of preview widgets. The GtkPreviewInfo struct contains the following fields. (These fields should be considered read-only. They should never be set by an application.)

GdkVisual *visual; the visual used by all previews.
GdkColormap *cmap; the colormap used by all previews.
gdouble gamma; the gamma correction value used by all previews (See gtk_preview_set_gamma()).


union GtkDitherInfo

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

This union not used in GTK+.

Property Details

The “expand” property

  “expand”                   gboolean

Whether the preview widget should take up the entire space it is allocated.

Flags: Read / Write

Default value: FALSE

See Also

GdkRGB

the backend used by GtkPreview.