set_grayval — Set single gray values in an image.
set_grayval sets the gray values of the input image
Image at the positions (Row,Column) to
the values specified by Grayval. If Image is a
multi-channel image, you can either set a single gray value for a
pixel and thus set it for all available channels, or you can set the
gray values g for all channels individually by
concatenating them within Grayval. For example, for a
three-channel image three gray values (according to the order of the
channels) are specified for each pixel:
[g(channel0,pixel0), g(channel1,pixel0), g(channel2,pixel0), g(channel0,pixel1), ... ].
Please note that for complex or vector field images, two gray values
per pixel must be specified (per channel).
If the image is of type direction, gray values that are not
in the value range that is valid for direction images are set to
the value 255 to mark them as invalid.
The operator set_grayval produces quite some overhead.
Typically, it is used to set single gray values of an image. It is
not suitable for programming image processing operations such as
filters. In this case it is more useful to use the operator
get_image_pointer1 and to directly use the C or C++
interface for integrating own procedures.
Note also that set_grayval modifies the content of an
already existing image (Image). Besides, even other image
objects may be affected: For example, if you created Image
via copy_obj from another image object, set_grayval
will also modify the image matrix of this other image
object. Therefore, set_grayval should only be used to
overpaint newly created image objects.
This operator modifies the state of the following input parameter:
During execution of this operator, access to the value of this parameter must be synchronized if it is used across multiple threads.
Image (input_object, state is modified) (multichannel-)image → object (byte / direction / cyclic / int1 / int2 / uint2 / int4 / int8 / real / complex / vector_field)
Image to be modified.
Row (input_control) point.y(-array) → (integer)
Row coordinates of the pixels to be modified.
Default value: 0
Suggested values: 0, 10, 50, 127, 255, 511
Typical range of values: 0
≤
Row
Restriction: 0 <= Row && Row < height(Image)
Column (input_control) point.x(-array) → (integer)
Column coordinates of the pixels to be modified.
Default value: 0
Suggested values: 0, 10, 50, 127, 255, 511
Typical range of values: 0
≤
Column
Restriction: 0 <= Column && Column < width(Image)
Grayval (input_control) grayval(-array) → (real / integer)
Gray values to be used.
Default value: 255.0
Suggested values: 0.0, 1.0, 10.0, 128.0, 255.0
set_grayval returns TRUE if all parameters are correct. If
the input is empty the behavior can be set via
set_system(::'no_object_result',<Result>:). If necessary,
an exception is raised.
read_image,
get_image_pointer1,
gen_image_proto,
gen_image1
get_image_pointer1,
paint_gray,
paint_region
get_grayval,
gen_image_const,
gen_image1,
gen_image_proto
Foundation