Class DataView

Creates a new data-displaying widget for data.

A newly created DataView doesn't display anything. You have to add some layers to it, at least a base layer with DataView.set_base_layer(), and possibly others with DataView.set_alpha_layer() and DataView.set_top_layer().

The top layer is special. It must be a vector layer and can receive mouse and keyboard events.

The base layer it also special. It must be always present, and must not be transparent or vector.

Parameters:

• data - A Container containing the data to display. (Container)

Returns:

A newly created data view as a GtkWidget. (gtk.Widget)

Returns the base layer this data view currently uses.

A base layer should be always present.

Returns:

The currently used base layer. (PixmapLayer)

Plugs layer to data_view as the base layer.

If another base layer is present, it's unplugged.

The layer must not be a vector layer. Theoretically, it can be None to use no base layer, but then data_view will probably display garbage.

Parameters:

• layer - A layer to be used as the base layer for data_view. (PixmapLayer)

Returns the alpha layer this data view currently uses, or None if none is present.

Returns:

The currently used alpha layer. (PixmapLayer)

Plugs layer to data_view as the alpha layer.

If another alpha layer is present, it's unplugged.

The layer must not be a vector layer. It can be None, meaning no alpha layer is to be used.

Parameters:

• layer - A layer to be used as the alpha layer for data_view. (PixmapLayer)

Returns the top layer this data view currently uses, or None if none is present.

Returns:

The currently used top layer. (VectorLayer)

Plugs layer to data_view as the top layer.

If another top layer is present, it's unplugged.

The layer must be a vector layer. It can be None, meaning no top layer is to be used.

Parameters:

• layer - A layer to be used as the top layer for data_view. (VectorLayer)

Gets the prefix for the container data channel that the data view is currently set to display.

Returns:

The container data prefix (eg. "/0/data"). (string)

Sets the prefix for the container data channel to display in a data view.

This function only affects where the data view itself takes parameters from, it does not affect layer keys.

Parameters:

• prefix - Container prefix for data (eg. "/0/data"). (string)

Return the horizontal excess of widget size to data size.

Do not use. Only useful for DataWindow implementation.

Returns:

The execess. (float)

Return the vertical excess of widget size to data size.

Do not use. Only useful for DataWindow implementation.

Returns:

The execess. (float)

Sets zoom of data_view to zoom.

Zoom greater than 1 means larger image on screen and vice versa.

Note window manager can prevent the window from resize and thus the zoom from change.

Parameters:

• zoom - A new zoom value. (float)

Returns current ideal zoom of a data view.

More precisely the zoom value requested by DataView.set_zoom(), if it's in use (real zoom may differ a bit due to pixel rounding). If zoom was set by explicite widget size change, real and requested zoom are considered to be the same.

When a resize is queued, the new zoom value is returned.

In other words, this is the zoom data_view would like to have. Use DataView.get_real_zoom() to get the real zoom.

Returns:

The zoom as a ratio between ideal displayed size and base data field size. (float)

Returns current real zoom of a data view.

This is the zoom value a data view may not wish to have, but was imposed by window manager or other constraints. Unlike ideal zoom set by DataView.set_zoom(), this value cannot be set.

When a resize is queued, the current (old) value is returned.

Returns:

The zoom as a ratio between real displayed size and base data field size. (float)

Returns the data container used by data_view.

Returns:

The data as a Container. (Container)

Fixes screen coordinates xscr and yscr to be inside the data-displaying area (which can be smaller than widget size).

Returns:

Tuple consisting of 2 values (xscr, yscr). ((IntInOutArg), (IntInOutArg))

Fixes screen coordinates of line endpoints to be inside the data-displaying area (which can be smaller than widget size).

Returns:

Tuple consisting of 4 values (x0scr, y0scr, x1scr, y1scr). ((IntInOutArg), (IntInOutArg), (IntInOutArg), (IntInOutArg))

Recomputes screen coordinates relative to widget origin to physical coordinates in the sample.

Note that data fields offsets are not taken into account. Coordinates xreal, yreal are just relative coordinates to the top left field corner.

Parameters:

• xscr - A screen x-coordinate relative to widget origin. (int)
• yscr - A screen y-coordinate relative to widget origin. (int)

Returns:

Tuple consisting of 2 values (xreal, yreal). ((float), (float))

Recomputes physical coordinate in the sample to screen coordinate relative to widget origin.

Note that data fields offsets are not taken into account. Coordinates xreal, yreal are just relative coordinates to the top left field corner.

Parameters:

• xreal - A physical x-coordinate in the data sample. (float)
• yreal - A physical y-coordinate in the data sample. (float)

Returns:

Tuple consisting of 2 values (xscr, yscr). ((int), (int))

Recomputes physical coordinate in the sample to screen coordinate relative to widget origin, keeping them as floating point values.

Note that data fields offsets are not taken into account. Coordinates xreal, yreal are just relative coordinates to the top left field corner.

Parameters:

• xreal - A physical x-coordinate in the data sample. (float)
• yreal - A physical y-coordinate in the data sample. (float)

Returns:

Tuple consisting of 2 values (xscr, yscr). ((float), (float))

Returns the ratio between horizontal physical lengths and horizontal screen lengths in pixels.

Returns:

The horizontal measure. (float)

Returns the ratio between vertical physical lengths and horizontal screen lengths in pixels.

Returns:

The vertical measure. (float)

Obtains pixel dimensions of data displayed by a data view.

This is a convenience method, the same values could be obtained by DataField.get_xres() and DataField.get_yres() of the data field displayed by the base layer.

Returns:

Tuple consisting of 2 values (xres, yres). ((int), (int))

Obtains physical dimensions of data displayed by a data view.

Physical coordinates are always taken from data field displayed by the base layer. This is a convenience method, the same values could be obtained by DataField.get_xreal() and DataField.get_yreal() of the data field displayed by the base layer.

Returns:

Tuple consisting of 2 values (xreal, yreal). ((float), (float))

Obtains physical offsets of data displayed by a data view.

Physical coordinates are always taken from data field displayed by the base layer. This is a convenience method, the same values could be obtained by DataField.get_xoffset() and DataField.get_yoffset() of the data field displayed by the base layer.

Returns:

Tuple consisting of 2 values (xoffset, yoffset). ((float), (float))

Creates and returns a pixbuf from the data view.

If the data is not square, the resulting pixbuf is also nonsquare. The returned pixbuf also never has an alpha channel.

Parameters:

• max_width - Pixbuf width that should not be exceeeded. Value smaller than 1 means unlimited size. (int)
• max_height - Pixbuf height that should not be exceeeded. Value smaller than 1 means unlimited size. (int)

Returns:

The pixbuf as a newly created GdkPixbuf, it should be freed when no longer needed. It is never larger than the actual data size, as max_width and max_height are only upper limits. (gdk.Pixbuf)

Exports data view to a pixbuf.

Parameters:

• zoom - Zoom to export data with (unrelated to data view zoom). (float)
• draw_alpha - True to draw alpha layer (mask). (bool)
• draw_top - True to draw top layer (selection). (bool)

Returns:

A newly created pixbuf, it must be freed by caller. (gdk.Pixbuf)

Fills metric matrix for a data view.

The metric matrix essentially transforms distances in physical coordinates to screen distances. It is to be used with functions like gwy_math_find_nearest_point() and gwy_math_find_nearest_line() when the distance should be screen-Euclidean.

Returns:

(list)