gen_checker_region — Create a checkered region.
gen_checker_region( : RegionChecker : WidthRegion, HeightRegion, WidthPattern, HeightPattern : )
The operator gen_checker_region returns a checkered region.
Every black field of the checkerboard belongs to the region.
The horizontal and vertical expansion of the region is limited by
WidthRegion, HeightRegion respectively,
the size of the fields of the checkerboard by
WidthPattern * HeightPattern.
If a very small pattern is chosen
(WidthPattern < 4) the created region requires much storage.
RegionChecker (output_object) region → object
Created checkerboard region.
WidthRegion (input_control) extent.x → (integer)
Largest occurring x value of the region.
Default: 511
Suggested values: 10, 20, 31, 63, 127, 255, 300, 400, 511
Value range:
1
≤
WidthRegion
(lin)
Minimum increment: 1
Recommended increment: 10
HeightRegion (input_control) extent.y → (integer)
Largest occurring y value of the region.
Default: 511
Suggested values: 10, 20, 31, 63, 127, 255, 300, 400, 511
Value range:
1
≤
HeightRegion
(lin)
Minimum increment: 1
Recommended increment: 10
WidthPattern (input_control) extent.x → (integer)
Width of a field of the checkerboard.
Default: 64
Suggested values: 1, 2, 4, 8, 16, 20, 32, 64, 100, 128, 200, 300, 500
Value range:
1
≤
WidthPattern
(lin)
Minimum increment: 1
Recommended increment: 10
Restriction:
WidthPattern < WidthRegion
HeightPattern (input_control) extent.y → (integer)
Height of a field of the checkerboard.
Default: 64
Suggested values: 1, 2, 4, 8, 16, 20, 32, 64, 100, 128, 200, 300, 500
Value range:
1
≤
HeightPattern
(lin)
Minimum increment: 1
Recommended increment: 10
Restriction:
HeightPattern < HeightRegion
gen_checker_region(Checker,512,512,32,64)
dev_set_draw('fill')
dev_display (Checker)
The required storage (in bytes) for the region is:
O((WidthRegion * HeightRegion) /
WidthPattern)
The operator gen_checker_region returns the value 2 (
H_MSG_TRUE)
if the parameter values are correct.
Otherwise an exception is raised.
The clipping according to the current image format is set via the operator
set_system('clip_region',<'true'/'false'>).
gen_grid_region,
gen_region_polygon_filled,
gen_region_points,
gen_region_runs,
gen_rectangle1,
concat_obj,
gen_random_region,
gen_random_regions
Foundation