NineSlice

Remarks

A nine-slice is rectangle arithmetic, which is why it is here and not beside either of its callers. Two consumers need exactly the same nine pairs of rectangles — a user interface stretching a panel's background and a renderer stretching a sprite — and they cannot reference each other: Vixen.Ui describes a frame without a device and Vixen.Rendering draws without knowing what an element tree is. The alternative was the same twenty lines in both, which is two places for the corner convention to disagree.

⚠ Unitless on purpose. The same four numbers are texels when they cut a texture region, document pixels when they cut a destination box, and zero-to-one when they cut a UV rectangle — and Scaled is what moves between them. A type that named its unit would need three of itself, and the split is identical in all three.

The order is CSS's: left, top, right, bottom is not what a reader expects, but it is what border-image-slice, Thickness and every stylesheet in the repository already write, and a fifth ordering in the same codebase is a mistake nobody will see in a diff — the numbers are all floats and swapping two of them still compiles.

Fields and properties (10)

• public float Left

  How far the left column reaches in from the left edge.

• public float Top

  How far the top row reaches down from the top edge.

• public float Right

  How far the right column reaches in from the right edge.

• public float Bottom

  How far the bottom row reaches up from the bottom edge.

• public const int CellCount

  How many cells Split writes.

• public const int Centre

  Where the middle cell lands in a split, for a caller that draws it separately.

• public static NineSlice None

  No inset at all: one cell covering the whole rectangle.

• public bool IsEmpty

  Whether there is nothing to cut, so the rectangle is its own single cell.

• public float Horizontal

  What the two columns of border take up together.

• public float Vertical

  What the two rows of border take up together.

Methods (5)

• public NineSlice(float Left, float Top, float Right, float Bottom)

  Four inset edges, and the cut of a rectangle into the nine they describe.

• public static NineSlice Uniform(float amount)

  The same inset on all four edges.

• public NineSlice Scaled(float x, float y)

  The same inset measured in different units.

• public NineSlice Fit(float width, float height)

  The inset shrunk until its borders fit inside a box, preserving their proportions.

• public void Split(Rectangle box, Span<Rectangle> into)

  Cuts a rectangle into the nine this inset describes.

Used by (20)

• DrawCommandVixen.Ui
• DrawContextVixen.Ui
• ImageVixen.Ui.Controls
• NineSliceImageTestsVixen.Ui.Tests
• NineSliceTestsVixen.Core.Mathematics.Tests
• SpriteVixen.Rendering
• SpriteGeometryVixen.Rendering
• SpriteRenderFeatureTestsVixen.Rendering.Tests
• SpriteSheetVixen.Rendering
• SpriteTestsVixen.Rendering.Tests
• TypeRegistrationVixen.Core.Mathematics
• UiGeometryBuilderVixen.Ui
• Vixen_Core_Mathematics_NineSliceSerializerVixen.Core.Mathematics
• Vixen_Rendering_Sprites_SpriteSerializerVixen.Rendering
• SpriteDocumentTestsVixen.Editor.AssetEditors.Tests
• SpriteRectVixen.Editor.Assets
• SpriteSliceOptionsVixen.Editor.Assets
• SpriteSlicerVixen.Editor.Assets
• SpriteSlicerTestsVixen.Editor.Assets.Tests
• TextureImporterTestsVixen.Editor.Assets.Tests