set_paint — Define the gray value output mode.
set_paint defines the output mode for gray value display
(single- or multichannel) in the window. The mode is used by
This page describes the different modes that can be used for gray value output. It should be noted that the mode 'default' is the most suitable in almost all cases.
Gray images can also be interpreted as 3D data, depending on the
gray value. To view these 3D plots, select the modes '3d_plot'.
If your graphics card supports OpenGL, choose this for a high quality plot
that is well suited for interactive display (see
on how to make the display interactive).
Three-channel images are interpreted as RGB images.
Vector field images can be viewed as 'vector_field'.
All available painting modes can be queried with
Parameters for modes that need more than one parameter can be passed the following ways:
Only the name of the mode is passed: The defaults or the most recently used values are used, respectively.
All values are passed: All output characteristics can be set.
Only the first n values are passed: Only the passed values are changed.
Some of the values are replaced by an asterisk ('*'): The value of the replaced parameters is not changed.
If the current mode is 'default', HALCON chooses a suitable
algorithm for the output of 2- and 3-channel images. No
set_paint call is necessary in this case.
set_paint there are other operators that affect
the output of gray values. The most important of them are
Some output modes display gray values using
region output (e.g. 'histogram','contourline','3d_plot_lines', etc.). In
these modes, parameters set with
influence gray value output. This can lead to unexpected results when
set_paint(WindowHandle,'histogram'). Here, the convex hull
of the histogram is displayed.
optimal display on given hardware
Gray values are interpreted as a 3D height field and displayed using OpenGL. The first parameter specifies the way in which the height field is displayed. The following modes are available:
The height field is displayed as a closed surface and colored using texture mapping. The texture is passed as the second channel (for a gray-valued texture) or as the second to fourth channel (for a colored texture) of the image to display.
The height field is displayed as a closed surface and colored using the current LUT.
The height field is displayed as a hidden line plot and colored using the current LUT.
Similar to 'contourline' height lines are extracted and displayed at their actual height. Again the lines are colored using the current LUT.
The second parameter contains the step width, i.e. at what intervals samples in row and column direction are taken from the image. The smaller this parameter is chosen, the coarser the resulting height field. However, computation time increases while this parameter decreases. In the case of 'contour_lines' this parameter corresponds to the number of intervals the height range is divided into.
The third to sixth parameter are the four values of a unit quaternion,
describing the orientation of the height field (see
axis_angle_to_quat for more information on quaternions).
The seventh parameter is the zooming factor. Smaller values implicate higher zooming.
The last three parameters are the row, column, and height position of the actual center of view. This values must be scaled to the interval [-0.5, 0.5].
You can set the third or the seventh parameter in the tuple to
'auto'. Then, the zooming factor and the center of view are
determined automatically such that the plot of the height field fills the
window as good as possible. It is important that the part of the window is
set correctly (using
set_paint is called.
By setting the third value in the tuple to 'auto', the previous
orientation (or the default one) is kept, by setting the seventh parameter
to 'auto', the provided orientation is used. It is not possible
to set any parameters after 'auto' in the tuple. Furthermore
'auto' will only work correctly if 'scale_plot' is set
to 'true' using
Depending on the speed of your graphics card, the display of the height
field is performed at interactive rates. See the operator
update_window_pose for an intuitive way of modifying the
parameters of the 3D plot (e.g., with the mouse).
The colors of the axis are influenced by the colors set using
set_colored. The first
three colors set this way are used as colors for row, column, and height
axis (in this order).
Additional parameters concerning the 3D plot can be set using the operator
If you intend to use '3d_plot' on a Unix-like system, make sure you have sufficient permissions on your graphics device.
output the first channel.
output as RGB image with 'median_cut'.
Vector field images:
output a vector field. It is possible to display
vector fields containing relative coordinates
or vector fields containing absolute coordinates.
This behavior is controlled via the optional parameter
Mode. Possible values for Mode are 'auto' (the
visualization depends on the semantic type of the
vector field), 'absolute', or 'relative'. The default
value is 'auto'.
In the 'vector_field' mode, a circle with diameter
CircleSize is drawn for each vector at the position
of the pixel. Furthermore, a line segment is drawn
with the current vector.
The step size for drawing the vectors, i.e., the
distance between the drawn vectors, can be set
with the parameter Step. Short vectors can be
suppressed with the parameter MinLength. The
fourth parameter value scales
the vector length. It should be noted that by
setting 'vector_field' only the internal
parameters Mode, Step, MinLength, ScaleLength,
and CircleSize are
changed. The current display mode is not
changed. Vector field images are always
displayed as vector field, no matter which mode
is selected with
Output of every 16th vector, that is longer than 2 pixel. Each vector is multiplied by 3 for output.
→(string / integer / real)
Output mode. Additional parameters possible.
Default value: 'default'
List of values: '3d_plot', 'default', 'vector_field'
set_paint returns 2 (H_MSG_TRUE) if the parameter is correct and the
window is valid. Otherwise an exception is raised.