Enum RegionOp

Namespace

Terminal.Gui

Assembly

Terminal.Gui.dll

Specifies the operation to perform when combining two regions or a Region with a Rectangle>, defining how their rectangular areas are merged, intersected, or subtracted.

public enum RegionOp

Fields

Difference = 0

Subtracts the second (op) region or rectangle from the first region, removing any areas where the op overlaps the first region. The result includes only the portions of the first region that do not intersect with the op.

For example, if the first region contains rectangle A = (0,0,10,10) and the op is B = (5,5,5,5), the result would include rectangles covering A minus the overlapping part of B, such as (0,0,10,5), (0,5,5,5), and (5,10,5,5).

If the op region is empty or null, the operation has no effect unless the first region is also empty, in which case it clears the first region.

Intersect = 1

Intersects the first region with the second (op) region or rectangle, retaining only the areas where both regions overlap. The result includes rectangles covering the common areas, excluding any parts unique to either region.

For example, if the first region contains A = (0,0,10,10) and the op is B = (5,5,5,5), the result would be a single rectangle (5,5,5,5), representing the intersection.

If either region is empty or null, the result clears the first region, as there’s no intersection possible.

MinimalUnion = 3

Performs a minimal union (inclusive-or) of the first region and the second (op) region or rectangle, merging adjacent or overlapping rectangles into the smallest possible set of non-overlapping rectangles that cover the combined area.

This operation minimizes the number of rectangles, producing a more compact representation compared to Union. For example, if the first region contains A = (0,0,5,5) and the op is B = (5,0,5,5), the result would be a single rectangle (0,0,10,5), reducing redundancy.

This operation always minimizes the output and has lower performance than Union.

If the op region is empty or null, the first region remains unchanged.

Replace = 6

Replaces the first region entirely with the second (op) region or rectangle, discarding the first region's current rectangles and adopting the op's rectangles.

For example, if the first region contains (0,0,5,5) and the op is (10,10,5,5), the first region will be cleared and replaced with (10,10,5,5).

If the op region is empty or null, the first region is cleared. This operation is useful for resetting or overwriting region state.

ReverseDifference = 5

Subtracts the first region from the second (op) region or rectangle, retaining only the areas of the op that do not overlap with the first region. The result replaces the first region with these areas.

For example, if the first region contains A = (5,5,5,5) and the op is B = (0,0,10,10), the result would include rectangles covering B minus A, such as (0,0,10,5), (0,5,5,5), and (5,10,5,5).

If the first region is empty or null, the op region replaces the first region. If the op region is empty, the first region is cleared.

Union = 2

Performs a union (inclusive-or) of the first region and the second (op) region or rectangle, combining all areas covered by either region into a single contiguous region without holes (unless explicitly subtracted).

The formal union (∪) includes all points in at least one rectangle, producing a granular set of non-overlapping rectangles that cover the combined area. For example, if the first region contains A = (0,0,5,5) and the op is B = (5,0,5,5), the result might include (0,0,5,5) and (5,0,5,5) unless minimized.

This operation uses granular output (preserving detailed rectangles). To minimize the result use MinimalUnion instead.

If the op region is empty or null, the first region remains unchanged.

XOR = 4

Performs an exclusive-or (XOR) of the first region and the second (op) region or rectangle, retaining only the areas that are unique to each region—i.e., areas present in one region but not both.

For example, if the first region contains A = (0,0,10,10) and the op is B = (5,5,5,5), the result would include rectangles covering (0,0,10,5), (0,5,5,5), (5,10,5,5), and (5,5,5,5), excluding the intersection (5,5,5,5).

If the op region is empty or null, this operation excludes the first region from itself (clearing it) or adds the first region to the op (if op is empty), depending on the logic.

Remarks

Each operation modifies the first region's set of rectangles based on the second (op) region or rectangle, producing a new set of non-overlapping rectangles. The operations align with set theory, enabling flexible manipulation for TUI layout, clipping, or drawing. Developers can choose between granular outputs (e.g., Union) that preserve detailed rectangles or minimal outputs (e.g., MinimalUnion) that reduce the rectangle count for compactness.